drivers/target/target_core_user.c

   1 /*
   2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
   3  * Copyright (C) 2014 Red Hat, Inc.
   4  * Copyright (C) 2015 Arrikto, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <linux/spinlock.h>
  21 #include <linux/module.h>
  22 #include <linux/idr.h>
  23 #include <linux/kernel.h>
  24 #include <linux/timer.h>
  25 #include <linux/parser.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/uio_driver.h>
  28 #include <linux/stringify.h>
  29 #include <linux/bitops.h>
  30 #include <linux/highmem.h>
  31 #include <linux/configfs.h>
  32 #include <net/genetlink.h>
  33 #include <scsi/scsi_common.h>
  34 #include <scsi/scsi_proto.h>
  35 #include <target/target_core_base.h>
  36 #include <target/target_core_fabric.h>
  37 #include <target/target_core_backend.h>
  38
  39 #include <linux/target_core_user.h>
  40
  41 /*
  42  * Define a shared-memory interface for LIO to pass SCSI commands and
  43  * data to userspace for processing. This is to allow backends that
  44  * are too complex for in-kernel support to be possible.
  45  *
  46  * It uses the UIO framework to do a lot of the device-creation and
  47  * introspection work for us.
  48  *
  49  * See the .h file for how the ring is laid out. Note that while the
  50  * command ring is defined, the particulars of the data area are
  51  * not. Offset values in the command entry point to other locations
  52  * internal to the mmap()ed area. There is separate space outside the
  53  * command ring for data buffers. This leaves maximum flexibility for
  54  * moving buffer allocations, or even page flipping or other
  55  * allocation techniques, without altering the command ring layout.
  56  *
  57  * SECURITY:
  58  * The user process must be assumed to be malicious. There's no way to
  59  * prevent it breaking the command ring protocol if it wants, but in
  60  * order to prevent other issues we must only ever read *data* from
  61  * the shared memory area, not offsets or sizes. This applies to
  62  * command ring entries as well as the mailbox. Extra code needed for
  63  * this may have a 'UAM' comment.
  64  */
  65
  66
  67 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
  68
  69 #define DATA_BLOCK_BITS 256
  70 #define DATA_BLOCK_SIZE 4096
  71
  72 #define CMDR_SIZE (16 * 4096)
  73 #define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
  74
  75 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
  76
  77 static struct device *tcmu_root_device;
  78
  79 struct tcmu_hba {
  80         u32 host_id;
  81 };
  82
  83 #define TCMU_CONFIG_LEN 256
  84
  85 struct tcmu_dev {
  86         struct se_device se_dev;
  87
  88         char *name;
  89         struct se_hba *hba;
  90
  91 #define TCMU_DEV_BIT_OPEN 0
  92 #define TCMU_DEV_BIT_BROKEN 1
  93         unsigned long flags;
  94
  95         struct uio_info uio_info;
  96
  97         struct tcmu_mailbox *mb_addr;
  98         size_t dev_size;
  99         u32 cmdr_size;
 100         u32 cmdr_last_cleaned;
 101         /* Offset of data area from start of mb */
 102         /* Must add data_off and mb_addr to get the address */
 103         size_t data_off;
 104         size_t data_size;
 105
 106         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
 107
 108         wait_queue_head_t wait_cmdr;
 109         /* TODO should this be a mutex? */
 110         spinlock_t cmdr_lock;
 111
 112         struct idr commands;
 113         spinlock_t commands_lock;
 114
 115         struct timer_list timeout;
 116         unsigned int cmd_time_out;
 117
 118         char dev_config[TCMU_CONFIG_LEN];
 119 };
 120
 121 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
 122
 123 #define CMDR_OFF sizeof(struct tcmu_mailbox)
 124
 125 struct tcmu_cmd {
 126         struct se_cmd *se_cmd;
 127         struct tcmu_dev *tcmu_dev;
 128
 129         uint16_t cmd_id;
 130
 131         /* Can't use se_cmd when cleaning up expired cmds, because if
 132            cmd has been completed then accessing se_cmd is off limits */
 133         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
 134
 135         unsigned long deadline;
 136
 137 #define TCMU_CMD_BIT_EXPIRED 0
 138         unsigned long flags;
 139 };
 140
 141 static struct kmem_cache *tcmu_cmd_cache;
 142
 143 /* multicast group */
 144 enum tcmu_multicast_groups {
 145         TCMU_MCGRP_CONFIG,
 146 };
 147
 148 static const struct genl_multicast_group tcmu_mcgrps[] = {
 149         [TCMU_MCGRP_CONFIG] = { .name = "config", },
 150 };
 151
 152 /* Our generic netlink family */
 153 static struct genl_family tcmu_genl_family __ro_after_init = {
 154         .module = THIS_MODULE,
 155         .hdrsize = 0,
 156         .name = "TCM-USER",
 157         .version = 1,
 158         .maxattr = TCMU_ATTR_MAX,
 159         .mcgrps = tcmu_mcgrps,
 160         .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
 161         .netnsok = true,
 162 };
 163
 164 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
 165 {
 166         struct se_device *se_dev = se_cmd->se_dev;
 167         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 168         struct tcmu_cmd *tcmu_cmd;
 169         int cmd_id;
 170
 171         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
 172         if (!tcmu_cmd)
 173                 return NULL;
 174
 175         tcmu_cmd->se_cmd = se_cmd;
 176         tcmu_cmd->tcmu_dev = udev;
 177         if (udev->cmd_time_out)
 178                 tcmu_cmd->deadline = jiffies +
 179                                         msecs_to_jiffies(udev->cmd_time_out);
 180
 181         idr_preload(GFP_KERNEL);
 182         spin_lock_irq(&udev->commands_lock);
 183         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
 184                 USHRT_MAX, GFP_NOWAIT);
 185         spin_unlock_irq(&udev->commands_lock);
 186         idr_preload_end();
 187
 188         if (cmd_id < 0) {
 189                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 190                 return NULL;
 191         }
 192         tcmu_cmd->cmd_id = cmd_id;
 193
 194         return tcmu_cmd;
 195 }
 196
 197 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
 198 {
 199         unsigned long offset = offset_in_page(vaddr);
 200
 201         size = round_up(size+offset, PAGE_SIZE);
 202         vaddr -= offset;
 203
 204         while (size) {
 205                 flush_dcache_page(virt_to_page(vaddr));
 206                 size -= PAGE_SIZE;
 207         }
 208 }
 209
 210 /*
 211  * Some ring helper functions. We don't assume size is a power of 2 so
 212  * we can't use circ_buf.h.
