drivers/scsi/st.c

   1 /*
   2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3    file Documentation/scsi/st.txt for more information.
   4
   5    History:
   6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7    Contribution and ideas from several people including (in alphabetical
   8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10    Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12    Copyright 1992 - 2016 Kai Makisara
  13    email Kai.Makisara@kolumbus.fi
  14
  15    Some small formal changes - aeb, 950809
  16
  17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18  */
  19
  20 static const char *verstr = "20160209";
  21
  22 #include <linux/module.h>
  23
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/slab.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/cdrom.h>
  34 #include <linux/ioctl.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/delay.h>
  42 #include <linux/mutex.h>
  43
  44 #include <linux/uaccess.h>
  45 #include <asm/dma.h>
  46
  47 #include <scsi/scsi.h>
  48 #include <scsi/scsi_dbg.h>
  49 #include <scsi/scsi_device.h>
  50 #include <scsi/scsi_driver.h>
  51 #include <scsi/scsi_eh.h>
  52 #include <scsi/scsi_host.h>
  53 #include <scsi/scsi_ioctl.h>
  54 #include <scsi/sg.h>
  55
  56
  57 /* The driver prints some debugging information on the console if DEBUG
  58    is defined and non-zero. */
  59 #define DEBUG 1
  60 #define NO_DEBUG 0
  61
  62 #define ST_DEB_MSG  KERN_NOTICE
  63 #if DEBUG
  64 /* The message level for the debug messages is currently set to KERN_NOTICE
  65    so that people can easily see the messages. Later when the debugging messages
  66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67 #define DEB(a) a
  68 #define DEBC(a) if (debugging) { a ; }
  69 #else
  70 #define DEB(a)
  71 #define DEBC(a)
  72 #endif
  73
  74 #define ST_KILOBYTE 1024
  75
  76 #include "st_options.h"
  77 #include "st.h"
  78
  79 static int buffer_kbs;
  80 static int max_sg_segs;
  81 static int try_direct_io = TRY_DIRECT_IO;
  82 static int try_rdio = 1;
  83 static int try_wdio = 1;
  84 static int debug_flag;
  85
  86 static struct class st_sysfs_class;
  87 static const struct attribute_group *st_dev_groups[];
  88 static const struct attribute_group *st_drv_groups[];
  89
  90 MODULE_AUTHOR("Kai Makisara");
  91 MODULE_DESCRIPTION("SCSI tape (st) driver");
  92 MODULE_LICENSE("GPL");
  93 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97  * of sysfs parameters (which module_param doesn't yet support).
  98  * Sysfs parameters defined explicitly later.
  99  */
 100 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104 module_param_named(try_direct_io, try_direct_io, int, 0);
 105 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106 module_param_named(debug_flag, debug_flag, int, 0);
 107 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110 /* Extra parameters for testing */
 111 module_param_named(try_rdio, try_rdio, int, 0);
 112 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113 module_param_named(try_wdio, try_wdio, int, 0);
 114 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116 #ifndef MODULE
 117 static int write_threshold_kbs;  /* retained for compatibility */
 118 static struct st_dev_parm {
 119         char *name;
 120         int *val;
 121 } parms[] __initdata = {
 122         {
 123                 "buffer_kbs", &buffer_kbs
 124         },
 125         {       /* Retained for compatibility with 2.4 */
 126                 "write_threshold_kbs", &write_threshold_kbs
 127         },
 128         {
 129                 "max_sg_segs", NULL
 130         },
 131         {
 132                 "try_direct_io", &try_direct_io
 133         },
 134         {
 135                 "debug_flag", &debug_flag
 136         }
 137 };
 138 #endif
 139
 140 /* Restrict the number of modes so that names for all are assigned */
 141 #if ST_NBR_MODES > 16
 142 #error "Maximum number of modes is 16"
 143 #endif
 144 /* Bit reversed order to get same names for same minors with all
 145    mode counts */
 146 static const char *st_formats[] = {
 147         "",  "r", "k", "s", "l", "t", "o", "u",
 148         "m", "v", "p", "x", "a", "y", "q", "z"};
 149
 150 /* The default definitions have been moved to st_options.h */
 151
 152 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154 /* The buffer size should fit into the 24 bits for length in the
 155    6-byte SCSI read and write commands. */
 156 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158 #endif
 159
 160 static int debugging = DEBUG;
 161
 162 #define MAX_RETRIES 0
 163 #define MAX_WRITE_RETRIES 0
 164 #define MAX_READY_RETRIES 0
 165 #define NO_TAPE  NOT_READY
 166
 167 #define ST_TIMEOUT (900 * HZ)
 168 #define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170 /* Remove mode bits and auto-rewind bit (7) */
 171 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180    24 bits) */
 181 #define SET_DENS_AND_BLK 0x10001
 182
 183 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184 static int st_max_sg_segs = ST_MAX_SG;
 185
 186 static int modes_defined;
 187
 188 static int enlarge_buffer(struct st_buffer *, int, int);
 189 static void clear_buffer(struct st_buffer *);
 190 static void normalize_buffer(struct st_buffer *);
 191 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192 static int from_buffer(struct st_buffer *, char __user *, int);
 193 static void move_buffer_data(struct st_buffer *, int);
 194
 195 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196                               unsigned long, size_t, int);
 197 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199 static int st_probe(struct device *);
 200 static int st_remove(struct device *);
 201
 202 static struct scsi_driver st_template = {
 203         .gendrv = {
 204                 .name           = "st",
 205                 .owner          = THIS_MODULE,
 206                 .probe          = st_probe,
 207                 .remove         = st_remove,
 208                 .groups         = st_drv_groups,
 209         },
 210 };
 211
 212 static int st_compression(struct scsi_tape *, int);
 213
 214 static int find_partition(struct scsi_tape *);
 215 static int switch_partition(struct scsi_tape *);
 216
 217 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219 static void scsi_tape_release(struct kref *);
 220
 221 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223 static DEFINE_MUTEX(st_ref_mutex);
 224 static DEFINE_SPINLOCK(st_index_lock);
 225 static DEFINE_SPINLOCK(st_use_lock);
 226 static DEFINE_IDR(st_index_idr);
 227
 228
 229 \f
 230 #include "osst_detect.h"
 231 #ifndef SIGS_FROM_OSST
 232 #define SIGS_FROM_OSST \
 233         {"OnStream", "SC-", "", "osst"}, \
 234         {"OnStream", "DI-", "", "osst"}, \
 235         {"OnStream", "DP-", "", "osst"}, \
 236         {"OnStream", "USB", "", "osst"}, \
 237         {"OnStream", "FW-", "", "osst"}
 238 #endif
 239
 240 static struct scsi_tape *scsi_tape_get(int dev)
 241 {
 242         struct scsi_tape *STp = NULL;
 243
 244         mutex_lock(&st_ref_mutex);
 245         spin_lock(&st_index_lock);
 246
 247         STp = idr_find(&st_index_idr, dev);
 248         if (!STp) goto out;
 249
 250         kref_get(&STp->kref);
 251
 252         if (!STp->device)
 253                 goto out_put;
 254
 255         if (scsi_device_get(STp->device))
 256                 goto out_put;
 257
 258         goto out;
 259
 260 out_put:
 261         kref_put(&STp->kref, scsi_tape_release);
 262         STp = NULL;
 263 out:
 264         spin_unlock(&st_index_lock);
 265         mutex_unlock(&st_ref_mutex);
 266         return STp;
 267 }
 268
 269 static void scsi_tape_put(struct scsi_tape *STp)
 270 {
 271         struct scsi_device *sdev = STp->device;
 272
 273         mutex_lock(&st_ref_mutex);
 274         kref_put(&STp->kref, scsi_tape_release);
 275         scsi_device_put(sdev);
 276         mutex_unlock(&st_ref_mutex);
 277 }
 278
 279 struct st_reject_data {
 280         char *vendor;
 281         char *model;
 282         char *rev;
 283         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284 };
 285
 286 static struct st_reject_data reject_list[] = {
 287         /* {"XXX", "Yy-", "", NULL},  example */
 288         SIGS_FROM_OSST,
 289         {NULL, }};
 290
 291 /* If the device signature is on the list of incompatible drives, the
 292    function returns a pointer to the name of the correct driver (if known) */
 293 static char * st_incompatible(struct scsi_device* SDp)
 294 {
 295         struct st_reject_data *rp;
 296
 297         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301                         if (rp->driver_hint)
 302                                 return rp->driver_hint;
 303                         else
 304                                 return "unknown";
 305                 }
 306         return NULL;
 307 }
 308 \f
 309
 310 static inline char *tape_name(struct scsi_tape *tape)
 311 {
 312         return tape->disk->disk_name;
 313 }
 314
 315 #define st_printk(prefix, t, fmt, a...) \
 316         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317 #ifdef DEBUG
 318 #define DEBC_printk(t, fmt, a...) \
 319         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320 #else
 321 #define DEBC_printk(t, fmt, a...)
 322 #endif
 323
 324 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325 {
 326         const u8 *ucp;
 327         const u8 *sense = SRpnt->sense;
 328
 329         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331         s->flags = 0;
 332
 333         if (s->have_sense) {
 334                 s->deferred = 0;
 335                 s->remainder_valid =
 336                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337                 switch (sense[0] & 0x7f) {
 338                 case 0x71:
 339                         s->deferred = 1;
 340                 case 0x70:
 341                         s->fixed_format = 1;
 342                         s->flags = sense[2] & 0xe0;
 343                         break;
 344                 case 0x73:
 345                         s->deferred = 1;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = tape_name(STp);
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390                                result, driver_byte(result), host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418         STp->pos_unknown |= STp->device->was_reset;
 419
 420         if (cmdstatp->have_sense &&
 421             scode == RECOVERED_ERROR
 422 #if ST_RECOVERED_WRITE_FATAL
 423             && SRpnt->cmd[0] != WRITE_6
 424             && SRpnt->cmd[0] != WRITE_FILEMARKS
 425 #endif
 426             ) {
 427                 STp->recover_count++;
 428                 STp->recover_reg++;
 429
 430                 DEB(
 431                 if (debugging) {
 432                         if (SRpnt->cmd[0] == READ_6)
 433                                 stp = "read";
 434                         else if (SRpnt->cmd[0] == WRITE_6)
 435                                 stp = "write";
 436                         else
 437                                 stp = "ioctl";
 438                         st_printk(ST_DEB_MSG, STp,
 439                                   "Recovered %s error (%d).\n",
 440                                   stp, STp->recover_count);
 441                 } ) /* end DEB */
 442
 443                 if (cmdstatp->flags == 0)
 444                         return 0;
 445         }
 446         return (-EIO);
 447 }
 448
 449 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450 {
 451         struct st_request *streq;
 452
 453         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454         if (streq)
 455                 streq->stp = stp;
 456         else {
 457                 st_printk(KERN_ERR, stp,
 458                           "Can't get SCSI request.\n");
 459                 if (signal_pending(current))
 460                         stp->buffer->syscall_result = -EINTR;
 461                 else
 462                         stp->buffer->syscall_result = -EBUSY;
 463         }
 464
 465         return streq;
 466 }
 467
 468 static void st_release_request(struct st_request *streq)
 469 {
 470         kfree(streq);
 471 }
 472
 473 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474 {
 475         ktime_t now;
 476
 477         now = ktime_get();
 478         if (scsi_req(req)->cmd[0] == WRITE_6) {
 479                 now = ktime_sub(now, STp->stats->write_time);
 480                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482                 atomic64_inc(&STp->stats->write_cnt);
 483                 if (scsi_req(req)->result) {
 484                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 485                                 - STp->buffer->cmdstat.residual,
 486                                 &STp->stats->write_byte_cnt);
 487                         if (STp->buffer->cmdstat.residual > 0)
 488                                 atomic64_inc(&STp->stats->resid_cnt);
 489                 } else
 490                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 491                                 &STp->stats->write_byte_cnt);
 492         } else if (scsi_req(req)->cmd[0] == READ_6) {
 493                 now = ktime_sub(now, STp->stats->read_time);
 494                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496                 atomic64_inc(&STp->stats->read_cnt);
 497                 if (scsi_req(req)->result) {
 498                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 499                                 - STp->buffer->cmdstat.residual,
 500                                 &STp->stats->read_byte_cnt);
 501                         if (STp->buffer->cmdstat.residual > 0)
 502                                 atomic64_inc(&STp->stats->resid_cnt);
 503                 } else
 504                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 505                                 &STp->stats->read_byte_cnt);
 506         } else {
 507                 now = ktime_sub(now, STp->stats->other_time);
 508                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509                 atomic64_inc(&STp->stats->other_cnt);
 510         }
 511         atomic64_dec(&STp->stats->in_flight);
 512 }
 513
 514 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 515 {
 516         struct st_request *SRpnt = req->end_io_data;
 517         struct scsi_request *rq = scsi_req(req);
 518         struct scsi_tape *STp = SRpnt->stp;
 519         struct bio *tmp;
 520
 521         STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 522         STp->buffer->cmdstat.residual = rq->resid_len;
 523
 524         st_do_stats(STp, req);
 525
 526         tmp = SRpnt->bio;
 527         if (rq->sense_len)
 528                 memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 529         if (SRpnt->waiting)
 530                 complete(SRpnt->waiting);
 531
 532         blk_rq_unmap_user(tmp);
 533         __blk_put_request(req->q, req);
 534 }
 535
 536 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 537                            int data_direction, void *buffer, unsigned bufflen,
 538                            int timeout, int retries)
 539 {
 540         struct request *req;
 541         struct scsi_request *rq;
 542         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 543         int err = 0;
 544         struct scsi_tape *STp = SRpnt->stp;
 545
 546         req = blk_get_request(SRpnt->stp->device->request_queue,
 547                         data_direction == DMA_TO_DEVICE ?
