drivers/scsi/st.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   4    file Documentation/scsi/st.txt for more information.
   5
   6    History:
   7    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   8    Contribution and ideas from several people including (in alphabetical
   9    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
  10    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  11    Michael Schaefer, J"org Weule, and Eric Youngdale.
  12
  13    Copyright 1992 - 2016 Kai Makisara
  14    email Kai.Makisara@kolumbus.fi
  15
  16    Some small formal changes - aeb, 950809
  17
  18    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  19  */
  20
  21 static const char *verstr = "20160209";
  22
  23 #include <linux/module.h>
  24
  25 #include <linux/compat.h>
  26 #include <linux/fs.h>
  27 #include <linux/kernel.h>
  28 #include <linux/sched/signal.h>
  29 #include <linux/mm.h>
  30 #include <linux/init.h>
  31 #include <linux/string.h>
  32 #include <linux/slab.h>
  33 #include <linux/errno.h>
  34 #include <linux/mtio.h>
  35 #include <linux/cdrom.h>
  36 #include <linux/ioctl.h>
  37 #include <linux/fcntl.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/blkdev.h>
  40 #include <linux/moduleparam.h>
  41 #include <linux/cdev.h>
  42 #include <linux/idr.h>
  43 #include <linux/delay.h>
  44 #include <linux/mutex.h>
  45
  46 #include <linux/uaccess.h>
  47 #include <asm/dma.h>
  48
  49 #include <scsi/scsi.h>
  50 #include <scsi/scsi_dbg.h>
  51 #include <scsi/scsi_device.h>
  52 #include <scsi/scsi_driver.h>
  53 #include <scsi/scsi_eh.h>
  54 #include <scsi/scsi_host.h>
  55 #include <scsi/scsi_ioctl.h>
  56 #include <scsi/sg.h>
  57
  58
  59 /* The driver prints some debugging information on the console if DEBUG
  60    is defined and non-zero. */
  61 #define DEBUG 1
  62 #define NO_DEBUG 0
  63
  64 #define ST_DEB_MSG  KERN_NOTICE
  65 #if DEBUG
  66 /* The message level for the debug messages is currently set to KERN_NOTICE
  67    so that people can easily see the messages. Later when the debugging messages
  68    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  69 #define DEB(a) a
  70 #define DEBC(a) if (debugging) { a ; }
  71 #else
  72 #define DEB(a)
  73 #define DEBC(a)
  74 #endif
  75
  76 #define ST_KILOBYTE 1024
  77
  78 #include "st_options.h"
  79 #include "st.h"
  80
  81 static int buffer_kbs;
  82 static int max_sg_segs;
  83 static int try_direct_io = TRY_DIRECT_IO;
  84 static int try_rdio = 1;
  85 static int try_wdio = 1;
  86 static int debug_flag;
  87
  88 static struct class st_sysfs_class;
  89 static const struct attribute_group *st_dev_groups[];
  90 static const struct attribute_group *st_drv_groups[];
  91
  92 MODULE_AUTHOR("Kai Makisara");
  93 MODULE_DESCRIPTION("SCSI tape (st) driver");
  94 MODULE_LICENSE("GPL");
  95 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  96 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  97
  98 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  99  * of sysfs parameters (which module_param doesn't yet support).
 100  * Sysfs parameters defined explicitly later.
 101  */
 102 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 103 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 104 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 105 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 106 module_param_named(try_direct_io, try_direct_io, int, 0);
 107 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 108 module_param_named(debug_flag, debug_flag, int, 0);
 109 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 110
 111
 112 /* Extra parameters for testing */
 113 module_param_named(try_rdio, try_rdio, int, 0);
 114 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 115 module_param_named(try_wdio, try_wdio, int, 0);
 116 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 117
 118 #ifndef MODULE
 119 static int write_threshold_kbs;  /* retained for compatibility */
 120 static struct st_dev_parm {
 121         char *name;
 122         int *val;
 123 } parms[] __initdata = {
 124         {
 125                 "buffer_kbs", &buffer_kbs
 126         },
 127         {       /* Retained for compatibility with 2.4 */
 128                 "write_threshold_kbs", &write_threshold_kbs
 129         },
 130         {
 131                 "max_sg_segs", NULL
 132         },
 133         {
 134                 "try_direct_io", &try_direct_io
 135         },
 136         {
 137                 "debug_flag", &debug_flag
 138         }
 139 };
 140 #endif
 141
 142 /* Restrict the number of modes so that names for all are assigned */
 143 #if ST_NBR_MODES > 16
 144 #error "Maximum number of modes is 16"
 145 #endif
 146 /* Bit reversed order to get same names for same minors with all
 147    mode counts */
 148 static const char *st_formats[] = {
 149         "",  "r", "k", "s", "l", "t", "o", "u",
 150         "m", "v", "p", "x", "a", "y", "q", "z"};
 151
 152 /* The default definitions have been moved to st_options.h */
 153
 154 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 155
 156 /* The buffer size should fit into the 24 bits for length in the
 157    6-byte SCSI read and write commands. */
 158 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 159 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 160 #endif
 161
 162 static int debugging = DEBUG;
 163
 164 #define MAX_RETRIES 0
 165 #define MAX_WRITE_RETRIES 0
 166 #define MAX_READY_RETRIES 0
 167 #define NO_TAPE  NOT_READY
 168
 169 #define ST_TIMEOUT (900 * HZ)
 170 #define ST_LONG_TIMEOUT (14000 * HZ)
 171
 172 /* Remove mode bits and auto-rewind bit (7) */
 173 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 174         (iminor(x) & ((1 << ST_MODE_SHIFT)-1)))
 175 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 176
 177 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 178 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 179   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 180
 181 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 182    24 bits) */
 183 #define SET_DENS_AND_BLK 0x10001
 184
 185 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 186 static int st_max_sg_segs = ST_MAX_SG;
 187
 188 static int modes_defined;
 189
 190 static int enlarge_buffer(struct st_buffer *, int, int);
 191 static void clear_buffer(struct st_buffer *);
 192 static void normalize_buffer(struct st_buffer *);
 193 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 194 static int from_buffer(struct st_buffer *, char __user *, int);
 195 static void move_buffer_data(struct st_buffer *, int);
 196
 197 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 198                               unsigned long, size_t, int);
 199 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 200
 201 static int st_probe(struct device *);
 202 static int st_remove(struct device *);
 203
 204 static struct scsi_driver st_template = {
 205         .gendrv = {
 206                 .name           = "st",
 207                 .owner          = THIS_MODULE,
 208                 .probe          = st_probe,
 209                 .remove         = st_remove,
 210                 .groups         = st_drv_groups,
 211         },
 212 };
 213
 214 static int st_compression(struct scsi_tape *, int);
 215
 216 static int find_partition(struct scsi_tape *);
 217 static int switch_partition(struct scsi_tape *);
 218
 219 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 220
 221 static void scsi_tape_release(struct kref *);
 222
 223 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 224
 225 static DEFINE_MUTEX(st_ref_mutex);
 226 static DEFINE_SPINLOCK(st_index_lock);
 227 static DEFINE_SPINLOCK(st_use_lock);
 228 static DEFINE_IDR(st_index_idr);
 229
 230
 231 \f
 232 #ifndef SIGS_FROM_OSST
 233 #define SIGS_FROM_OSST \
 234         {"OnStream", "SC-", "", "osst"}, \
 235         {"OnStream", "DI-", "", "osst"}, \
 236         {"OnStream", "DP-", "", "osst"}, \
 237         {"OnStream", "USB", "", "osst"}, \
 238         {"OnStream", "FW-", "", "osst"}
 239 #endif
 240
 241 static struct scsi_tape *scsi_tape_get(int dev)
 242 {
 243         struct scsi_tape *STp = NULL;
 244
 245         mutex_lock(&st_ref_mutex);
 246         spin_lock(&st_index_lock);
 247
 248         STp = idr_find(&st_index_idr, dev);
 249         if (!STp) goto out;
 250
 251         kref_get(&STp->kref);
 252
 253         if (!STp->device)
 254                 goto out_put;
 255
 256         if (scsi_device_get(STp->device))
 257                 goto out_put;
 258
 259         goto out;
 260
 261 out_put:
 262         kref_put(&STp->kref, scsi_tape_release);
 263         STp = NULL;
 264 out:
 265         spin_unlock(&st_index_lock);
 266         mutex_unlock(&st_ref_mutex);
 267         return STp;
 268 }
 269
 270 static void scsi_tape_put(struct scsi_tape *STp)
 271 {
 272         struct scsi_device *sdev = STp->device;
 273
 274         mutex_lock(&st_ref_mutex);
 275         kref_put(&STp->kref, scsi_tape_release);
 276         scsi_device_put(sdev);
 277         mutex_unlock(&st_ref_mutex);
 278 }
 279
 280 struct st_reject_data {
 281         char *vendor;
 282         char *model;
 283         char *rev;
 284         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 285 };
 286
 287 static struct st_reject_data reject_list[] = {
 288         /* {"XXX", "Yy-", "", NULL},  example */
 289         SIGS_FROM_OSST,
 290         {NULL, }};
 291
 292 /* If the device signature is on the list of incompatible drives, the
 293    function returns a pointer to the name of the correct driver (if known) */
 294 static char * st_incompatible(struct scsi_device* SDp)
 295 {
 296         struct st_reject_data *rp;
 297
 298         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 299                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 300                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 301                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 302                         if (rp->driver_hint)
 303                                 return rp->driver_hint;
 304                         else
 305                                 return "unknown";
 306                 }
 307         return NULL;
 308 }
 309 \f
 310
 311 static inline char *tape_name(struct scsi_tape *tape)
 312 {
 313         return tape->disk->disk_name;
 314 }
 315
 316 #define st_printk(prefix, t, fmt, a...) \
 317         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 318 #ifdef DEBUG
 319 #define DEBC_printk(t, fmt, a...) \
 320         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 321 #else
 322 #define DEBC_printk(t, fmt, a...)
 323 #endif
 324
 325 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 326 {
 327         const u8 *ucp;
 328         const u8 *sense = SRpnt->sense;
 329
 330         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 331                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 332         s->flags = 0;
 333
 334         if (s->have_sense) {
 335                 s->deferred = 0;
 336                 s->remainder_valid =
 337                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 338                 switch (sense[0] & 0x7f) {
 339                 case 0x71:
 340                         s->deferred = 1;
 341                         /* fall through */
 342                 case 0x70:
 343                         s->fixed_format = 1;
 344                         s->flags = sense[2] & 0xe0;
 345                         break;
 346                 case 0x73:
 347                         s->deferred = 1;
 348                         /* fall through */
 349                 case 0x72:
 350                         s->fixed_format = 0;
 351                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 352                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 353                         break;
 354                 }
 355         }
 356 }
 357
 358
 359 /* Convert the result to success code */
 360 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 361 {
 362         int result = SRpnt->result;
 363         u8 scode;
 364         DEB(const char *stp;)
 365         char *name = tape_name(STp);
 366         struct st_cmdstatus *cmdstatp;
 367
 368         if (!result)
 369                 return 0;
 370
 371         cmdstatp = &STp->buffer->cmdstat;
 372         st_analyze_sense(SRpnt, cmdstatp);
 373
 374         if (cmdstatp->have_sense)
 375                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 376         else
 377                 scode = 0;
 378
 379         DEB(
 380         if (debugging) {
 381                 st_printk(ST_DEB_MSG, STp,
 382                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 383                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 384                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 385                 if (cmdstatp->have_sense)
 386                         __scsi_print_sense(STp->device, name,
 387                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 388         } ) /* end DEB */
 389         if (!debugging) { /* Abnormal conditions for tape */
 390                 if (!cmdstatp->have_sense)
 391                         st_printk(KERN_WARNING, STp,
 392                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 393                                result, driver_byte(result), host_byte(result));
 394                 else if (cmdstatp->have_sense &&
 395                          scode != NO_SENSE &&
 396                          scode != RECOVERED_ERROR &&
 397                          /* scode != UNIT_ATTENTION && */
 398                          scode != BLANK_CHECK &&
 399                          scode != VOLUME_OVERFLOW &&
 400                          SRpnt->cmd[0] != MODE_SENSE &&
 401                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 402
 403                         __scsi_print_sense(STp->device, name,
 404                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 405                 }
 406         }
 407
 408         if (cmdstatp->fixed_format &&
 409             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 410                 if (STp->cln_sense_value)
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) == STp->cln_sense_value);
 413                 else
 414                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 415                                                STp->cln_sense_mask) != 0);
 416         }
 417         if (cmdstatp->have_sense &&
 418             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 419                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 420
 421         STp->pos_unknown |= STp->device->was_reset;
 422
 423         if (cmdstatp->have_sense &&
 424             scode == RECOVERED_ERROR
 425 #if ST_RECOVERED_WRITE_FATAL
 426             && SRpnt->cmd[0] != WRITE_6
 427             && SRpnt->cmd[0] != WRITE_FILEMARKS
 428 #endif
 429             ) {
 430                 STp->recover_count++;
 431                 STp->recover_reg++;
 432
 433                 DEB(
 434                 if (debugging) {
 435                         if (SRpnt->cmd[0] == READ_6)
 436                                 stp = "read";
 437                         else if (SRpnt->cmd[0] == WRITE_6)
 438                                 stp = "write";
 439                         else
 440                                 stp = "ioctl";
 441                         st_printk(ST_DEB_MSG, STp,
 442                                   "Recovered %s error (%d).\n",
 443                                   stp, STp->recover_count);
 444                 } ) /* end DEB */
 445
 446                 if (cmdstatp->flags == 0)
 447                         return 0;
 448         }
 449         return (-EIO);
 450 }
 451
 452 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 453 {
 454         struct st_request *streq;
 455
 456         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 457         if (streq)
 458                 streq->stp = stp;
 459         else {
 460                 st_printk(KERN_ERR, stp,
 461                           "Can't get SCSI request.\n");
 462                 if (signal_pending(current))
 463                         stp->buffer->syscall_result = -EINTR;
 464                 else
 465                         stp->buffer->syscall_result = -EBUSY;
 466         }
 467
 468         return streq;
 469 }
 470
 471 static void st_release_request(struct st_request *streq)
 472 {
 473         kfree(streq);
 474 }
 475
 476 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 477 {
 478         ktime_t now;
 479
 480         now = ktime_get();
 481         if (scsi_req(req)->cmd[0] == WRITE_6) {
 482                 now = ktime_sub(now, STp->stats->write_time);
 483                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 484                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 485                 atomic64_inc(&STp->stats->write_cnt);
 486                 if (scsi_req(req)->result) {
 487                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 488                                 - STp->buffer->cmdstat.residual,
 489                                 &STp->stats->write_byte_cnt);
 490                         if (STp->buffer->cmdstat.residual > 0)
 491                                 atomic64_inc(&STp->stats->resid_cnt);
 492                 } else
 493                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 494                                 &STp->stats->write_byte_cnt);
 495         } else if (scsi_req(req)->cmd[0] == READ_6) {
 496                 now = ktime_sub(now, STp->stats->read_time);
 497                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 498                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 499                 atomic64_inc(&STp->stats->read_cnt);
 500                 if (scsi_req(req)->result) {
 501                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 502                                 - STp->buffer->cmdstat.residual,
 503                                 &STp->stats->read_byte_cnt);
 504                         if (STp->buffer->cmdstat.residual > 0)
 505                                 atomic64_inc(&STp->stats->resid_cnt);
 506                 } else
 507                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 508                                 &STp->stats->read_byte_cnt);
 509         } else {
 510                 now = ktime_sub(now, STp->stats->other_time);
 511                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 512                 atomic64_inc(&STp->stats->other_cnt);
 513         }
 514         atomic64_dec(&STp->stats->in_flight);
 515 }
 516
 517 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 518 {
 519         struct st_request *SRpnt = req->end_io_data;
 520         struct scsi_request *rq = scsi_req(req);
 521         struct scsi_tape *STp = SRpnt->stp;
 522         struct bio *tmp;
 523
 524         STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 525         STp->buffer->cmdstat.residual = rq->resid_len;
 526
 527         st_do_stats(STp, req);
 528
 529         tmp = SRpnt->bio;
 530         if (rq->sense_len)
 531                 memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 532         if (SRpnt->waiting)
 533                 complete(SRpnt->waiting);
 534
 535         blk_rq_unmap_user(tmp);
 536         blk_put_request(req);
 537 }
 538
 539 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 540                            int data_direction, void *buffer, unsigned bufflen,
 541                            int timeout, int retries)
 542 {
 543         struct request *req;
 544         struct scsi_request *rq;
 545         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 546         int err = 0;
 547         struct scsi_tape *STp = SRpnt->stp;
 548
 549         req = blk_get_request(SRpnt->stp->device->request_queue,
 550                         data_direction == DMA_TO_DEVICE ?
 551                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 552         if (IS_ERR(req))
 553                 return DRIVER_ERROR << 24;
 554         rq = scsi_req(req);
 555         req->rq_flags |= RQF_QUIET;
 556
 557         mdata->null_mapped = 1;
 558
 559         if (bufflen) {
 560                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 561                                       GFP_KERNEL);
 562                 if (err) {
 563                         blk_put_request(req);
 564                         return DRIVER_ERROR << 24;
 565                 }
 566         }
 567
 568         atomic64_inc(&STp->stats->in_flight);
 569         if (cmd[0] == WRITE_6) {
 570                 atomic_set(&STp->stats->last_write_size, bufflen);
 571                 STp->stats->write_time = ktime_get();
 572         } else if (cmd[0] == READ_6) {
 573                 atomic_set(&STp->stats->last_read_size, bufflen);
 574                 STp->stats->read_time = ktime_get();
 575         } else {
 576                 STp->stats->other_time = ktime_get();
 577         }
 578
 579         SRpnt->bio = req->bio;
 580         rq->cmd_len = COMMAND_SIZE(cmd[0]);
 581         memset(rq->cmd, 0, BLK_MAX_CDB);
 582         memcpy(rq->cmd, cmd, rq->cmd_len);
 583         req->timeout = timeout;
 584         rq->retries = retries;
 585         req->end_io_data = SRpnt;
 586
 587         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 588         return 0;
 589 }
 590
 591 /* Do the scsi command. Waits until command performed if do_wait is true.