 213  */
 214 static inline size_t spc_used(size_t head, size_t tail, size_t size)
 215 {
 216         int diff = head - tail;
 217
 218         if (diff >= 0)
 219                 return diff;
 220         else
 221                 return size + diff;
 222 }
 223
 224 static inline size_t spc_free(size_t head, size_t tail, size_t size)
 225 {
 226         /* Keep 1 byte unused or we can't tell full from empty */
 227         return (size - spc_used(head, tail, size) - 1);
 228 }
 229
 230 static inline size_t head_to_end(size_t head, size_t size)
 231 {
 232         return size - head;
 233 }
 234
 235 static inline void new_iov(struct iovec **iov, int *iov_cnt,
 236                            struct tcmu_dev *udev)
 237 {
 238         struct iovec *iovec;
 239
 240         if (*iov_cnt != 0)
 241                 (*iov)++;
 242         (*iov_cnt)++;
 243
 244         iovec = *iov;
 245         memset(iovec, 0, sizeof(struct iovec));
 246 }
 247
 248 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
 249
 250 /* offset is relative to mb_addr */
 251 static inline size_t get_block_offset(struct tcmu_dev *dev,
 252                 int block, int remaining)
 253 {
 254         return dev->data_off + block * DATA_BLOCK_SIZE +
 255                 DATA_BLOCK_SIZE - remaining;
 256 }
 257
 258 static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov)
 259 {
 260         return (size_t)iov->iov_base + iov->iov_len;
 261 }
 262
 263 static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
 264         struct scatterlist *data_sg, unsigned int data_nents,
 265         struct iovec **iov, int *iov_cnt, bool copy_data)
 266 {
 267         int i, block;
 268         int block_remaining = 0;
 269         void *from, *to;
 270         size_t copy_bytes, to_offset;
 271         struct scatterlist *sg;
 272
 273         for_each_sg(data_sg, sg, data_nents, i) {
 274                 int sg_remaining = sg->length;
 275                 from = kmap_atomic(sg_page(sg)) + sg->offset;
 276                 while (sg_remaining > 0) {
 277                         if (block_remaining == 0) {
 278                                 block = find_first_zero_bit(udev->data_bitmap,
 279                                                 DATA_BLOCK_BITS);
 280                                 block_remaining = DATA_BLOCK_SIZE;
 281                                 set_bit(block, udev->data_bitmap);
 282                         }
 283                         copy_bytes = min_t(size_t, sg_remaining,
 284                                         block_remaining);
 285                         to_offset = get_block_offset(udev, block,
 286                                         block_remaining);
 287                         to = (void *)udev->mb_addr + to_offset;
 288                         if (*iov_cnt != 0 &&
 289                             to_offset == iov_tail(udev, *iov)) {
 290                                 (*iov)->iov_len += copy_bytes;
 291                         } else {
 292                                 new_iov(iov, iov_cnt, udev);
 293                                 (*iov)->iov_base = (void __user *) to_offset;
 294                                 (*iov)->iov_len = copy_bytes;
 295                         }
 296                         if (copy_data) {
 297                                 memcpy(to, from + sg->length - sg_remaining,
 298                                         copy_bytes);
 299                                 tcmu_flush_dcache_range(to, copy_bytes);
 300                         }
 301                         sg_remaining -= copy_bytes;
 302                         block_remaining -= copy_bytes;
 303                 }
 304                 kunmap_atomic(from - sg->offset);
 305         }
 306 }
 307
 308 static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd)
 309 {
 310         bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap,
 311                    DATA_BLOCK_BITS);
 312 }
 313
 314 static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
 315                              bool bidi)
 316 {
 317         struct se_cmd *se_cmd = cmd->se_cmd;
 318         int i, block;
 319         int block_remaining = 0;
 320         void *from, *to;
 321         size_t copy_bytes, from_offset;
 322         struct scatterlist *sg, *data_sg;
 323         unsigned int data_nents;
 324         DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 325
 326         bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 327
 328         if (!bidi) {
 329                 data_sg = se_cmd->t_data_sg;
 330                 data_nents = se_cmd->t_data_nents;
 331         } else {
 332                 uint32_t count;
 333
 334                 /*
 335                  * For bidi case, the first count blocks are for Data-Out
 336                  * buffer blocks, and before gathering the Data-In buffer
 337                  * the Data-Out buffer blocks should be discarded.