 548                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
 549         if (IS_ERR(req))
 550                 return DRIVER_ERROR << 24;
 551         rq = scsi_req(req);
 552         req->rq_flags |= RQF_QUIET;
 553
 554         mdata->null_mapped = 1;
 555
 556         if (bufflen) {
 557                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 558                                       GFP_KERNEL);
 559                 if (err) {
 560                         blk_put_request(req);
 561                         return DRIVER_ERROR << 24;
 562                 }
 563         }
 564
 565         atomic64_inc(&STp->stats->in_flight);
 566         if (cmd[0] == WRITE_6) {
 567                 atomic_set(&STp->stats->last_write_size, bufflen);
 568                 STp->stats->write_time = ktime_get();
 569         } else if (cmd[0] == READ_6) {
 570                 atomic_set(&STp->stats->last_read_size, bufflen);
 571                 STp->stats->read_time = ktime_get();
 572         } else {
 573                 STp->stats->other_time = ktime_get();
 574         }
 575
 576         SRpnt->bio = req->bio;
 577         rq->cmd_len = COMMAND_SIZE(cmd[0]);
 578         memset(rq->cmd, 0, BLK_MAX_CDB);
 579         memcpy(rq->cmd, cmd, rq->cmd_len);
 580         req->timeout = timeout;
 581         rq->retries = retries;
 582         req->end_io_data = SRpnt;
 583
 584         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 585         return 0;
 586 }
 587
 588 /* Do the scsi command. Waits until command performed if do_wait is true.
 589    Otherwise write_behind_check() is used to check that the command
 590    has finished. */
 591 static struct st_request *
 592 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 593            int bytes, int direction, int timeout, int retries, int do_wait)
 594 {
 595         struct completion *waiting;
 596         struct rq_map_data *mdata = &STp->buffer->map_data;
 597         int ret;
 598
 599         /* if async, make sure there's no command outstanding */
 600         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 601                 st_printk(KERN_ERR, STp,
 602                           "Async command already active.\n");
 603                 if (signal_pending(current))
 604                         (STp->buffer)->syscall_result = (-EINTR);
 605                 else
 606                         (STp->buffer)->syscall_result = (-EBUSY);
 607                 return NULL;
 608         }
 609
 610         if (!SRpnt) {
 611                 SRpnt = st_allocate_request(STp);
 612                 if (!SRpnt)
 613                         return NULL;
 614         }
 615
 616         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 617            which IO is outstanding. It's nulled out when the IO completes. */
 618         if (!do_wait)
 619                 (STp->buffer)->last_SRpnt = SRpnt;
 620
 621         waiting = &STp->wait;
 622         init_completion(waiting);
 623         SRpnt->waiting = waiting;
 624
 625         if (STp->buffer->do_dio) {
 626                 mdata->page_order = 0;
 627                 mdata->nr_entries = STp->buffer->sg_segs;
 628                 mdata->pages = STp->buffer->mapped_pages;
 629         } else {
 630                 mdata->page_order = STp->buffer->reserved_page_order;
 631                 mdata->nr_entries =
 632                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 633                 mdata->pages = STp->buffer->reserved_pages;
 634                 mdata->offset = 0;
 635         }
 636
 637         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 638         STp->buffer->cmdstat.have_sense = 0;
 639         STp->buffer->syscall_result = 0;
 640
 641         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 642                               retries);
 643         if (ret) {
 644                 /* could not allocate the buffer or request was too large */
 645                 (STp->buffer)->syscall_result = (-EBUSY);
 646                 (STp->buffer)->last_SRpnt = NULL;
 647         } else if (do_wait) {
 648                 wait_for_completion(waiting);
 649                 SRpnt->waiting = NULL;
 650                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 651         }
 652
 653         return SRpnt;
 654 }
 655
 656
 657 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 658    write has been correct but EOM early warning reached, -EIO if write ended in
 659    error or zero if write successful. Asynchronous writes are used only in
 660    variable block mode. */
 661 static int write_behind_check(struct scsi_tape * STp)
 662 {
 663         int retval = 0;
 664         struct st_buffer *STbuffer;
 665         struct st_partstat *STps;
 666         struct st_cmdstatus *cmdstatp;
 667         struct st_request *SRpnt;
 668
 669         STbuffer = STp->buffer;
 670         if (!STbuffer->writing)
 671                 return 0;
 672
 673         DEB(
 674         if (STp->write_pending)
 675                 STp->nbr_waits++;
 676         else
 677                 STp->nbr_finished++;
 678         ) /* end DEB */
 679
 680         wait_for_completion(&(STp->wait));
 681         SRpnt = STbuffer->last_SRpnt;
 682         STbuffer->last_SRpnt = NULL;
 683         SRpnt->waiting = NULL;
 684
 685         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 686         st_release_request(SRpnt);
 687
 688         STbuffer->buffer_bytes -= STbuffer->writing;
 689         STps = &(STp->ps[STp->partition]);
 690         if (STps->drv_block >= 0) {
 691                 if (STp->block_size == 0)
 692                         STps->drv_block++;
 693                 else
 694                         STps->drv_block += STbuffer->writing / STp->block_size;
 695         }
 696
 697         cmdstatp = &STbuffer->cmdstat;
 698         if (STbuffer->syscall_result) {
 699                 retval = -EIO;
 700                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 701                     (cmdstatp->flags & SENSE_EOM) &&
 702                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 703                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 704                         /* EOM at write-behind, has all data been written? */
 705                         if (!cmdstatp->remainder_valid ||
 706                             cmdstatp->uremainder64 == 0)
 707                                 retval = -ENOSPC;
 708                 }
 709                 if (retval == -EIO)
 710                         STps->drv_block = -1;
 711         }
 712         STbuffer->writing = 0;
 713
 714         DEB(if (debugging && retval)
 715                     st_printk(ST_DEB_MSG, STp,
 716                                 "Async write error %x, return value %d.\n",
 717                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 718
 719         return retval;
 720 }
 721
 722
 723 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 724    it messes up the block number). */
 725 static int cross_eof(struct scsi_tape * STp, int forward)
 726 {
 727         struct st_request *SRpnt;
 728         unsigned char cmd[MAX_COMMAND_SIZE];
 729
 730         cmd[0] = SPACE;
 731         cmd[1] = 0x01;          /* Space FileMarks */
 732         if (forward) {
 733                 cmd[2] = cmd[3] = 0;
 734                 cmd[4] = 1;
 735         } else
 736                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 737         cmd[5] = 0;
 738
 739         DEBC_printk(STp, "Stepping over filemark %s.\n",
 740                     forward ? "forward" : "backward");
 741
 742         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 743                            STp->device->request_queue->rq_timeout,
 744                            MAX_RETRIES, 1);
 745         if (!SRpnt)
 746                 return (STp->buffer)->syscall_result;
 747
 748         st_release_request(SRpnt);
 749         SRpnt = NULL;
 750
 751         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 752                 st_printk(KERN_ERR, STp,
 753                           "Stepping over filemark %s failed.\n",
 754                           forward ? "forward" : "backward");
 755
 756         return (STp->buffer)->syscall_result;
 757 }
 758
 759
 760 /* Flush the write buffer (never need to write if variable blocksize). */
 761 static int st_flush_write_buffer(struct scsi_tape * STp)
 762 {
 763         int transfer, blks;
 764         int result;
 765         unsigned char cmd[MAX_COMMAND_SIZE];
 766         struct st_request *SRpnt;
 767         struct st_partstat *STps;
 768
 769         result = write_behind_check(STp);
 770         if (result)
 771                 return result;
 772
 773         result = 0;
 774         if (STp->dirty == 1) {
 775
 776                 transfer = STp->buffer->buffer_bytes;
 777                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 778
 779                 memset(cmd, 0, MAX_COMMAND_SIZE);
 780                 cmd[0] = WRITE_6;
 781                 cmd[1] = 1;
 782                 blks = transfer / STp->block_size;
 783                 cmd[2] = blks >> 16;
 784                 cmd[3] = blks >> 8;
 785                 cmd[4] = blks;
 786
 787                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 788                                    STp->device->request_queue->rq_timeout,
 789                                    MAX_WRITE_RETRIES, 1);
 790                 if (!SRpnt)
 791                         return (STp->buffer)->syscall_result;
 792
 793                 STps = &(STp->ps[STp->partition]);
 794                 if ((STp->buffer)->syscall_result != 0) {
 795                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 796
 797                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 798                             (cmdstatp->flags & SENSE_EOM) &&
 799                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 800                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 801                             (!cmdstatp->remainder_valid ||
 802                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 803                                 STp->dirty = 0;
 804                                 (STp->buffer)->buffer_bytes = 0;
 805                                 if (STps->drv_block >= 0)
 806                                         STps->drv_block += blks;
 807                                 result = (-ENOSPC);
 808                         } else {
 809                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 810                                 STps->drv_block = (-1);
 811                                 result = (-EIO);
 812                         }
 813                 } else {
 814                         if (STps->drv_block >= 0)
 815                                 STps->drv_block += blks;
 816                         STp->dirty = 0;
 817                         (STp->buffer)->buffer_bytes = 0;
 818                 }
 819                 st_release_request(SRpnt);
 820                 SRpnt = NULL;
 821         }
 822         return result;
 823 }
 824
 825
 826 /* Flush the tape buffer. The tape will be positioned correctly unless
 827    seek_next is true. */
 828 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 829 {
 830         int backspace, result;
 831         struct st_buffer *STbuffer;
 832         struct st_partstat *STps;
 833
 834         STbuffer = STp->buffer;
 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         case MTFSF:
2728                 cmd[0] = SPACE;
2729                 cmd[1] = 0x01;  /* Space FileMarks */
2730                 cmd[2] = (arg >> 16);
2731                 cmd[3] = (arg >> 8);
2732                 cmd[4] = arg;
2733                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2734                 if (fileno >= 0)
2735                         fileno += arg;
2736                 blkno = 0;
2737                 at_sm &= (arg == 0);
2738                 break;
2739         case MTBSFM:
2740                 chg_eof = 0;    /* Changed from the FSF after this */
2741         case MTBSF:
2742                 cmd[0] = SPACE;
2743                 cmd[1] = 0x01;  /* Space FileMarks */
2744                 ltmp = (-arg);
2745                 cmd[2] = (ltmp >> 16);
2746                 cmd[3] = (ltmp >> 8);
2747                 cmd[4] = ltmp;
2748                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2749                 if (fileno >= 0)
2750                         fileno -= arg;
2751                 blkno = (-1);   /* We can't know the block number */
2752                 at_sm &= (arg == 0);
2753                 break;
2754         case MTFSR:
2755                 cmd[0] = SPACE;
2756                 cmd[1] = 0x00;  /* Space Blocks */
2757                 cmd[2] = (arg >> 16);
2758                 cmd[3] = (arg >> 8);
2759                 cmd[4] = arg;
2760                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2761                 if (blkno >= 0)
2762                         blkno += arg;
2763                 at_sm &= (arg == 0);
2764                 break;
2765         case MTBSR:
2766                 cmd[0] = SPACE;
2767                 cmd[1] = 0x00;  /* Space Blocks */
2768                 ltmp = (-arg);
2769                 cmd[2] = (ltmp >> 16);
2770                 cmd[3] = (ltmp >> 8);
2771                 cmd[4] = ltmp;
2772                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2773                 if (blkno >= 0)
2774                         blkno -= arg;
2775                 at_sm &= (arg == 0);
2776                 break;
2777         case MTFSS:
2778                 cmd[0] = SPACE;
2779                 cmd[1] = 0x04;  /* Space Setmarks */
2780                 cmd[2] = (arg >> 16);
2781                 cmd[3] = (arg >> 8);
2782                 cmd[4] = arg;
2783                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2784                 if (arg != 0) {
2785                         blkno = fileno = (-1);
2786                         at_sm = 1;
2787                 }
2788                 break;
2789         case MTBSS:
2790                 cmd[0] = SPACE;
2791                 cmd[1] = 0x04;  /* Space Setmarks */
2792                 ltmp = (-arg);
2793                 cmd[2] = (ltmp >> 16);
2794                 cmd[3] = (ltmp >> 8);