 592    Otherwise write_behind_check() is used to check that the command
 593    has finished. */
 594 static struct st_request *
 595 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 596            int bytes, int direction, int timeout, int retries, int do_wait)
 597 {
 598         struct completion *waiting;
 599         struct rq_map_data *mdata = &STp->buffer->map_data;
 600         int ret;
 601
 602         /* if async, make sure there's no command outstanding */
 603         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 604                 st_printk(KERN_ERR, STp,
 605                           "Async command already active.\n");
 606                 if (signal_pending(current))
 607                         (STp->buffer)->syscall_result = (-EINTR);
 608                 else
 609                         (STp->buffer)->syscall_result = (-EBUSY);
 610                 return NULL;
 611         }
 612
 613         if (!SRpnt) {
 614                 SRpnt = st_allocate_request(STp);
 615                 if (!SRpnt)
 616                         return NULL;
 617         }
 618
 619         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 620            which IO is outstanding. It's nulled out when the IO completes. */
 621         if (!do_wait)
 622                 (STp->buffer)->last_SRpnt = SRpnt;
 623
 624         waiting = &STp->wait;
 625         init_completion(waiting);
 626         SRpnt->waiting = waiting;
 627
 628         if (STp->buffer->do_dio) {
 629                 mdata->page_order = 0;
 630                 mdata->nr_entries = STp->buffer->sg_segs;
 631                 mdata->pages = STp->buffer->mapped_pages;
 632         } else {
 633                 mdata->page_order = STp->buffer->reserved_page_order;
 634                 mdata->nr_entries =
 635                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 636                 mdata->pages = STp->buffer->reserved_pages;
 637                 mdata->offset = 0;
 638         }
 639
 640         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 641         STp->buffer->cmdstat.have_sense = 0;
 642         STp->buffer->syscall_result = 0;
 643
 644         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 645                               retries);
 646         if (ret) {
 647                 /* could not allocate the buffer or request was too large */
 648                 (STp->buffer)->syscall_result = (-EBUSY);
 649                 (STp->buffer)->last_SRpnt = NULL;
 650         } else if (do_wait) {
 651                 wait_for_completion(waiting);
 652                 SRpnt->waiting = NULL;
 653                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 654         }
 655
 656         return SRpnt;
 657 }
 658
 659
 660 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 661    write has been correct but EOM early warning reached, -EIO if write ended in
 662    error or zero if write successful. Asynchronous writes are used only in
 663    variable block mode. */
 664 static int write_behind_check(struct scsi_tape * STp)
 665 {
 666         int retval = 0;
 667         struct st_buffer *STbuffer;
 668         struct st_partstat *STps;
 669         struct st_cmdstatus *cmdstatp;
 670         struct st_request *SRpnt;
 671
 672         STbuffer = STp->buffer;
 673         if (!STbuffer->writing)
 674                 return 0;
 675
 676         DEB(
 677         if (STp->write_pending)
 678                 STp->nbr_waits++;
 679         else
 680                 STp->nbr_finished++;
 681         ) /* end DEB */
 682
 683         wait_for_completion(&(STp->wait));
 684         SRpnt = STbuffer->last_SRpnt;
 685         STbuffer->last_SRpnt = NULL;
 686         SRpnt->waiting = NULL;
 687
 688         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 689         st_release_request(SRpnt);
 690
 691         STbuffer->buffer_bytes -= STbuffer->writing;
 692         STps = &(STp->ps[STp->partition]);
 693         if (STps->drv_block >= 0) {
 694                 if (STp->block_size == 0)
 695                         STps->drv_block++;
 696                 else
 697                         STps->drv_block += STbuffer->writing / STp->block_size;
 698         }
 699
 700         cmdstatp = &STbuffer->cmdstat;
 701         if (STbuffer->syscall_result) {
 702                 retval = -EIO;
 703                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 704                     (cmdstatp->flags & SENSE_EOM) &&
 705                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 706                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 707                         /* EOM at write-behind, has all data been written? */
 708                         if (!cmdstatp->remainder_valid ||
 709                             cmdstatp->uremainder64 == 0)
 710                                 retval = -ENOSPC;
 711                 }
 712                 if (retval == -EIO)
 713                         STps->drv_block = -1;
 714         }
 715         STbuffer->writing = 0;
 716
 717         DEB(if (debugging && retval)
 718                     st_printk(ST_DEB_MSG, STp,
 719                                 "Async write error %x, return value %d.\n",
 720                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 721
 722         return retval;
 723 }
 724
 725
 726 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 727    it messes up the block number). */
 728 static int cross_eof(struct scsi_tape * STp, int forward)
 729 {
 730         struct st_request *SRpnt;
 731         unsigned char cmd[MAX_COMMAND_SIZE];
 732
 733         cmd[0] = SPACE;
 734         cmd[1] = 0x01;          /* Space FileMarks */
 735         if (forward) {
 736                 cmd[2] = cmd[3] = 0;
 737                 cmd[4] = 1;
 738         } else
 739                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 740         cmd[5] = 0;
 741
 742         DEBC_printk(STp, "Stepping over filemark %s.\n",
 743                     forward ? "forward" : "backward");
 744
 745         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 746                            STp->device->request_queue->rq_timeout,
 747                            MAX_RETRIES, 1);
 748         if (!SRpnt)
 749                 return (STp->buffer)->syscall_result;
 750
 751         st_release_request(SRpnt);
 752         SRpnt = NULL;
 753
 754         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 755                 st_printk(KERN_ERR, STp,
 756                           "Stepping over filemark %s failed.\n",
 757                           forward ? "forward" : "backward");
 758
 759         return (STp->buffer)->syscall_result;
 760 }
 761
 762
 763 /* Flush the write buffer (never need to write if variable blocksize). */
 764 static int st_flush_write_buffer(struct scsi_tape * STp)
 765 {
 766         int transfer, blks;
 767         int result;
 768         unsigned char cmd[MAX_COMMAND_SIZE];
 769         struct st_request *SRpnt;
 770         struct st_partstat *STps;
 771
 772         result = write_behind_check(STp);
 773         if (result)
 774                 return result;
 775
 776         result = 0;
 777         if (STp->dirty == 1) {
 778
 779                 transfer = STp->buffer->buffer_bytes;
 780                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 781
 782                 memset(cmd, 0, MAX_COMMAND_SIZE);
 783                 cmd[0] = WRITE_6;
 784                 cmd[1] = 1;
 785                 blks = transfer / STp->block_size;
 786                 cmd[2] = blks >> 16;
 787                 cmd[3] = blks >> 8;
 788                 cmd[4] = blks;
 789
 790                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 791                                    STp->device->request_queue->rq_timeout,
 792                                    MAX_WRITE_RETRIES, 1);
 793                 if (!SRpnt)
 794                         return (STp->buffer)->syscall_result;
 795
 796                 STps = &(STp->ps[STp->partition]);
 797                 if ((STp->buffer)->syscall_result != 0) {
 798                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 799
 800                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 801                             (cmdstatp->flags & SENSE_EOM) &&
 802                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 803                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 804                             (!cmdstatp->remainder_valid ||
 805                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 806                                 STp->dirty = 0;
 807                                 (STp->buffer)->buffer_bytes = 0;
 808                                 if (STps->drv_block >= 0)
 809                                         STps->drv_block += blks;
 810                                 result = (-ENOSPC);
 811                         } else {
 812                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 813                                 STps->drv_block = (-1);
 814                                 result = (-EIO);
 815                         }
 816                 } else {
 817                         if (STps->drv_block >= 0)
 818                                 STps->drv_block += blks;
 819                         STp->dirty = 0;
 820                         (STp->buffer)->buffer_bytes = 0;
 821                 }
 822                 st_release_request(SRpnt);
 823                 SRpnt = NULL;
 824         }
 825         return result;
 826 }
 827
 828
 829 /* Flush the tape buffer. The tape will be positioned correctly unless
 830    seek_next is true. */
 831 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 832 {
 833         int backspace, result;
 834         struct st_partstat *STps;
 835
 836         /*
 837          * If there was a bus reset, block further access
 838          * to this device.
 839          */
 840         if (STp->pos_unknown)
 841                 return (-EIO);
 842
 843         if (STp->ready != ST_READY)
 844                 return 0;
 845         STps = &(STp->ps[STp->partition]);
 846         if (STps->rw == ST_WRITING)     /* Writing */
 847                 return st_flush_write_buffer(STp);
 848
 849         if (STp->block_size == 0)
 850                 return 0;
 851
 852         backspace = ((STp->buffer)->buffer_bytes +
 853                      (STp->buffer)->read_pointer) / STp->block_size -
 854             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 855             STp->block_size;
 856         (STp->buffer)->buffer_bytes = 0;
 857         (STp->buffer)->read_pointer = 0;
 858         result = 0;
 859         if (!seek_next) {
 860                 if (STps->eof == ST_FM_HIT) {
 861                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 862                         if (!result)
 863                                 STps->eof = ST_NOEOF;
 864                         else {
 865                                 if (STps->drv_file >= 0)
 866                                         STps->drv_file++;
 867                                 STps->drv_block = 0;
 868                         }
 869                 }
 870                 if (!result && backspace > 0)
 871                         result = st_int_ioctl(STp, MTBSR, backspace);
 872         } else if (STps->eof == ST_FM_HIT) {
 873                 if (STps->drv_file >= 0)
 874                         STps->drv_file++;
 875                 STps->drv_block = 0;
 876                 STps->eof = ST_NOEOF;
 877         }
 878         return result;
 879
 880 }
 881 \f
 882 /* Set the mode parameters */
 883 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 884 {
 885         int set_it = 0;
 886         unsigned long arg;
 887
 888         if (!STp->density_changed &&
 889             STm->default_density >= 0 &&
 890             STm->default_density != STp->density) {
 891                 arg = STm->default_density;
 892                 set_it = 1;
 893         } else
 894                 arg = STp->density;
 895         arg <<= MT_ST_DENSITY_SHIFT;
 896         if (!STp->blksize_changed &&
 897             STm->default_blksize >= 0 &&
 898             STm->default_blksize != STp->block_size) {
 899                 arg |= STm->default_blksize;
 900                 set_it = 1;
 901         } else
 902                 arg |= STp->block_size;
 903         if (set_it &&
 904             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 905                 st_printk(KERN_WARNING, STp,
 906                           "Can't set default block size to %d bytes "
 907                           "and density %x.\n",
 908                           STm->default_blksize, STm->default_density);
 909                 if (modes_defined)
 910                         return (-EINVAL);
 911         }
 912         return 0;
 913 }
 914
 915
 916 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 917 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 918 {
 919         int retval;
 920
 921         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 922
 923         retval = scsi_set_medium_removal(STp->device,
 924                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 925         if (!retval)
 926                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 927         else
 928                 STp->door_locked = ST_LOCK_FAILS;
 929         return retval;
 930 }
 931
 932
 933 /* Set the internal state after reset */
 934 static void reset_state(struct scsi_tape *STp)
 935 {
 936         int i;
 937         struct st_partstat *STps;
 938
 939         STp->pos_unknown = 0;
 940         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 941                 STps = &(STp->ps[i]);
 942                 STps->rw = ST_IDLE;
 943                 STps->eof = ST_NOEOF;
 944                 STps->at_sm = 0;
 945                 STps->last_block_valid = 0;
 946                 STps->drv_block = -1;
 947                 STps->drv_file = -1;
 948         }
 949         if (STp->can_partitions) {
 950                 STp->partition = find_partition(STp);
 951                 if (STp->partition < 0)
 952                         STp->partition = 0;
 953                 STp->new_partition = STp->partition;
 954         }
 955 }
 956 \f
 957 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 958    error code. */
 959 #define CHKRES_READY       0
 960 #define CHKRES_NEW_SESSION 1
 961 #define CHKRES_NOT_READY   2
 962 #define CHKRES_NO_TAPE     3
 963
 964 #define MAX_ATTENTIONS    10
 965
 966 static int test_ready(struct scsi_tape *STp, int do_wait)
 967 {
 968         int attentions, waits, max_wait, scode;
 969         int retval = CHKRES_READY, new_session = 0;
 970         unsigned char cmd[MAX_COMMAND_SIZE];
 971         struct st_request *SRpnt = NULL;
 972         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 973
 974         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 975
 976         for (attentions=waits=0; ; ) {
 977                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 978                 cmd[0] = TEST_UNIT_READY;
 979                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 980                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 981
 982                 if (!SRpnt) {
 983                         retval = (STp->buffer)->syscall_result;
 984                         break;
 985                 }
 986
 987                 if (cmdstatp->have_sense) {
 988
 989                         scode = cmdstatp->sense_hdr.sense_key;
 990
 991                         if (scode == UNIT_ATTENTION) { /* New media? */
 992                                 new_session = 1;
 993                                 if (attentions < MAX_ATTENTIONS) {
 994                                         attentions++;
 995                                         continue;
 996                                 }
 997                                 else {
 998                                         retval = (-EIO);
 999                                         break;
1000                                 }
1001                         }
1002
1003                         if (scode == NOT_READY) {
1004                                 if (waits < max_wait) {
1005                                         if (msleep_interruptible(1000)) {
1006                                                 retval = (-EINTR);
1007                                                 break;
1008                                         }
1009                                         waits++;
1010                                         continue;
1011                                 }
1012                                 else {
1013                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1014                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1015                                                 retval = CHKRES_NO_TAPE;
1016                                         else
1017                                                 retval = CHKRES_NOT_READY;
1018                                         break;
1019                                 }
1020                         }
1021                 }
1022
1023                 retval = (STp->buffer)->syscall_result;
1024                 if (!retval)
1025                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1026                 break;
1027         }
1028
1029         if (SRpnt != NULL)
1030                 st_release_request(SRpnt);
1031         return retval;
1032 }
1033
1034
1035 /* See if the drive is ready and gather information about the tape. Return values:
1036    < 0   negative error code from errno.h
1037    0     drive ready
1038    1     drive not ready (possibly no tape)
1039 */
1040 static int check_tape(struct scsi_tape *STp, struct file *filp)
1041 {
1042         int i, retval, new_session = 0, do_wait;
1043         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1044         unsigned short st_flags = filp->f_flags;
1045         struct st_request *SRpnt = NULL;
1046         struct st_modedef *STm;
1047         struct st_partstat *STps;
1048         struct inode *inode = file_inode(filp);
1049         int mode = TAPE_MODE(inode);
1050
1051         STp->ready = ST_READY;
1052
1053         if (mode != STp->current_mode) {
1054                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1055                             STp->current_mode, mode);
1056                 new_session = 1;
1057                 STp->current_mode = mode;
1058         }
1059         STm = &(STp->modes[STp->current_mode]);
1060
1061         saved_cleaning = STp->cleaning_req;
1062         STp->cleaning_req = 0;
1063
1064         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1065         retval = test_ready(STp, do_wait);
1066
1067         if (retval < 0)
1068             goto err_out;
1069
1070         if (retval == CHKRES_NEW_SESSION) {
1071                 STp->pos_unknown = 0;
1072                 STp->partition = STp->new_partition = 0;
1073                 if (STp->can_partitions)
1074                         STp->nbr_partitions = 1; /* This guess will be updated later
1075                                                     if necessary */
1076                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1077                         STps = &(STp->ps[i]);
1078                         STps->rw = ST_IDLE;
1079                         STps->eof = ST_NOEOF;
1080                         STps->at_sm = 0;
1081                         STps->last_block_valid = 0;
1082                         STps->drv_block = 0;
1083                         STps->drv_file = 0;
1084                 }
1085                 new_session = 1;
1086         }
1087         else {
1088                 STp->cleaning_req |= saved_cleaning;
1089
1090                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1091                         if (retval == CHKRES_NO_TAPE)
1092                                 STp->ready = ST_NO_TAPE;
1093                         else
1094                                 STp->ready = ST_NOT_READY;
1095
1096                         STp->density = 0;       /* Clear the erroneous "residue" */
1097                         STp->write_prot = 0;
1098                         STp->block_size = 0;
1099                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1100                         STp->partition = STp->new_partition = 0;
1101                         STp->door_locked = ST_UNLOCKED;
1102                         return CHKRES_NOT_READY;
1103                 }
1104         }
1105
1106         if (STp->omit_blklims)
1107                 STp->min_block = STp->max_block = (-1);
1108         else {
1109                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1110                 cmd[0] = READ_BLOCK_LIMITS;
1111
1112                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1113                                    STp->device->request_queue->rq_timeout,
1114                                    MAX_READY_RETRIES, 1);
1115                 if (!SRpnt) {
1116                         retval = (STp->buffer)->syscall_result;
1117                         goto err_out;
1118                 }
1119
1120                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1121                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1122                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1123                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1124                             (STp->buffer)->b_data[5];
1125                         if ( DEB( debugging || ) !STp->inited)
1126                                 st_printk(KERN_INFO, STp,
1127                                           "Block limits %d - %d bytes.\n",
1128                                           STp->min_block, STp->max_block);
1129                 } else {
1130                         STp->min_block = STp->max_block = (-1);
1131                         DEBC_printk(STp, "Can't read block limits.\n");
1132                 }
1133         }
1134
1135         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1136         cmd[0] = MODE_SENSE;
1137         cmd[4] = 12;
1138
1139         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1140                            STp->device->request_queue->rq_timeout,
1141                            MAX_READY_RETRIES, 1);
1142         if (!SRpnt) {
1143                 retval = (STp->buffer)->syscall_result;
1144                 goto err_out;
1145         }
1146
1147         if ((STp->buffer)->syscall_result != 0) {
1148                 DEBC_printk(STp, "No Mode Sense.\n");
1149                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1150                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1151                 STp->drv_write_prot = 0;
1152         } else {
1153                 DEBC_printk(STp,"Mode sense. Length %d, "
1154                             "medium %x, WBS %x, BLL %d\n",
1155                             (STp->buffer)->b_data[0],
1156                             (STp->buffer)->b_data[1],
1157                             (STp->buffer)->b_data[2],
1158                             (STp->buffer)->b_data[3]);
1159
1160                 if ((STp->buffer)->b_data[3] >= 8) {
1161                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1162                         STp->density = (STp->buffer)->b_data[4];
1163                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1164                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1165                         DEBC_printk(STp, "Density %x, tape length: %x, "
1166                                     "drv buffer: %d\n",
1167                                     STp->density,
1168                                     (STp->buffer)->b_data[5] * 65536 +
1169                                     (STp->buffer)->b_data[6] * 256 +
1170                                     (STp->buffer)->b_data[7],
1171                                     STp->drv_buffer);
1172                 }
1173                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1174                 if (!STp->drv_buffer && STp->immediate_filemark) {
1175                         st_printk(KERN_WARNING, STp,
1176                                   "non-buffered tape: disabling "
1177                                   "writing immediate filemarks\n");
1178                         STp->immediate_filemark = 0;
1179                 }
1180         }
1181         st_release_request(SRpnt);
1182         SRpnt = NULL;
1183         STp->inited = 1;
1184
1185         if (STp->block_size > 0)
1186                 (STp->buffer)->buffer_blocks =
1187                         (STp->buffer)->buffer_size / STp->block_size;
1188         else
1189                 (STp->buffer)->buffer_blocks = 1;
1190         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1191
1192         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1193                     STp->block_size, (STp->buffer)->buffer_size,
1194                     (STp->buffer)->buffer_blocks);
1195
1196         if (STp->drv_write_prot) {
1197                 STp->write_prot = 1;
1198
1199                 DEBC_printk(STp, "Write protected\n");
1200
1201                 if (do_wait &&
1202                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1203                      (st_flags & O_ACCMODE) == O_RDWR)) {
1204                         retval = (-EROFS);
1205                         goto err_out;
1206                 }
1207         }
1208
1209         if (STp->can_partitions && STp->nbr_partitions < 1) {
1210                 /* This code is reached when the device is opened for the first time
1211                    after the driver has been initialized with tape in the drive and the
1212                    partition support has been enabled. */
1213                 DEBC_printk(STp, "Updating partition number in status.\n");
1214                 if ((STp->partition = find_partition(STp)) < 0) {
1215                         retval = STp->partition;
1216                         goto err_out;
1217                 }
1218                 STp->new_partition = STp->partition;
1219                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1220         }
1221
1222         if (new_session) {      /* Change the drive parameters for the new mode */
1223                 STp->density_changed = STp->blksize_changed = 0;
1224                 STp->compression_changed = 0;
1225                 if (!(STm->defaults_for_writes) &&
1226                     (retval = set_mode_densblk(STp, STm)) < 0)
1227                     goto err_out;
1228
1229                 if (STp->default_drvbuffer != 0xff) {
1230                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1231                                 st_printk(KERN_WARNING, STp,
1232                                           "Can't set default drive "
1233                                           "buffering to %d.\n",
1234                                           STp->default_drvbuffer);
1235                 }
1236         }
1237
1238         return CHKRES_READY;
1239
1240  err_out:
1241         return retval;
1242 }
1243
1244
1245 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1246    module count. */
1247 static int st_open(struct inode *inode, struct file *filp)