 338                  */
 339                 count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
 340                 while (count--) {
 341                         block = find_first_bit(bitmap, DATA_BLOCK_BITS);
 342                         clear_bit(block, bitmap);
 343                 }
 344
 345                 data_sg = se_cmd->t_bidi_data_sg;
 346                 data_nents = se_cmd->t_bidi_data_nents;
 347         }
 348
 349         for_each_sg(data_sg, sg, data_nents, i) {
 350                 int sg_remaining = sg->length;
 351                 to = kmap_atomic(sg_page(sg)) + sg->offset;
 352                 while (sg_remaining > 0) {
 353                         if (block_remaining == 0) {
 354                                 block = find_first_bit(bitmap,
 355                                                 DATA_BLOCK_BITS);
 356                                 block_remaining = DATA_BLOCK_SIZE;
 357                                 clear_bit(block, bitmap);
 358                         }
 359                         copy_bytes = min_t(size_t, sg_remaining,
 360                                         block_remaining);
 361                         from_offset = get_block_offset(udev, block,
 362                                         block_remaining);
 363                         from = (void *) udev->mb_addr + from_offset;
 364                         tcmu_flush_dcache_range(from, copy_bytes);
 365                         memcpy(to + sg->length - sg_remaining, from,
 366                                         copy_bytes);
 367
 368                         sg_remaining -= copy_bytes;
 369                         block_remaining -= copy_bytes;
 370                 }
 371                 kunmap_atomic(to - sg->offset);
 372         }
 373 }
 374
 375 static inline size_t spc_bitmap_free(unsigned long *bitmap)
 376 {
 377         return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
 378                         bitmap_weight(bitmap, DATA_BLOCK_BITS));
 379 }
 380
 381 /*
 382  * We can't queue a command until we have space available on the cmd ring *and*
 383  * space available on the data area.
 384  *
 385  * Called with ring lock held.
 386  */
 387 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
 388 {
 389         struct tcmu_mailbox *mb = udev->mb_addr;
 390         size_t space, cmd_needed;
 391         u32 cmd_head;
 392
 393         tcmu_flush_dcache_range(mb, sizeof(*mb));
 394
 395         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 396
 397         /*
 398          * If cmd end-of-ring space is too small then we need space for a NOP plus
 399          * original cmd - cmds are internally contiguous.
 400          */
 401         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
 402                 cmd_needed = cmd_size;
 403         else
 404                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
 405
 406         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
 407         if (space < cmd_needed) {
 408                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
 409                        udev->cmdr_last_cleaned, udev->cmdr_size);
 410                 return false;
 411         }
 412
 413         space = spc_bitmap_free(udev->data_bitmap);
 414         if (space < data_needed) {
 415                 pr_debug("no data space: only %zu available, but ask for %zu\n",
 416                                 space, data_needed);
 417                 return false;
 418         }
 419
 420         return true;
 421 }
 422
 423 static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
 424 {
 425         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 426         size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
 427
 428         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 429                 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
 430                 data_length += round_up(se_cmd->t_bidi_data_sg->length,
 431                                 DATA_BLOCK_SIZE);
 432         }
 433
 434         return data_length;
 435 }
 436
 437 static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
 438 {
 439         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
 440
 441         return data_length / DATA_BLOCK_SIZE;
 442 }
 443
 444 static sense_reason_t
 445 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 446 {
 447         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 448         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 449         size_t base_command_size, command_size;
 450         struct tcmu_mailbox *mb;
 451         struct tcmu_cmd_entry *entry;
 452         struct iovec *iov;
 453         int iov_cnt;
 454         uint32_t cmd_head;
 455         uint64_t cdb_off;
 456         bool copy_to_data_area;
 457         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
 458         DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
 459
 460         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
 461                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 462
 463         /*
 464          * Must be a certain minimum size for response sense info, but
 465          * also may be larger if the iov array is large.