2795                 cmd[4] = ltmp;
2796                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2797                 if (arg != 0) {
2798                         blkno = fileno = (-1);
2799                         at_sm = 1;
2800                 }
2801                 break;
2802         case MTWEOF:
2803         case MTWEOFI:
2804         case MTWSM:
2805                 if (STp->write_prot)
2806                         return (-EACCES);
2807                 cmd[0] = WRITE_FILEMARKS;
2808                 if (cmd_in == MTWSM)
2809                         cmd[1] = 2;
2810                 if (cmd_in == MTWEOFI ||
2811                     (cmd_in == MTWEOF && STp->immediate_filemark))
2812                         cmd[1] |= 1;
2813                 cmd[2] = (arg >> 16);
2814                 cmd[3] = (arg >> 8);
2815                 cmd[4] = arg;
2816                 timeout = STp->device->request_queue->rq_timeout;
2817                 DEBC(
2818                         if (cmd_in != MTWSM)
2819                                 st_printk(ST_DEB_MSG, STp,
2820                                           "Writing %d filemarks.\n",
2821                                           cmd[2] * 65536 +
2822                                           cmd[3] * 256 +
2823                                           cmd[4]);
2824                         else
2825                                 st_printk(ST_DEB_MSG, STp,
2826                                           "Writing %d setmarks.\n",
2827                                           cmd[2] * 65536 +
2828                                           cmd[3] * 256 +
2829                                           cmd[4]);
2830                 )
2831                 if (fileno >= 0)
2832                         fileno += arg;
2833                 blkno = 0;
2834                 at_sm = (cmd_in == MTWSM);
2835                 break;
2836         case MTREW:
2837                 cmd[0] = REZERO_UNIT;
2838                 if (STp->immediate) {
2839                         cmd[1] = 1;     /* Don't wait for completion */
2840                         timeout = STp->device->request_queue->rq_timeout;
2841                 }
2842                 DEBC_printk(STp, "Rewinding tape.\n");
2843                 fileno = blkno = at_sm = 0;
2844                 break;
2845         case MTNOP:
2846                 DEBC_printk(STp, "No op on tape.\n");
2847                 return 0;       /* Should do something ? */
2848                 break;
2849         case MTRETEN:
2850                 cmd[0] = START_STOP;
2851                 if (STp->immediate) {
2852                         cmd[1] = 1;     /* Don't wait for completion */
2853                         timeout = STp->device->request_queue->rq_timeout;
2854                 }
2855                 cmd[4] = 3;
2856                 DEBC_printk(STp, "Retensioning tape.\n");
2857                 fileno = blkno = at_sm = 0;
2858                 break;
2859         case MTEOM:
2860                 if (!STp->fast_mteom) {
2861                         /* space to the end of tape */
2862                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2863                         fileno = STps->drv_file;
2864                         if (STps->eof >= ST_EOD_1)
2865                                 return 0;
2866                         /* The next lines would hide the number of spaced FileMarks
2867                            That's why I inserted the previous lines. I had no luck
2868                            with detecting EOM with FSF, so we go now to EOM.
2869                            Joerg Weule */
2870                 } else
2871                         fileno = (-1);
2872                 cmd[0] = SPACE;
2873                 cmd[1] = 3;
2874                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2875                 blkno = -1;
2876                 at_sm = 0;
2877                 break;
2878         case MTERASE:
2879                 if (STp->write_prot)
2880                         return (-EACCES);
2881                 cmd[0] = ERASE;
2882                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2883                 if (STp->immediate) {
2884                         cmd[1] |= 2;    /* Don't wait for completion */
2885                         timeout = STp->device->request_queue->rq_timeout;
2886                 }
2887                 else
2888                         timeout = STp->long_timeout * 8;
2889
2890                 DEBC_printk(STp, "Erasing tape.\n");
2891                 fileno = blkno = at_sm = 0;
2892                 break;
2893         case MTSETBLK:          /* Set block length */
2894         case MTSETDENSITY:      /* Set tape density */
2895         case MTSETDRVBUFFER:    /* Set drive buffering */
2896         case SET_DENS_AND_BLK:  /* Set density and block size */
2897                 chg_eof = 0;
2898                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2899                         return (-EIO);  /* Not allowed if data in buffer */
2900                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2901                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2902                     STp->max_block > 0 &&
2903                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2904                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2905                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2906                         return (-EINVAL);
2907                 }
2908                 cmd[0] = MODE_SELECT;
2909                 if ((STp->use_pf & USE_PF))
2910                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2911                 cmd[4] = datalen = 12;
2912                 direction = DMA_TO_DEVICE;
2913
2914                 memset((STp->buffer)->b_data, 0, 12);
2915                 if (cmd_in == MTSETDRVBUFFER)
2916                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2917                 else
2918                         (STp->buffer)->b_data[2] =
2919                             STp->drv_buffer << 4;
2920                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2921                 if (cmd_in == MTSETDENSITY) {
2922                         (STp->buffer)->b_data[4] = arg;
2923                         STp->density_changed = 1;       /* At least we tried ;-) */
2924                 } else if (cmd_in == SET_DENS_AND_BLK)
2925                         (STp->buffer)->b_data[4] = arg >> 24;
2926                 else
2927                         (STp->buffer)->b_data[4] = STp->density;
2928                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2929                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2930                         if (cmd_in == MTSETBLK)
2931                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2932                 } else
2933                         ltmp = STp->block_size;
2934                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2935                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2936                 (STp->buffer)->b_data[11] = ltmp;
2937                 timeout = STp->device->request_queue->rq_timeout;
2938                 DEBC(
2939                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2940                                 st_printk(ST_DEB_MSG, STp,
2941                                           "Setting block size to %d bytes.\n",
2942                                           (STp->buffer)->b_data[9] * 65536 +
2943                                           (STp->buffer)->b_data[10] * 256 +
2944                                           (STp->buffer)->b_data[11]);
2945                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2946                                 st_printk(ST_DEB_MSG, STp,
2947                                           "Setting density code to %x.\n",
2948                                           (STp->buffer)->b_data[4]);
2949                         if (cmd_in == MTSETDRVBUFFER)
2950                                 st_printk(ST_DEB_MSG, STp,
2951                                           "Setting drive buffer code to %d.\n",
2952                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2953                 )
2954                 break;
2955         default:
2956                 return (-ENOSYS);
2957         }
2958
2959         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2960                            timeout, MAX_RETRIES, 1);
2961         if (!SRpnt)
2962                 return (STp->buffer)->syscall_result;
2963
2964         ioctl_result = (STp->buffer)->syscall_result;
2965
2966         if (!ioctl_result) {    /* SCSI command successful */
2967                 st_release_request(SRpnt);
2968                 SRpnt = NULL;
2969                 STps->drv_block = blkno;
2970                 STps->drv_file = fileno;
2971                 STps->at_sm = at_sm;
2972
2973                 if (cmd_in == MTBSFM)
2974                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2975                 else if (cmd_in == MTFSFM)
2976                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2977
2978                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2979                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2980                         if (STp->block_size != 0) {
2981                                 (STp->buffer)->buffer_blocks =
2982                                     (STp->buffer)->buffer_size / STp->block_size;
2983                         }
2984                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2985                         if (cmd_in == SET_DENS_AND_BLK)
2986                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2987                 } else if (cmd_in == MTSETDRVBUFFER)
2988                         STp->drv_buffer = (arg & 7);
2989                 else if (cmd_in == MTSETDENSITY)
2990                         STp->density = arg;
2991
2992                 if (cmd_in == MTEOM)
2993                         STps->eof = ST_EOD;
2994                 else if (cmd_in == MTFSF)
2995                         STps->eof = ST_FM;
2996                 else if (chg_eof)
2997                         STps->eof = ST_NOEOF;
2998
2999                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3000                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3001         } else { /* SCSI command was not completely successful. Don't return
3002                     from this block without releasing the SCSI command block! */
3003                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3004
3005                 if (cmdstatp->flags & SENSE_EOM) {
3006                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3007                             cmd_in != MTBSR && cmd_in != MTBSS)
3008                                 STps->eof = ST_EOM_OK;
3009                         STps->drv_block = 0;
3010                 }
3011
3012                 if (cmdstatp->remainder_valid)
3013                         undone = (int)cmdstatp->uremainder64;
3014                 else
3015                         undone = 0;
3016
3017                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3018                     cmdstatp->have_sense &&
3019                     (cmdstatp->flags & SENSE_EOM)) {
3020                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3021                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3022                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3023                                 STps->eof = ST_NOEOF;
3024                         } else {  /* Writing EOF(s) failed */
3025                                 if (fileno >= 0)
3026                                         fileno -= undone;
3027                                 if (undone < arg)
3028                                         STps->eof = ST_NOEOF;
3029                         }
3030                         STps->drv_file = fileno;
3031                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3032                         if (fileno >= 0)
3033                                 STps->drv_file = fileno - undone;
3034                         else
3035                                 STps->drv_file = fileno;
3036                         STps->drv_block = -1;
3037                         STps->eof = ST_NOEOF;
3038                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3039                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3040                                 undone = (-undone);
3041                         if (STps->drv_file >= 0)
3042                                 STps->drv_file = fileno + undone;
3043                         STps->drv_block = 0;
3044                         STps->eof = ST_NOEOF;
3045                 } else if (cmd_in == MTFSR) {
3046                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3047                                 if (STps->drv_file >= 0)
3048                                         STps->drv_file++;
3049                                 STps->drv_block = 0;
3050                                 STps->eof = ST_FM;
3051                         } else {
3052                                 if (blkno >= undone)
3053                                         STps->drv_block = blkno - undone;
3054                                 else
3055                                         STps->drv_block = (-1);
3056                                 STps->eof = ST_NOEOF;
3057                         }
3058                 } else if (cmd_in == MTBSR) {
3059                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3060                                 STps->drv_file--;
3061                                 STps->drv_block = (-1);
3062                         } else {
3063                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3064                                         undone = (-undone);
3065                                 if (STps->drv_block >= 0)
3066                                         STps->drv_block = blkno + undone;
3067                         }
3068                         STps->eof = ST_NOEOF;
3069                 } else if (cmd_in == MTEOM) {
3070                         STps->drv_file = (-1);
3071                         STps->drv_block = (-1);
3072                         STps->eof = ST_EOD;