1248 {
1249         int i, retval = (-EIO);
1250         int resumed = 0;
1251         struct scsi_tape *STp;
1252         struct st_partstat *STps;
1253         int dev = TAPE_NR(inode);
1254
1255         /*
1256          * We really want to do nonseekable_open(inode, filp); here, but some
1257          * versions of tar incorrectly call lseek on tapes and bail out if that
1258          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1259          */
1260         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1261
1262         if (!(STp = scsi_tape_get(dev))) {
1263                 return -ENXIO;
1264         }
1265
1266         filp->private_data = STp;
1267
1268         spin_lock(&st_use_lock);
1269         if (STp->in_use) {
1270                 spin_unlock(&st_use_lock);
1271                 scsi_tape_put(STp);
1272                 DEBC_printk(STp, "Device already in use.\n");
1273                 return (-EBUSY);
1274         }
1275
1276         STp->in_use = 1;
1277         spin_unlock(&st_use_lock);
1278         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1279
1280         if (scsi_autopm_get_device(STp->device) < 0) {
1281                 retval = -EIO;
1282                 goto err_out;
1283         }
1284         resumed = 1;
1285         if (!scsi_block_when_processing_errors(STp->device)) {
1286                 retval = (-ENXIO);
1287                 goto err_out;
1288         }
1289
1290         /* See that we have at least a one page buffer available */
1291         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1292                 st_printk(KERN_WARNING, STp,
1293                           "Can't allocate one page tape buffer.\n");
1294                 retval = (-EOVERFLOW);
1295                 goto err_out;
1296         }
1297
1298         (STp->buffer)->cleared = 0;
1299         (STp->buffer)->writing = 0;
1300         (STp->buffer)->syscall_result = 0;
1301
1302         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1303
1304         STp->dirty = 0;
1305         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1306                 STps = &(STp->ps[i]);
1307                 STps->rw = ST_IDLE;
1308         }
1309         STp->try_dio_now = STp->try_dio;
1310         STp->recover_count = 0;
1311         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1312              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1313
1314         retval = check_tape(STp, filp);
1315         if (retval < 0)
1316                 goto err_out;
1317         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1318             retval != CHKRES_READY) {
1319                 if (STp->ready == NO_TAPE)
1320                         retval = (-ENOMEDIUM);
1321                 else
1322                         retval = (-EIO);
1323                 goto err_out;
1324         }
1325         return 0;
1326
1327  err_out:
1328         normalize_buffer(STp->buffer);
1329         spin_lock(&st_use_lock);
1330         STp->in_use = 0;
1331         spin_unlock(&st_use_lock);
1332         if (resumed)
1333                 scsi_autopm_put_device(STp->device);
1334         scsi_tape_put(STp);
1335         return retval;
1336
1337 }
1338 \f
1339
1340 /* Flush the tape buffer before close */
1341 static int st_flush(struct file *filp, fl_owner_t id)
1342 {
1343         int result = 0, result2;
1344         unsigned char cmd[MAX_COMMAND_SIZE];
1345         struct st_request *SRpnt;
1346         struct scsi_tape *STp = filp->private_data;
1347         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1348         struct st_partstat *STps = &(STp->ps[STp->partition]);
1349
1350         if (file_count(filp) > 1)
1351                 return 0;
1352
1353         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1354                 result = st_flush_write_buffer(STp);
1355                 if (result != 0 && result != (-ENOSPC))
1356                         goto out;
1357         }
1358
1359         if (STp->can_partitions &&
1360             (result2 = switch_partition(STp)) < 0) {
1361                 DEBC_printk(STp, "switch_partition at close failed.\n");
1362                 if (result == 0)
1363                         result = result2;
1364                 goto out;
1365         }
1366
1367         DEBC( if (STp->nbr_requests)
1368                 st_printk(KERN_DEBUG, STp,
1369                           "Number of r/w requests %d, dio used in %d, "
1370                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1371                           STp->nbr_pages));
1372
1373         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1374                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1375
1376 #if DEBUG
1377                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1378                             STp->nbr_waits, STp->nbr_finished);
1379 #endif
1380                 memset(cmd, 0, MAX_COMMAND_SIZE);
1381                 cmd[0] = WRITE_FILEMARKS;
1382                 if (STp->immediate_filemark)
1383                         cmd[1] = 1;
1384                 cmd[4] = 1 + STp->two_fm;
1385
1386                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1387                                    STp->device->request_queue->rq_timeout,
1388                                    MAX_WRITE_RETRIES, 1);
1389                 if (!SRpnt) {
1390                         result = (STp->buffer)->syscall_result;
1391                         goto out;
1392                 }
1393
1394                 if (STp->buffer->syscall_result == 0 ||
1395                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1396                      (cmdstatp->flags & SENSE_EOM) &&
1397                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1398                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1399                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1400                         /* Write successful at EOM */
1401                         st_release_request(SRpnt);
1402                         SRpnt = NULL;
1403                         if (STps->drv_file >= 0)
1404                                 STps->drv_file++;
1405                         STps->drv_block = 0;
1406                         if (STp->two_fm)
1407                                 cross_eof(STp, 0);
1408                         STps->eof = ST_FM;
1409                 }
1410                 else { /* Write error */
1411                         st_release_request(SRpnt);
1412                         SRpnt = NULL;
1413                         st_printk(KERN_ERR, STp,
1414                                   "Error on write filemark.\n");
1415                         if (result == 0)
1416                                 result = (-EIO);
1417                 }
1418
1419                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1420         } else if (!STp->rew_at_close) {
1421                 STps = &(STp->ps[STp->partition]);
1422                 if (!STm->sysv || STps->rw != ST_READING) {
1423                         if (STp->can_bsr)
1424                                 result = flush_buffer(STp, 0);
1425                         else if (STps->eof == ST_FM_HIT) {
1426                                 result = cross_eof(STp, 0);
1427                                 if (result) {
1428                                         if (STps->drv_file >= 0)
1429                                                 STps->drv_file++;
1430                                         STps->drv_block = 0;
1431                                         STps->eof = ST_FM;
1432                                 } else
1433                                         STps->eof = ST_NOEOF;
1434                         }
1435                 } else if ((STps->eof == ST_NOEOF &&
1436                             !(result = cross_eof(STp, 1))) ||
1437                            STps->eof == ST_FM_HIT) {
1438                         if (STps->drv_file >= 0)
1439                                 STps->drv_file++;
1440                         STps->drv_block = 0;
1441                         STps->eof = ST_FM;
1442                 }
1443         }
1444
1445       out:
1446         if (STp->rew_at_close) {
1447                 result2 = st_int_ioctl(STp, MTREW, 1);
1448                 if (result == 0)
1449                         result = result2;
1450         }
1451         return result;
1452 }
1453
1454
1455 /* Close the device and release it. BKL is not needed: this is the only thread
1456    accessing this tape. */
1457 static int st_release(struct inode *inode, struct file *filp)
1458 {
1459         int result = 0;
1460         struct scsi_tape *STp = filp->private_data;
1461
1462         if (STp->door_locked == ST_LOCKED_AUTO)
1463                 do_door_lock(STp, 0);
1464
1465         normalize_buffer(STp->buffer);
1466         spin_lock(&st_use_lock);
1467         STp->in_use = 0;
1468         spin_unlock(&st_use_lock);
1469         scsi_autopm_put_device(STp->device);
1470         scsi_tape_put(STp);
1471
1472         return result;
1473 }
1474 \f
1475 /* The checks common to both reading and writing */
1476 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1477 {
1478         ssize_t retval = 0;
1479
1480         /*
1481          * If we are in the middle of error recovery, don't let anyone
1482          * else try and use this device.  Also, if error recovery fails, it
1483          * may try and take the device offline, in which case all further
1484          * access to the device is prohibited.
1485          */
1486         if (!scsi_block_when_processing_errors(STp->device)) {
1487                 retval = (-ENXIO);
1488                 goto out;
1489         }
1490
1491         if (STp->ready != ST_READY) {
1492                 if (STp->ready == ST_NO_TAPE)
1493                         retval = (-ENOMEDIUM);
1494                 else
1495                         retval = (-EIO);
1496                 goto out;
1497         }
1498
1499         if (! STp->modes[STp->current_mode].defined) {
1500                 retval = (-ENXIO);
1501                 goto out;
1502         }
1503
1504
1505         /*
1506          * If there was a bus reset, block further access
1507          * to this device.
1508          */
1509         if (STp->pos_unknown) {
1510                 retval = (-EIO);
1511                 goto out;
1512         }
1513
1514         if (count == 0)
1515                 goto out;
1516
1517         DEB(
1518         if (!STp->in_use) {
1519                 st_printk(ST_DEB_MSG, STp,
1520                           "Incorrect device.\n");
1521                 retval = (-EIO);
1522                 goto out;
1523         } ) /* end DEB */
1524
1525         if (STp->can_partitions &&
1526             (retval = switch_partition(STp)) < 0)
1527                 goto out;
1528
1529         if (STp->block_size == 0 && STp->max_block > 0 &&
1530             (count < STp->min_block || count > STp->max_block)) {
1531                 retval = (-EINVAL);
1532                 goto out;
1533         }
1534
1535         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1536             !do_door_lock(STp, 1))
1537                 STp->door_locked = ST_LOCKED_AUTO;
1538
1539  out:
1540         return retval;
1541 }
1542
1543
1544 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1545                            size_t count, int is_read)
1546 {
1547         int i, bufsize, retval = 0;
1548         struct st_buffer *STbp = STp->buffer;
1549
1550         if (is_read)
1551                 i = STp->try_dio_now && try_rdio;
1552         else
1553                 i = STp->try_dio_now && try_wdio;
1554
1555         if (i && ((unsigned long)buf & queue_dma_alignment(
1556                                         STp->device->request_queue)) == 0) {
1557                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1558                                        count, (is_read ? READ : WRITE));
1559                 if (i > 0) {
1560                         STbp->do_dio = i;
1561                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1562                 }
1563                 else
1564                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1565                 STbp->sg_segs = STbp->do_dio;
1566                 DEB(
1567                      if (STbp->do_dio) {
1568                         STp->nbr_dio++;
1569                         STp->nbr_pages += STbp->do_dio;
1570                      }
1571                 )
1572         } else
1573                 STbp->do_dio = 0;
1574         DEB( STp->nbr_requests++; )
1575
1576         if (!STbp->do_dio) {
1577                 if (STp->block_size)
1578                         bufsize = STp->block_size > st_fixed_buffer_size ?
1579                                 STp->block_size : st_fixed_buffer_size;
1580                 else {
1581                         bufsize = count;
1582                         /* Make sure that data from previous user is not leaked even if
1583                            HBA does not return correct residual */
1584                         if (is_read && STp->sili && !STbp->cleared)
1585                                 clear_buffer(STbp);
1586                 }
1587
1588                 if (bufsize > STbp->buffer_size &&
1589                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1590                         st_printk(KERN_WARNING, STp,
1591                                   "Can't allocate %d byte tape buffer.\n",
1592                                   bufsize);
1593                         retval = (-EOVERFLOW);
1594                         goto out;
1595                 }
1596                 if (STp->block_size)
1597                         STbp->buffer_blocks = bufsize / STp->block_size;
1598         }
1599
1600  out:
1601         return retval;
1602 }
1603
1604
1605 /* Can be called more than once after each setup_buffer() */
1606 static void release_buffering(struct scsi_tape *STp, int is_read)
1607 {
1608         struct st_buffer *STbp;
1609
1610         STbp = STp->buffer;
1611         if (STbp->do_dio) {
1612                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1613                 STbp->do_dio = 0;
1614                 STbp->sg_segs = 0;
1615         }
1616 }
1617
1618
1619 /* Write command */
1620 static ssize_t
1621 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1622 {
1623         ssize_t total;
1624         ssize_t i, do_count, blks, transfer;
1625         ssize_t retval;
1626         int undone, retry_eot = 0, scode;
1627         int async_write;
1628         unsigned char cmd[MAX_COMMAND_SIZE];
1629         const char __user *b_point;
1630         struct st_request *SRpnt = NULL;
1631         struct scsi_tape *STp = filp->private_data;
1632         struct st_modedef *STm;
1633         struct st_partstat *STps;
1634         struct st_buffer *STbp;
1635
1636         if (mutex_lock_interruptible(&STp->lock))
1637                 return -ERESTARTSYS;
1638
1639         retval = rw_checks(STp, filp, count);
1640         if (retval || count == 0)
1641                 goto out;
1642
1643         /* Write must be integral number of blocks */
1644         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1645                 st_printk(KERN_WARNING, STp,
1646                           "Write not multiple of tape block size.\n");
1647                 retval = (-EINVAL);
1648                 goto out;
1649         }
1650
1651         STm = &(STp->modes[STp->current_mode]);
1652         STps = &(STp->ps[STp->partition]);
1653
1654         if (STp->write_prot) {
1655                 retval = (-EACCES);
1656                 goto out;
1657         }
1658
1659
1660         if (STps->rw == ST_READING) {
1661                 retval = flush_buffer(STp, 0);
1662                 if (retval)
1663                         goto out;
1664                 STps->rw = ST_WRITING;
1665         } else if (STps->rw != ST_WRITING &&
1666                    STps->drv_file == 0 && STps->drv_block == 0) {
1667                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1668                         goto out;
1669                 if (STm->default_compression != ST_DONT_TOUCH &&
1670                     !(STp->compression_changed)) {
1671                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1672                                 st_printk(KERN_WARNING, STp,
1673                                           "Can't set default compression.\n");
1674                                 if (modes_defined) {
1675                                         retval = (-EINVAL);
1676                                         goto out;
1677                                 }
1678                         }
1679                 }
1680         }
1681
1682         STbp = STp->buffer;
1683         i = write_behind_check(STp);
1684         if (i) {
1685                 if (i == -ENOSPC)
1686                         STps->eof = ST_EOM_OK;
1687                 else
1688                         STps->eof = ST_EOM_ERROR;
1689         }
1690
1691         if (STps->eof == ST_EOM_OK) {
1692                 STps->eof = ST_EOD_1;  /* allow next write */
1693                 retval = (-ENOSPC);
1694                 goto out;
1695         }
1696         else if (STps->eof == ST_EOM_ERROR) {
1697                 retval = (-EIO);
1698                 goto out;
1699         }
1700
1701         /* Check the buffer readability in cases where copy_user might catch
1702            the problems after some tape movement. */
1703         if (STp->block_size != 0 &&
1704             !STbp->do_dio &&
1705             (copy_from_user(&i, buf, 1) != 0 ||
1706              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1707                 retval = (-EFAULT);
1708                 goto out;
1709         }
1710
1711         retval = setup_buffering(STp, buf, count, 0);
1712         if (retval)
1713                 goto out;
1714
1715         total = count;
1716
1717         memset(cmd, 0, MAX_COMMAND_SIZE);
1718         cmd[0] = WRITE_6;
1719         cmd[1] = (STp->block_size != 0);
1720
1721         STps->rw = ST_WRITING;
1722
1723         b_point = buf;
1724         while (count > 0 && !retry_eot) {
1725
1726                 if (STbp->do_dio) {
1727                         do_count = count;
1728                 }
1729                 else {
1730                         if (STp->block_size == 0)
1731                                 do_count = count;
1732                         else {
1733                                 do_count = STbp->buffer_blocks * STp->block_size -
1734                                         STbp->buffer_bytes;
1735                                 if (do_count > count)
1736                                         do_count = count;
1737                         }
1738
1739                         i = append_to_buffer(b_point, STbp, do_count);
1740                         if (i) {
1741                                 retval = i;
1742                                 goto out;
1743                         }
1744                 }
1745                 count -= do_count;
1746                 b_point += do_count;
1747
1748                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1749                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1750
1751                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1752                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1753                     STbp->buffer_bytes < STbp->buffer_size) {
1754                         STp->dirty = 1;
1755                         /* Don't write a buffer that is not full enough. */
1756                         if (!async_write && count == 0)
1757                                 break;
1758                 }
1759
1760         retry_write:
1761                 if (STp->block_size == 0)
1762                         blks = transfer = do_count;
1763                 else {
1764                         if (!STbp->do_dio)
1765                                 blks = STbp->buffer_bytes;
1766                         else
1767                                 blks = do_count;
1768                         blks /= STp->block_size;
1769                         transfer = blks * STp->block_size;
1770                 }
1771                 cmd[2] = blks >> 16;
1772                 cmd[3] = blks >> 8;
1773                 cmd[4] = blks;
1774
1775                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1776                                    STp->device->request_queue->rq_timeout,
1777                                    MAX_WRITE_RETRIES, !async_write);
1778                 if (!SRpnt) {
1779                         retval = STbp->syscall_result;
1780                         goto out;
1781                 }
1782                 if (async_write && !STbp->syscall_result) {
1783                         STbp->writing = transfer;
1784                         STp->dirty = !(STbp->writing ==
1785                                        STbp->buffer_bytes);
1786                         SRpnt = NULL;  /* Prevent releasing this request! */
1787                         DEB( STp->write_pending = 1; )
1788                         break;
1789                 }
1790
1791                 if (STbp->syscall_result != 0) {
1792                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1793
1794                         DEBC_printk(STp, "Error on write:\n");
1795                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1796                                 scode = cmdstatp->sense_hdr.sense_key;
1797                                 if (cmdstatp->remainder_valid)
1798                                         undone = (int)cmdstatp->uremainder64;
1799                                 else if (STp->block_size == 0 &&
1800                                          scode == VOLUME_OVERFLOW)
1801                                         undone = transfer;
1802                                 else
1803                                         undone = 0;
1804                                 if (STp->block_size != 0)
1805                                         undone *= STp->block_size;
1806                                 if (undone <= do_count) {
1807                                         /* Only data from this write is not written */
1808                                         count += undone;
1809                                         b_point -= undone;
1810                                         do_count -= undone;
1811                                         if (STp->block_size)
1812                                                 blks = (transfer - undone) / STp->block_size;
1813                                         STps->eof = ST_EOM_OK;
1814                                         /* Continue in fixed block mode if all written
1815                                            in this request but still something left to write
1816                                            (retval left to zero)
1817                                         */
1818                                         if (STp->block_size == 0 ||
1819                                             undone > 0 || count == 0)
1820                                                 retval = (-ENOSPC); /* EOM within current request */
1821                                         DEBC_printk(STp, "EOM with %d "
1822                                                     "bytes unwritten.\n",
1823                                                     (int)count);
1824                                 } else {
1825                                         /* EOT within data buffered earlier (possible only
1826                                            in fixed block mode without direct i/o) */
1827                                         if (!retry_eot && !cmdstatp->deferred &&
1828                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1829                                                 move_buffer_data(STp->buffer, transfer - undone);
1830                                                 retry_eot = 1;
1831                                                 if (STps->drv_block >= 0) {
1832                                                         STps->drv_block += (transfer - undone) /
1833                                                                 STp->block_size;
1834                                                 }
1835                                                 STps->eof = ST_EOM_OK;
1836                                                 DEBC_printk(STp, "Retry "
1837                                                             "write of %d "
1838                                                             "bytes at EOM.\n",
1839                                                             STp->buffer->buffer_bytes);
1840                                                 goto retry_write;
1841                                         }
1842                                         else {
1843                                                 /* Either error within data buffered by driver or
1844                                                    failed retry */
1845                                                 count -= do_count;
1846                                                 blks = do_count = 0;
1847                                                 STps->eof = ST_EOM_ERROR;
1848                                                 STps->drv_block = (-1); /* Too cautious? */
1849                                                 retval = (-EIO);        /* EOM for old data */
1850                                                 DEBC_printk(STp, "EOM with "
1851                                                             "lost data.\n");
1852                                         }
1853                                 }
1854                         } else {
1855                                 count += do_count;
1856                                 STps->drv_block = (-1);         /* Too cautious? */
1857                                 retval = STbp->syscall_result;
1858                         }
1859
1860                 }
1861
1862                 if (STps->drv_block >= 0) {
1863                         if (STp->block_size == 0)
1864                                 STps->drv_block += (do_count > 0);
1865                         else
1866                                 STps->drv_block += blks;
1867                 }
1868
1869                 STbp->buffer_bytes = 0;
1870                 STp->dirty = 0;
1871
1872                 if (retval || retry_eot) {
1873                         if (count < total)
1874                                 retval = total - count;
1875                         goto out;
1876                 }
1877         }
1878
1879         if (STps->eof == ST_EOD_1)
1880                 STps->eof = ST_EOM_OK;
1881         else if (STps->eof != ST_EOM_OK)
1882                 STps->eof = ST_NOEOF;
1883         retval = total - count;
1884
1885  out:
1886         if (SRpnt != NULL)
1887                 st_release_request(SRpnt);
1888         release_buffering(STp, 0);
1889         mutex_unlock(&STp->lock);
1890
1891         return retval;
1892 }
1893 \f
1894 /* Read data from the tape. Returns zero in the normal case, one if the
1895    eof status has changed, and the negative error code in case of a
1896    fatal error. Otherwise updates the buffer and the eof state.
