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, unsigned long *cmd_bitmap,
 315                 struct scatterlist *data_sg, unsigned int data_nents)
 316 {
 317         int i, block;
 318         int block_remaining = 0;
 319         void *from, *to;
 320         size_t copy_bytes, from_offset;
 321         struct scatterlist *sg;
 322
 323         for_each_sg(data_sg, sg, data_nents, i) {
 324                 int sg_remaining = sg->length;
 325                 to = kmap_atomic(sg_page(sg)) + sg->offset;
 326                 while (sg_remaining > 0) {
 327                         if (block_remaining == 0) {
 328                                 block = find_first_bit(cmd_bitmap,
 329                                                 DATA_BLOCK_BITS);
 330                                 block_remaining = DATA_BLOCK_SIZE;
 331                                 clear_bit(block, cmd_bitmap);
 332                         }
 333                         copy_bytes = min_t(size_t, sg_remaining,
 334                                         block_remaining);
 335                         from_offset = get_block_offset(udev, block,
 336                                         block_remaining);
 337                         from = (void *) udev->mb_addr + from_offset;
 338                         tcmu_flush_dcache_range(from, copy_bytes);
 339                         memcpy(to + sg->length - sg_remaining, from,
 340                                         copy_bytes);
 341
 342                         sg_remaining -= copy_bytes;
 343                         block_remaining -= copy_bytes;
 344                 }
 345                 kunmap_atomic(to - sg->offset);
 346         }
 347 }
 348
 349 static inline size_t spc_bitmap_free(unsigned long *bitmap)
 350 {
 351         return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
 352                         bitmap_weight(bitmap, DATA_BLOCK_BITS));
 353 }
 354
 355 /*
 356  * We can't queue a command until we have space available on the cmd ring *and*
 357  * space available on the data area.
 358  *
 359  * Called with ring lock held.
 360  */
 361 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
 362 {
 363         struct tcmu_mailbox *mb = udev->mb_addr;
 364         size_t space, cmd_needed;
 365         u32 cmd_head;
 366
 367         tcmu_flush_dcache_range(mb, sizeof(*mb));
 368
 369         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 370
 371         /*
 372          * If cmd end-of-ring space is too small then we need space for a NOP plus
 373          * original cmd - cmds are internally contiguous.
 374          */
 375         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
 376                 cmd_needed = cmd_size;
 377         else
 378                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
 379
 380         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
 381         if (space < cmd_needed) {
 382                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
 383                        udev->cmdr_last_cleaned, udev->cmdr_size);
 384                 return false;
 385         }
 386
 387         space = spc_bitmap_free(udev->data_bitmap);
 388         if (space < data_needed) {
 389                 pr_debug("no data space: only %zu available, but ask for %zu\n",
 390                                 space, data_needed);
 391                 return false;
 392         }
 393
 394         return true;
 395 }
 396
 397 static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
 398 {
 399         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 400         size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
 401
 402         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 403                 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
 404                 data_length += round_up(se_cmd->t_bidi_data_sg->length,
 405                                 DATA_BLOCK_SIZE);
 406         }
 407
 408         return data_length;
 409 }
 410
 411 static sense_reason_t
 412 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 413 {
 414         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 415         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 416         size_t base_command_size, command_size;
 417         struct tcmu_mailbox *mb;
 418         struct tcmu_cmd_entry *entry;
 419         struct iovec *iov;
 420         int iov_cnt;
 421         uint32_t cmd_head;
 422         uint64_t cdb_off;
 423         bool copy_to_data_area;
 424         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
 425         DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
 426
 427         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
 428                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 429
 430         /*
 431          * Must be a certain minimum size for response sense info, but
 432          * also may be larger if the iov array is large.