 466          *
 467          * We prepare way too many iovs for potential uses here, because it's
 468          * expensive to tell how many regions are freed in the bitmap
 469         */
 470         base_command_size = max(offsetof(struct tcmu_cmd_entry,
 471                                 req.iov[tcmu_cmd_get_block_cnt(tcmu_cmd)]),
 472                                 sizeof(struct tcmu_cmd_entry));
 473         command_size = base_command_size
 474                 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
 475
 476         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
 477
 478         spin_lock_irq(&udev->cmdr_lock);
 479
 480         mb = udev->mb_addr;
 481         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 482         if ((command_size > (udev->cmdr_size / 2)) ||
 483             data_length > udev->data_size) {
 484                 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
 485                         "cmd ring/data area\n", command_size, data_length,
 486                         udev->cmdr_size, udev->data_size);
 487                 spin_unlock_irq(&udev->cmdr_lock);
 488                 return TCM_INVALID_CDB_FIELD;
 489         }
 490
 491         while (!is_ring_space_avail(udev, command_size, data_length)) {
 492                 int ret;
 493                 DEFINE_WAIT(__wait);
 494
 495                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
 496
 497                 pr_debug("sleeping for ring space\n");
 498                 spin_unlock_irq(&udev->cmdr_lock);
 499                 if (udev->cmd_time_out)
 500                         ret = schedule_timeout(
 501                                         msecs_to_jiffies(udev->cmd_time_out));
 502                 else
 503                         ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
 504                 finish_wait(&udev->wait_cmdr, &__wait);
 505                 if (!ret) {
 506                         pr_warn("tcmu: command timed out\n");
 507                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 508                 }
 509
 510                 spin_lock_irq(&udev->cmdr_lock);
 511
 512                 /* We dropped cmdr_lock, cmd_head is stale */
 513                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 514         }
 515
 516         /* Insert a PAD if end-of-ring space is too small */
 517         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
 518                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
 519
 520                 entry = (void *) mb + CMDR_OFF + cmd_head;
 521                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 522                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
 523                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
 524                 entry->hdr.cmd_id = 0; /* not used for PAD */
 525                 entry->hdr.kflags = 0;
 526                 entry->hdr.uflags = 0;
 527
 528                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
 529
 530                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 531                 WARN_ON(cmd_head != 0);
 532         }
 533
 534         entry = (void *) mb + CMDR_OFF + cmd_head;
 535         tcmu_flush_dcache_range(entry, sizeof(*entry));
 536         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
 537         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
 538         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
 539         entry->hdr.kflags = 0;
 540         entry->hdr.uflags = 0;
 541
 542         bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);
 543
 544         /* Handle allocating space from the data area */
 545         iov = &entry->req.iov[0];
 546         iov_cnt = 0;
 547         copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
 548                 || se_cmd->se_cmd_flags & SCF_BIDI);
 549         alloc_and_scatter_data_area(udev, se_cmd->t_data_sg,
 550                 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area);
 551         entry->req.iov_cnt = iov_cnt;
 552         entry->req.iov_dif_cnt = 0;
 553
 554         /* Handle BIDI commands */
 555         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 556                 iov_cnt = 0;
 557                 iov++;
 558                 alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
 559                                 se_cmd->t_bidi_data_nents, &iov, &iov_cnt,
 560                                 false);
 561                 entry->req.iov_bidi_cnt = iov_cnt;
 562         }
 563         /* cmd's data_bitmap is what changed in process */
 564         bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
 565                         DATA_BLOCK_BITS);
 566
 567         /* All offsets relative to mb_addr, not start of entry! */
 568         cdb_off = CMDR_OFF + cmd_head + base_command_size;
 569         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
 570         entry->req.cdb_off = cdb_off;
 571         tcmu_flush_dcache_range(entry, sizeof(*entry));
 572
 573         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
 574         tcmu_flush_dcache_range(mb, sizeof(*mb));
 575
 576         spin_unlock_irq(&udev->cmdr_lock);
 577
 578         /* TODO: only if FLUSH and FUA? */
 579         uio_event_notify(&udev->uio_info);
 580
 581         if (udev->cmd_time_out)
 582                 mod_timer(&udev->timeout, round_jiffies_up(jiffies +
 583                           msecs_to_jiffies(udev->cmd_time_out)));
 584
 585         return TCM_NO_SENSE;
 586 }
 587
 588 static sense_reason_t
 589 tcmu_queue_cmd(struct se_cmd *se_cmd)
 590 {
 591         struct se_device *se_dev = se_cmd->se_dev;
 592         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 593         struct tcmu_cmd *tcmu_cmd;
 594         sense_reason_t ret;
 595
 596         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
 597         if (!tcmu_cmd)
 598                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 599
 600         ret = tcmu_queue_cmd_ring(tcmu_cmd);
 601         if (ret != TCM_NO_SENSE) {
 602                 pr_err("TCMU: Could not queue command\n");
 603                 spin_lock_irq(&udev->commands_lock);
 604                 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
 605                 spin_unlock_irq(&udev->commands_lock);
 606
 607                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 608         }
 609
 610         return ret;
 611 }
 612
 613 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
 614 {
 615         struct se_cmd *se_cmd = cmd->se_cmd;
 616         struct tcmu_dev *udev = cmd->tcmu_dev;
 617
 618         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 619                 /*
 620                  * cmd has been completed already from timeout, just reclaim