1897
1898    Does release user buffer mapping if it is set.
1899 */
1900 static long read_tape(struct scsi_tape *STp, long count,
1901                       struct st_request ** aSRpnt)
1902 {
1903         int transfer, blks, bytes;
1904         unsigned char cmd[MAX_COMMAND_SIZE];
1905         struct st_request *SRpnt;
1906         struct st_modedef *STm;
1907         struct st_partstat *STps;
1908         struct st_buffer *STbp;
1909         int retval = 0;
1910
1911         if (count == 0)
1912                 return 0;
1913
1914         STm = &(STp->modes[STp->current_mode]);
1915         STps = &(STp->ps[STp->partition]);
1916         if (STps->eof == ST_FM_HIT)
1917                 return 1;
1918         STbp = STp->buffer;
1919
1920         if (STp->block_size == 0)
1921                 blks = bytes = count;
1922         else {
1923                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1924                         blks = (STp->buffer)->buffer_blocks;
1925                         bytes = blks * STp->block_size;
1926                 } else {
1927                         bytes = count;
1928                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1929                                 bytes = (STp->buffer)->buffer_size;
1930                         blks = bytes / STp->block_size;
1931                         bytes = blks * STp->block_size;
1932                 }
1933         }
1934
1935         memset(cmd, 0, MAX_COMMAND_SIZE);
1936         cmd[0] = READ_6;
1937         cmd[1] = (STp->block_size != 0);
1938         if (!cmd[1] && STp->sili)
1939                 cmd[1] |= 2;
1940         cmd[2] = blks >> 16;
1941         cmd[3] = blks >> 8;
1942         cmd[4] = blks;
1943
1944         SRpnt = *aSRpnt;
1945         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1946                            STp->device->request_queue->rq_timeout,
1947                            MAX_RETRIES, 1);
1948         release_buffering(STp, 1);
1949         *aSRpnt = SRpnt;
1950         if (!SRpnt)
1951                 return STbp->syscall_result;
1952
1953         STbp->read_pointer = 0;
1954         STps->at_sm = 0;
1955
1956         /* Something to check */
1957         if (STbp->syscall_result) {
1958                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1959
1960                 retval = 1;
1961                 DEBC_printk(STp,
1962                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1963                             SRpnt->sense[0], SRpnt->sense[1],
1964                             SRpnt->sense[2], SRpnt->sense[3],
1965                             SRpnt->sense[4], SRpnt->sense[5],
1966                             SRpnt->sense[6], SRpnt->sense[7]);
1967                 if (cmdstatp->have_sense) {
1968
1969                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1970                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1971
1972                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1973                                 /* Compute the residual count */
1974                                 if (cmdstatp->remainder_valid)
1975                                         transfer = (int)cmdstatp->uremainder64;
1976                                 else
1977                                         transfer = 0;
1978                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1979                                         if (STp->block_size == 0)
1980                                                 transfer = bytes;
1981                                         /* Some drives set ILI with MEDIUM ERROR */
1982                                         cmdstatp->flags &= ~SENSE_ILI;
1983                                 }
1984
1985                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1986                                         if (STp->block_size == 0 &&
1987                                             transfer < 0) {
1988                                                 st_printk(KERN_NOTICE, STp,
1989                                                           "Failed to read %d "
1990                                                           "byte block with %d "
1991                                                           "byte transfer.\n",
1992                                                           bytes - transfer,
1993                                                           bytes);
1994                                                 if (STps->drv_block >= 0)
1995                                                         STps->drv_block += 1;
1996                                                 STbp->buffer_bytes = 0;
1997                                                 return (-ENOMEM);
1998                                         } else if (STp->block_size == 0) {
1999                                                 STbp->buffer_bytes = bytes - transfer;
2000                                         } else {
2001                                                 st_release_request(SRpnt);
2002                                                 SRpnt = *aSRpnt = NULL;
2003                                                 if (transfer == blks) { /* We did not get anything, error */
2004                                                         st_printk(KERN_NOTICE, STp,
2005                                                                   "Incorrect "
2006                                                                   "block size.\n");
2007                                                         if (STps->drv_block >= 0)
2008                                                                 STps->drv_block += blks - transfer + 1;
2009                                                         st_int_ioctl(STp, MTBSR, 1);
2010                                                         return (-EIO);
2011                                                 }
2012                                                 /* We have some data, deliver it */
2013                                                 STbp->buffer_bytes = (blks - transfer) *
2014                                                     STp->block_size;
2015                                                 DEBC_printk(STp, "ILI but "
2016                                                             "enough data "
2017                                                             "received %ld "
2018                                                             "%d.\n", count,
2019                                                             STbp->buffer_bytes);
2020                                                 if (STps->drv_block >= 0)
2021                                                         STps->drv_block += 1;
2022                                                 if (st_int_ioctl(STp, MTBSR, 1))
2023                                                         return (-EIO);
2024                                         }
2025                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2026                                         if (STps->eof != ST_FM_HIT)
2027                                                 STps->eof = ST_FM_HIT;
2028                                         else
2029                                                 STps->eof = ST_EOD_2;
2030                                         if (STp->block_size == 0)
2031                                                 STbp->buffer_bytes = 0;
2032                                         else
2033                                                 STbp->buffer_bytes =
2034                                                     bytes - transfer * STp->block_size;
2035                                         DEBC_printk(STp, "EOF detected (%d "
2036                                                     "bytes read).\n",
2037                                                     STbp->buffer_bytes);
2038                                 } else if (cmdstatp->flags & SENSE_EOM) {
2039                                         if (STps->eof == ST_FM)
2040                                                 STps->eof = ST_EOD_1;
2041                                         else
2042                                                 STps->eof = ST_EOM_OK;
2043                                         if (STp->block_size == 0)
2044                                                 STbp->buffer_bytes = bytes - transfer;
2045                                         else
2046                                                 STbp->buffer_bytes =
2047                                                     bytes - transfer * STp->block_size;
2048
2049                                         DEBC_printk(STp, "EOM detected (%d "
2050                                                     "bytes read).\n",
2051                                                     STbp->buffer_bytes);
2052                                 }
2053                         }
2054                         /* end of EOF, EOM, ILI test */
2055                         else {  /* nonzero sense key */
2056                                 DEBC_printk(STp, "Tape error while reading.\n");
2057                                 STps->drv_block = (-1);
2058                                 if (STps->eof == ST_FM &&
2059                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2060                                         DEBC_printk(STp, "Zero returned for "
2061                                                     "first BLANK CHECK "
2062                                                     "after EOF.\n");
2063                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2064                                 } else  /* Some other extended sense code */
2065                                         retval = (-EIO);
2066                         }
2067
2068                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2069                                 STbp->buffer_bytes = 0;
2070                 }
2071                 /* End of extended sense test */
2072                 else {          /* Non-extended sense */
2073                         retval = STbp->syscall_result;
2074                 }
2075
2076         }
2077         /* End of error handling */
2078         else {                  /* Read successful */
2079                 STbp->buffer_bytes = bytes;
2080                 if (STp->sili) /* In fixed block mode residual is always zero here */
2081                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2082         }
2083
2084         if (STps->drv_block >= 0) {
2085                 if (STp->block_size == 0)
2086                         STps->drv_block++;
2087                 else
2088                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2089         }
2090         return retval;
2091 }
2092 \f
2093
2094 /* Read command */
2095 static ssize_t
2096 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2097 {
2098         ssize_t total;
2099         ssize_t retval = 0;
2100         ssize_t i, transfer;
2101         int special, do_dio = 0;
2102         struct st_request *SRpnt = NULL;
2103         struct scsi_tape *STp = filp->private_data;
2104         struct st_modedef *STm;
2105         struct st_partstat *STps;
2106         struct st_buffer *STbp = STp->buffer;
2107
2108         if (mutex_lock_interruptible(&STp->lock))
2109                 return -ERESTARTSYS;
2110
2111         retval = rw_checks(STp, filp, count);
2112         if (retval || count == 0)
2113                 goto out;
2114
2115         STm = &(STp->modes[STp->current_mode]);
2116         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2117                 if (!STm->do_read_ahead) {
2118                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2119                         goto out;
2120                 }
2121                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2122         }
2123
2124         STps = &(STp->ps[STp->partition]);
2125         if (STps->rw == ST_WRITING) {
2126                 retval = flush_buffer(STp, 0);
2127                 if (retval)
2128                         goto out;
2129                 STps->rw = ST_READING;
2130         }
2131         DEB(
2132         if (debugging && STps->eof != ST_NOEOF)
2133                 st_printk(ST_DEB_MSG, STp,
2134                           "EOF/EOM flag up (%d). Bytes %d\n",
2135                           STps->eof, STbp->buffer_bytes);
2136         ) /* end DEB */
2137
2138         retval = setup_buffering(STp, buf, count, 1);
2139         if (retval)
2140                 goto out;
2141         do_dio = STbp->do_dio;
2142
2143         if (STbp->buffer_bytes == 0 &&
2144             STps->eof >= ST_EOD_1) {
2145                 if (STps->eof < ST_EOD) {
2146                         STps->eof += 1;
2147                         retval = 0;
2148                         goto out;
2149                 }
2150                 retval = (-EIO);        /* EOM or Blank Check */
2151                 goto out;
2152         }
2153
2154         if (do_dio) {
2155                 /* Check the buffer writability before any tape movement. Don't alter
2156                    buffer data. */
2157                 if (copy_from_user(&i, buf, 1) != 0 ||
2158                     copy_to_user(buf, &i, 1) != 0 ||
2159                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2160                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2161                         retval = (-EFAULT);
2162                         goto out;
2163                 }
2164         }
2165
2166         STps->rw = ST_READING;
2167
2168
2169         /* Loop until enough data in buffer or a special condition found */
2170         for (total = 0, special = 0; total < count && !special;) {
2171
2172                 /* Get new data if the buffer is empty */
2173                 if (STbp->buffer_bytes == 0) {
2174                         special = read_tape(STp, count - total, &SRpnt);
2175                         if (special < 0) {      /* No need to continue read */
2176                                 retval = special;
2177                                 goto out;
2178                         }
2179                 }
2180
2181                 /* Move the data from driver buffer to user buffer */
2182                 if (STbp->buffer_bytes > 0) {
2183                         DEB(
2184                         if (debugging && STps->eof != ST_NOEOF)
2185                                 st_printk(ST_DEB_MSG, STp,
2186                                           "EOF up (%d). Left %d, needed %d.\n",
2187                                           STps->eof, STbp->buffer_bytes,
2188                                           (int)(count - total));
2189                         ) /* end DEB */
2190                         transfer = STbp->buffer_bytes < count - total ?
2191                             STbp->buffer_bytes : count - total;
2192                         if (!do_dio) {
2193                                 i = from_buffer(STbp, buf, transfer);
2194                                 if (i) {
2195                                         retval = i;
2196                                         goto out;
2197                                 }
2198                         }
2199                         buf += transfer;
2200                         total += transfer;
2201                 }
2202
2203                 if (STp->block_size == 0)
2204                         break;  /* Read only one variable length block */
2205
2206         }                       /* for (total = 0, special = 0;
2207                                    total < count && !special; ) */
2208
2209         /* Change the eof state if no data from tape or buffer */
2210         if (total == 0) {
2211                 if (STps->eof == ST_FM_HIT) {
2212                         STps->eof = ST_FM;
2213                         STps->drv_block = 0;
2214                         if (STps->drv_file >= 0)
2215                                 STps->drv_file++;
2216                 } else if (STps->eof == ST_EOD_1) {
2217                         STps->eof = ST_EOD_2;
2218                         STps->drv_block = 0;
2219                         if (STps->drv_file >= 0)
2220                                 STps->drv_file++;
2221                 } else if (STps->eof == ST_EOD_2)
2222                         STps->eof = ST_EOD;
2223         } else if (STps->eof == ST_FM)
2224                 STps->eof = ST_NOEOF;
2225         retval = total;
2226
2227  out:
2228         if (SRpnt != NULL) {
2229                 st_release_request(SRpnt);
2230                 SRpnt = NULL;
2231         }
2232         if (do_dio) {
2233                 release_buffering(STp, 1);
2234                 STbp->buffer_bytes = 0;
2235         }
2236         mutex_unlock(&STp->lock);
2237
2238         return retval;
2239 }
2240 \f
2241
2242
2243 DEB(
2244 /* Set the driver options */
2245 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2246 {
2247         if (debugging) {
2248                 st_printk(KERN_INFO, STp,
2249                           "Mode %d options: buffer writes: %d, "
2250                           "async writes: %d, read ahead: %d\n",
2251                           STp->current_mode, STm->do_buffer_writes,
2252                           STm->do_async_writes, STm->do_read_ahead);
2253                 st_printk(KERN_INFO, STp,
2254                           "    can bsr: %d, two FMs: %d, "
2255                           "fast mteom: %d, auto lock: %d,\n",
2256                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2257                           STp->do_auto_lock);
2258                 st_printk(KERN_INFO, STp,
2259                           "    defs for wr: %d, no block limits: %d, "
2260                           "partitions: %d, s2 log: %d\n",
2261                           STm->defaults_for_writes, STp->omit_blklims,
2262                           STp->can_partitions, STp->scsi2_logical);
2263                 st_printk(KERN_INFO, STp,
2264                           "    sysv: %d nowait: %d sili: %d "
2265                           "nowait_filemark: %d\n",
2266                           STm->sysv, STp->immediate, STp->sili,
2267                           STp->immediate_filemark);
2268                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2269         }
2270 }
2271         )
2272
2273
2274 static int st_set_options(struct scsi_tape *STp, long options)
2275 {
2276         int value;
2277         long code;
2278         struct st_modedef *STm;
2279         struct cdev *cd0, *cd1;
2280         struct device *d0, *d1;
2281
2282         STm = &(STp->modes[STp->current_mode]);
2283         if (!STm->defined) {
2284                 cd0 = STm->cdevs[0];
2285                 cd1 = STm->cdevs[1];
2286                 d0  = STm->devs[0];
2287                 d1  = STm->devs[1];
2288                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2289                 STm->cdevs[0] = cd0;
2290                 STm->cdevs[1] = cd1;
2291                 STm->devs[0]  = d0;
2292                 STm->devs[1]  = d1;
2293                 modes_defined = 1;
2294                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2295                             STp->current_mode);
2296         }
2297
2298         code = options & MT_ST_OPTIONS;
2299         if (code == MT_ST_BOOLEANS) {
2300                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2301                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2302                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2303                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2304                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2305                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2306                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2307                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2308                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2309                 if ((STp->device)->scsi_level >= SCSI_2)
2310                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2311                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2312                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2313                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2314                 STm->sysv = (options & MT_ST_SYSV) != 0;
2315                 STp->sili = (options & MT_ST_SILI) != 0;
2316                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2317                      st_log_options(STp, STm); )
2318         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2319                 value = (code == MT_ST_SETBOOLEANS);
2320                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2321                         STm->do_buffer_writes = value;
2322                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2323                         STm->do_async_writes = value;
2324                 if ((options & MT_ST_DEF_WRITES) != 0)
2325                         STm->defaults_for_writes = value;
2326                 if ((options & MT_ST_READ_AHEAD) != 0)
2327                         STm->do_read_ahead = value;
2328                 if ((options & MT_ST_TWO_FM) != 0)
2329                         STp->two_fm = value;
2330                 if ((options & MT_ST_FAST_MTEOM) != 0)
2331                         STp->fast_mteom = value;
2332                 if ((options & MT_ST_AUTO_LOCK) != 0)
2333                         STp->do_auto_lock = value;
2334                 if ((options & MT_ST_CAN_BSR) != 0)
2335                         STp->can_bsr = value;
2336                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2337                         STp->omit_blklims = value;
2338                 if ((STp->device)->scsi_level >= SCSI_2 &&
2339                     (options & MT_ST_CAN_PARTITIONS) != 0)
2340                         STp->can_partitions = value;
2341                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2342                         STp->scsi2_logical = value;
2343                 if ((options & MT_ST_NOWAIT) != 0)
2344                         STp->immediate = value;
2345                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2346                         STp->immediate_filemark = value;
2347                 if ((options & MT_ST_SYSV) != 0)
2348                         STm->sysv = value;
2349                 if ((options & MT_ST_SILI) != 0)
2350                         STp->sili = value;
2351                 DEB(
2352                 if ((options & MT_ST_DEBUGGING) != 0)
2353                         debugging = value;
2354                         st_log_options(STp, STm); )
2355         } else if (code == MT_ST_WRITE_THRESHOLD) {
2356                 /* Retained for compatibility */
2357         } else if (code == MT_ST_DEF_BLKSIZE) {
2358                 value = (options & ~MT_ST_OPTIONS);
2359                 if (value == ~MT_ST_OPTIONS) {
2360                         STm->default_blksize = (-1);
2361                         DEBC_printk(STp, "Default block size disabled.\n");
2362                 } else {
2363                         STm->default_blksize = value;
2364                         DEBC_printk(STp,"Default block size set to "
2365                                     "%d bytes.\n", STm->default_blksize);
2366                         if (STp->ready == ST_READY) {
2367                                 STp->blksize_changed = 0;
2368                                 set_mode_densblk(STp, STm);
2369                         }
2370                 }
2371         } else if (code == MT_ST_TIMEOUTS) {
2372                 value = (options & ~MT_ST_OPTIONS);
2373                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2374                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2375                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2376                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2377                 } else {
2378                         blk_queue_rq_timeout(STp->device->request_queue,
2379                                              value * HZ);
2380                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2381                                     value);
2382                 }
2383         } else if (code == MT_ST_SET_CLN) {
2384                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2385                 if (value != 0 &&
2386                         (value < EXTENDED_SENSE_START ||
2387                                 value >= SCSI_SENSE_BUFFERSIZE))
2388                         return (-EINVAL);
2389                 STp->cln_mode = value;
2390                 STp->cln_sense_mask = (options >> 8) & 0xff;
2391                 STp->cln_sense_value = (options >> 16) & 0xff;
2392                 st_printk(KERN_INFO, STp,
2393                           "Cleaning request mode %d, mask %02x, value %02x\n",
2394                           value, STp->cln_sense_mask, STp->cln_sense_value);
2395         } else if (code == MT_ST_DEF_OPTIONS) {
2396                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2397                 value = (options & MT_ST_CLEAR_DEFAULT);
2398                 if (code == MT_ST_DEF_DENSITY) {
2399                         if (value == MT_ST_CLEAR_DEFAULT) {
2400                                 STm->default_density = (-1);
2401                                 DEBC_printk(STp,
2402                                             "Density default disabled.\n");
2403                         } else {
2404                                 STm->default_density = value & 0xff;
2405                                 DEBC_printk(STp, "Density default set to %x\n",
2406                                             STm->default_density);
2407                                 if (STp->ready == ST_READY) {
2408                                         STp->density_changed = 0;
2409                                         set_mode_densblk(STp, STm);
2410                                 }
2411                         }
2412                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2413                         if (value == MT_ST_CLEAR_DEFAULT) {
2414                                 STp->default_drvbuffer = 0xff;
2415                                 DEBC_printk(STp,
2416                                             "Drive buffer default disabled.\n");
2417                         } else {
2418                                 STp->default_drvbuffer = value & 7;
2419                                 DEBC_printk(STp,
2420                                             "Drive buffer default set to %x\n",
2421                                             STp->default_drvbuffer);
2422                                 if (STp->ready == ST_READY)
2423                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2424                         }
2425                 } else if (code == MT_ST_DEF_COMPRESSION) {
2426                         if (value == MT_ST_CLEAR_DEFAULT) {
2427                                 STm->default_compression = ST_DONT_TOUCH;
2428                                 DEBC_printk(STp,
2429                                             "Compression default disabled.\n");
2430                         } else {
2431                                 if ((value & 0xff00) != 0) {
2432                                         STp->c_algo = (value & 0xff00) >> 8;
2433                                         DEBC_printk(STp, "Compression "
2434                                                     "algorithm set to 0x%x.\n",
2435                                                     STp->c_algo);
2436                                 }
2437                                 if ((value & 0xff) != 0xff) {
2438                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2439                                         DEBC_printk(STp, "Compression default "
2440                                                     "set to %x\n",
2441                                                     (value & 1));
2442                                         if (STp->ready == ST_READY) {
2443                                                 STp->compression_changed = 0;
2444                                                 st_compression(STp, (STm->default_compression == ST_YES));
2445                                         }
2446                                 }
2447                         }
2448                 }
2449         } else
2450                 return (-EIO);
2451
2452         return 0;
2453 }
2454 \f
2455 #define MODE_HEADER_LENGTH  4
2456
2457 /* Mode header and page byte offsets */
2458 #define MH_OFF_DATA_LENGTH     0
2459 #define MH_OFF_MEDIUM_TYPE     1
2460 #define MH_OFF_DEV_SPECIFIC    2
2461 #define MH_OFF_BDESCS_LENGTH   3
2462 #define MP_OFF_PAGE_NBR        0
2463 #define MP_OFF_PAGE_LENGTH     1
2464
2465 /* Mode header and page bit masks */
2466 #define MH_BIT_WP              0x80
2467 #define MP_MSK_PAGE_NBR        0x3f
2468
2469 /* Don't return block descriptors */
2470 #define MODE_SENSE_OMIT_BDESCS 0x08
2471
2472 #define MODE_SELECT_PAGE_FORMAT 0x10
2473
2474 /* Read a mode page into the tape buffer. The block descriptors are included
2475    if incl_block_descs is true. The page control is ored to the page number
2476    parameter, if necessary. */
2477 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2478 {
2479         unsigned char cmd[MAX_COMMAND_SIZE];
2480         struct st_request *SRpnt;
2481
2482         memset(cmd, 0, MAX_COMMAND_SIZE);
2483         cmd[0] = MODE_SENSE;
2484         if (omit_block_descs)
2485                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2486         cmd[2] = page;
2487         cmd[4] = 255;
2488
2489         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2490                            STp->device->request_queue->rq_timeout, 0, 1);
2491         if (SRpnt == NULL)
2492                 return (STp->buffer)->syscall_result;
2493
2494         st_release_request(SRpnt);
2495
2496         return STp->buffer->syscall_result;
2497 }
2498
2499
2500 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2501    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2502 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2503 {
2504         int pgo;
2505         unsigned char cmd[MAX_COMMAND_SIZE];
2506         struct st_request *SRpnt;
2507         int timeout;
2508
2509         memset(cmd, 0, MAX_COMMAND_SIZE);
2510         cmd[0] = MODE_SELECT;
2511         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2512         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2513         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2514
2515         /* Clear reserved fields */
2516         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2517         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2518         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2519         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2520
2521         timeout = slow ?