 433          *
 434          * We prepare way too many iovs for potential uses here, because it's
 435          * expensive to tell how many regions are freed in the bitmap
 436         */
 437         base_command_size = max(offsetof(struct tcmu_cmd_entry,
 438                                 req.iov[se_cmd->t_bidi_data_nents +
 439                                         se_cmd->t_data_nents]),
 440                                 sizeof(struct tcmu_cmd_entry));
 441         command_size = base_command_size
 442                 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
 443
 444         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
 445
 446         spin_lock_irq(&udev->cmdr_lock);
 447
 448         mb = udev->mb_addr;
 449         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 450         if ((command_size > (udev->cmdr_size / 2)) ||
 451             data_length > udev->data_size) {
 452                 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
 453                         "cmd ring/data area\n", command_size, data_length,
 454                         udev->cmdr_size, udev->data_size);
 455                 spin_unlock_irq(&udev->cmdr_lock);
 456                 return TCM_INVALID_CDB_FIELD;
 457         }
 458
 459         while (!is_ring_space_avail(udev, command_size, data_length)) {
 460                 int ret;
 461                 DEFINE_WAIT(__wait);
 462
 463                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
 464
 465                 pr_debug("sleeping for ring space\n");
 466                 spin_unlock_irq(&udev->cmdr_lock);
 467                 if (udev->cmd_time_out)
 468                         ret = schedule_timeout(
 469                                         msecs_to_jiffies(udev->cmd_time_out));
 470                 else
 471                         ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
 472                 finish_wait(&udev->wait_cmdr, &__wait);
 473                 if (!ret) {
 474                         pr_warn("tcmu: command timed out\n");
 475                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 476                 }
 477
 478                 spin_lock_irq(&udev->cmdr_lock);
 479
 480                 /* We dropped cmdr_lock, cmd_head is stale */
 481                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 482         }
 483
 484         /* Insert a PAD if end-of-ring space is too small */
 485         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
 486                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
 487
 488                 entry = (void *) mb + CMDR_OFF + cmd_head;
 489                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 490                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
 491                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
 492                 entry->hdr.cmd_id = 0; /* not used for PAD */
 493                 entry->hdr.kflags = 0;
 494                 entry->hdr.uflags = 0;
 495
 496                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
 497
 498                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 499                 WARN_ON(cmd_head != 0);
 500         }
 501
 502         entry = (void *) mb + CMDR_OFF + cmd_head;
 503         tcmu_flush_dcache_range(entry, sizeof(*entry));
 504         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
 505         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
 506         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
 507         entry->hdr.kflags = 0;
 508         entry->hdr.uflags = 0;
 509
 510         bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);
 511
 512         /* Handle allocating space from the data area */
 513         iov = &entry->req.iov[0];
 514         iov_cnt = 0;
 515         copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
 516                 || se_cmd->se_cmd_flags & SCF_BIDI);
 517         alloc_and_scatter_data_area(udev, se_cmd->t_data_sg,
 518                 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area);
 519         entry->req.iov_cnt = iov_cnt;
 520         entry->req.iov_dif_cnt = 0;
 521
 522         /* Handle BIDI commands */
 523         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 524                 iov_cnt = 0;
 525                 iov++;
 526                 alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
 527                                 se_cmd->t_bidi_data_nents, &iov, &iov_cnt,
 528                                 false);
 529                 entry->req.iov_bidi_cnt = iov_cnt;
 530         }
 531         /* cmd's data_bitmap is what changed in process */
 532         bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
 533                         DATA_BLOCK_BITS);
 534
 535         /* All offsets relative to mb_addr, not start of entry! */
 536         cdb_off = CMDR_OFF + cmd_head + base_command_size;
 537         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
 538         entry->req.cdb_off = cdb_off;
 539         tcmu_flush_dcache_range(entry, sizeof(*entry));
 540
 541         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
 542         tcmu_flush_dcache_range(mb, sizeof(*mb));
 543
 544         spin_unlock_irq(&udev->cmdr_lock);
 545
 546         /* TODO: only if FLUSH and FUA? */
 547         uio_event_notify(&udev->uio_info);
 548
 549         if (udev->cmd_time_out)
 550                 mod_timer(&udev->timeout, round_jiffies_up(jiffies +
 551                           msecs_to_jiffies(udev->cmd_time_out)));
 552
 553         return TCM_NO_SENSE;
 554 }
 555
 556 static sense_reason_t
 557 tcmu_queue_cmd(struct se_cmd *se_cmd)
 558 {
 559         struct se_device *se_dev = se_cmd->se_dev;
 560         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 561         struct tcmu_cmd *tcmu_cmd;
 562         sense_reason_t ret;
 563
 564         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
 565         if (!tcmu_cmd)
 566                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 567
 568         ret = tcmu_queue_cmd_ring(tcmu_cmd);
 569         if (ret != TCM_NO_SENSE) {