 621                  * data area space and free cmd
 622                  */
 623                 free_data_area(udev, cmd);
 624
 625                 kmem_cache_free(tcmu_cmd_cache, cmd);
 626                 return;
 627         }
 628
 629         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
 630                 free_data_area(udev, cmd);
 631                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
 632                         cmd->se_cmd);
 633                 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
 634         } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
 635                 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
 636                                se_cmd->scsi_sense_length);
 637                 free_data_area(udev, cmd);
 638         } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
 639                 /* Get Data-In buffer before clean up */
 640                 gather_data_area(udev, cmd, true);
 641                 free_data_area(udev, cmd);
 642         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
 643                 gather_data_area(udev, cmd, false);
 644                 free_data_area(udev, cmd);
 645         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
 646                 free_data_area(udev, cmd);
 647         } else if (se_cmd->data_direction != DMA_NONE) {
 648                 pr_warn("TCMU: data direction was %d!\n",
 649                         se_cmd->data_direction);
 650         }
 651
 652         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
 653         cmd->se_cmd = NULL;
 654
 655         kmem_cache_free(tcmu_cmd_cache, cmd);
 656 }
 657
 658 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
 659 {
 660         struct tcmu_mailbox *mb;
 661         unsigned long flags;
 662         int handled = 0;
 663
 664         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
 665                 pr_err("ring broken, not handling completions\n");
 666                 return 0;
 667         }
 668
 669         spin_lock_irqsave(&udev->cmdr_lock, flags);
 670
 671         mb = udev->mb_addr;
 672         tcmu_flush_dcache_range(mb, sizeof(*mb));
 673
 674         while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
 675
 676                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
 677                 struct tcmu_cmd *cmd;
 678
 679                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 680
 681                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
 682                         UPDATE_HEAD(udev->cmdr_last_cleaned,
 683                                     tcmu_hdr_get_len(entry->hdr.len_op),
 684                                     udev->cmdr_size);
 685                         continue;
 686                 }
 687                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
 688
 689                 spin_lock(&udev->commands_lock);
 690                 cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
 691                 spin_unlock(&udev->commands_lock);
 692
 693                 if (!cmd) {
 694                         pr_err("cmd_id not found, ring is broken\n");
 695                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
 696                         break;
 697                 }
 698
 699                 tcmu_handle_completion(cmd, entry);
 700
 701                 UPDATE_HEAD(udev->cmdr_last_cleaned,
 702                             tcmu_hdr_get_len(entry->hdr.len_op),
 703                             udev->cmdr_size);
 704
 705                 handled++;
 706         }
 707
 708         if (mb->cmd_tail == mb->cmd_head)
 709                 del_timer(&udev->timeout); /* no more pending cmds */
 710
 711         spin_unlock_irqrestore(&udev->cmdr_lock, flags);
 712
 713         wake_up(&udev->wait_cmdr);
 714
 715         return handled;
 716 }
 717
 718 static int tcmu_check_expired_cmd(int id, void *p, void *data)
 719 {
 720         struct tcmu_cmd *cmd = p;
 721
 722         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
 723                 return 0;
 724
 725         if (!time_after(jiffies, cmd->deadline))
 726                 return 0;
 727
 728         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
 729         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
 730         cmd->se_cmd = NULL;
 731
 732         return 0;
 733 }
 734
 735 static void tcmu_device_timedout(unsigned long data)
 736 {
 737         struct tcmu_dev *udev = (struct tcmu_dev *)data;
 738         unsigned long flags;
 739         int handled;
 740
 741         handled = tcmu_handle_completions(udev);
 742
 743         pr_warn("%d completions handled from timeout\n", handled);
 744
 745         spin_lock_irqsave(&udev->commands_lock, flags);
 746         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
 747         spin_unlock_irqrestore(&udev->commands_lock, flags);
 748
 749         /*
 750          * We don't need to wakeup threads on wait_cmdr since they have their
 751          * own timeout.
 752          */
 753 }
 754
 755 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
 756 {
 757         struct tcmu_hba *tcmu_hba;
 758
 759         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
 760         if (!tcmu_hba)
 761                 return -ENOMEM;
 762
 763         tcmu_hba->host_id = host_id;
 764         hba->hba_ptr = tcmu_hba;
 765
 766         return 0;
 767 }
 768
 769 static void tcmu_detach_hba(struct se_hba *hba)
 770 {
 771         kfree(hba->hba_ptr);
 772         hba->hba_ptr = NULL;
 773 }
 774
 775 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
 776 {
 777         struct tcmu_dev *udev;
 778
 779         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
 780         if (!udev)
 781                 return NULL;
 782
 783         udev->name = kstrdup(name, GFP_KERNEL);
 784         if (!udev->name) {
 785                 kfree(udev);
 786                 return NULL;
 787         }
 788
 789         udev->hba = hba;
 790         udev->cmd_time_out = TCMU_TIME_OUT;
 791
 792         init_waitqueue_head(&udev->wait_cmdr);
 793         spin_lock_init(&udev->cmdr_lock);
 794
 795         idr_init(&udev->commands);
 796         spin_lock_init(&udev->commands_lock);
 797
 798         setup_timer(&udev->timeout, tcmu_device_timedout,
 799                 (unsigned long)udev);
 800
 801         return &udev->se_dev;
 802 }
 803
 804 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
 805 {
 806         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
 807
 808         tcmu_handle_completions(tcmu_dev);
 809
 810         return 0;
 811 }
 812
 813 /*
 814  * mmap code from uio.c. Copied here because we want to hook mmap()
 815  * and this stuff must come along.