2522                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2523         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2524                            timeout, 0, 1);
2525         if (SRpnt == NULL)
2526                 return (STp->buffer)->syscall_result;
2527
2528         st_release_request(SRpnt);
2529
2530         return STp->buffer->syscall_result;
2531 }
2532
2533
2534 #define COMPRESSION_PAGE        0x0f
2535 #define COMPRESSION_PAGE_LENGTH 16
2536
2537 #define CP_OFF_DCE_DCC          2
2538 #define CP_OFF_C_ALGO           7
2539
2540 #define DCE_MASK  0x80
2541 #define DCC_MASK  0x40
2542 #define RED_MASK  0x60
2543
2544
2545 /* Control the compression with mode page 15. Algorithm not changed if zero.
2546
2547    The block descriptors are read and written because Sony SDT-7000 does not
2548    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2549    Including block descriptors should not cause any harm to other drives. */
2550
2551 static int st_compression(struct scsi_tape * STp, int state)
2552 {
2553         int retval;
2554         int mpoffs;  /* Offset to mode page start */
2555         unsigned char *b_data = (STp->buffer)->b_data;
2556
2557         if (STp->ready != ST_READY)
2558                 return (-EIO);
2559
2560         /* Read the current page contents */
2561         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2562         if (retval) {
2563                 DEBC_printk(STp, "Compression mode page not supported.\n");
2564                 return (-EIO);
2565         }
2566
2567         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2568         DEBC_printk(STp, "Compression state is %d.\n",
2569                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2570
2571         /* Check if compression can be changed */
2572         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2573                 DEBC_printk(STp, "Compression not supported.\n");
2574                 return (-EIO);
2575         }
2576
2577         /* Do the change */
2578         if (state) {
2579                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2580                 if (STp->c_algo != 0)
2581                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2582         }
2583         else {
2584                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2585                 if (STp->c_algo != 0)
2586                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2587         }
2588
2589         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2590         if (retval) {
2591                 DEBC_printk(STp, "Compression change failed.\n");
2592                 return (-EIO);
2593         }
2594         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2595
2596         STp->compression_changed = 1;
2597         return 0;
2598 }
2599
2600
2601 /* Process the load and unload commands (does unload if the load code is zero) */
2602 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2603 {
2604         int retval = (-EIO), timeout;
2605         unsigned char cmd[MAX_COMMAND_SIZE];
2606         struct st_partstat *STps;
2607         struct st_request *SRpnt;
2608
2609         if (STp->ready != ST_READY && !load_code) {
2610                 if (STp->ready == ST_NO_TAPE)
2611                         return (-ENOMEDIUM);
2612                 else
2613                         return (-EIO);
2614         }
2615
2616         memset(cmd, 0, MAX_COMMAND_SIZE);
2617         cmd[0] = START_STOP;
2618         if (load_code)
2619                 cmd[4] |= 1;
2620         /*
2621          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2622          */
2623         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2624             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2625                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2626                             (cmd[4]) ? "" : "un",
2627                             load_code - MT_ST_HPLOADER_OFFSET);
2628                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2629         }
2630         if (STp->immediate) {
2631                 cmd[1] = 1;     /* Don't wait for completion */
2632                 timeout = STp->device->request_queue->rq_timeout;
2633         }
2634         else
2635                 timeout = STp->long_timeout;
2636
2637         DEBC(
2638                 if (!load_code)
2639                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2640                 else
2641                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2642                 );
2643
2644         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2645                            timeout, MAX_RETRIES, 1);
2646         if (!SRpnt)
2647                 return (STp->buffer)->syscall_result;
2648
2649         retval = (STp->buffer)->syscall_result;
2650         st_release_request(SRpnt);
2651
2652         if (!retval) {  /* SCSI command successful */
2653
2654                 if (!load_code) {
2655                         STp->rew_at_close = 0;
2656                         STp->ready = ST_NO_TAPE;
2657                 }
2658                 else {
2659                         STp->rew_at_close = STp->autorew_dev;
2660                         retval = check_tape(STp, filp);
2661                         if (retval > 0)
2662                                 retval = 0;
2663                 }
2664         }
2665         else {
2666                 STps = &(STp->ps[STp->partition]);
2667                 STps->drv_file = STps->drv_block = (-1);
2668         }
2669
2670         return retval;
2671 }
2672 \f
2673 #if DEBUG
2674 #define ST_DEB_FORWARD  0
2675 #define ST_DEB_BACKWARD 1
2676 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2677 {
2678         s32 sc;
2679
2680         if (!debugging)
2681                 return;
2682
2683         sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2684         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2685         if (direction)
2686                 sc = -sc;
2687         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2688                   direction ? "backward" : "forward", sc, units);
2689 }
2690 #else
2691 #define ST_DEB_FORWARD  0
2692 #define ST_DEB_BACKWARD 1
2693 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2694 #endif
2695
2696
2697 /* Internal ioctl function */
2698 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2699 {
2700         int timeout;
2701         long ltmp;
2702         int ioctl_result;
2703         int chg_eof = 1;
2704         unsigned char cmd[MAX_COMMAND_SIZE];
2705         struct st_request *SRpnt;
2706         struct st_partstat *STps;
2707         int fileno, blkno, at_sm, undone;
2708         int datalen = 0, direction = DMA_NONE;
2709
2710         WARN_ON(STp->buffer->do_dio != 0);
2711         if (STp->ready != ST_READY) {
2712                 if (STp->ready == ST_NO_TAPE)
2713                         return (-ENOMEDIUM);
2714                 else
2715                         return (-EIO);
2716         }
2717         timeout = STp->long_timeout;
2718         STps = &(STp->ps[STp->partition]);
2719         fileno = STps->drv_file;
2720         blkno = STps->drv_block;
2721         at_sm = STps->at_sm;
2722
2723         memset(cmd, 0, MAX_COMMAND_SIZE);
2724         switch (cmd_in) {
2725         case MTFSFM:
2726                 chg_eof = 0;    /* Changed from the FSF after this */
2727                 /* fall through */
2728         case MTFSF:
2729                 cmd[0] = SPACE;
2730                 cmd[1] = 0x01;  /* Space FileMarks */
2731                 cmd[2] = (arg >> 16);
2732                 cmd[3] = (arg >> 8);
2733                 cmd[4] = arg;
2734                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2735                 if (fileno >= 0)
2736                         fileno += arg;
2737                 blkno = 0;
2738                 at_sm &= (arg == 0);
2739                 break;
2740         case MTBSFM:
2741                 chg_eof = 0;    /* Changed from the FSF after this */
2742                 /* fall through */
2743         case MTBSF:
2744                 cmd[0] = SPACE;
2745                 cmd[1] = 0x01;  /* Space FileMarks */
2746                 ltmp = (-arg);
2747                 cmd[2] = (ltmp >> 16);
2748                 cmd[3] = (ltmp >> 8);
2749                 cmd[4] = ltmp;
2750                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2751                 if (fileno >= 0)
2752                         fileno -= arg;
2753                 blkno = (-1);   /* We can't know the block number */
2754                 at_sm &= (arg == 0);
2755                 break;
2756         case MTFSR:
2757                 cmd[0] = SPACE;
2758                 cmd[1] = 0x00;  /* Space Blocks */
2759                 cmd[2] = (arg >> 16);
2760                 cmd[3] = (arg >> 8);
2761                 cmd[4] = arg;
2762                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2763                 if (blkno >= 0)
2764                         blkno += arg;
2765                 at_sm &= (arg == 0);
2766                 break;
2767         case MTBSR:
2768                 cmd[0] = SPACE;
2769                 cmd[1] = 0x00;  /* Space Blocks */
2770                 ltmp = (-arg);
2771                 cmd[2] = (ltmp >> 16);
2772                 cmd[3] = (ltmp >> 8);
2773                 cmd[4] = ltmp;
2774                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2775                 if (blkno >= 0)
2776                         blkno -= arg;
2777                 at_sm &= (arg == 0);
2778                 break;
2779         case MTFSS:
2780                 cmd[0] = SPACE;
2781                 cmd[1] = 0x04;  /* Space Setmarks */
2782                 cmd[2] = (arg >> 16);
2783                 cmd[3] = (arg >> 8);
2784                 cmd[4] = arg;
2785                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2786                 if (arg != 0) {
2787                         blkno = fileno = (-1);
2788                         at_sm = 1;
2789                 }
2790                 break;
2791         case MTBSS:
2792                 cmd[0] = SPACE;
2793                 cmd[1] = 0x04;  /* Space Setmarks */
2794                 ltmp = (-arg);
2795                 cmd[2] = (ltmp >> 16);
2796                 cmd[3] = (ltmp >> 8);
2797                 cmd[4] = ltmp;
2798                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2799                 if (arg != 0) {
2800                         blkno = fileno = (-1);
2801                         at_sm = 1;
2802                 }
2803                 break;
2804         case MTWEOF:
2805         case MTWEOFI:
2806         case MTWSM:
2807                 if (STp->write_prot)
2808                         return (-EACCES);
2809                 cmd[0] = WRITE_FILEMARKS;
2810                 if (cmd_in == MTWSM)
2811                         cmd[1] = 2;
2812                 if (cmd_in == MTWEOFI ||
2813                     (cmd_in == MTWEOF && STp->immediate_filemark))
2814                         cmd[1] |= 1;
2815                 cmd[2] = (arg >> 16);
2816                 cmd[3] = (arg >> 8);
2817                 cmd[4] = arg;
2818                 timeout = STp->device->request_queue->rq_timeout;
2819                 DEBC(
2820                         if (cmd_in != MTWSM)
2821                                 st_printk(ST_DEB_MSG, STp,
2822                                           "Writing %d filemarks.\n",
2823                                           cmd[2] * 65536 +
2824                                           cmd[3] * 256 +
2825                                           cmd[4]);
2826                         else
2827                                 st_printk(ST_DEB_MSG, STp,
2828                                           "Writing %d setmarks.\n",
2829                                           cmd[2] * 65536 +
2830                                           cmd[3] * 256 +
2831                                           cmd[4]);
2832                 )
2833                 if (fileno >= 0)
2834                         fileno += arg;
2835                 blkno = 0;
2836                 at_sm = (cmd_in == MTWSM);
2837                 break;
2838         case MTREW:
2839                 cmd[0] = REZERO_UNIT;
2840                 if (STp->immediate) {
2841                         cmd[1] = 1;     /* Don't wait for completion */
2842                         timeout = STp->device->request_queue->rq_timeout;
2843                 }
2844                 DEBC_printk(STp, "Rewinding tape.\n");
2845                 fileno = blkno = at_sm = 0;
2846                 break;
2847         case MTNOP:
2848                 DEBC_printk(STp, "No op on tape.\n");
2849                 return 0;       /* Should do something ? */
2850                 break;
2851         case MTRETEN:
2852                 cmd[0] = START_STOP;
2853                 if (STp->immediate) {
2854                         cmd[1] = 1;     /* Don't wait for completion */
2855                         timeout = STp->device->request_queue->rq_timeout;
2856                 }
2857                 cmd[4] = 3;
2858                 DEBC_printk(STp, "Retensioning tape.\n");
2859                 fileno = blkno = at_sm = 0;
2860                 break;
2861         case MTEOM:
2862                 if (!STp->fast_mteom) {
2863                         /* space to the end of tape */
2864                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2865                         fileno = STps->drv_file;
2866                         if (STps->eof >= ST_EOD_1)
2867                                 return 0;
2868                         /* The next lines would hide the number of spaced FileMarks
2869                            That's why I inserted the previous lines. I had no luck
2870                            with detecting EOM with FSF, so we go now to EOM.
2871                            Joerg Weule */
2872                 } else
2873                         fileno = (-1);
2874                 cmd[0] = SPACE;
2875                 cmd[1] = 3;
2876                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2877                 blkno = -1;
2878                 at_sm = 0;
2879                 break;
2880         case MTERASE:
2881                 if (STp->write_prot)
2882                         return (-EACCES);
2883                 cmd[0] = ERASE;
2884                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2885                 if (STp->immediate) {
2886                         cmd[1] |= 2;    /* Don't wait for completion */
2887                         timeout = STp->device->request_queue->rq_timeout;
2888                 }
2889                 else
2890                         timeout = STp->long_timeout * 8;
2891
2892                 DEBC_printk(STp, "Erasing tape.\n");
2893                 fileno = blkno = at_sm = 0;
2894                 break;
2895         case MTSETBLK:          /* Set block length */
2896         case MTSETDENSITY:      /* Set tape density */
2897         case MTSETDRVBUFFER:    /* Set drive buffering */
2898         case SET_DENS_AND_BLK:  /* Set density and block size */
2899                 chg_eof = 0;
2900                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2901                         return (-EIO);  /* Not allowed if data in buffer */
2902                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2903                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2904                     STp->max_block > 0 &&
2905                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2906                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2907                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2908                         return (-EINVAL);
2909                 }
2910                 cmd[0] = MODE_SELECT;
2911                 if ((STp->use_pf & USE_PF))
2912                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2913                 cmd[4] = datalen = 12;
2914                 direction = DMA_TO_DEVICE;
2915
2916                 memset((STp->buffer)->b_data, 0, 12);
2917                 if (cmd_in == MTSETDRVBUFFER)
2918                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2919                 else
2920                         (STp->buffer)->b_data[2] =
2921                             STp->drv_buffer << 4;
2922                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2923                 if (cmd_in == MTSETDENSITY) {
2924                         (STp->buffer)->b_data[4] = arg;
2925                         STp->density_changed = 1;       /* At least we tried ;-) */
2926                 } else if (cmd_in == SET_DENS_AND_BLK)
2927                         (STp->buffer)->b_data[4] = arg >> 24;
2928                 else
2929                         (STp->buffer)->b_data[4] = STp->density;
2930                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2931                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2932                         if (cmd_in == MTSETBLK)
2933                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2934                 } else
2935                         ltmp = STp->block_size;
2936                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2937                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2938                 (STp->buffer)->b_data[11] = ltmp;
2939                 timeout = STp->device->request_queue->rq_timeout;
2940                 DEBC(
2941                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2942                                 st_printk(ST_DEB_MSG, STp,
2943                                           "Setting block size to %d bytes.\n",
2944                                           (STp->buffer)->b_data[9] * 65536 +
2945                                           (STp->buffer)->b_data[10] * 256 +
2946                                           (STp->buffer)->b_data[11]);
2947                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2948                                 st_printk(ST_DEB_MSG, STp,
2949                                           "Setting density code to %x.\n",
2950                                           (STp->buffer)->b_data[4]);
2951                         if (cmd_in == MTSETDRVBUFFER)
2952                                 st_printk(ST_DEB_MSG, STp,
2953                                           "Setting drive buffer code to %d.\n",
2954                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2955                 )
2956                 break;
2957         default:
2958                 return (-ENOSYS);
2959         }
2960
2961         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2962                            timeout, MAX_RETRIES, 1);
2963         if (!SRpnt)
2964                 return (STp->buffer)->syscall_result;
2965
2966         ioctl_result = (STp->buffer)->syscall_result;
2967
2968         if (!ioctl_result) {    /* SCSI command successful */
2969                 st_release_request(SRpnt);
2970                 SRpnt = NULL;
2971                 STps->drv_block = blkno;
2972                 STps->drv_file = fileno;
2973                 STps->at_sm = at_sm;
2974
2975                 if (cmd_in == MTBSFM)
2976                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2977                 else if (cmd_in == MTFSFM)
2978                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2979
2980                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2981                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2982                         if (STp->block_size != 0) {
2983                                 (STp->buffer)->buffer_blocks =
2984                                     (STp->buffer)->buffer_size / STp->block_size;
2985                         }
2986                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2987                         if (cmd_in == SET_DENS_AND_BLK)
2988                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2989                 } else if (cmd_in == MTSETDRVBUFFER)
2990                         STp->drv_buffer = (arg & 7);
2991                 else if (cmd_in == MTSETDENSITY)
2992                         STp->density = arg;
2993
2994                 if (cmd_in == MTEOM)
2995                         STps->eof = ST_EOD;
2996                 else if (cmd_in == MTFSF)
2997                         STps->eof = ST_FM;
2998                 else if (chg_eof)
2999                         STps->eof = ST_NOEOF;
3000
3001                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3002                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3003         } else { /* SCSI command was not completely successful. Don't return
3004                     from this block without releasing the SCSI command block! */
3005                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3006
3007                 if (cmdstatp->flags & SENSE_EOM) {
3008                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3009                             cmd_in != MTBSR && cmd_in != MTBSS)
3010                                 STps->eof = ST_EOM_OK;
3011                         STps->drv_block = 0;
3012                 }
3013
3014                 if (cmdstatp->remainder_valid)
3015                         undone = (int)cmdstatp->uremainder64;
3016                 else
3017                         undone = 0;
3018
3019                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3020                     cmdstatp->have_sense &&
3021                     (cmdstatp->flags & SENSE_EOM)) {
3022                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3023                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3024                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3025                                 STps->eof = ST_NOEOF;
3026                         } else {  /* Writing EOF(s) failed */
3027                                 if (fileno >= 0)
3028                                         fileno -= undone;
3029                                 if (undone < arg)
3030                                         STps->eof = ST_NOEOF;
3031                         }
3032                         STps->drv_file = fileno;
3033                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3034                         if (fileno >= 0)
3035                                 STps->drv_file = fileno - undone;
3036                         else
3037                                 STps->drv_file = fileno;
3038                         STps->drv_block = -1;
3039                         STps->eof = ST_NOEOF;
3040                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3041                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3042                                 undone = (-undone);
3043                         if (STps->drv_file >= 0)
3044                                 STps->drv_file = fileno + undone;
3045                         STps->drv_block = 0;
3046                         STps->eof = ST_NOEOF;
3047                 } else if (cmd_in == MTFSR) {
3048                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3049                                 if (STps->drv_file >= 0)
3050                                         STps->drv_file++;
3051                                 STps->drv_block = 0;
3052                                 STps->eof = ST_FM;
3053                         } else {
3054                                 if (blkno >= undone)
3055                                         STps->drv_block = blkno - undone;
3056                                 else
3057                                         STps->drv_block = (-1);
3058                                 STps->eof = ST_NOEOF;
3059                         }
3060                 } else if (cmd_in == MTBSR) {
3061                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3062                                 STps->drv_file--;