 570                 pr_err("TCMU: Could not queue command\n");
 571                 spin_lock_irq(&udev->commands_lock);
 572                 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
 573                 spin_unlock_irq(&udev->commands_lock);
 574
 575                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 576         }
 577
 578         return ret;
 579 }
 580
 581 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
 582 {
 583         struct se_cmd *se_cmd = cmd->se_cmd;
 584         struct tcmu_dev *udev = cmd->tcmu_dev;
 585
 586         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 587                 /*
 588                  * cmd has been completed already from timeout, just reclaim
 589                  * data area space and free cmd
 590                  */
 591                 free_data_area(udev, cmd);
 592
 593                 kmem_cache_free(tcmu_cmd_cache, cmd);
 594                 return;
 595         }
 596
 597         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
 598                 free_data_area(udev, cmd);
 599                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
 600                         cmd->se_cmd);
 601                 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
 602         } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
 603                 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
 604                                se_cmd->scsi_sense_length);
 605                 free_data_area(udev, cmd);
 606         } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
 607                 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 608
 609                 /* Get Data-In buffer before clean up */
 610                 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 611                 gather_data_area(udev, bitmap,
 612                         se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
 613                 free_data_area(udev, cmd);
 614         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
 615                 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 616
 617                 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 618                 gather_data_area(udev, bitmap,
 619                         se_cmd->t_data_sg, se_cmd->t_data_nents);
 620                 free_data_area(udev, cmd);
 621         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
 622                 free_data_area(udev, cmd);
 623         } else if (se_cmd->data_direction != DMA_NONE) {
 624                 pr_warn("TCMU: data direction was %d!\n",
 625                         se_cmd->data_direction);
 626         }
 627
 628         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
 629         cmd->se_cmd = NULL;
 630
 631         kmem_cache_free(tcmu_cmd_cache, cmd);
 632 }
 633
 634 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
 635 {
 636         struct tcmu_mailbox *mb;
 637         unsigned long flags;
 638         int handled = 0;
 639
 640         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
 641                 pr_err("ring broken, not handling completions\n");
 642                 return 0;
 643         }
 644
 645         spin_lock_irqsave(&udev->cmdr_lock, flags);
 646
 647         mb = udev->mb_addr;
 648         tcmu_flush_dcache_range(mb, sizeof(*mb));
 649
 650         while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
 651
 652                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
 653                 struct tcmu_cmd *cmd;
 654
 655                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 656
 657                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
 658                         UPDATE_HEAD(udev->cmdr_last_cleaned,
 659                                     tcmu_hdr_get_len(entry->hdr.len_op),
 660                                     udev->cmdr_size);
 661                         continue;
 662                 }
 663                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
 664
 665                 spin_lock(&udev->commands_lock);
 666                 cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
 667                 spin_unlock(&udev->commands_lock);
 668
 669                 if (!cmd) {
 670                         pr_err("cmd_id not found, ring is broken\n");
 671                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
 672                         break;
 673                 }
 674
 675                 tcmu_handle_completion(cmd, entry);
 676
 677                 UPDATE_HEAD(udev->cmdr_last_cleaned,
 678                             tcmu_hdr_get_len(entry->hdr.len_op),
 679                             udev->cmdr_size);
 680
 681                 handled++;
 682         }
 683
 684         if (mb->cmd_tail == mb->cmd_head)
 685                 del_timer(&udev->timeout); /* no more pending cmds */
 686
 687         spin_unlock_irqrestore(&udev->cmdr_lock, flags);
 688
 689         wake_up(&udev->wait_cmdr);
 690
 691         return handled;
 692 }
 693
 694 static int tcmu_check_expired_cmd(int id, void *p, void *data)
 695 {
 696         struct tcmu_cmd *cmd = p;
 697
 698         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
 699                 return 0;
 700
 701         if (!time_after(jiffies, cmd->deadline))
 702                 return 0;
 703
 704         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
 705         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
 706         cmd->se_cmd = NULL;
 707
 708         return 0;
 709 }
 710
 711 static void tcmu_device_timedout(unsigned long data)
 712 {
 713         struct tcmu_dev *udev = (struct tcmu_dev *)data;
 714         unsigned long flags;
 715         int handled;
 716
 717         handled = tcmu_handle_completions(udev);
 718
 719         pr_warn("%d completions handled from timeout\n", handled);
 720
 721         spin_lock_irqsave(&udev->commands_lock, flags);
 722         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
 723         spin_unlock_irqrestore(&udev->commands_lock, flags);
 724
 725         /*
 726          * We don't need to wakeup threads on wait_cmdr since they have their
 727          * own timeout.