 816  */
 817 static int tcmu_find_mem_index(struct vm_area_struct *vma)
 818 {
 819         struct tcmu_dev *udev = vma->vm_private_data;
 820         struct uio_info *info = &udev->uio_info;
 821
 822         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 823                 if (info->mem[vma->vm_pgoff].size == 0)
 824                         return -1;
 825                 return (int)vma->vm_pgoff;
 826         }
 827         return -1;
 828 }
 829
 830 static int tcmu_vma_fault(struct vm_fault *vmf)
 831 {
 832         struct tcmu_dev *udev = vmf->vma->vm_private_data;
 833         struct uio_info *info = &udev->uio_info;
 834         struct page *page;
 835         unsigned long offset;
 836         void *addr;
 837
 838         int mi = tcmu_find_mem_index(vmf->vma);
 839         if (mi < 0)
 840                 return VM_FAULT_SIGBUS;
 841
 842         /*
 843          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 844          * to use mem[N].
 845          */
 846         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 847
 848         addr = (void *)(unsigned long)info->mem[mi].addr + offset;
 849         if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
 850                 page = virt_to_page(addr);
 851         else
 852                 page = vmalloc_to_page(addr);
 853         get_page(page);
 854         vmf->page = page;
 855         return 0;
 856 }
 857
 858 static const struct vm_operations_struct tcmu_vm_ops = {
 859         .fault = tcmu_vma_fault,
 860 };
 861
 862 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
 863 {
 864         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 865
 866         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 867         vma->vm_ops = &tcmu_vm_ops;
 868
 869         vma->vm_private_data = udev;
 870
 871         /* Ensure the mmap is exactly the right size */
 872         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
 873                 return -EINVAL;
 874
 875         return 0;
 876 }
 877
 878 static int tcmu_open(struct uio_info *info, struct inode *inode)
 879 {
 880         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 881
 882         /* O_EXCL not supported for char devs, so fake it? */
 883         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
 884                 return -EBUSY;
 885
 886         pr_debug("open\n");
 887
 888         return 0;
 889 }
 890
 891 static int tcmu_release(struct uio_info *info, struct inode *inode)
 892 {
 893         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 894
 895         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
 896
 897         pr_debug("close\n");
 898
 899         return 0;
 900 }
 901
 902 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
 903 {
 904         struct sk_buff *skb;
 905         void *msg_header;
 906         int ret = -ENOMEM;
 907
 908         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 909         if (!skb)
 910                 return ret;
 911
 912         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
 913         if (!msg_header)
 914                 goto free_skb;
 915
 916         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
 917         if (ret < 0)
 918                 goto free_skb;
 919
 920         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
 921         if (ret < 0)
 922                 goto free_skb;
 923
 924         genlmsg_end(skb, msg_header);
 925
 926         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
 927                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
 928
 929         /* We don't care if no one is listening */
 930         if (ret == -ESRCH)
 931                 ret = 0;
 932
 933         return ret;
 934 free_skb:
 935         nlmsg_free(skb);
 936         return ret;
 937 }
 938
 939 static int tcmu_configure_device(struct se_device *dev)
 940 {
 941         struct tcmu_dev *udev = TCMU_DEV(dev);
 942         struct tcmu_hba *hba = udev->hba->hba_ptr;
 943         struct uio_info *info;
 944         struct tcmu_mailbox *mb;
 945         size_t size;
 946         size_t used;
 947         int ret = 0;
 948         char *str;
 949
 950         info = &udev->uio_info;
 951
 952         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
 953                         udev->dev_config);
 954         size += 1; /* for \0 */
 955         str = kmalloc(size, GFP_KERNEL);
 956         if (!str)
 957                 return -ENOMEM;
 958
 959         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
 960
 961         if (udev->dev_config[0])
 962                 snprintf(str + used, size - used, "/%s", udev->dev_config);
 963
 964         info->name = str;
 965
 966         udev->mb_addr = vzalloc(TCMU_RING_SIZE);
 967         if (!udev->mb_addr) {
 968                 ret = -ENOMEM;
 969                 goto err_vzalloc;
 970         }
 971
 972         /* mailbox fits in first part of CMDR space */
 973         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
 974         udev->data_off = CMDR_SIZE;
 975         udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
 976
 977         mb = udev->mb_addr;
 978         mb->version = TCMU_MAILBOX_VERSION;
 979         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
 980         mb->cmdr_off = CMDR_OFF;
 981         mb->cmdr_size = udev->cmdr_size;
 982
 983         WARN_ON(!PAGE_ALIGNED(udev->data_off));
 984         WARN_ON(udev->data_size % PAGE_SIZE);
 985         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
 986
 987         info->version = __stringify(TCMU_MAILBOX_VERSION);
 988
 989         info->mem[0].name = "tcm-user command & data buffer";
 990         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
 991         info->mem[0].size = TCMU_RING_SIZE;
 992         info->mem[0].memtype = UIO_MEM_VIRTUAL;
 993
 994         info->irqcontrol = tcmu_irqcontrol;
 995         info->irq = UIO_IRQ_CUSTOM;
 996
 997         info->mmap = tcmu_mmap;