3063                                 STps->drv_block = (-1);
3064                         } else {
3065                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3066                                         undone = (-undone);
3067                                 if (STps->drv_block >= 0)
3068                                         STps->drv_block = blkno + undone;
3069                         }
3070                         STps->eof = ST_NOEOF;
3071                 } else if (cmd_in == MTEOM) {
3072                         STps->drv_file = (-1);
3073                         STps->drv_block = (-1);
3074                         STps->eof = ST_EOD;
3075                 } else if (cmd_in == MTSETBLK ||
3076                            cmd_in == MTSETDENSITY ||
3077                            cmd_in == MTSETDRVBUFFER ||
3078                            cmd_in == SET_DENS_AND_BLK) {
3079                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3080                             !(STp->use_pf & PF_TESTED)) {
3081                                 /* Try the other possible state of Page Format if not
3082                                    already tried */
3083                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3084                                 st_release_request(SRpnt);
3085                                 SRpnt = NULL;
3086                                 return st_int_ioctl(STp, cmd_in, arg);
3087                         }
3088                 } else if (chg_eof)
3089                         STps->eof = ST_NOEOF;
3090
3091                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3092                         STps->eof = ST_EOD;
3093
3094                 st_release_request(SRpnt);
3095                 SRpnt = NULL;
3096         }
3097
3098         return ioctl_result;
3099 }
3100 \f
3101
3102 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3103    structure. */
3104
3105 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3106                         int logical)
3107 {
3108         int result;
3109         unsigned char scmd[MAX_COMMAND_SIZE];
3110         struct st_request *SRpnt;
3111
3112         if (STp->ready != ST_READY)
3113                 return (-EIO);
3114
3115         memset(scmd, 0, MAX_COMMAND_SIZE);
3116         if ((STp->device)->scsi_level < SCSI_2) {
3117                 scmd[0] = QFA_REQUEST_BLOCK;
3118                 scmd[4] = 3;
3119         } else {
3120                 scmd[0] = READ_POSITION;
3121                 if (!logical && !STp->scsi2_logical)
3122                         scmd[1] = 1;
3123         }
3124         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3125                            STp->device->request_queue->rq_timeout,
3126                            MAX_READY_RETRIES, 1);
3127         if (!SRpnt)
3128                 return (STp->buffer)->syscall_result;
3129
3130         if ((STp->buffer)->syscall_result != 0 ||
3131             (STp->device->scsi_level >= SCSI_2 &&
3132              ((STp->buffer)->b_data[0] & 4) != 0)) {
3133                 *block = *partition = 0;
3134                 DEBC_printk(STp, " Can't read tape position.\n");
3135                 result = (-EIO);
3136         } else {
3137                 result = 0;
3138                 if ((STp->device)->scsi_level < SCSI_2) {
3139                         *block = ((STp->buffer)->b_data[0] << 16)
3140                             + ((STp->buffer)->b_data[1] << 8)
3141                             + (STp->buffer)->b_data[2];
3142                         *partition = 0;
3143                 } else {
3144                         *block = ((STp->buffer)->b_data[4] << 24)
3145                             + ((STp->buffer)->b_data[5] << 16)
3146                             + ((STp->buffer)->b_data[6] << 8)
3147                             + (STp->buffer)->b_data[7];
3148                         *partition = (STp->buffer)->b_data[1];
3149                         if (((STp->buffer)->b_data[0] & 0x80) &&
3150                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3151                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3152                 }
3153                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3154                             *block, *partition);
3155         }
3156         st_release_request(SRpnt);
3157         SRpnt = NULL;
3158
3159         return result;
3160 }
3161
3162
3163 /* Set the tape block and partition. Negative partition means that only the
3164    block should be set in vendor specific way. */
3165 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3166                         int logical)
3167 {
3168         struct st_partstat *STps;
3169         int result, p;
3170         unsigned int blk;
3171         int timeout;
3172         unsigned char scmd[MAX_COMMAND_SIZE];
3173         struct st_request *SRpnt;
3174
3175         if (STp->ready != ST_READY)
3176                 return (-EIO);
3177         timeout = STp->long_timeout;
3178         STps = &(STp->ps[STp->partition]);
3179
3180         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3181                     block, partition);
3182         DEB(if (partition < 0)
3183                 return (-EIO); )
3184
3185         /* Update the location at the partition we are leaving */
3186         if ((!STp->can_partitions && partition != 0) ||
3187             partition >= ST_NBR_PARTITIONS)
3188                 return (-EINVAL);
3189         if (partition != STp->partition) {
3190                 if (get_location(STp, &blk, &p, 1))
3191                         STps->last_block_valid = 0;
3192                 else {
3193                         STps->last_block_valid = 1;
3194                         STps->last_block_visited = blk;
3195                         DEBC_printk(STp, "Visited block %d for "
3196                                     "partition %d saved.\n",
3197                                     blk, STp->partition);
3198                 }
3199         }
3200
3201         memset(scmd, 0, MAX_COMMAND_SIZE);
3202         if ((STp->device)->scsi_level < SCSI_2) {
3203                 scmd[0] = QFA_SEEK_BLOCK;
3204                 scmd[2] = (block >> 16);
3205                 scmd[3] = (block >> 8);
3206                 scmd[4] = block;
3207                 scmd[5] = 0;
3208         } else {
3209                 scmd[0] = SEEK_10;
3210                 scmd[3] = (block >> 24);
3211                 scmd[4] = (block >> 16);
3212                 scmd[5] = (block >> 8);
3213                 scmd[6] = block;
3214                 if (!logical && !STp->scsi2_logical)
3215                         scmd[1] = 4;
3216                 if (STp->partition != partition) {
3217                         scmd[1] |= 2;
3218                         scmd[8] = partition;
3219                         DEBC_printk(STp, "Trying to change partition "
3220                                     "from %d to %d\n", STp->partition,
3221                                     partition);
3222                 }
3223         }
3224         if (STp->immediate) {
3225                 scmd[1] |= 1;           /* Don't wait for completion */
3226                 timeout = STp->device->request_queue->rq_timeout;
3227         }
3228
3229         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3230                            timeout, MAX_READY_RETRIES, 1);
3231         if (!SRpnt)
3232                 return (STp->buffer)->syscall_result;
3233
3234         STps->drv_block = STps->drv_file = (-1);
3235         STps->eof = ST_NOEOF;
3236         if ((STp->buffer)->syscall_result != 0) {
3237                 result = (-EIO);
3238                 if (STp->can_partitions &&
3239                     (STp->device)->scsi_level >= SCSI_2 &&
3240                     (p = find_partition(STp)) >= 0)
3241                         STp->partition = p;
3242         } else {
3243                 if (STp->can_partitions) {
3244                         STp->partition = partition;
3245                         STps = &(STp->ps[partition]);
3246                         if (!STps->last_block_valid ||
3247                             STps->last_block_visited != block) {
3248                                 STps->at_sm = 0;
3249                                 STps->rw = ST_IDLE;
3250                         }
3251                 } else
3252                         STps->at_sm = 0;
3253                 if (block == 0)
3254                         STps->drv_block = STps->drv_file = 0;
3255                 result = 0;
3256         }
3257
3258         st_release_request(SRpnt);
3259         SRpnt = NULL;
3260
3261         return result;
3262 }
3263
3264
3265 /* Find the current partition number for the drive status. Called from open and
3266    returns either partition number of negative error code. */
3267 static int find_partition(struct scsi_tape *STp)
3268 {
3269         int i, partition;
3270         unsigned int block;
3271
3272         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3273                 return i;
3274         if (partition >= ST_NBR_PARTITIONS)
3275                 return (-EIO);
3276         return partition;
3277 }
3278
3279
3280 /* Change the partition if necessary */
3281 static int switch_partition(struct scsi_tape *STp)
3282 {
3283         struct st_partstat *STps;
3284
3285         if (STp->partition == STp->new_partition)
3286                 return 0;
3287         STps = &(STp->ps[STp->new_partition]);
3288         if (!STps->last_block_valid)
3289                 STps->last_block_visited = 0;
3290         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3291 }
3292 \f
3293 /* Functions for reading and writing the medium partition mode page. */
3294
3295 #define PART_PAGE   0x11
3296 #define PART_PAGE_FIXED_LENGTH 8
3297
3298 #define PP_OFF_MAX_ADD_PARTS   2
3299 #define PP_OFF_NBR_ADD_PARTS   3
3300 #define PP_OFF_FLAGS           4
3301 #define PP_OFF_PART_UNITS      6
3302 #define PP_OFF_RESERVED        7
3303
3304 #define PP_BIT_IDP             0x20
3305 #define PP_BIT_FDP             0x80
3306 #define PP_MSK_PSUM_MB         0x10
3307 #define PP_MSK_PSUM_UNITS      0x18
3308 #define PP_MSK_POFM            0x04
3309
3310 /* Get the number of partitions on the tape. As a side effect reads the
3311    mode page into the tape buffer. */
3312 static int nbr_partitions(struct scsi_tape *STp)
3313 {
3314         int result;
3315
3316         if (STp->ready != ST_READY)
3317                 return (-EIO);
3318
3319         result = read_mode_page(STp, PART_PAGE, 1);
3320
3321         if (result) {
3322                 DEBC_printk(STp, "Can't read medium partition page.\n");
3323                 result = (-EIO);
3324         } else {
3325                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3326                                               PP_OFF_NBR_ADD_PARTS] + 1;
3327                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3328         }
3329
3330         return result;
3331 }
3332
3333
3334 static int format_medium(struct scsi_tape *STp, int format)
3335 {
3336         int result = 0;
3337         int timeout = STp->long_timeout;
3338         unsigned char scmd[MAX_COMMAND_SIZE];
3339         struct st_request *SRpnt;
3340
3341         memset(scmd, 0, MAX_COMMAND_SIZE);
3342         scmd[0] = FORMAT_UNIT;
3343         scmd[2] = format;
3344         if (STp->immediate) {
3345                 scmd[1] |= 1;           /* Don't wait for completion */
3346                 timeout = STp->device->request_queue->rq_timeout;
3347         }
3348         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3349         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3350                            timeout, MAX_RETRIES, 1);
3351         if (!SRpnt)
3352                 result = STp->buffer->syscall_result;
3353         return result;
3354 }
3355
3356
3357 /* Partition the tape into two partitions if size > 0 or one partition if
3358    size == 0.
3359
3360    The block descriptors are read and written because Sony SDT-7000 does not
3361    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3362
3363    My HP C1533A drive returns only one partition size field. This is used to
3364    set the size of partition 1. There is no size field for the default partition.
3365    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3366    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3367    The following algorithm is used to accommodate both drives: if the number of
3368    partition size fields is greater than the maximum number of additional partitions
3369    in the mode page, the second field is used. Otherwise the first field is used.
3370
3371    For Seagate DDS drives the page length must be 8 when no partitions is defined
3372    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3373    is acceptable also to some other old drives and enforced if the first partition
3374    size field is used for the first additional partition size.
3375
3376    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3377  */
3378 static int partition_tape(struct scsi_tape *STp, int size)
3379 {
3380         int result;
3381         int target_partition;
3382         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3383         int pgo, psd_cnt, psdo;
3384         int psum = PP_MSK_PSUM_MB, units = 0;
3385         unsigned char *bp;
3386
3387         result = read_mode_page(STp, PART_PAGE, 0);
3388         if (result) {
3389                 DEBC_printk(STp, "Can't read partition mode page.\n");
3390                 return result;
3391         }
3392         target_partition = 1;
3393         if (size < 0) {
3394                 target_partition = 0;
3395                 size = -size;
3396         }
3397
3398         /* The mode page is in the buffer. Let's modify it and write it. */
3399         bp = (STp->buffer)->b_data;
3400         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3401         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3402                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3403
3404         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3405
3406         if (scsi3) {
3407                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3408                 if (needs_format && size == 0) {
3409                         /* No need to write the mode page when clearing
3410                          *  partitioning
3411                          */
3412                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3413                         result = format_medium(STp, 0);
3414                         goto out;
3415                 }
3416                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3417                         psd_cnt = 2;
3418                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3419                         /* Use units scaling for large partitions if the device
3420                          * suggests it and no precision lost. Required for IBM
3421                          * TS1140/50 drives that don't support MB units.
3422                          */
3423                         if (size >= 1000 && (size % 1000) == 0) {
3424                                 size /= 1000;
3425                                 psum = PP_MSK_PSUM_UNITS;
3426                                 units = 9; /* GB */
3427                         }
3428                 }
3429                 /* Try it anyway if too large to specify in MB */
3430                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3431                         size /= 1000;
3432                         psum = PP_MSK_PSUM_UNITS;
3433                         units = 9;  /* GB */
3434                 }
3435         }
3436
3437         if (size >= 65535 ||  /* Does not fit into two bytes */
3438             (target_partition == 0 && psd_cnt < 2)) {
3439                 result = -EINVAL;
3440                 goto out;
3441         }
3442
3443         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3444         /* The second condition is for HP DDS which use only one partition size
3445          * descriptor
3446          */
3447         if (target_partition > 0 &&
3448             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3449              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3450                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3451                 psdo += 2;
3452         }
3453         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3454
3455         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3456                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3457                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3458
3459         if (size == 0) {
3460                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3461                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3462                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3463                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3464         } else {
3465                 bp[psdo] = (size >> 8) & 0xff;
3466                 bp[psdo + 1] = size & 0xff;
3467                 if (target_partition == 0)
3468                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3469                 bp[pgo + 3] = 1;
3470                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3471                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3472                 DEBC_printk(STp,
3473                             "Formatting tape with two partitions (%i = %d MB).\n",
3474                             target_partition, units > 0 ? size * 1000 : size);
3475         }
3476         bp[pgo + PP_OFF_PART_UNITS] = 0;
3477         bp[pgo + PP_OFF_RESERVED] = 0;
3478         if (size != 1 || units != 0) {
3479                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3480                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3481                 bp[pgo + PP_OFF_PART_UNITS] = units;
3482         } else
3483                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3484                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3485         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3486
3487         result = write_mode_page(STp, PART_PAGE, 1);
3488
3489         if (!result && needs_format)
3490                 result = format_medium(STp, 1);
3491
3492         if (result) {
3493                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3494                 result = (-EIO);
3495         }
3496
3497 out:
3498         return result;
3499 }
3500 \f
3501
3502
3503 /* The ioctl command */
3504 static long st_ioctl_common(struct file *file, unsigned int cmd_in, void __user *p)
3505 {
3506         int i, cmd_nr, cmd_type, bt;
3507         int retval = 0;
3508         unsigned int blk;
3509         struct scsi_tape *STp = file->private_data;
3510         struct st_modedef *STm;
3511         struct st_partstat *STps;
3512
3513         if (mutex_lock_interruptible(&STp->lock))
3514                 return -ERESTARTSYS;
3515
3516         DEB(
3517         if (debugging && !STp->in_use) {
3518                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3519                 retval = (-EIO);
3520                 goto out;
3521         } ) /* end DEB */
3522
3523         STm = &(STp->modes[STp->current_mode]);
3524         STps = &(STp->ps[STp->partition]);
3525
3526         /*
3527          * If we are in the middle of error recovery, don't let anyone
3528          * else try and use this device.  Also, if error recovery fails, it
3529          * may try and take the device offline, in which case all further
3530          * access to the device is prohibited.
3531          */
3532         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3533                         file->f_flags & O_NDELAY);
3534         if (retval)
3535                 goto out;
3536
3537         cmd_type = _IOC_TYPE(cmd_in);
3538         cmd_nr = _IOC_NR(cmd_in);
3539
3540         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3541                 struct mtop mtc;
3542
3543                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3544                         retval = (-EINVAL);
3545                         goto out;
3546                 }
3547
3548                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3549                 if (i) {
3550                         retval = (-EFAULT);
3551                         goto out;
3552                 }
3553
3554                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3555                         st_printk(KERN_WARNING, STp,
3556                                   "MTSETDRVBUFFER only allowed for root.\n");
3557                         retval = (-EPERM);
3558                         goto out;
3559                 }
3560                 if (!STm->defined &&
3561                     (mtc.mt_op != MTSETDRVBUFFER &&
3562                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3563                         retval = (-ENXIO);
3564                         goto out;
3565                 }
3566
3567                 if (!STp->pos_unknown) {
3568
3569                         if (STps->eof == ST_FM_HIT) {
3570                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3571                                     mtc.mt_op == MTEOM) {
3572                                         mtc.mt_count -= 1;
3573                                         if (STps->drv_file >= 0)
3574                                                 STps->drv_file += 1;
3575                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3576                                         mtc.mt_count += 1;
3577                                         if (STps->drv_file >= 0)
3578                                                 STps->drv_file += 1;
3579                                 }
3580                         }
3581
3582                         if (mtc.mt_op == MTSEEK) {
3583                                 /* Old position must be restored if partition will be
3584                                    changed */
3585                                 i = !STp->can_partitions ||
3586                                     (STp->new_partition != STp->partition);
3587                         } else {
3588                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3589                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3590                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3591                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3592                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3593                                     mtc.mt_op == MTCOMPRESSION;
3594                         }
3595                         i = flush_buffer(STp, i);
3596                         if (i < 0) {
3597                                 retval = i;
3598                                 goto out;
3599                         }
3600                         if (STps->rw == ST_WRITING &&
3601                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3602                              mtc.mt_op == MTSEEK ||
3603                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3604                                 i = st_int_ioctl(STp, MTWEOF, 1);
3605                                 if (i < 0) {
3606                                         retval = i;
3607                                         goto out;
3608                                 }
3609                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3610                                         mtc.mt_count++;
3611                                 STps->rw = ST_IDLE;
3612                              }
3613
3614                 } else {
3615                         /*
3616                          * If there was a bus reset, block further access
3617                          * to this device.  If the user wants to rewind the tape,
3618                          * then reset the flag and allow access again.