 728          */
 729 }
 730
 731 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
 732 {
 733         struct tcmu_hba *tcmu_hba;
 734
 735         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
 736         if (!tcmu_hba)
 737                 return -ENOMEM;
 738
 739         tcmu_hba->host_id = host_id;
 740         hba->hba_ptr = tcmu_hba;
 741
 742         return 0;
 743 }
 744
 745 static void tcmu_detach_hba(struct se_hba *hba)
 746 {
 747         kfree(hba->hba_ptr);
 748         hba->hba_ptr = NULL;
 749 }
 750
 751 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
 752 {
 753         struct tcmu_dev *udev;
 754
 755         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
 756         if (!udev)
 757                 return NULL;
 758
 759         udev->name = kstrdup(name, GFP_KERNEL);
 760         if (!udev->name) {
 761                 kfree(udev);
 762                 return NULL;
 763         }
 764
 765         udev->hba = hba;
 766         udev->cmd_time_out = TCMU_TIME_OUT;
 767
 768         init_waitqueue_head(&udev->wait_cmdr);
 769         spin_lock_init(&udev->cmdr_lock);
 770
 771         idr_init(&udev->commands);
 772         spin_lock_init(&udev->commands_lock);
 773
 774         setup_timer(&udev->timeout, tcmu_device_timedout,
 775                 (unsigned long)udev);
 776
 777         return &udev->se_dev;
 778 }
 779
 780 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
 781 {
 782         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
 783
 784         tcmu_handle_completions(tcmu_dev);
 785
 786         return 0;
 787 }
 788
 789 /*
 790  * mmap code from uio.c. Copied here because we want to hook mmap()
 791  * and this stuff must come along.
 792  */
 793 static int tcmu_find_mem_index(struct vm_area_struct *vma)
 794 {
 795         struct tcmu_dev *udev = vma->vm_private_data;
 796         struct uio_info *info = &udev->uio_info;
 797
 798         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 799                 if (info->mem[vma->vm_pgoff].size == 0)
 800                         return -1;
 801                 return (int)vma->vm_pgoff;
 802         }
 803         return -1;
 804 }
 805
 806 static int tcmu_vma_fault(struct vm_fault *vmf)
 807 {
 808         struct tcmu_dev *udev = vmf->vma->vm_private_data;
 809         struct uio_info *info = &udev->uio_info;
 810         struct page *page;
 811         unsigned long offset;
 812         void *addr;
 813
 814         int mi = tcmu_find_mem_index(vmf->vma);
 815         if (mi < 0)
 816                 return VM_FAULT_SIGBUS;
 817
 818         /*
 819          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 820          * to use mem[N].