 998         info->open = tcmu_open;
 999         info->release = tcmu_release;
1000
1001         ret = uio_register_device(tcmu_root_device, info);
1002         if (ret)
1003                 goto err_register;
1004
1005         /* User can set hw_block_size before enable the device */
1006         if (dev->dev_attrib.hw_block_size == 0)
1007                 dev->dev_attrib.hw_block_size = 512;
1008         /* Other attributes can be configured in userspace */
1009         if (!dev->dev_attrib.hw_max_sectors)
1010                 dev->dev_attrib.hw_max_sectors = 128;
1011         dev->dev_attrib.hw_queue_depth = 128;
1012
1013         ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
1014                                  udev->uio_info.uio_dev->minor);
1015         if (ret)
1016                 goto err_netlink;
1017
1018         return 0;
1019
1020 err_netlink:
1021         uio_unregister_device(&udev->uio_info);
1022 err_register:
1023         vfree(udev->mb_addr);
1024 err_vzalloc:
1025         kfree(info->name);
1026
1027         return ret;
1028 }
1029
1030 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
1031 {
1032         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1033                 kmem_cache_free(tcmu_cmd_cache, cmd);
1034                 return 0;
1035         }
1036         return -EINVAL;
1037 }
1038
1039 static void tcmu_dev_call_rcu(struct rcu_head *p)
1040 {
1041         struct se_device *dev = container_of(p, struct se_device, rcu_head);
1042         struct tcmu_dev *udev = TCMU_DEV(dev);
1043
1044         kfree(udev);
1045 }
1046
1047 static bool tcmu_dev_configured(struct tcmu_dev *udev)
1048 {
1049         return udev->uio_info.uio_dev ? true : false;
1050 }
1051
1052 static void tcmu_free_device(struct se_device *dev)
1053 {
1054         struct tcmu_dev *udev = TCMU_DEV(dev);
1055         struct tcmu_cmd *cmd;
1056         bool all_expired = true;
1057         int i;
1058
1059         del_timer_sync(&udev->timeout);
1060
1061         vfree(udev->mb_addr);
1062
1063         /* Upper layer should drain all requests before calling this */
1064         spin_lock_irq(&udev->commands_lock);
1065         idr_for_each_entry(&udev->commands, cmd, i) {
1066                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1067                         all_expired = false;
1068         }
1069         idr_destroy(&udev->commands);
1070         spin_unlock_irq(&udev->commands_lock);
1071         WARN_ON(!all_expired);
1072
1073         if (tcmu_dev_configured(udev)) {
1074                 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
1075                                    udev->uio_info.uio_dev->minor);
1076
1077                 uio_unregister_device(&udev->uio_info);
1078                 kfree(udev->uio_info.name);
1079                 kfree(udev->name);
1080         }
1081         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1082 }
1083
1084 enum {
1085         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
1086         Opt_err,
1087 };
1088
1089 static match_table_t tokens = {
1090         {Opt_dev_config, "dev_config=%s"},
1091         {Opt_dev_size, "dev_size=%u"},
1092         {Opt_hw_block_size, "hw_block_size=%u"},
1093         {Opt_hw_max_sectors, "hw_max_sectors=%u"},
1094         {Opt_err, NULL}
1095 };
1096
1097 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
1098 {
1099         unsigned long tmp_ul;
1100         char *arg_p;
1101         int ret;
1102
1103         arg_p = match_strdup(arg);
1104         if (!arg_p)
1105                 return -ENOMEM;
1106
1107         ret = kstrtoul(arg_p, 0, &tmp_ul);
1108         kfree(arg_p);
1109         if (ret < 0) {
1110                 pr_err("kstrtoul() failed for dev attrib\n");
1111                 return ret;
1112         }
1113         if (!tmp_ul) {
1114                 pr_err("dev attrib must be nonzero\n");
1115                 return -EINVAL;
1116         }
1117         *dev_attrib = tmp_ul;
1118         return 0;
1119 }
1120
1121 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1122                 const char *page, ssize_t count)
1123 {
1124         struct tcmu_dev *udev = TCMU_DEV(dev);
1125         char *orig, *ptr, *opts, *arg_p;
1126         substring_t args[MAX_OPT_ARGS];
1127         int ret = 0, token;
1128
1129         opts = kstrdup(page, GFP_KERNEL);
1130         if (!opts)
1131                 return -ENOMEM;
1132
1133         orig = opts;
1134
1135         while ((ptr = strsep(&opts, ",\n")) != NULL) {
1136                 if (!*ptr)
1137                         continue;
1138
1139                 token = match_token(ptr, tokens, args);
1140                 switch (token) {
1141                 case Opt_dev_config:
1142                         if (match_strlcpy(udev->dev_config, &args[0],
1143                                           TCMU_CONFIG_LEN) == 0) {
1144                                 ret = -EINVAL;
1145                                 break;
1146                         }
1147                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1148                         break;
1149                 case Opt_dev_size:
1150                         arg_p = match_strdup(&args[0]);
1151                         if (!arg_p) {
1152                                 ret = -ENOMEM;
1153                                 break;
1154                         }
1155                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1156                         kfree(arg_p);
1157                         if (ret < 0)
1158                                 pr_err("kstrtoul() failed for dev_size=\n");
1159                         break;
1160                 case Opt_hw_block_size:
1161                         ret = tcmu_set_dev_attrib(&args[0],
1162                                         &(dev->dev_attrib.hw_block_size));
1163                         break;
1164                 case Opt_hw_max_sectors:
1165                         ret = tcmu_set_dev_attrib(&args[0],