3619                          */
3620                         if (mtc.mt_op != MTREW &&
3621                             mtc.mt_op != MTOFFL &&
3622                             mtc.mt_op != MTRETEN &&
3623                             mtc.mt_op != MTERASE &&
3624                             mtc.mt_op != MTSEEK &&
3625                             mtc.mt_op != MTEOM) {
3626                                 retval = (-EIO);
3627                                 goto out;
3628                         }
3629                         reset_state(STp);
3630                         /* remove this when the midlevel properly clears was_reset */
3631                         STp->device->was_reset = 0;
3632                 }
3633
3634                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3635                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3636                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3637                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3638
3639                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3640                         do_door_lock(STp, 0);   /* Ignore result! */
3641
3642                 if (mtc.mt_op == MTSETDRVBUFFER &&
3643                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3644                         retval = st_set_options(STp, mtc.mt_count);
3645                         goto out;
3646                 }
3647
3648                 if (mtc.mt_op == MTSETPART) {
3649                         if (!STp->can_partitions ||
3650                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3651                                 retval = (-EINVAL);
3652                                 goto out;
3653                         }
3654                         if (mtc.mt_count >= STp->nbr_partitions &&
3655                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3656                                 retval = (-EIO);
3657                                 goto out;
3658                         }
3659                         if (mtc.mt_count >= STp->nbr_partitions) {
3660                                 retval = (-EINVAL);
3661                                 goto out;
3662                         }
3663                         STp->new_partition = mtc.mt_count;
3664                         retval = 0;
3665                         goto out;
3666                 }
3667
3668                 if (mtc.mt_op == MTMKPART) {
3669                         if (!STp->can_partitions) {
3670                                 retval = (-EINVAL);
3671                                 goto out;
3672                         }
3673                         i = do_load_unload(STp, file, 1);
3674                         if (i < 0) {
3675                                 retval = i;
3676                                 goto out;
3677                         }
3678                         i = partition_tape(STp, mtc.mt_count);
3679                         if (i < 0) {
3680                                 retval = i;
3681                                 goto out;
3682                         }
3683                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3684                                 STp->ps[i].rw = ST_IDLE;
3685                                 STp->ps[i].at_sm = 0;
3686                                 STp->ps[i].last_block_valid = 0;
3687                         }
3688                         STp->partition = STp->new_partition = 0;
3689                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3690                         STps->drv_block = STps->drv_file = 0;
3691                         retval = 0;
3692                         goto out;
3693                 }
3694
3695                 if (mtc.mt_op == MTSEEK) {
3696                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3697                         if (!STp->can_partitions)
3698                                 STp->ps[0].rw = ST_IDLE;
3699                         retval = i;
3700                         goto out;
3701                 }
3702
3703                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3704                         retval = do_load_unload(STp, file, 0);
3705                         goto out;
3706                 }
3707
3708                 if (mtc.mt_op == MTLOAD) {
3709                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3710                         goto out;
3711                 }
3712
3713                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3714                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3715                         goto out;
3716                 }
3717
3718                 if (STp->can_partitions && STp->ready == ST_READY &&
3719                     (i = switch_partition(STp)) < 0) {
3720                         retval = i;
3721                         goto out;
3722                 }
3723
3724                 if (mtc.mt_op == MTCOMPRESSION)
3725                         retval = st_compression(STp, (mtc.mt_count & 1));
3726                 else
3727                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3728                 goto out;
3729         }
3730         if (!STm->defined) {
3731                 retval = (-ENXIO);
3732                 goto out;
3733         }
3734
3735         if ((i = flush_buffer(STp, 0)) < 0) {
3736                 retval = i;
3737                 goto out;
3738         }
3739         if (STp->can_partitions &&
3740             (i = switch_partition(STp)) < 0) {
3741                 retval = i;
3742                 goto out;
3743         }
3744
3745         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3746                 struct mtget mt_status;
3747
3748                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3749                          retval = (-EINVAL);
3750                          goto out;
3751                 }
3752
3753                 mt_status.mt_type = STp->tape_type;
3754                 mt_status.mt_dsreg =
3755                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3756                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3757                 mt_status.mt_blkno = STps->drv_block;
3758                 mt_status.mt_fileno = STps->drv_file;
3759                 if (STp->block_size != 0) {
3760                         if (STps->rw == ST_WRITING)
3761                                 mt_status.mt_blkno +=
3762                                     (STp->buffer)->buffer_bytes / STp->block_size;
3763                         else if (STps->rw == ST_READING)
3764                                 mt_status.mt_blkno -=
3765                                         ((STp->buffer)->buffer_bytes +
3766                                          STp->block_size - 1) / STp->block_size;
3767                 }
3768
3769                 mt_status.mt_gstat = 0;
3770                 if (STp->drv_write_prot)
3771                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3772                 if (mt_status.mt_blkno == 0) {
3773                         if (mt_status.mt_fileno == 0)
3774                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3775                         else
3776                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3777                 }
3778                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3779                 mt_status.mt_resid = STp->partition;
3780                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3781                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3782                 else if (STps->eof >= ST_EOM_OK)
3783                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3784                 if (STp->density == 1)
3785                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3786                 else if (STp->density == 2)
3787                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3788                 else if (STp->density == 3)
3789                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3790                 if (STp->ready == ST_READY)
3791                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3792                 if (STp->ready == ST_NO_TAPE)
3793                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3794                 if (STps->at_sm)
3795                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3796                 if (STm->do_async_writes ||
3797                     (STm->do_buffer_writes && STp->block_size != 0) ||
3798                     STp->drv_buffer != 0)
3799                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3800                 if (STp->cleaning_req)
3801                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3802
3803                 retval = put_user_mtget(p, &mt_status);
3804                 if (retval)
3805                         goto out;
3806
3807                 STp->recover_reg = 0;           /* Clear after read */
3808                 goto out;
3809         }                       /* End of MTIOCGET */
3810         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3811                 struct mtpos mt_pos;
3812                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3813                          retval = (-EINVAL);
3814                          goto out;
3815                 }
3816                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3817                         retval = i;
3818                         goto out;
3819                 }
3820                 mt_pos.mt_blkno = blk;
3821                 retval = put_user_mtpos(p, &mt_pos);
3822                 goto out;
3823         }
3824         mutex_unlock(&STp->lock);
3825         switch (cmd_in) {
3826                 case SCSI_IOCTL_STOP_UNIT:
3827                         /* unload */
3828                         retval = scsi_ioctl(STp->device, cmd_in, p);
3829                         if (!retval) {
3830                                 STp->rew_at_close = 0;
3831                                 STp->ready = ST_NO_TAPE;
3832                         }
3833                         return retval;
3834
3835                 case SCSI_IOCTL_GET_IDLUN:
3836                 case SCSI_IOCTL_GET_BUS_NUMBER:
3837                         break;
3838
3839                 default:
3840                         if ((cmd_in == SG_IO ||
3841                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3842                              cmd_in == CDROM_SEND_PACKET) &&
3843                             !capable(CAP_SYS_RAWIO))
3844                                 i = -EPERM;
3845                         else
3846                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3847                                                    file->f_mode, cmd_in, p);
3848                         if (i != -ENOTTY)
3849                                 return i;
3850                         break;
3851         }
3852         return -ENOTTY;
3853
3854  out:
3855         mutex_unlock(&STp->lock);
3856         return retval;
3857 }
3858
3859 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3860 {
3861         void __user *p = (void __user *)arg;
3862         struct scsi_tape *STp = file->private_data;
3863         int ret;
3864
3865         ret = st_ioctl_common(file, cmd_in, p);
3866         if (ret != -ENOTTY)
3867                 return ret;
3868
3869         return scsi_ioctl(STp->device, cmd_in, p);
3870 }
3871
3872 #ifdef CONFIG_COMPAT
3873 static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3874 {
3875         void __user *p = compat_ptr(arg);
3876         struct scsi_tape *STp = file->private_data;
3877         int ret;
3878
3879         /* argument conversion is handled using put_user_mtpos/put_user_mtget */
3880         switch (cmd_in) {
3881         case MTIOCPOS32:
3882                 return st_ioctl_common(file, MTIOCPOS, p);
3883         case MTIOCGET32:
3884                 return st_ioctl_common(file, MTIOCGET, p);
3885         }
3886
3887         ret = st_ioctl_common(file, cmd_in, p);
3888         if (ret != -ENOTTY)
3889                 return ret;
3890
3891         return scsi_compat_ioctl(STp->device, cmd_in, p);
3892 }
3893 #endif
3894
3895 \f
3896
3897 /* Try to allocate a new tape buffer. Calling function must not hold
3898    dev_arr_lock. */
3899 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3900 {
3901         struct st_buffer *tb;
3902
3903         tb = kzalloc(sizeof(struct st_buffer), GFP_KERNEL);
3904         if (!tb) {
3905                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3906                 return NULL;
3907         }
3908         tb->frp_segs = 0;
3909         tb->use_sg = max_sg;
3910         tb->dma = need_dma;
3911         tb->buffer_size = 0;
3912
3913         tb->reserved_pages = kcalloc(max_sg, sizeof(struct page *),
3914                                      GFP_KERNEL);
3915         if (!tb->reserved_pages) {
3916                 kfree(tb);
3917                 return NULL;
3918         }
3919
3920         return tb;
3921 }
3922
3923
3924 /* Try to allocate enough space in the tape buffer */
3925 #define ST_MAX_ORDER 6
3926
3927 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3928 {
3929         int segs, max_segs, b_size, order, got;
3930         gfp_t priority;
3931
3932         if (new_size <= STbuffer->buffer_size)
3933                 return 1;
3934
3935         if (STbuffer->buffer_size <= PAGE_SIZE)
3936                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3937
3938         max_segs = STbuffer->use_sg;
3939
3940         priority = GFP_KERNEL | __GFP_NOWARN;
3941         if (need_dma)
3942                 priority |= GFP_DMA;
3943
3944         if (STbuffer->cleared)
3945                 priority |= __GFP_ZERO;
3946
3947         if (STbuffer->frp_segs) {
3948                 order = STbuffer->reserved_page_order;
3949                 b_size = PAGE_SIZE << order;
3950         } else {
3951                 for (b_size = PAGE_SIZE, order = 0;
3952                      order < ST_MAX_ORDER &&
3953                              max_segs * (PAGE_SIZE << order) < new_size;
3954                      order++, b_size *= 2)
3955                         ;  /* empty */
3956                 STbuffer->reserved_page_order = order;
3957         }
3958         if (max_segs * (PAGE_SIZE << order) < new_size) {
3959                 if (order == ST_MAX_ORDER)
3960                         return 0;
3961                 normalize_buffer(STbuffer);
3962                 return enlarge_buffer(STbuffer, new_size, need_dma);
3963         }
3964
3965         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3966              segs < max_segs && got < new_size;) {
3967                 struct page *page;
3968
3969                 page = alloc_pages(priority, order);
3970                 if (!page) {
3971                         DEB(STbuffer->buffer_size = got);
3972                         normalize_buffer(STbuffer);
3973                         return 0;
3974                 }
3975
3976                 STbuffer->frp_segs += 1;
3977                 got += b_size;
3978                 STbuffer->buffer_size = got;
3979                 STbuffer->reserved_pages[segs] = page;
3980                 segs++;
3981         }
3982         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3983
3984         return 1;
3985 }
3986
3987
3988 /* Make sure that no data from previous user is in the internal buffer */
3989 static void clear_buffer(struct st_buffer * st_bp)
3990 {
3991         int i;
3992
3993         for (i=0; i < st_bp->frp_segs; i++)
3994                 memset(page_address(st_bp->reserved_pages[i]), 0,
3995                        PAGE_SIZE << st_bp->reserved_page_order);
3996         st_bp->cleared = 1;
3997 }
3998
3999
4000 /* Release the extra buffer */
4001 static void normalize_buffer(struct st_buffer * STbuffer)
4002 {
4003         int i, order = STbuffer->reserved_page_order;
4004
4005         for (i = 0; i < STbuffer->frp_segs; i++) {
4006                 __free_pages(STbuffer->reserved_pages[i], order);
4007                 STbuffer->buffer_size -= (PAGE_SIZE << order);
4008         }
4009         STbuffer->frp_segs = 0;
4010         STbuffer->sg_segs = 0;
4011         STbuffer->reserved_page_order = 0;
4012         STbuffer->map_data.offset = 0;
4013 }
4014
4015
4016 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
4017    negative error code. */
4018 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
4019 {
4020         int i, cnt, res, offset;
4021         int length = PAGE_SIZE << st_bp->reserved_page_order;
4022
4023         for (i = 0, offset = st_bp->buffer_bytes;
4024              i < st_bp->frp_segs && offset >= length; i++)
4025                 offset -= length;
4026         if (i == st_bp->frp_segs) {     /* Should never happen */
4027                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4028                 return (-EIO);
4029         }
4030         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4031                 struct page *page = st_bp->reserved_pages[i];
4032                 cnt = length - offset < do_count ? length - offset : do_count;
4033                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4034                 if (res)
4035                         return (-EFAULT);
4036                 do_count -= cnt;
4037                 st_bp->buffer_bytes += cnt;
4038                 ubp += cnt;
4039                 offset = 0;
4040         }
4041         if (do_count) /* Should never happen */
4042                 return (-EIO);
4043
4044         return 0;
4045 }
4046
4047
4048 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4049    negative error code. */
4050 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4051 {
4052         int i, cnt, res, offset;
4053         int length = PAGE_SIZE << st_bp->reserved_page_order;
4054
4055         for (i = 0, offset = st_bp->read_pointer;
4056              i < st_bp->frp_segs && offset >= length; i++)
4057                 offset -= length;
4058         if (i == st_bp->frp_segs) {     /* Should never happen */
4059                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4060                 return (-EIO);
4061         }
4062         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4063                 struct page *page = st_bp->reserved_pages[i];
4064                 cnt = length - offset < do_count ? length - offset : do_count;
4065                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4066                 if (res)
4067                         return (-EFAULT);
4068                 do_count -= cnt;
4069                 st_bp->buffer_bytes -= cnt;
4070                 st_bp->read_pointer += cnt;
4071                 ubp += cnt;
4072                 offset = 0;
4073         }
4074         if (do_count) /* Should never happen */
4075                 return (-EIO);
4076
4077         return 0;
4078 }
4079
4080
4081 /* Move data towards start of buffer */
4082 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4083 {
4084         int src_seg, dst_seg, src_offset = 0, dst_offset;
4085         int count, total;
4086         int length = PAGE_SIZE << st_bp->reserved_page_order;
4087
4088         if (offset == 0)
4089                 return;
4090
4091         total=st_bp->buffer_bytes - offset;
4092         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4093                 src_offset = offset;
4094                 if (src_offset < length)
4095                         break;
4096                 offset -= length;
4097         }
4098
4099         st_bp->buffer_bytes = st_bp->read_pointer = total;
4100         for (dst_seg=dst_offset=0; total > 0; ) {
4101                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4102                 struct page *spage = st_bp->reserved_pages[src_seg];
4103
4104                 count = min(length - dst_offset, length - src_offset);
4105                 memmove(page_address(dpage) + dst_offset,
4106                         page_address(spage) + src_offset, count);
4107                 src_offset += count;
4108                 if (src_offset >= length) {
4109                         src_seg++;
4110                         src_offset = 0;
4111                 }
4112                 dst_offset += count;
4113                 if (dst_offset >= length) {
4114                         dst_seg++;
4115                         dst_offset = 0;
4116                 }
4117                 total -= count;
4118         }
4119 }
4120
4121 /* Validate the options from command line or module parameters */
4122 static void validate_options(void)
4123 {
4124         if (buffer_kbs > 0)
4125                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4126         if (max_sg_segs >= ST_FIRST_SG)
4127                 st_max_sg_segs = max_sg_segs;
4128 }
4129
4130 #ifndef MODULE
4131 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4132  */
4133 static int __init st_setup(char *str)
4134 {
4135         int i, len, ints[5];
4136         char *stp;
4137
4138         stp = get_options(str, ARRAY_SIZE(ints), ints);
4139
4140         if (ints[0] > 0) {
4141                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4142                         if (parms[i].val)
4143                                 *parms[i].val = ints[i + 1];
4144         } else {
4145                 while (stp != NULL) {
4146                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4147                                 len = strlen(parms[i].name);
4148                                 if (!strncmp(stp, parms[i].name, len) &&
4149                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4150                                         if (parms[i].val)
4151                                                 *parms[i].val =
4152                                                         simple_strtoul(stp + len + 1, NULL, 0);
4153                                         else
4154                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4155                                                        parms[i].name);
4156                                         break;
4157                                 }
4158                         }
4159                         if (i >= ARRAY_SIZE(parms))
4160                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4161                                         stp);
4162                         stp = strchr(stp, ',');
4163                         if (stp)
4164                                 stp++;
4165                 }
4166         }
4167
4168         validate_options();
4169
4170         return 1;
4171 }
4172
4173 __setup("st=", st_setup);
4174
4175 #endif
4176
4177 static const struct file_operations st_fops =
4178 {
4179         .owner =        THIS_MODULE,
4180         .read =         st_read,
4181         .write =        st_write,
4182         .unlocked_ioctl = st_ioctl,
4183 #ifdef CONFIG_COMPAT
4184         .compat_ioctl = st_compat_ioctl,
4185 #endif
4186         .open =         st_open,
4187         .flush =        st_flush,
4188         .release =      st_release,
4189         .llseek =       noop_llseek,
4190 };
4191
4192 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4193 {
4194         int i, error;
4195         dev_t cdev_devno;
4196         struct cdev *cdev;
4197         struct device *dev;
4198         struct st_modedef *STm = &(tape->modes[mode]);
4199         char name[10];
4200         int dev_num = tape->index;
4201
4202         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4203
4204         cdev = cdev_alloc();
4205         if (!cdev) {
4206                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4207                 error = -ENOMEM;
4208                 goto out;
4209         }
4210         cdev->owner = THIS_MODULE;
4211         cdev->ops = &st_fops;
4212         STm->cdevs[rew] = cdev;
4213
4214         error = cdev_add(cdev, cdev_devno, 1);
4215         if (error) {
4216                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4217                        rew ? "non" : "auto", mode);
4218                 pr_err("st%d: Device not attached.\n", dev_num);
4219                 goto out_free;
4220         }
4221
4222         i = mode << (4 - ST_NBR_MODE_BITS);
4223         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4224                  tape->disk->disk_name, st_formats[i]);
4225
4226         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4227                             cdev_devno, &tape->modes[mode], "%s", name);
4228         if (IS_ERR(dev)) {
4229                 pr_err("st%d: device_create failed\n", dev_num);
4230                 error = PTR_ERR(dev);
4231                 goto out_free;
4232         }
4233
4234         STm->devs[rew] = dev;
4235
4236         return 0;
4237 out_free:
4238         cdev_del(STm->cdevs[rew]);
4239 out:
4240         STm->cdevs[rew] = NULL;
4241         STm->devs[rew] = NULL;
4242         return error;
4243 }
4244
4245 static int create_cdevs(struct scsi_tape *tape)
4246 {
4247         int mode, error;
4248         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4249                 error = create_one_cdev(tape, mode, 0);
4250                 if (error)
4251                         return error;
4252                 error = create_one_cdev(tape, mode, 1);
4253                 if (error)
4254                         return error;
4255         }
4256
4257         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4258                                  &tape->modes[0].devs[0]->kobj, "tape");
4259 }
4260
4261 static void remove_cdevs(struct scsi_tape *tape)
4262 {
4263         int mode, rew;
4264         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4265         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4266                 struct st_modedef *STm = &(tape->modes[mode]);
4267                 for (rew = 0; rew < 2; rew++) {
4268                         if (STm->cdevs[rew])
4269                                 cdev_del(STm->cdevs[rew]);
4270                         if (STm->devs[rew])
4271                                 device_unregister(STm->devs[rew]);
4272                 }
4273         }
4274 }
4275
4276 static int st_probe(struct device *dev)
4277 {
4278         struct scsi_device *SDp = to_scsi_device(dev);
4279         struct gendisk *disk = NULL;
4280         struct scsi_tape *tpnt = NULL;
4281         struct st_modedef *STm;
4282         struct st_partstat *STps;
4283         struct st_buffer *buffer;
4284         int i, error;
4285         char *stp;
4286
4287         if (SDp->type != TYPE_TAPE)
4288                 return -ENODEV;
4289         if ((stp = st_incompatible(SDp))) {
4290                 sdev_printk(KERN_INFO, SDp,
4291                             "OnStream tapes are no longer supported;\n");
4292                 sdev_printk(KERN_INFO, SDp,
4293                             "please mail to linux-scsi@vger.kernel.org.\n");
4294                 return -ENODEV;
4295         }
4296
4297         scsi_autopm_get_device(SDp);
4298         i = queue_max_segments(SDp->request_queue);
4299         if (st_max_sg_segs < i)
4300                 i = st_max_sg_segs;
4301         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4302         if (buffer == NULL) {
4303                 sdev_printk(KERN_ERR, SDp,
4304                             "st: Can't allocate new tape buffer. "
4305                             "Device not attached.\n");
4306                 goto out;
4307         }
4308
4309         disk = alloc_disk(1);
4310         if (!disk) {
4311                 sdev_printk(KERN_ERR, SDp,
4312                             "st: out of memory. Device not attached.\n");
4313                 goto out_buffer_free;
4314         }
4315
4316         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_KERNEL);
4317         if (tpnt == NULL) {
4318                 sdev_printk(KERN_ERR, SDp,
4319                             "st: Can't allocate device descriptor.\n");
4320                 goto out_put_disk;
4321         }
4322         kref_init(&tpnt->kref);
4323         tpnt->disk = disk;
4324         disk->private_data = &tpnt->driver;
4325         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4326          * take queue reference that release_disk() expects. */
4327         if (!blk_get_queue(SDp->request_queue))
4328                 goto out_put_disk;
4329         disk->queue = SDp->request_queue;
4330         tpnt->driver = &st_template;
4331
4332         tpnt->device = SDp;
4333         if (SDp->scsi_level <= 2)
4334                 tpnt->tape_type = MT_ISSCSI1;
4335         else
4336                 tpnt->tape_type = MT_ISSCSI2;
4337
4338         tpnt->buffer = buffer;
4339         tpnt->buffer->last_SRpnt = NULL;
4340
4341         tpnt->inited = 0;
4342         tpnt->dirty = 0;
4343         tpnt->in_use = 0;
4344         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4345         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4346         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4347         tpnt->density = 0;
4348         tpnt->do_auto_lock = ST_AUTO_LOCK;
4349         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4350         tpnt->can_partitions = 0;
4351         tpnt->two_fm = ST_TWO_FM;
4352         tpnt->fast_mteom = ST_FAST_MTEOM;
4353         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4354         tpnt->sili = ST_SILI;
4355         tpnt->immediate = ST_NOWAIT;
4356         tpnt->immediate_filemark = 0;
4357         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4358         tpnt->partition = 0;
4359         tpnt->new_partition = 0;
4360         tpnt->nbr_partitions = 0;
4361         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4362         tpnt->long_timeout = ST_LONG_TIMEOUT;
4363         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4364
4365         for (i = 0; i < ST_NBR_MODES; i++) {
4366                 STm = &(tpnt->modes[i]);
4367                 STm->defined = 0;
4368                 STm->sysv = ST_SYSV;
4369                 STm->defaults_for_writes = 0;
4370                 STm->do_async_writes = ST_ASYNC_WRITES;
4371                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4372                 STm->do_read_ahead = ST_READ_AHEAD;
4373                 STm->default_compression = ST_DONT_TOUCH;
4374                 STm->default_blksize = (-1);    /* No forced size */
4375                 STm->default_density = (-1);    /* No forced density */
4376                 STm->tape = tpnt;
4377         }
4378
4379         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4380                 STps = &(tpnt->ps[i]);
4381                 STps->rw = ST_IDLE;
4382                 STps->eof = ST_NOEOF;
4383                 STps->at_sm = 0;
4384                 STps->last_block_valid = 0;
4385                 STps->drv_block = (-1);
4386                 STps->drv_file = (-1);
4387         }
4388
4389         tpnt->current_mode = 0;
4390         tpnt->modes[0].defined = 1;
4391
4392         tpnt->density_changed = tpnt->compression_changed =
4393             tpnt->blksize_changed = 0;
4394         mutex_init(&tpnt->lock);
4395
4396         idr_preload(GFP_KERNEL);
4397         spin_lock(&st_index_lock);
4398         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4399         spin_unlock(&st_index_lock);
4400         idr_preload_end();
4401         if (error < 0) {
4402                 pr_warn("st: idr allocation failed: %d\n", error);
4403                 goto out_put_queue;
4404         }
4405         tpnt->index = error;
4406         sprintf(disk->disk_name, "st%d", tpnt->index);
4407         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4408         if (tpnt->stats == NULL) {
4409                 sdev_printk(KERN_ERR, SDp,
4410                             "st: Can't allocate statistics.\n");
4411                 goto out_idr_remove;
4412         }
4413
4414         dev_set_drvdata(dev, tpnt);
4415
4416
4417         error = create_cdevs(tpnt);
4418         if (error)
4419                 goto out_remove_devs;
4420         scsi_autopm_put_device(SDp);
4421
4422         sdev_printk(KERN_NOTICE, SDp,
4423                     "Attached scsi tape %s\n", tape_name(tpnt));
4424         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4425                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4426                     queue_dma_alignment(SDp->request_queue) + 1);
4427
4428         return 0;
4429
4430 out_remove_devs:
4431         remove_cdevs(tpnt);
4432         kfree(tpnt->stats);
4433 out_idr_remove:
4434         spin_lock(&st_index_lock);
4435         idr_remove(&st_index_idr, tpnt->index);
4436         spin_unlock(&st_index_lock);
4437 out_put_queue:
4438         blk_put_queue(disk->queue);
4439 out_put_disk:
4440         put_disk(disk);
4441         kfree(tpnt);
4442 out_buffer_free:
4443         kfree(buffer);
4444 out:
4445         scsi_autopm_put_device(SDp);
4446         return -ENODEV;
4447 };
4448
4449
4450 static int st_remove(struct device *dev)
4451 {
4452         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4453         int index = tpnt->index;
4454
4455         scsi_autopm_get_device(to_scsi_device(dev));
4456         remove_cdevs(tpnt);
4457
4458         mutex_lock(&st_ref_mutex);
4459         kref_put(&tpnt->kref, scsi_tape_release);
4460         mutex_unlock(&st_ref_mutex);
4461         spin_lock(&st_index_lock);
4462         idr_remove(&st_index_idr, index);
4463         spin_unlock(&st_index_lock);
4464         return 0;
4465 }
4466
4467 /**
4468  *      scsi_tape_release - Called to free the Scsi_Tape structure
4469  *      @kref: pointer to embedded kref
4470  *
4471  *      st_ref_mutex must be held entering this routine.  Because it is
4472  *      called on last put, you should always use the scsi_tape_get()
4473  *      scsi_tape_put() helpers which manipulate the semaphore directly
4474  *      and never do a direct kref_put().