 821          */
 822         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 823
 824         addr = (void *)(unsigned long)info->mem[mi].addr + offset;
 825         if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
 826                 page = virt_to_page(addr);
 827         else
 828                 page = vmalloc_to_page(addr);
 829         get_page(page);
 830         vmf->page = page;
 831         return 0;
 832 }
 833
 834 static const struct vm_operations_struct tcmu_vm_ops = {
 835         .fault = tcmu_vma_fault,
 836 };
 837
 838 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
 839 {
 840         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 841
 842         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 843         vma->vm_ops = &tcmu_vm_ops;
 844
 845         vma->vm_private_data = udev;
 846
 847         /* Ensure the mmap is exactly the right size */
 848         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
 849                 return -EINVAL;
 850
 851         return 0;
 852 }
 853
 854 static int tcmu_open(struct uio_info *info, struct inode *inode)
 855 {
 856         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 857
 858         /* O_EXCL not supported for char devs, so fake it? */
 859         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
 860                 return -EBUSY;
 861
 862         pr_debug("open\n");
 863
 864         return 0;
 865 }
 866
 867 static int tcmu_release(struct uio_info *info, struct inode *inode)
 868 {
 869         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 870
 871         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
 872
 873         pr_debug("close\n");
 874
 875         return 0;
 876 }
 877
 878 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
 879 {
 880         struct sk_buff *skb;
 881         void *msg_header;
 882         int ret = -ENOMEM;
 883
 884         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 885         if (!skb)
 886                 return ret;
 887
 888         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
 889         if (!msg_header)
 890                 goto free_skb;
 891
 892         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
 893         if (ret < 0)
 894                 goto free_skb;
 895
 896         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
 897         if (ret < 0)
 898                 goto free_skb;
 899
 900         genlmsg_end(skb, msg_header);
 901
 902         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
 903                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
 904
 905         /* We don't care if no one is listening */
 906         if (ret == -ESRCH)
 907                 ret = 0;
 908
 909         return ret;
 910 free_skb:
 911         nlmsg_free(skb);
 912         return ret;
 913 }
 914
 915 static int tcmu_configure_device(struct se_device *dev)
 916 {
 917         struct tcmu_dev *udev = TCMU_DEV(dev);
 918         struct tcmu_hba *hba = udev->hba->hba_ptr;
 919         struct uio_info *info;
 920         struct tcmu_mailbox *mb;
 921         size_t size;
 922         size_t used;
 923         int ret = 0;
 924         char *str;
 925
 926         info = &udev->uio_info;
 927
 928         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
 929                         udev->dev_config);
 930         size += 1; /* for \0 */
 931         str = kmalloc(size, GFP_KERNEL);
 932         if (!str)
 933                 return -ENOMEM;
 934
 935         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
 936
 937         if (udev->dev_config[0])
 938                 snprintf(str + used, size - used, "/%s", udev->dev_config);
 939
 940         info->name = str;
 941
 942         udev->mb_addr = vzalloc(TCMU_RING_SIZE);
 943         if (!udev->mb_addr) {
 944                 ret = -ENOMEM;
 945                 goto err_vzalloc;
 946         }
 947
 948         /* mailbox fits in first part of CMDR space */
 949         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
 950         udev->data_off = CMDR_SIZE;
 951         udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
 952
 953         mb = udev->mb_addr;
 954         mb->version = TCMU_MAILBOX_VERSION;
 955         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
 956         mb->cmdr_off = CMDR_OFF;
 957         mb->cmdr_size = udev->cmdr_size;
 958
 959         WARN_ON(!PAGE_ALIGNED(udev->data_off));
 960         WARN_ON(udev->data_size % PAGE_SIZE);
 961         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
 962
 963         info->version = __stringify(TCMU_MAILBOX_VERSION);