3073                 } else if (cmd_in == MTSETBLK ||
3074                            cmd_in == MTSETDENSITY ||
3075                            cmd_in == MTSETDRVBUFFER ||
3076                            cmd_in == SET_DENS_AND_BLK) {
3077                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3078                             !(STp->use_pf & PF_TESTED)) {
3079                                 /* Try the other possible state of Page Format if not
3080                                    already tried */
3081                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3082                                 st_release_request(SRpnt);
3083                                 SRpnt = NULL;
3084                                 return st_int_ioctl(STp, cmd_in, arg);
3085                         }
3086                 } else if (chg_eof)
3087                         STps->eof = ST_NOEOF;
3088
3089                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3090                         STps->eof = ST_EOD;
3091
3092                 st_release_request(SRpnt);
3093                 SRpnt = NULL;
3094         }
3095
3096         return ioctl_result;
3097 }
3098 \f
3099
3100 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3101    structure. */
3102
3103 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3104                         int logical)
3105 {
3106         int result;
3107         unsigned char scmd[MAX_COMMAND_SIZE];
3108         struct st_request *SRpnt;
3109
3110         if (STp->ready != ST_READY)
3111                 return (-EIO);
3112
3113         memset(scmd, 0, MAX_COMMAND_SIZE);
3114         if ((STp->device)->scsi_level < SCSI_2) {
3115                 scmd[0] = QFA_REQUEST_BLOCK;
3116                 scmd[4] = 3;
3117         } else {
3118                 scmd[0] = READ_POSITION;
3119                 if (!logical && !STp->scsi2_logical)
3120                         scmd[1] = 1;
3121         }
3122         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3123                            STp->device->request_queue->rq_timeout,
3124                            MAX_READY_RETRIES, 1);
3125         if (!SRpnt)
3126                 return (STp->buffer)->syscall_result;
3127
3128         if ((STp->buffer)->syscall_result != 0 ||
3129             (STp->device->scsi_level >= SCSI_2 &&
3130              ((STp->buffer)->b_data[0] & 4) != 0)) {
3131                 *block = *partition = 0;
3132                 DEBC_printk(STp, " Can't read tape position.\n");
3133                 result = (-EIO);
3134         } else {
3135                 result = 0;
3136                 if ((STp->device)->scsi_level < SCSI_2) {
3137                         *block = ((STp->buffer)->b_data[0] << 16)
3138                             + ((STp->buffer)->b_data[1] << 8)
3139                             + (STp->buffer)->b_data[2];
3140                         *partition = 0;
3141                 } else {
3142                         *block = ((STp->buffer)->b_data[4] << 24)
3143                             + ((STp->buffer)->b_data[5] << 16)
3144                             + ((STp->buffer)->b_data[6] << 8)
3145                             + (STp->buffer)->b_data[7];
3146                         *partition = (STp->buffer)->b_data[1];
3147                         if (((STp->buffer)->b_data[0] & 0x80) &&
3148                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3149                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3150                 }
3151                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3152                             *block, *partition);
3153         }
3154         st_release_request(SRpnt);
3155         SRpnt = NULL;
3156
3157         return result;
3158 }
3159
3160
3161 /* Set the tape block and partition. Negative partition means that only the
3162    block should be set in vendor specific way. */
3163 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3164                         int logical)
3165 {
3166         struct st_partstat *STps;
3167         int result, p;
3168         unsigned int blk;
3169         int timeout;
3170         unsigned char scmd[MAX_COMMAND_SIZE];
3171         struct st_request *SRpnt;
3172
3173         if (STp->ready != ST_READY)
3174                 return (-EIO);
3175         timeout = STp->long_timeout;
3176         STps = &(STp->ps[STp->partition]);
3177
3178         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3179                     block, partition);
3180         DEB(if (partition < 0)
3181                 return (-EIO); )
3182
3183         /* Update the location at the partition we are leaving */
3184         if ((!STp->can_partitions && partition != 0) ||
3185             partition >= ST_NBR_PARTITIONS)
3186                 return (-EINVAL);
3187         if (partition != STp->partition) {
3188                 if (get_location(STp, &blk, &p, 1))
3189                         STps->last_block_valid = 0;
3190                 else {
3191                         STps->last_block_valid = 1;
3192                         STps->last_block_visited = blk;
3193                         DEBC_printk(STp, "Visited block %d for "
3194                                     "partition %d saved.\n",
3195                                     blk, STp->partition);
3196                 }
3197         }
3198
3199         memset(scmd, 0, MAX_COMMAND_SIZE);
3200         if ((STp->device)->scsi_level < SCSI_2) {
3201                 scmd[0] = QFA_SEEK_BLOCK;
3202                 scmd[2] = (block >> 16);
3203                 scmd[3] = (block >> 8);
3204                 scmd[4] = block;
3205                 scmd[5] = 0;
3206         } else {
3207                 scmd[0] = SEEK_10;
3208                 scmd[3] = (block >> 24);
3209                 scmd[4] = (block >> 16);
3210                 scmd[5] = (block >> 8);
3211                 scmd[6] = block;
3212                 if (!logical && !STp->scsi2_logical)
3213                         scmd[1] = 4;
3214                 if (STp->partition != partition) {
3215                         scmd[1] |= 2;
3216                         scmd[8] = partition;
3217                         DEBC_printk(STp, "Trying to change partition "
3218                                     "from %d to %d\n", STp->partition,
3219                                     partition);
3220                 }
3221         }
3222         if (STp->immediate) {
3223                 scmd[1] |= 1;           /* Don't wait for completion */
3224                 timeout = STp->device->request_queue->rq_timeout;
3225         }
3226
3227         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3228                            timeout, MAX_READY_RETRIES, 1);
3229         if (!SRpnt)
3230                 return (STp->buffer)->syscall_result;
3231
3232         STps->drv_block = STps->drv_file = (-1);
3233         STps->eof = ST_NOEOF;
3234         if ((STp->buffer)->syscall_result != 0) {
3235                 result = (-EIO);
3236                 if (STp->can_partitions &&
3237                     (STp->device)->scsi_level >= SCSI_2 &&
3238                     (p = find_partition(STp)) >= 0)
3239                         STp->partition = p;
3240         } else {
3241                 if (STp->can_partitions) {
3242                         STp->partition = partition;
3243                         STps = &(STp->ps[partition]);
3244                         if (!STps->last_block_valid ||
3245                             STps->last_block_visited != block) {
3246                                 STps->at_sm = 0;
3247                                 STps->rw = ST_IDLE;
3248                         }
3249                 } else
3250                         STps->at_sm = 0;
3251                 if (block == 0)
3252                         STps->drv_block = STps->drv_file = 0;
3253                 result = 0;
3254         }
3255
3256         st_release_request(SRpnt);
3257         SRpnt = NULL;
3258
3259         return result;
3260 }
3261
3262
3263 /* Find the current partition number for the drive status. Called from open and
3264    returns either partition number of negative error code. */
3265 static int find_partition(struct scsi_tape *STp)
3266 {
3267         int i, partition;
3268         unsigned int block;
3269
3270         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3271                 return i;
3272         if (partition >= ST_NBR_PARTITIONS)
3273                 return (-EIO);
3274         return partition;
3275 }
3276
3277
3278 /* Change the partition if necessary */
3279 static int switch_partition(struct scsi_tape *STp)
3280 {
3281         struct st_partstat *STps;
3282
3283         if (STp->partition == STp->new_partition)
3284                 return 0;
3285         STps = &(STp->ps[STp->new_partition]);
3286         if (!STps->last_block_valid)
3287                 STps->last_block_visited = 0;
3288         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3289 }
3290 \f
3291 /* Functions for reading and writing the medium partition mode page. */
3292
3293 #define PART_PAGE   0x11
3294 #define PART_PAGE_FIXED_LENGTH 8
3295
3296 #define PP_OFF_MAX_ADD_PARTS   2
3297 #define PP_OFF_NBR_ADD_PARTS   3
3298 #define PP_OFF_FLAGS           4
3299 #define PP_OFF_PART_UNITS      6
3300 #define PP_OFF_RESERVED        7
3301
3302 #define PP_BIT_IDP             0x20
3303 #define PP_BIT_FDP             0x80
3304 #define PP_MSK_PSUM_MB         0x10
3305 #define PP_MSK_PSUM_UNITS      0x18
3306 #define PP_MSK_POFM            0x04
3307
3308 /* Get the number of partitions on the tape. As a side effect reads the
3309    mode page into the tape buffer. */
3310 static int nbr_partitions(struct scsi_tape *STp)
3311 {
3312         int result;
3313
3314         if (STp->ready != ST_READY)
3315                 return (-EIO);
3316
3317         result = read_mode_page(STp, PART_PAGE, 1);
3318
3319         if (result) {
3320                 DEBC_printk(STp, "Can't read medium partition page.\n");
3321                 result = (-EIO);
3322         } else {
3323                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3324                                               PP_OFF_NBR_ADD_PARTS] + 1;
3325                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3326         }
3327
3328         return result;
3329 }
3330
3331
3332 static int format_medium(struct scsi_tape *STp, int format)
3333 {
3334         int result = 0;
3335         int timeout = STp->long_timeout;
3336         unsigned char scmd[MAX_COMMAND_SIZE];
3337         struct st_request *SRpnt;
3338
3339         memset(scmd, 0, MAX_COMMAND_SIZE);
3340         scmd[0] = FORMAT_UNIT;
3341         scmd[2] = format;
3342         if (STp->immediate) {
3343                 scmd[1] |= 1;           /* Don't wait for completion */
3344                 timeout = STp->device->request_queue->rq_timeout;
3345         }
3346         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3347         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3348                            timeout, MAX_RETRIES, 1);
3349         if (!SRpnt)
3350                 result = STp->buffer->syscall_result;
3351         return result;
3352 }
3353
3354
3355 /* Partition the tape into two partitions if size > 0 or one partition if
3356    size == 0.
3357
3358    The block descriptors are read and written because Sony SDT-7000 does not
3359    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3360
3361    My HP C1533A drive returns only one partition size field. This is used to
3362    set the size of partition 1. There is no size field for the default partition.
3363    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3364    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3365    The following algorithm is used to accommodate both drives: if the number of
3366    partition size fields is greater than the maximum number of additional partitions
3367    in the mode page, the second field is used. Otherwise the first field is used.
3368
3369    For Seagate DDS drives the page length must be 8 when no partitions is defined
3370    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3371    is acceptable also to some other old drives and enforced if the first partition
3372    size field is used for the first additional partition size.
3373
3374    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3375  */
3376 static int partition_tape(struct scsi_tape *STp, int size)
3377 {
3378         int result;
3379         int target_partition;
3380         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3381         int pgo, psd_cnt, psdo;
3382         int psum = PP_MSK_PSUM_MB, units = 0;
3383         unsigned char *bp;
3384
3385         result = read_mode_page(STp, PART_PAGE, 0);
3386         if (result) {
3387                 DEBC_printk(STp, "Can't read partition mode page.\n");
3388                 return result;
3389         }
3390         target_partition = 1;
3391         if (size < 0) {
3392                 target_partition = 0;
3393                 size = -size;
3394         }
3395
3396         /* The mode page is in the buffer. Let's modify it and write it. */
3397         bp = (STp->buffer)->b_data;
3398         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3399         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3400                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3401
3402         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3403
3404         if (scsi3) {
3405                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3406                 if (needs_format && size == 0) {
3407                         /* No need to write the mode page when clearing
3408                          *  partitioning
3409                          */
3410                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3411                         result = format_medium(STp, 0);
3412                         goto out;
3413                 }
3414                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3415                         psd_cnt = 2;
3416                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3417                         /* Use units scaling for large partitions if the device
3418                          * suggests it and no precision lost. Required for IBM
3419                          * TS1140/50 drives that don't support MB units.