1166                                         &(dev->dev_attrib.hw_max_sectors));
1167                         break;
1168                 default:
1169                         break;
1170                 }
1171
1172                 if (ret)
1173                         break;
1174         }
1175
1176         kfree(orig);
1177         return (!ret) ? count : ret;
1178 }
1179
1180 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1181 {
1182         struct tcmu_dev *udev = TCMU_DEV(dev);
1183         ssize_t bl = 0;
1184
1185         bl = sprintf(b + bl, "Config: %s ",
1186                      udev->dev_config[0] ? udev->dev_config : "NULL");
1187         bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1188
1189         return bl;
1190 }
1191
1192 static sector_t tcmu_get_blocks(struct se_device *dev)
1193 {
1194         struct tcmu_dev *udev = TCMU_DEV(dev);
1195
1196         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1197                        dev->dev_attrib.block_size);
1198 }
1199
1200 static sense_reason_t
1201 tcmu_parse_cdb(struct se_cmd *cmd)
1202 {
1203         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
1204 }
1205
1206 static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
1207 {
1208         struct se_dev_attrib *da = container_of(to_config_group(item),
1209                                         struct se_dev_attrib, da_group);
1210         struct tcmu_dev *udev = container_of(da->da_dev,
1211                                         struct tcmu_dev, se_dev);
1212
1213         return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
1214 }
1215
1216 static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
1217                                        size_t count)
1218 {
1219         struct se_dev_attrib *da = container_of(to_config_group(item),
1220                                         struct se_dev_attrib, da_group);
1221         struct tcmu_dev *udev = container_of(da->da_dev,
1222                                         struct tcmu_dev, se_dev);
1223         u32 val;
1224         int ret;
1225
1226         if (da->da_dev->export_count) {
1227                 pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
1228                 return -EINVAL;
1229         }
1230
1231         ret = kstrtou32(page, 0, &val);
1232         if (ret < 0)
1233                 return ret;
1234
1235         udev->cmd_time_out = val * MSEC_PER_SEC;
1236         return count;
1237 }
1238 CONFIGFS_ATTR(tcmu_, cmd_time_out);
1239
1240 static struct configfs_attribute **tcmu_attrs;
1241
1242 static struct target_backend_ops tcmu_ops = {
1243         .name                   = "user",
1244         .owner                  = THIS_MODULE,
1245         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1246         .attach_hba             = tcmu_attach_hba,
1247         .detach_hba             = tcmu_detach_hba,
1248         .alloc_device           = tcmu_alloc_device,
1249         .configure_device       = tcmu_configure_device,
1250         .free_device            = tcmu_free_device,
1251         .parse_cdb              = tcmu_parse_cdb,
1252         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1253         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1254         .get_device_type        = sbc_get_device_type,
1255         .get_blocks             = tcmu_get_blocks,
1256         .tb_dev_attrib_attrs    = NULL,
1257 };
1258
1259 static int __init tcmu_module_init(void)
1260 {
1261         int ret, i, len = 0;
1262
1263         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1264
1265         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1266                                 sizeof(struct tcmu_cmd),
1267                                 __alignof__(struct tcmu_cmd),
1268                                 0, NULL);
1269         if (!tcmu_cmd_cache)
1270                 return -ENOMEM;
1271
1272         tcmu_root_device = root_device_register("tcm_user");
1273         if (IS_ERR(tcmu_root_device)) {
1274                 ret = PTR_ERR(tcmu_root_device);
1275                 goto out_free_cache;
1276         }
1277
1278         ret = genl_register_family(&tcmu_genl_family);
1279         if (ret < 0) {
1280                 goto out_unreg_device;
1281         }
1282
1283         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
1284                 len += sizeof(struct configfs_attribute *);
1285         }
1286         len += sizeof(struct configfs_attribute *) * 2;
1287
1288         tcmu_attrs = kzalloc(len, GFP_KERNEL);
1289         if (!tcmu_attrs) {
1290                 ret = -ENOMEM;
1291                 goto out_unreg_genl;
1292         }
1293
1294         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
1295                 tcmu_attrs[i] = passthrough_attrib_attrs[i];
1296         }
1297         tcmu_attrs[i] = &tcmu_attr_cmd_time_out;
1298         tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
1299
1300         ret = transport_backend_register(&tcmu_ops);
1301         if (ret)
1302                 goto out_attrs;
1303
1304         return 0;
1305
1306 out_attrs:
1307         kfree(tcmu_attrs);
1308 out_unreg_genl:
1309         genl_unregister_family(&tcmu_genl_family);
1310 out_unreg_device:
1311         root_device_unregister(tcmu_root_device);
1312 out_free_cache:
1313         kmem_cache_destroy(tcmu_cmd_cache);
1314
1315         return ret;
1316 }
1317
1318 static void __exit tcmu_module_exit(void)
1319 {
1320         target_backend_unregister(&tcmu_ops);
1321         kfree(tcmu_attrs);
1322         genl_unregister_family(&tcmu_genl_family);
1323         root_device_unregister(tcmu_root_device);
1324         kmem_cache_destroy(tcmu_cmd_cache);
1325 }
1326
1327 MODULE_DESCRIPTION("TCM USER subsystem plugin");
1328 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1329 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1330 MODULE_LICENSE("GPL");
1331
1332 module_init(tcmu_module_init);
1333 module_exit(tcmu_module_exit);