4475  **/
4476 static void scsi_tape_release(struct kref *kref)
4477 {
4478         struct scsi_tape *tpnt = to_scsi_tape(kref);
4479         struct gendisk *disk = tpnt->disk;
4480
4481         tpnt->device = NULL;
4482
4483         if (tpnt->buffer) {
4484                 normalize_buffer(tpnt->buffer);
4485                 kfree(tpnt->buffer->reserved_pages);
4486                 kfree(tpnt->buffer);
4487         }
4488
4489         disk->private_data = NULL;
4490         put_disk(disk);
4491         kfree(tpnt->stats);
4492         kfree(tpnt);
4493         return;
4494 }
4495
4496 static struct class st_sysfs_class = {
4497         .name = "scsi_tape",
4498         .dev_groups = st_dev_groups,
4499 };
4500
4501 static int __init init_st(void)
4502 {
4503         int err;
4504
4505         validate_options();
4506
4507         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4508                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4509
4510         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4511         if (debugging) {
4512                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4513                         debugging);
4514         }
4515
4516         err = class_register(&st_sysfs_class);
4517         if (err) {
4518                 pr_err("Unable register sysfs class for SCSI tapes\n");
4519                 return err;
4520         }
4521
4522         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4523                                      ST_MAX_TAPE_ENTRIES, "st");
4524         if (err) {
4525                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4526                        SCSI_TAPE_MAJOR);
4527                 goto err_class;
4528         }
4529
4530         err = scsi_register_driver(&st_template.gendrv);
4531         if (err)
4532                 goto err_chrdev;
4533
4534         return 0;
4535
4536 err_chrdev:
4537         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4538                                  ST_MAX_TAPE_ENTRIES);
4539 err_class:
4540         class_unregister(&st_sysfs_class);
4541         return err;
4542 }
4543
4544 static void __exit exit_st(void)
4545 {
4546         scsi_unregister_driver(&st_template.gendrv);
4547         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4548                                  ST_MAX_TAPE_ENTRIES);
4549         class_unregister(&st_sysfs_class);
4550         idr_destroy(&st_index_idr);
4551         printk(KERN_INFO "st: Unloaded.\n");
4552 }
4553
4554 module_init(init_st);
4555 module_exit(exit_st);
4556
4557
4558 /* The sysfs driver interface. Read-only at the moment */
4559 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4560 {
4561         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4562 }
4563 static DRIVER_ATTR_RO(try_direct_io);
4564
4565 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4566 {
4567         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4568 }
4569 static DRIVER_ATTR_RO(fixed_buffer_size);
4570
4571 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4572 {
4573         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4574 }
4575 static DRIVER_ATTR_RO(max_sg_segs);
4576
4577 static ssize_t version_show(struct device_driver *ddd, char *buf)
4578 {
4579         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4580 }
4581 static DRIVER_ATTR_RO(version);
4582
4583 #if DEBUG
4584 static ssize_t debug_flag_store(struct device_driver *ddp,
4585         const char *buf, size_t count)
4586 {
4587 /* We only care what the first byte of the data is the rest is unused.
4588  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4589  * other values have -EINVAL returned if they are passed in.
4590  */
4591         if (count > 0) {
4592                 if (buf[0] == '0') {
4593                         debugging = NO_DEBUG;
4594                         return count;
4595                 } else if (buf[0] == '1') {
4596                         debugging = 1;
4597                         return count;
4598                 }
4599         }
4600         return -EINVAL;
4601 }
4602
4603 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4604 {
4605         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4606 }
4607 static DRIVER_ATTR_RW(debug_flag);
4608 #endif
4609
4610 static struct attribute *st_drv_attrs[] = {
4611         &driver_attr_try_direct_io.attr,
4612         &driver_attr_fixed_buffer_size.attr,
4613         &driver_attr_max_sg_segs.attr,
4614         &driver_attr_version.attr,
4615 #if DEBUG
4616         &driver_attr_debug_flag.attr,
4617 #endif
4618         NULL,
4619 };
4620 ATTRIBUTE_GROUPS(st_drv);
4621
4622 /* The sysfs simple class interface */
4623 static ssize_t
4624 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4625 {
4626         struct st_modedef *STm = dev_get_drvdata(dev);
4627         ssize_t l = 0;
4628
4629         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4630         return l;
4631 }
4632 static DEVICE_ATTR_RO(defined);
4633
4634 static ssize_t
4635 default_blksize_show(struct device *dev, struct device_attribute *attr,
4636                      char *buf)
4637 {
4638         struct st_modedef *STm = dev_get_drvdata(dev);
4639         ssize_t l = 0;
4640
4641         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4642         return l;
4643 }
4644 static DEVICE_ATTR_RO(default_blksize);
4645
4646 static ssize_t
4647 default_density_show(struct device *dev, struct device_attribute *attr,
4648                      char *buf)
4649 {
4650         struct st_modedef *STm = dev_get_drvdata(dev);
4651         ssize_t l = 0;
4652         char *fmt;
4653
4654         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4655         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4656         return l;
4657 }
4658 static DEVICE_ATTR_RO(default_density);
4659
4660 static ssize_t
4661 default_compression_show(struct device *dev, struct device_attribute *attr,
4662                          char *buf)
4663 {
4664         struct st_modedef *STm = dev_get_drvdata(dev);
4665         ssize_t l = 0;
4666
4667         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4668         return l;
4669 }
4670 static DEVICE_ATTR_RO(default_compression);
4671
4672 static ssize_t
4673 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4674 {
4675         struct st_modedef *STm = dev_get_drvdata(dev);
4676         struct scsi_tape *STp = STm->tape;
4677         int options;
4678         ssize_t l = 0;
4679
4680         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4681         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4682         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4683         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4684         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4685         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4686         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4687         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4688         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4689         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4690         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4691         options |= STm->sysv ? MT_ST_SYSV : 0;
4692         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4693         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4694         options |= STp->sili ? MT_ST_SILI : 0;
4695
4696         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4697         return l;
4698 }
4699 static DEVICE_ATTR_RO(options);
4700
4701 /* Support for tape stats */
4702
4703 /**
4704  * read_cnt_show - return read count - count of reads made from tape drive
4705  * @dev: struct device
4706  * @attr: attribute structure
4707  * @buf: buffer to return formatted data in
4708  */
4709 static ssize_t read_cnt_show(struct device *dev,
4710         struct device_attribute *attr, char *buf)
4711 {
4712         struct st_modedef *STm = dev_get_drvdata(dev);
4713
4714         return sprintf(buf, "%lld",
4715                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4716 }
4717 static DEVICE_ATTR_RO(read_cnt);
4718
4719 /**
4720  * read_byte_cnt_show - return read byte count - tape drives
4721  * may use blocks less than 512 bytes this gives the raw byte count of
4722  * of data read from the tape drive.
4723  * @dev: struct device
4724  * @attr: attribute structure
4725  * @buf: buffer to return formatted data in
4726  */
4727 static ssize_t read_byte_cnt_show(struct device *dev,
4728         struct device_attribute *attr, char *buf)
4729 {
4730         struct st_modedef *STm = dev_get_drvdata(dev);
4731
4732         return sprintf(buf, "%lld",
4733                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4734 }
4735 static DEVICE_ATTR_RO(read_byte_cnt);
4736
4737 /**
4738  * read_ns_show - return read ns - overall time spent waiting on reads in ns.
4739  * @dev: struct device
4740  * @attr: attribute structure
4741  * @buf: buffer to return formatted data in
4742  */
4743 static ssize_t read_ns_show(struct device *dev,
4744         struct device_attribute *attr, char *buf)
4745 {
4746         struct st_modedef *STm = dev_get_drvdata(dev);
4747
4748         return sprintf(buf, "%lld",
4749                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4750 }
4751 static DEVICE_ATTR_RO(read_ns);
4752
4753 /**
4754  * write_cnt_show - write count - number of user calls
4755  * to write(2) that have written data to tape.
4756  * @dev: struct device
4757  * @attr: attribute structure
4758  * @buf: buffer to return formatted data in
4759  */
4760 static ssize_t write_cnt_show(struct device *dev,
4761         struct device_attribute *attr, char *buf)
4762 {
4763         struct st_modedef *STm = dev_get_drvdata(dev);
4764
4765         return sprintf(buf, "%lld",
4766                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4767 }
4768 static DEVICE_ATTR_RO(write_cnt);
4769
4770 /**
4771  * write_byte_cnt_show - write byte count - raw count of
4772  * bytes written to tape.
4773  * @dev: struct device
4774  * @attr: attribute structure
4775  * @buf: buffer to return formatted data in
4776  */
4777 static ssize_t write_byte_cnt_show(struct device *dev,
4778         struct device_attribute *attr, char *buf)
4779 {
4780         struct st_modedef *STm = dev_get_drvdata(dev);
4781
4782         return sprintf(buf, "%lld",
4783                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4784 }
4785 static DEVICE_ATTR_RO(write_byte_cnt);
4786
4787 /**
4788  * write_ns_show - write ns - number of nanoseconds waiting on write
4789  * requests to complete.
4790  * @dev: struct device
4791  * @attr: attribute structure
4792  * @buf: buffer to return formatted data in
4793  */
4794 static ssize_t write_ns_show(struct device *dev,
4795         struct device_attribute *attr, char *buf)
4796 {
4797         struct st_modedef *STm = dev_get_drvdata(dev);
4798
4799         return sprintf(buf, "%lld",
4800                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4801 }
4802 static DEVICE_ATTR_RO(write_ns);
4803
4804 /**
4805  * in_flight_show - number of I/Os currently in flight -
4806  * in most cases this will be either 0 or 1. It may be higher if someone
4807  * has also issued other SCSI commands such as via an ioctl.
4808  * @dev: struct device
4809  * @attr: attribute structure
4810  * @buf: buffer to return formatted data in
4811  */
4812 static ssize_t in_flight_show(struct device *dev,
4813         struct device_attribute *attr, char *buf)
4814 {
4815         struct st_modedef *STm = dev_get_drvdata(dev);
4816
4817         return sprintf(buf, "%lld",
4818                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4819 }
4820 static DEVICE_ATTR_RO(in_flight);
4821
4822 /**
4823  * io_ns_show - io wait ns - this is the number of ns spent
4824  * waiting on all I/O to complete. This includes tape movement commands
4825  * such as rewinding, seeking to end of file or tape, it also includes
4826  * read and write. To determine the time spent on tape movement
4827  * subtract the read and write ns from this value.
4828  * @dev: struct device
4829  * @attr: attribute structure
4830  * @buf: buffer to return formatted data in
4831  */
4832 static ssize_t io_ns_show(struct device *dev,
4833         struct device_attribute *attr, char *buf)
4834 {
4835         struct st_modedef *STm = dev_get_drvdata(dev);
4836
4837         return sprintf(buf, "%lld",
4838                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4839 }
4840 static DEVICE_ATTR_RO(io_ns);
4841
4842 /**
4843  * other_cnt_show - other io count - this is the number of
4844  * I/O requests other than read and write requests.
4845  * Typically these are tape movement requests but will include driver
4846  * tape movement. This includes only requests issued by the st driver.
4847  * @dev: struct device
4848  * @attr: attribute structure
4849  * @buf: buffer to return formatted data in
4850  */
4851 static ssize_t other_cnt_show(struct device *dev,
4852         struct device_attribute *attr, char *buf)
4853 {
4854         struct st_modedef *STm = dev_get_drvdata(dev);
4855
4856         return sprintf(buf, "%lld",
4857                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4858 }
4859 static DEVICE_ATTR_RO(other_cnt);
4860
4861 /**
4862  * resid_cnt_show - A count of the number of times we get a residual
4863  * count - this should indicate someone issuing reads larger than the
4864  * block size on tape.
4865  * @dev: struct device
4866  * @attr: attribute structure
4867  * @buf: buffer to return formatted data in
4868  */
4869 static ssize_t resid_cnt_show(struct device *dev,
4870         struct device_attribute *attr, char *buf)
4871 {
4872         struct st_modedef *STm = dev_get_drvdata(dev);
4873
4874         return sprintf(buf, "%lld",
4875                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4876 }
4877 static DEVICE_ATTR_RO(resid_cnt);
4878
4879 static struct attribute *st_dev_attrs[] = {
4880         &dev_attr_defined.attr,
4881         &dev_attr_default_blksize.attr,
4882         &dev_attr_default_density.attr,
4883         &dev_attr_default_compression.attr,
4884         &dev_attr_options.attr,
4885         NULL,
4886 };
4887
4888 static struct attribute *st_stats_attrs[] = {
4889         &dev_attr_read_cnt.attr,
4890         &dev_attr_read_byte_cnt.attr,
4891         &dev_attr_read_ns.attr,
4892         &dev_attr_write_cnt.attr,
4893         &dev_attr_write_byte_cnt.attr,
4894         &dev_attr_write_ns.attr,
4895         &dev_attr_in_flight.attr,
4896         &dev_attr_io_ns.attr,
4897         &dev_attr_other_cnt.attr,
4898         &dev_attr_resid_cnt.attr,
4899         NULL,
4900 };
4901
4902 static struct attribute_group stats_group = {
4903         .name = "stats",
4904         .attrs = st_stats_attrs,
4905 };
4906
4907 static struct attribute_group st_group = {
4908         .attrs = st_dev_attrs,
4909 };
4910
4911 static const struct attribute_group *st_dev_groups[] = {
4912         &st_group,
4913         &stats_group,
4914         NULL,
4915 };
4916
4917 /* The following functions may be useful for a larger audience. */
4918 static int sgl_map_user_pages(struct st_buffer *STbp,
4919                               const unsigned int max_pages, unsigned long uaddr,
4920                               size_t count, int rw)
4921 {
4922         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4923         unsigned long start = uaddr >> PAGE_SHIFT;
4924         const int nr_pages = end - start;
4925         int res, i, j;
4926         struct page **pages;
4927         struct rq_map_data *mdata = &STbp->map_data;
4928
4929         /* User attempted Overflow! */
4930         if ((uaddr + count) < uaddr)
4931                 return -EINVAL;
4932
4933         /* Too big */
4934         if (nr_pages > max_pages)
4935                 return -ENOMEM;
4936
4937         /* Hmm? */
4938         if (count == 0)
4939                 return 0;
4940
4941         pages = kmalloc_array(max_pages, sizeof(*pages), GFP_KERNEL);
4942         if (pages == NULL)
4943                 return -ENOMEM;
4944
4945         /* Try to fault in all of the necessary pages */
4946         /* rw==READ means read from drive, write into memory area */
4947         res = get_user_pages_fast(uaddr, nr_pages, rw == READ ? FOLL_WRITE : 0,
4948                                   pages);
4949
4950         /* Errors and no page mapped should return here */
4951         if (res < nr_pages)
4952                 goto out_unmap;
4953
4954         for (i=0; i < nr_pages; i++) {
4955                 /* FIXME: flush superflous for rw==READ,
4956                  * probably wrong function for rw==WRITE
4957                  */
4958                 flush_dcache_page(pages[i]);
4959         }
4960
4961         mdata->offset = uaddr & ~PAGE_MASK;
4962         STbp->mapped_pages = pages;
4963
4964         return nr_pages;
4965  out_unmap:
4966         if (res > 0) {
4967                 for (j=0; j < res; j++)
4968                         put_page(pages[j]);
4969                 res = 0;
4970         }
4971         kfree(pages);
4972         return res;
4973 }
4974
4975
4976 /* And unmap them... */
4977 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4978                                 const unsigned int nr_pages, int dirtied)
4979 {
4980         int i;
4981
4982         for (i=0; i < nr_pages; i++) {
4983                 struct page *page = STbp->mapped_pages[i];
4984
4985                 if (dirtied)
4986                         SetPageDirty(page);
4987                 /* FIXME: cache flush missing for rw==READ
4988                  * FIXME: call the correct reference counting function
4989                  */
4990                 put_page(page);
4991         }
4992         kfree(STbp->mapped_pages);
4993         STbp->mapped_pages = NULL;
4994
4995         return 0;
4996 }