3420                          */
3421                         if (size >= 1000 && (size % 1000) == 0) {
3422                                 size /= 1000;
3423                                 psum = PP_MSK_PSUM_UNITS;
3424                                 units = 9; /* GB */
3425                         }
3426                 }
3427                 /* Try it anyway if too large to specify in MB */
3428                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3429                         size /= 1000;
3430                         psum = PP_MSK_PSUM_UNITS;
3431                         units = 9;  /* GB */
3432                 }
3433         }
3434
3435         if (size >= 65535 ||  /* Does not fit into two bytes */
3436             (target_partition == 0 && psd_cnt < 2)) {
3437                 result = -EINVAL;
3438                 goto out;
3439         }
3440
3441         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3442         /* The second condition is for HP DDS which use only one partition size
3443          * descriptor
3444          */
3445         if (target_partition > 0 &&
3446             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3447              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3448                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3449                 psdo += 2;
3450         }
3451         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3452
3453         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3454                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3455                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3456
3457         if (size == 0) {
3458                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3459                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3460                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3461                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3462         } else {
3463                 bp[psdo] = (size >> 8) & 0xff;
3464                 bp[psdo + 1] = size & 0xff;
3465                 if (target_partition == 0)
3466                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3467                 bp[pgo + 3] = 1;
3468                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3469                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3470                 DEBC_printk(STp,
3471                             "Formatting tape with two partitions (%i = %d MB).\n",
3472                             target_partition, units > 0 ? size * 1000 : size);
3473         }
3474         bp[pgo + PP_OFF_PART_UNITS] = 0;
3475         bp[pgo + PP_OFF_RESERVED] = 0;
3476         if (size != 1 || units != 0) {
3477                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3478                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3479                 bp[pgo + PP_OFF_PART_UNITS] = units;
3480         } else
3481                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3482                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3483         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3484
3485         result = write_mode_page(STp, PART_PAGE, 1);
3486
3487         if (!result && needs_format)
3488                 result = format_medium(STp, 1);
3489
3490         if (result) {
3491                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3492                 result = (-EIO);
3493         }
3494
3495 out:
3496         return result;
3497 }
3498 \f
3499
3500
3501 /* The ioctl command */
3502 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3503 {
3504         int i, cmd_nr, cmd_type, bt;
3505         int retval = 0;
3506         unsigned int blk;
3507         struct scsi_tape *STp = file->private_data;
3508         struct st_modedef *STm;
3509         struct st_partstat *STps;
3510         void __user *p = (void __user *)arg;
3511
3512         if (mutex_lock_interruptible(&STp->lock))
3513                 return -ERESTARTSYS;
3514
3515         DEB(
3516         if (debugging && !STp->in_use) {
3517                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3518                 retval = (-EIO);
3519                 goto out;
3520         } ) /* end DEB */
3521
3522         STm = &(STp->modes[STp->current_mode]);
3523         STps = &(STp->ps[STp->partition]);
3524
3525         /*
3526          * If we are in the middle of error recovery, don't let anyone
3527          * else try and use this device.  Also, if error recovery fails, it
3528          * may try and take the device offline, in which case all further
3529          * access to the device is prohibited.
3530          */
3531         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3532                         file->f_flags & O_NDELAY);
3533         if (retval)
3534                 goto out;
3535
3536         cmd_type = _IOC_TYPE(cmd_in);
3537         cmd_nr = _IOC_NR(cmd_in);
3538
3539         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3540                 struct mtop mtc;
3541
3542                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3543                         retval = (-EINVAL);
3544                         goto out;
3545                 }
3546
3547                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3548                 if (i) {
3549                         retval = (-EFAULT);
3550                         goto out;
3551                 }
3552
3553                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3554                         st_printk(KERN_WARNING, STp,
3555                                   "MTSETDRVBUFFER only allowed for root.\n");
3556                         retval = (-EPERM);
3557                         goto out;
3558                 }
3559                 if (!STm->defined &&
3560                     (mtc.mt_op != MTSETDRVBUFFER &&
3561                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3562                         retval = (-ENXIO);
3563                         goto out;
3564                 }
3565
3566                 if (!STp->pos_unknown) {
3567
3568                         if (STps->eof == ST_FM_HIT) {
3569                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3570                                     mtc.mt_op == MTEOM) {
3571                                         mtc.mt_count -= 1;
3572                                         if (STps->drv_file >= 0)
3573                                                 STps->drv_file += 1;
3574                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3575                                         mtc.mt_count += 1;
3576                                         if (STps->drv_file >= 0)
3577                                                 STps->drv_file += 1;
3578                                 }
3579                         }
3580
3581                         if (mtc.mt_op == MTSEEK) {
3582                                 /* Old position must be restored if partition will be
3583                                    changed */
3584                                 i = !STp->can_partitions ||
3585                                     (STp->new_partition != STp->partition);
3586                         } else {
3587                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3588                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3589                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3590                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3591                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3592                                     mtc.mt_op == MTCOMPRESSION;
3593                         }
3594                         i = flush_buffer(STp, i);
3595                         if (i < 0) {
3596                                 retval = i;
3597                                 goto out;
3598                         }
3599                         if (STps->rw == ST_WRITING &&
3600                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3601                              mtc.mt_op == MTSEEK ||
3602                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3603                                 i = st_int_ioctl(STp, MTWEOF, 1);
3604                                 if (i < 0) {
3605                                         retval = i;
3606                                         goto out;
3607                                 }
3608                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3609                                         mtc.mt_count++;
3610                                 STps->rw = ST_IDLE;
3611                              }
3612
3613                 } else {
3614                         /*
3615                          * If there was a bus reset, block further access
3616                          * to this device.  If the user wants to rewind the tape,
3617                          * then reset the flag and allow access again.
3618                          */
3619                         if (mtc.mt_op != MTREW &&
3620                             mtc.mt_op != MTOFFL &&
3621                             mtc.mt_op != MTRETEN &&
3622                             mtc.mt_op != MTERASE &&
3623                             mtc.mt_op != MTSEEK &&
3624                             mtc.mt_op != MTEOM) {
3625                                 retval = (-EIO);
3626                                 goto out;
3627                         }
3628                         reset_state(STp);
3629                         /* remove this when the midlevel properly clears was_reset */
3630                         STp->device->was_reset = 0;
3631                 }
3632
3633                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3634                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3635                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3636                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3637
3638                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3639                         do_door_lock(STp, 0);   /* Ignore result! */
3640
3641                 if (mtc.mt_op == MTSETDRVBUFFER &&
3642                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3643                         retval = st_set_options(STp, mtc.mt_count);
3644                         goto out;
3645                 }
3646
3647                 if (mtc.mt_op == MTSETPART) {
3648                         if (!STp->can_partitions ||
3649                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3650                                 retval = (-EINVAL);
3651                                 goto out;
3652                         }
3653                         if (mtc.mt_count >= STp->nbr_partitions &&
3654                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3655                                 retval = (-EIO);
3656                                 goto out;
3657                         }
3658                         if (mtc.mt_count >= STp->nbr_partitions) {
3659                                 retval = (-EINVAL);
3660                                 goto out;
3661                         }
3662                         STp->new_partition = mtc.mt_count;
3663                         retval = 0;
3664                         goto out;
3665                 }
3666
3667                 if (mtc.mt_op == MTMKPART) {
3668                         if (!STp->can_partitions) {
3669                                 retval = (-EINVAL);
3670                                 goto out;
3671                         }
3672                         i = do_load_unload(STp, file, 1);
3673                         if (i < 0) {
3674                                 retval = i;
3675                                 goto out;
3676                         }
3677                         i = partition_tape(STp, mtc.mt_count);
3678                         if (i < 0) {
3679                                 retval = i;
3680                                 goto out;
3681                         }
3682                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3683                                 STp->ps[i].rw = ST_IDLE;
3684                                 STp->ps[i].at_sm = 0;
3685                                 STp->ps[i].last_block_valid = 0;
3686                         }
3687                         STp->partition = STp->new_partition = 0;
3688                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3689                         STps->drv_block = STps->drv_file = 0;
3690                         retval = 0;
3691                         goto out;
3692                 }
3693
3694                 if (mtc.mt_op == MTSEEK) {
3695                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3696                         if (!STp->can_partitions)
3697                                 STp->ps[0].rw = ST_IDLE;
3698                         retval = i;
3699                         goto out;
3700                 }
3701
3702                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3703                         retval = do_load_unload(STp, file, 0);
3704                         goto out;
3705                 }
3706
3707                 if (mtc.mt_op == MTLOAD) {
3708                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3709                         goto out;
3710                 }
3711
3712                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3713                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3714                         goto out;
3715                 }
3716
3717                 if (STp->can_partitions && STp->ready == ST_READY &&
3718                     (i = switch_partition(STp)) < 0) {
3719                         retval = i;
3720                         goto out;
3721                 }
3722
3723                 if (mtc.mt_op == MTCOMPRESSION)
3724                         retval = st_compression(STp, (mtc.mt_count & 1));
3725                 else
3726                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3727                 goto out;
3728         }
3729         if (!STm->defined) {
3730                 retval = (-ENXIO);
3731                 goto out;
3732         }
3733
3734         if ((i = flush_buffer(STp, 0)) < 0) {
3735                 retval = i;
3736                 goto out;
3737         }
3738         if (STp->can_partitions &&
3739             (i = switch_partition(STp)) < 0) {
3740                 retval = i;
3741                 goto out;
3742         }
3743
3744         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3745                 struct mtget mt_status;
3746
3747                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3748                          retval = (-EINVAL);
3749                          goto out;
3750                 }
3751
3752                 mt_status.mt_type = STp->tape_type;
3753                 mt_status.mt_dsreg =
3754                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3755                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3756                 mt_status.mt_blkno = STps->drv_block;
3757                 mt_status.mt_fileno = STps->drv_file;
3758                 if (STp->block_size != 0) {
3759                         if (STps->rw == ST_WRITING)
3760                                 mt_status.mt_blkno +=
3761                                     (STp->buffer)->buffer_bytes / STp->block_size;
3762                         else if (STps->rw == ST_READING)
3763                                 mt_status.mt_blkno -=
3764                                         ((STp->buffer)->buffer_bytes +
3765                                          STp->block_size - 1) / STp->block_size;
3766                 }
3767
3768                 mt_status.mt_gstat = 0;
3769                 if (STp->drv_write_prot)
3770                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3771                 if (mt_status.mt_blkno == 0) {
3772                         if (mt_status.mt_fileno == 0)
3773                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3774                         else
3775                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3776                 }
3777                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3778                 mt_status.mt_resid = STp->partition;
3779                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3780                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3781                 else if (STps->eof >= ST_EOM_OK)
3782                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3783                 if (STp->density == 1)
3784                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3785                 else if (STp->density == 2)
3786                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3787                 else if (STp->density == 3)
3788                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3789                 if (STp->ready == ST_READY)
3790                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3791                 if (STp->ready == ST_NO_TAPE)
3792                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3793                 if (STps->at_sm)
3794                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3795                 if (STm->do_async_writes ||
3796                     (STm->do_buffer_writes && STp->block_size != 0) ||
3797                     STp->drv_buffer != 0)
3798                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3799                 if (STp->cleaning_req)
3800                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3801
3802                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3803                 if (i) {
3804                         retval = (-EFAULT);
3805                         goto out;
3806                 }
3807
3808                 STp->recover_reg = 0;           /* Clear after read */
3809                 retval = 0;
3810                 goto out;
3811         }                       /* End of MTIOCGET */
3812         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3813                 struct mtpos mt_pos;
3814                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3815                          retval = (-EINVAL);
3816                          goto out;
3817                 }
3818                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3819                         retval = i;
3820                         goto out;
3821                 }
3822                 mt_pos.mt_blkno = blk;
3823                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3824                 if (i)
3825                         retval = (-EFAULT);
3826                 goto out;
3827         }
3828         mutex_unlock(&STp->lock);
3829         switch (cmd_in) {
3830                 case SCSI_IOCTL_GET_IDLUN:
3831                 case SCSI_IOCTL_GET_BUS_NUMBER:
3832                         break;
3833                 default:
3834                         if ((cmd_in == SG_IO ||
3835                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3836                              cmd_in == CDROM_SEND_PACKET) &&
3837                             !capable(CAP_SYS_RAWIO))
3838                                 i = -EPERM;
3839                         else
3840                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3841                                                    file->f_mode, cmd_in, p);
3842                         if (i != -ENOTTY)
3843                                 return i;
3844                         break;
3845         }
3846         retval = scsi_ioctl(STp->device, cmd_in, p);
3847         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3848                 STp->rew_at_close = 0;
3849                 STp->ready = ST_NO_TAPE;
3850         }
3851         return retval;
3852
3853  out:
3854         mutex_unlock(&STp->lock);
3855         return retval;
3856 }
3857
3858 #ifdef CONFIG_COMPAT
3859 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3860 {
3861         struct scsi_tape *STp = file->private_data;
3862         struct scsi_device *sdev = STp->device;
3863         int ret = -ENOIOCTLCMD;
3864         if (sdev->host->hostt->compat_ioctl) {
3865
3866                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3867
3868         }
3869         return ret;
3870 }
3871 #endif
3872
3873 \f
3874
3875 /* Try to allocate a new tape buffer. Calling function must not hold
3876    dev_arr_lock. */
3877 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3878 {
3879         struct st_buffer *tb;
3880
3881         tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3882         if (!tb) {
3883                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3884                 return NULL;
3885         }
3886         tb->frp_segs = 0;
3887         tb->use_sg = max_sg;
3888         tb->dma = need_dma;
3889         tb->buffer_size = 0;
3890
3891         tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3892                                      GFP_ATOMIC);
3893         if (!tb->reserved_pages) {
3894                 kfree(tb);
3895                 return NULL;
3896         }
3897
3898         return tb;
3899 }
3900
3901
3902 /* Try to allocate enough space in the tape buffer */
3903 #define ST_MAX_ORDER 6
3904
3905 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3906 {
3907         int segs, max_segs, b_size, order, got;
3908         gfp_t priority;
3909
3910         if (new_size <= STbuffer->buffer_size)
3911                 return 1;
3912
3913         if (STbuffer->buffer_size <= PAGE_SIZE)
3914                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3915
3916         max_segs = STbuffer->use_sg;
3917
3918         priority = GFP_KERNEL | __GFP_NOWARN;
3919         if (need_dma)
3920                 priority |= GFP_DMA;
3921
3922         if (STbuffer->cleared)
3923                 priority |= __GFP_ZERO;
3924
3925         if (STbuffer->frp_segs) {
3926                 order = STbuffer->reserved_page_order;
3927                 b_size = PAGE_SIZE << order;
3928         } else {
3929                 for (b_size = PAGE_SIZE, order = 0;
3930                      order < ST_MAX_ORDER &&
3931                              max_segs * (PAGE_SIZE << order) < new_size;
3932                      order++, b_size *= 2)
3933                         ;  /* empty */
3934                 STbuffer->reserved_page_order = order;
3935         }
3936         if (max_segs * (PAGE_SIZE << order) < new_size) {
3937                 if (order == ST_MAX_ORDER)
3938                         return 0;
3939                 normalize_buffer(STbuffer);
3940                 return enlarge_buffer(STbuffer, new_size, need_dma);
3941         }
3942
3943         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3944              segs < max_segs && got < new_size;) {
3945                 struct page *page;
3946
3947                 page = alloc_pages(priority, order);
3948                 if (!page) {
3949                         DEB(STbuffer->buffer_size = got);
3950                         normalize_buffer(STbuffer);
3951                         return 0;
3952                 }
3953
3954                 STbuffer->frp_segs += 1;
3955                 got += b_size;
3956                 STbuffer->buffer_size = got;
3957                 STbuffer->reserved_pages[segs] = page;
3958                 segs++;
3959         }
3960         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3961
3962         return 1;
3963 }
3964
3965
3966 /* Make sure that no data from previous user is in the internal buffer */
3967 static void clear_buffer(struct st_buffer * st_bp)
3968 {
3969         int i;
3970
3971         for (i=0; i < st_bp->frp_segs; i++)
3972                 memset(page_address(st_bp->reserved_pages[i]), 0,
3973                        PAGE_SIZE << st_bp->reserved_page_order);
3974         st_bp->cleared = 1;
3975 }
3976
3977
3978 /* Release the extra buffer */
3979 static void normalize_buffer(struct st_buffer * STbuffer)
3980 {
3981         int i, order = STbuffer->reserved_page_order;
3982
3983         for (i = 0; i < STbuffer->frp_segs; i++) {
3984                 __free_pages(STbuffer->reserved_pages[i], order);
3985                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3986         }
3987         STbuffer->frp_segs = 0;
3988         STbuffer->sg_segs = 0;
3989         STbuffer->reserved_page_order = 0;
3990         STbuffer->map_data.offset = 0;
3991 }
3992
3993
3994 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3995    negative error code. */
3996 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3997 {
3998         int i, cnt, res, offset;
3999         int length = PAGE_SIZE << st_bp->reserved_page_order;
4000
4001         for (i = 0, offset = st_bp->buffer_bytes;
4002              i < st_bp->frp_segs && offset >= length; i++)
4003                 offset -= length;
4004         if (i == st_bp->frp_segs) {     /* Should never happen */
4005                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4006                 return (-EIO);
4007         }
4008         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4009                 struct page *page = st_bp->reserved_pages[i];
4010                 cnt = length - offset < do_count ? length - offset : do_count;
4011                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4012                 if (res)
4013                         return (-EFAULT);
4014                 do_count -= cnt;
4015                 st_bp->buffer_bytes += cnt;
4016                 ubp += cnt;
4017                 offset = 0;
4018         }
4019         if (do_count) /* Should never happen */
4020                 return (-EIO);
4021
4022         return 0;
4023 }
4024
4025
4026 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4027    negative error code. */
4028 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4029 {
4030         int i, cnt, res, offset;
4031         int length = PAGE_SIZE << st_bp->reserved_page_order;
4032
4033         for (i = 0, offset = st_bp->read_pointer;
4034              i < st_bp->frp_segs && offset >= length; i++)
4035                 offset -= length;
4036         if (i == st_bp->frp_segs) {     /* Should never happen */
4037                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4038                 return (-EIO);
4039         }
4040         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4041                 struct page *page = st_bp->reserved_pages[i];
4042                 cnt = length - offset < do_count ? length - offset : do_count;
4043                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4044                 if (res)
4045                         return (-EFAULT);
4046                 do_count -= cnt;
4047                 st_bp->buffer_bytes -= cnt;
4048                 st_bp->read_pointer += cnt;
4049                 ubp += cnt;
4050                 offset = 0;
4051         }
4052         if (do_count) /* Should never happen */
4053                 return (-EIO);
4054
4055         return 0;
4056 }
4057
4058
4059 /* Move data towards start of buffer */
4060 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4061 {
4062         int src_seg, dst_seg, src_offset = 0, dst_offset;
4063         int count, total;
4064         int length = PAGE_SIZE << st_bp->reserved_page_order;
4065
4066         if (offset == 0)
4067                 return;
4068
4069         total=st_bp->buffer_bytes - offset;
4070         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4071                 src_offset = offset;
4072                 if (src_offset < length)
4073                         break;
4074                 offset -= length;
4075         }
4076
4077         st_bp->buffer_bytes = st_bp->read_pointer = total;
4078         for (dst_seg=dst_offset=0; total > 0; ) {
4079                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4080                 struct page *spage = st_bp->reserved_pages[src_seg];
4081
4082                 count = min(length - dst_offset, length - src_offset);
4083                 memmove(page_address(dpage) + dst_offset,
4084                         page_address(spage) + src_offset, count);
4085                 src_offset += count;
4086                 if (src_offset >= length) {
4087                         src_seg++;
4088                         src_offset = 0;
4089                 }
4090                 dst_offset += count;
4091                 if (dst_offset >= length) {
4092                         dst_seg++;
4093                         dst_offset = 0;
4094                 }
4095                 total -= count;
4096         }
4097 }
4098
4099 /* Validate the options from command line or module parameters */
4100 static void validate_options(void)
4101 {
4102         if (buffer_kbs > 0)
4103                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4104         if (max_sg_segs >= ST_FIRST_SG)
4105                 st_max_sg_segs = max_sg_segs;
4106 }
4107
4108 #ifndef MODULE
4109 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4110  */
4111 static int __init st_setup(char *str)
4112 {
4113         int i, len, ints[5];
4114         char *stp;
4115
4116         stp = get_options(str, ARRAY_SIZE(ints), ints);
4117
4118         if (ints[0] > 0) {
4119                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4120                         if (parms[i].val)
4121                                 *parms[i].val = ints[i + 1];
4122         } else {
4123                 while (stp != NULL) {
4124                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4125                                 len = strlen(parms[i].name);
4126                                 if (!strncmp(stp, parms[i].name, len) &&
4127                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4128                                         if (parms[i].val)
4129                                                 *parms[i].val =
4130                                                         simple_strtoul(stp + len + 1, NULL, 0);
4131                                         else
4132                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4133                                                        parms[i].name);
4134                                         break;
4135                                 }
4136                         }
4137                         if (i >= ARRAY_SIZE(parms))
4138                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4139                                         stp);
4140                         stp = strchr(stp, ',');
4141                         if (stp)
4142                                 stp++;
4143                 }
4144         }
4145
4146         validate_options();
4147
4148         return 1;
4149 }
4150
4151 __setup("st=", st_setup);
4152
4153 #endif
4154
4155 static const struct file_operations st_fops =
4156 {
4157         .owner =        THIS_MODULE,
4158         .read =         st_read,
4159         .write =        st_write,
4160         .unlocked_ioctl = st_ioctl,
4161 #ifdef CONFIG_COMPAT
4162         .compat_ioctl = st_compat_ioctl,
4163 #endif
4164         .open =         st_open,
4165         .flush =        st_flush,
4166         .release =      st_release,
4167         .llseek =       noop_llseek,
4168 };
4169
4170 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4171 {
4172         int i, error;
4173         dev_t cdev_devno;
4174         struct cdev *cdev;
4175         struct device *dev;
4176         struct st_modedef *STm = &(tape->modes[mode]);
4177         char name[10];
4178         int dev_num = tape->index;
4179
4180         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4181
4182         cdev = cdev_alloc();
4183         if (!cdev) {
4184                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4185                 error = -ENOMEM;
4186                 goto out;
4187         }
4188         cdev->owner = THIS_MODULE;
4189         cdev->ops = &st_fops;
4190         STm->cdevs[rew] = cdev;
4191
4192         error = cdev_add(cdev, cdev_devno, 1);
4193         if (error) {
4194                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4195                        rew ? "non" : "auto", mode);
4196                 pr_err("st%d: Device not attached.\n", dev_num);
4197                 goto out_free;
4198         }
4199
4200         i = mode << (4 - ST_NBR_MODE_BITS);
4201         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4202                  tape->disk->disk_name, st_formats[i]);
4203
4204         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4205                             cdev_devno, &tape->modes[mode], "%s", name);
4206         if (IS_ERR(dev)) {
4207                 pr_err("st%d: device_create failed\n", dev_num);
4208                 error = PTR_ERR(dev);
4209                 goto out_free;
4210         }
4211
4212         STm->devs[rew] = dev;
4213
4214         return 0;
4215 out_free:
4216         cdev_del(STm->cdevs[rew]);
4217 out:
4218         STm->cdevs[rew] = NULL;
4219         STm->devs[rew] = NULL;
4220         return error;
4221 }
4222
4223 static int create_cdevs(struct scsi_tape *tape)
4224 {
4225         int mode, error;
4226         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4227                 error = create_one_cdev(tape, mode, 0);
4228                 if (error)
4229                         return error;
4230                 error = create_one_cdev(tape, mode, 1);
4231                 if (error)
4232                         return error;
4233         }
4234
4235         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4236                                  &tape->modes[0].devs[0]->kobj, "tape");
4237 }
4238
4239 static void remove_cdevs(struct scsi_tape *tape)
4240 {
4241         int mode, rew;
4242         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4243         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4244                 struct st_modedef *STm = &(tape->modes[mode]);
4245                 for (rew = 0; rew < 2; rew++) {
4246                         if (STm->cdevs[rew])
4247                                 cdev_del(STm->cdevs[rew]);
4248                         if (STm->devs[rew])
4249                                 device_unregister(STm->devs[rew]);
4250                 }
4251         }
4252 }
4253
4254 static int st_probe(struct device *dev)
4255 {
4256         struct scsi_device *SDp = to_scsi_device(dev);
4257         struct gendisk *disk = NULL;
4258         struct scsi_tape *tpnt = NULL;
4259         struct st_modedef *STm;
4260         struct st_partstat *STps;
4261         struct st_buffer *buffer;
4262         int i, error;
4263         char *stp;
4264
4265         if (SDp->type != TYPE_TAPE)
4266                 return -ENODEV;
4267         if ((stp = st_incompatible(SDp))) {
4268                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4269                 sdev_printk(KERN_INFO, SDp,
4270                             "st: The suggested driver is %s.\n", stp);
4271                 return -ENODEV;
4272         }
4273
4274         scsi_autopm_get_device(SDp);
4275         i = queue_max_segments(SDp->request_queue);
4276         if (st_max_sg_segs < i)
4277                 i = st_max_sg_segs;
4278         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4279         if (buffer == NULL) {
4280                 sdev_printk(KERN_ERR, SDp,
4281                             "st: Can't allocate new tape buffer. "
4282                             "Device not attached.\n");
4283                 goto out;
4284         }
4285
4286         disk = alloc_disk(1);
4287         if (!disk) {
4288                 sdev_printk(KERN_ERR, SDp,
4289                             "st: out of memory. Device not attached.\n");
4290                 goto out_buffer_free;
4291         }
4292
4293         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4294         if (tpnt == NULL) {
4295                 sdev_printk(KERN_ERR, SDp,
4296                             "st: Can't allocate device descriptor.\n");
4297                 goto out_put_disk;
4298         }
4299         kref_init(&tpnt->kref);
4300         tpnt->disk = disk;
4301         disk->private_data = &tpnt->driver;
4302         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4303          * take queue reference that release_disk() expects. */
4304         if (!blk_get_queue(SDp->request_queue))
4305                 goto out_put_disk;
4306         disk->queue = SDp->request_queue;
4307         tpnt->driver = &st_template;
4308
4309         tpnt->device = SDp;
4310         if (SDp->scsi_level <= 2)
4311                 tpnt->tape_type = MT_ISSCSI1;
4312         else
4313                 tpnt->tape_type = MT_ISSCSI2;
4314
4315         tpnt->buffer = buffer;
4316         tpnt->buffer->last_SRpnt = NULL;
4317
4318         tpnt->inited = 0;
4319         tpnt->dirty = 0;
4320         tpnt->in_use = 0;
4321         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4322         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4323         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4324         tpnt->density = 0;
4325         tpnt->do_auto_lock = ST_AUTO_LOCK;
4326         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4327         tpnt->can_partitions = 0;
4328         tpnt->two_fm = ST_TWO_FM;
4329         tpnt->fast_mteom = ST_FAST_MTEOM;
4330         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4331         tpnt->sili = ST_SILI;
4332         tpnt->immediate = ST_NOWAIT;
4333         tpnt->immediate_filemark = 0;
4334         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4335         tpnt->partition = 0;
4336         tpnt->new_partition = 0;
4337         tpnt->nbr_partitions = 0;
4338         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4339         tpnt->long_timeout = ST_LONG_TIMEOUT;
4340         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4341
4342         for (i = 0; i < ST_NBR_MODES; i++) {
4343                 STm = &(tpnt->modes[i]);
4344                 STm->defined = 0;
4345                 STm->sysv = ST_SYSV;
4346                 STm->defaults_for_writes = 0;
4347                 STm->do_async_writes = ST_ASYNC_WRITES;
4348                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4349                 STm->do_read_ahead = ST_READ_AHEAD;
4350                 STm->default_compression = ST_DONT_TOUCH;
4351                 STm->default_blksize = (-1);    /* No forced size */
4352                 STm->default_density = (-1);    /* No forced density */
4353                 STm->tape = tpnt;
4354         }
4355
4356         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4357                 STps = &(tpnt->ps[i]);
4358                 STps->rw = ST_IDLE;
4359                 STps->eof = ST_NOEOF;
4360                 STps->at_sm = 0;
4361                 STps->last_block_valid = 0;
4362                 STps->drv_block = (-1);
4363                 STps->drv_file = (-1);
4364         }
4365
4366         tpnt->current_mode = 0;
4367         tpnt->modes[0].defined = 1;
4368
4369         tpnt->density_changed = tpnt->compression_changed =
4370             tpnt->blksize_changed = 0;
4371         mutex_init(&tpnt->lock);
4372
4373         idr_preload(GFP_KERNEL);
4374         spin_lock(&st_index_lock);
4375         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4376         spin_unlock(&st_index_lock);
4377         idr_preload_end();
4378         if (error < 0) {
4379                 pr_warn("st: idr allocation failed: %d\n", error);
4380                 goto out_put_queue;
4381         }
4382         tpnt->index = error;
4383         sprintf(disk->disk_name, "st%d", tpnt->index);
4384         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4385         if (tpnt->stats == NULL) {
4386                 sdev_printk(KERN_ERR, SDp,
4387                             "st: Can't allocate statistics.\n");
4388                 goto out_idr_remove;
4389         }
4390
4391         dev_set_drvdata(dev, tpnt);
4392
4393
4394         error = create_cdevs(tpnt);
4395         if (error)
4396                 goto out_remove_devs;
4397         scsi_autopm_put_device(SDp);
4398
4399         sdev_printk(KERN_NOTICE, SDp,
4400                     "Attached scsi tape %s\n", tape_name(tpnt));
4401         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4402                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4403                     queue_dma_alignment(SDp->request_queue) + 1);
4404
4405         return 0;
4406
4407 out_remove_devs:
4408         remove_cdevs(tpnt);
4409         kfree(tpnt->stats);
4410 out_idr_remove:
4411         spin_lock(&st_index_lock);
4412         idr_remove(&st_index_idr, tpnt->index);
4413         spin_unlock(&st_index_lock);
4414 out_put_queue:
4415         blk_put_queue(disk->queue);
4416 out_put_disk:
4417         put_disk(disk);
4418         kfree(tpnt);
4419 out_buffer_free:
4420         kfree(buffer);
4421 out:
4422         scsi_autopm_put_device(SDp);
4423         return -ENODEV;
4424 };
4425
4426
4427 static int st_remove(struct device *dev)
4428 {
4429         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4430         int index = tpnt->index;
4431
4432         scsi_autopm_get_device(to_scsi_device(dev));
4433         remove_cdevs(tpnt);
4434
4435         mutex_lock(&st_ref_mutex);
4436         kref_put(&tpnt->kref, scsi_tape_release);
4437         mutex_unlock(&st_ref_mutex);
4438         spin_lock(&st_index_lock);
4439         idr_remove(&st_index_idr, index);
4440         spin_unlock(&st_index_lock);
4441         return 0;
4442 }
4443
4444 /**
4445  *      scsi_tape_release - Called to free the Scsi_Tape structure
4446  *      @kref: pointer to embedded kref
4447  *
4448  *      st_ref_mutex must be held entering this routine.  Because it is
4449  *      called on last put, you should always use the scsi_tape_get()
4450  *      scsi_tape_put() helpers which manipulate the semaphore directly
4451  *      and never do a direct kref_put().
4452  **/
4453 static void scsi_tape_release(struct kref *kref)
4454 {
4455         struct scsi_tape *tpnt = to_scsi_tape(kref);
4456         struct gendisk *disk = tpnt->disk;
4457
4458         tpnt->device = NULL;
4459
4460         if (tpnt->buffer) {
4461                 normalize_buffer(tpnt->buffer);
4462                 kfree(tpnt->buffer->reserved_pages);
4463                 kfree(tpnt->buffer);
4464         }
4465
4466         disk->private_data = NULL;
4467         put_disk(disk);
4468         kfree(tpnt->stats);
4469         kfree(tpnt);
4470         return;
4471 }
4472
4473 static struct class st_sysfs_class = {
4474         .name = "scsi_tape",
4475         .dev_groups = st_dev_groups,
4476 };
4477
4478 static int __init init_st(void)
4479 {
4480         int err;
4481
4482         validate_options();
4483
4484         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4485                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4486
4487         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4488         if (debugging) {
4489                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4490                         debugging);
4491         }
4492
4493         err = class_register(&st_sysfs_class);
4494         if (err) {
4495                 pr_err("Unable register sysfs class for SCSI tapes\n");
4496                 return err;
4497         }
4498
4499         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4500                                      ST_MAX_TAPE_ENTRIES, "st");
4501         if (err) {
4502                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4503                        SCSI_TAPE_MAJOR);
4504                 goto err_class;
4505         }
4506
4507         err = scsi_register_driver(&st_template.gendrv);
4508         if (err)
4509                 goto err_chrdev;
4510
4511         return 0;
4512
4513 err_chrdev:
4514         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4515                                  ST_MAX_TAPE_ENTRIES);
4516 err_class:
4517         class_unregister(&st_sysfs_class);
4518         return err;
4519 }
4520
4521 static void __exit exit_st(void)
4522 {
4523         scsi_unregister_driver(&st_template.gendrv);
4524         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4525                                  ST_MAX_TAPE_ENTRIES);
4526         class_unregister(&st_sysfs_class);
4527         idr_destroy(&st_index_idr);
4528         printk(KERN_INFO "st: Unloaded.\n");
4529 }
4530
4531 module_init(init_st);
4532 module_exit(exit_st);
4533
4534
4535 /* The sysfs driver interface. Read-only at the moment */
4536 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4537 {
4538         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4539 }
4540 static DRIVER_ATTR_RO(try_direct_io);
4541
4542 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4543 {
4544         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4545 }
4546 static DRIVER_ATTR_RO(fixed_buffer_size);
4547
4548 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4549 {
4550         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4551 }
4552 static DRIVER_ATTR_RO(max_sg_segs);
4553
4554 static ssize_t version_show(struct device_driver *ddd, char *buf)
4555 {
4556         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4557 }
4558 static DRIVER_ATTR_RO(version);
4559
4560 #if DEBUG
4561 static ssize_t debug_flag_store(struct device_driver *ddp,
4562         const char *buf, size_t count)
4563 {
4564 /* We only care what the first byte of the data is the rest is unused.
4565  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4566  * other values have -EINVAL returned if they are passed in.
4567  */
4568         if (count > 0) {
4569                 if (buf[0] == '0') {
4570                         debugging = NO_DEBUG;
4571                         return count;
4572                 } else if (buf[0] == '1') {
4573                         debugging = 1;
4574                         return count;
4575                 }
4576         }
4577         return -EINVAL;
4578 }
4579
4580 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4581 {
4582         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4583 }
4584 static DRIVER_ATTR_RW(debug_flag);
4585 #endif
4586
4587 static struct attribute *st_drv_attrs[] = {
4588         &driver_attr_try_direct_io.attr,
4589         &driver_attr_fixed_buffer_size.attr,
4590         &driver_attr_max_sg_segs.attr,
4591         &driver_attr_version.attr,
4592 #if DEBUG
4593         &driver_attr_debug_flag.attr,
4594 #endif
4595         NULL,
4596 };
4597 ATTRIBUTE_GROUPS(st_drv);
4598
4599 /* The sysfs simple class interface */
4600 static ssize_t
4601 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4602 {
4603         struct st_modedef *STm = dev_get_drvdata(dev);
4604         ssize_t l = 0;
4605
4606         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4607         return l;
4608 }
4609 static DEVICE_ATTR_RO(defined);
4610
4611 static ssize_t
4612 default_blksize_show(struct device *dev, struct device_attribute *attr,
4613                      char *buf)
4614 {
4615         struct st_modedef *STm = dev_get_drvdata(dev);
4616         ssize_t l = 0;
4617
4618         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4619         return l;
4620 }
4621 static DEVICE_ATTR_RO(default_blksize);
4622
4623 static ssize_t
4624 default_density_show(struct device *dev, struct device_attribute *attr,
4625                      char *buf)
4626 {
4627         struct st_modedef *STm = dev_get_drvdata(dev);
4628         ssize_t l = 0;
4629         char *fmt;
4630
4631         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4632         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4633         return l;
4634 }
4635 static DEVICE_ATTR_RO(default_density);
4636
4637 static ssize_t
4638 default_compression_show(struct device *dev, struct device_attribute *attr,
4639                          char *buf)
4640 {
4641         struct st_modedef *STm = dev_get_drvdata(dev);
4642         ssize_t l = 0;
4643
4644         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4645         return l;
4646 }
4647 static DEVICE_ATTR_RO(default_compression);
4648
4649 static ssize_t
4650 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4651 {
4652         struct st_modedef *STm = dev_get_drvdata(dev);
4653         struct scsi_tape *STp = STm->tape;
4654         int options;
4655         ssize_t l = 0;
4656
4657         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4658         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4659         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4660         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4661         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4662         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4663         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4664         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4665         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4666         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4667         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4668         options |= STm->sysv ? MT_ST_SYSV : 0;
4669         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4670         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4671         options |= STp->sili ? MT_ST_SILI : 0;
4672
4673         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4674         return l;
4675 }
4676 static DEVICE_ATTR_RO(options);
4677
4678 /* Support for tape stats */
4679
4680 /**
4681  * read_cnt_show - return read count - count of reads made from tape drive
4682  * @dev: struct device
4683  * @attr: attribute structure
4684  * @buf: buffer to return formatted data in
4685  */
4686 static ssize_t read_cnt_show(struct device *dev,
4687         struct device_attribute *attr, char *buf)
4688 {
4689         struct st_modedef *STm = dev_get_drvdata(dev);
4690
4691         return sprintf(buf, "%lld",
4692                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4693 }
4694 static DEVICE_ATTR_RO(read_cnt);
4695
4696 /**
4697  * read_byte_cnt_show - return read byte count - tape drives
4698  * may use blocks less than 512 bytes this gives the raw byte count of
4699  * of data read from the tape drive.
4700  * @dev: struct device
4701  * @attr: attribute structure
4702  * @buf: buffer to return formatted data in
4703  */
4704 static ssize_t read_byte_cnt_show(struct device *dev,
4705         struct device_attribute *attr, char *buf)
4706 {
4707         struct st_modedef *STm = dev_get_drvdata(dev);
4708
4709         return sprintf(buf, "%lld",
4710                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4711 }
4712 static DEVICE_ATTR_RO(read_byte_cnt);
4713
4714 /**
4715  * read_us_show - return read us - overall time spent waiting on reads in ns.
4716  * @dev: struct device
4717  * @attr: attribute structure
4718  * @buf: buffer to return formatted data in
4719  */
4720 static ssize_t read_ns_show(struct device *dev,
4721         struct device_attribute *attr, char *buf)
4722 {
4723         struct st_modedef *STm = dev_get_drvdata(dev);
4724
4725         return sprintf(buf, "%lld",
4726                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4727 }
4728 static DEVICE_ATTR_RO(read_ns);
4729
4730 /**
4731  * write_cnt_show - write count - number of user calls
4732  * to write(2) that have written data to tape.
4733  * @dev: struct device
4734  * @attr: attribute structure
4735  * @buf: buffer to return formatted data in
4736  */
4737 static ssize_t write_cnt_show(struct device *dev,
4738         struct device_attribute *attr, char *buf)
4739 {
4740         struct st_modedef *STm = dev_get_drvdata(dev);
4741
4742         return sprintf(buf, "%lld",
4743                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4744 }
4745 static DEVICE_ATTR_RO(write_cnt);
4746
4747 /**
4748  * write_byte_cnt_show - write byte count - raw count of
4749  * bytes written to tape.
4750  * @dev: struct device
4751  * @attr: attribute structure
4752  * @buf: buffer to return formatted data in
4753  */
4754 static ssize_t write_byte_cnt_show(struct device *dev,
4755         struct device_attribute *attr, char *buf)
4756 {
4757         struct st_modedef *STm = dev_get_drvdata(dev);
4758
4759         return sprintf(buf, "%lld",
4760                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4761 }
4762 static DEVICE_ATTR_RO(write_byte_cnt);
4763
4764 /**
4765  * write_ns_show - write ns - number of nanoseconds waiting on write
4766  * requests to complete.
4767  * @dev: struct device
4768  * @attr: attribute structure
4769  * @buf: buffer to return formatted data in
4770  */
4771 static ssize_t write_ns_show(struct device *dev,
4772         struct device_attribute *attr, char *buf)
4773 {
4774         struct st_modedef *STm = dev_get_drvdata(dev);
4775
4776         return sprintf(buf, "%lld",
4777                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4778 }
4779 static DEVICE_ATTR_RO(write_ns);
4780
4781 /**
4782  * in_flight_show - number of I/Os currently in flight -
4783  * in most cases this will be either 0 or 1. It may be higher if someone
4784  * has also issued other SCSI commands such as via an ioctl.
4785  * @dev: struct device
4786  * @attr: attribute structure
4787  * @buf: buffer to return formatted data in
4788  */
4789 static ssize_t in_flight_show(struct device *dev,
4790         struct device_attribute *attr, char *buf)
4791 {
4792         struct st_modedef *STm = dev_get_drvdata(dev);
4793
4794         return sprintf(buf, "%lld",
4795                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4796 }
4797 static DEVICE_ATTR_RO(in_flight);
4798
4799 /**
4800  * io_ns_show - io wait ns - this is the number of ns spent
4801  * waiting on all I/O to complete. This includes tape movement commands
4802  * such as rewinding, seeking to end of file or tape, it also includes
4803  * read and write. To determine the time spent on tape movement
4804  * subtract the read and write ns from this value.
4805  * @dev: struct device
4806  * @attr: attribute structure
4807  * @buf: buffer to return formatted data in
4808  */
4809 static ssize_t io_ns_show(struct device *dev,
4810         struct device_attribute *attr, char *buf)
4811 {
4812         struct st_modedef *STm = dev_get_drvdata(dev);
4813
4814         return sprintf(buf, "%lld",
4815                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4816 }
4817 static DEVICE_ATTR_RO(io_ns);
4818
4819 /**
4820  * other_cnt_show - other io count - this is the number of
4821  * I/O requests other than read and write requests.
4822  * Typically these are tape movement requests but will include driver
4823  * tape movement. This includes only requests issued by the st driver.
4824  * @dev: struct device
4825  * @attr: attribute structure
4826  * @buf: buffer to return formatted data in
4827  */
4828 static ssize_t other_cnt_show(struct device *dev,
4829         struct device_attribute *attr, char *buf)
4830 {
4831         struct st_modedef *STm = dev_get_drvdata(dev);
4832
4833         return sprintf(buf, "%lld",
4834                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4835 }
4836 static DEVICE_ATTR_RO(other_cnt);
4837
4838 /**
4839  * resid_cnt_show - A count of the number of times we get a residual
4840  * count - this should indicate someone issuing reads larger than the
4841  * block size on tape.
4842  * @dev: struct device
4843  * @attr: attribute structure
4844  * @buf: buffer to return formatted data in
4845  */
4846 static ssize_t resid_cnt_show(struct device *dev,
4847         struct device_attribute *attr, char *buf)
4848 {
4849         struct st_modedef *STm = dev_get_drvdata(dev);
4850
4851         return sprintf(buf, "%lld",
4852                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4853 }
4854 static DEVICE_ATTR_RO(resid_cnt);
4855
4856 static struct attribute *st_dev_attrs[] = {
4857         &dev_attr_defined.attr,
4858         &dev_attr_default_blksize.attr,
4859         &dev_attr_default_density.attr,
4860         &dev_attr_default_compression.attr,
4861         &dev_attr_options.attr,
4862         NULL,
4863 };
4864
4865 static struct attribute *st_stats_attrs[] = {
4866         &dev_attr_read_cnt.attr,
4867         &dev_attr_read_byte_cnt.attr,
4868         &dev_attr_read_ns.attr,
4869         &dev_attr_write_cnt.attr,
4870         &dev_attr_write_byte_cnt.attr,
4871         &dev_attr_write_ns.attr,
4872         &dev_attr_in_flight.attr,
4873         &dev_attr_io_ns.attr,
4874         &dev_attr_other_cnt.attr,
4875         &dev_attr_resid_cnt.attr,
4876         NULL,
4877 };
4878
4879 static struct attribute_group stats_group = {
4880         .name = "stats",
4881         .attrs = st_stats_attrs,
4882 };
4883
4884 static struct attribute_group st_group = {
4885         .attrs = st_dev_attrs,
4886 };
4887
4888 static const struct attribute_group *st_dev_groups[] = {
4889         &st_group,
4890         &stats_group,
4891         NULL,
4892 };
4893
4894 /* The following functions may be useful for a larger audience. */
4895 static int sgl_map_user_pages(struct st_buffer *STbp,
4896                               const unsigned int max_pages, unsigned long uaddr,
4897                               size_t count, int rw)
4898 {
4899         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4900         unsigned long start = uaddr >> PAGE_SHIFT;
4901         const int nr_pages = end - start;
4902         int res, i, j;
4903         struct page **pages;
4904         struct rq_map_data *mdata = &STbp->map_data;
4905
4906         /* User attempted Overflow! */
4907         if ((uaddr + count) < uaddr)
4908                 return -EINVAL;
4909
4910         /* Too big */
4911         if (nr_pages > max_pages)
4912                 return -ENOMEM;
4913
4914         /* Hmm? */
4915         if (count == 0)
4916                 return 0;
4917
4918         if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4919                 return -ENOMEM;
4920
4921         /* Try to fault in all of the necessary pages */
4922         /* rw==READ means read from drive, write into memory area */
4923         res = get_user_pages_unlocked(
4924                 uaddr,
4925                 nr_pages,
4926                 pages,
4927                 rw == READ ? FOLL_WRITE : 0); /* don't force */
4928
4929         /* Errors and no page mapped should return here */
4930         if (res < nr_pages)
4931                 goto out_unmap;
4932
4933         for (i=0; i < nr_pages; i++) {
4934                 /* FIXME: flush superflous for rw==READ,
4935                  * probably wrong function for rw==WRITE
4936                  */
4937                 flush_dcache_page(pages[i]);
4938         }
4939
4940         mdata->offset = uaddr & ~PAGE_MASK;
4941         STbp->mapped_pages = pages;
4942
4943         return nr_pages;
4944  out_unmap:
4945         if (res > 0) {
4946                 for (j=0; j < res; j++)
4947                         put_page(pages[j]);
4948                 res = 0;
4949         }
4950         kfree(pages);
4951         return res;
4952 }
4953
4954
4955 /* And unmap them... */
4956 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4957                                 const unsigned int nr_pages, int dirtied)
4958 {
4959         int i;
4960
4961         for (i=0; i < nr_pages; i++) {
4962                 struct page *page = STbp->mapped_pages[i];
4963
4964                 if (dirtied)
4965                         SetPageDirty(page);
4966                 /* FIXME: cache flush missing for rw==READ
4967                  * FIXME: call the correct reference counting function
4968                  */
4969                 put_page(page);
4970         }
4971         kfree(STbp->mapped_pages);
4972         STbp->mapped_pages = NULL;
4973
4974         return 0;
4975 }