 964
 965         info->mem[0].name = "tcm-user command & data buffer";
 966         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
 967         info->mem[0].size = TCMU_RING_SIZE;
 968         info->mem[0].memtype = UIO_MEM_VIRTUAL;
 969
 970         info->irqcontrol = tcmu_irqcontrol;
 971         info->irq = UIO_IRQ_CUSTOM;
 972
 973         info->mmap = tcmu_mmap;
 974         info->open = tcmu_open;
 975         info->release = tcmu_release;
 976
 977         ret = uio_register_device(tcmu_root_device, info);
 978         if (ret)
 979                 goto err_register;
 980
 981         /* User can set hw_block_size before enable the device */
 982         if (dev->dev_attrib.hw_block_size == 0)
 983                 dev->dev_attrib.hw_block_size = 512;
 984         /* Other attributes can be configured in userspace */
 985         if (!dev->dev_attrib.hw_max_sectors)
 986                 dev->dev_attrib.hw_max_sectors = 128;
 987         dev->dev_attrib.hw_queue_depth = 128;
 988
 989         ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
 990                                  udev->uio_info.uio_dev->minor);
 991         if (ret)
 992                 goto err_netlink;
 993
 994         return 0;
 995
 996 err_netlink:
 997         uio_unregister_device(&udev->uio_info);
 998 err_register:
 999         vfree(udev->mb_addr);
1000 err_vzalloc:
1001         kfree(info->name);
1002
1003         return ret;
1004 }
1005
1006 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
1007 {
1008         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1009                 kmem_cache_free(tcmu_cmd_cache, cmd);
1010                 return 0;
1011         }
1012         return -EINVAL;
1013 }
1014
1015 static void tcmu_dev_call_rcu(struct rcu_head *p)
1016 {
1017         struct se_device *dev = container_of(p, struct se_device, rcu_head);
1018         struct tcmu_dev *udev = TCMU_DEV(dev);
1019
1020         kfree(udev);
1021 }
1022
1023 static bool tcmu_dev_configured(struct tcmu_dev *udev)
1024 {
1025         return udev->uio_info.uio_dev ? true : false;
1026 }
1027
1028 static void tcmu_free_device(struct se_device *dev)
1029 {
1030         struct tcmu_dev *udev = TCMU_DEV(dev);
1031         struct tcmu_cmd *cmd;
1032         bool all_expired = true;
1033         int i;
1034
1035         del_timer_sync(&udev->timeout);
1036
1037         vfree(udev->mb_addr);
1038
1039         /* Upper layer should drain all requests before calling this */
1040         spin_lock_irq(&udev->commands_lock);
1041         idr_for_each_entry(&udev->commands, cmd, i) {
1042                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1043                         all_expired = false;
1044         }
1045         idr_destroy(&udev->commands);
1046         spin_unlock_irq(&udev->commands_lock);
1047         WARN_ON(!all_expired);
1048
1049         if (tcmu_dev_configured(udev)) {
1050                 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
1051                                    udev->uio_info.uio_dev->minor);
1052
1053                 uio_unregister_device(&udev->uio_info);
1054                 kfree(udev->uio_info.name);
1055                 kfree(udev->name);
1056         }
1057         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1058 }
1059
1060 enum {
1061         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
1062         Opt_err,
1063 };
1064
1065 static match_table_t tokens = {
1066         {Opt_dev_config, "dev_config=%s"},
1067         {Opt_dev_size, "dev_size=%u"},
1068         {Opt_hw_block_size, "hw_block_size=%u"},
1069         {Opt_hw_max_sectors, "hw_max_sectors=%u"},
1070         {Opt_err, NULL}
1071 };
1072
1073 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
1074 {
1075         unsigned long tmp_ul;
1076         char *arg_p;
1077         int ret;
1078
1079         arg_p = match_strdup(arg);
1080         if (!arg_p)
1081                 return -ENOMEM;
1082
1083         ret = kstrtoul(arg_p, 0, &tmp_ul);
1084         kfree(arg_p);
1085         if (ret < 0) {
1086                 pr_err("kstrtoul() failed for dev attrib\n");
1087                 return ret;
1088         }
1089         if (!tmp_ul) {
1090                 pr_err("dev attrib must be nonzero\n");
1091                 return -EINVAL;
1092         }
1093         *dev_attrib = tmp_ul;
1094         return 0;
1095 }
1096
1097 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1098                 const char *page, ssize_t count)
1099 {
1100         struct tcmu_dev *udev = TCMU_DEV(dev);
1101         char *orig, *ptr, *opts, *arg_p;
1102         substring_t args[MAX_OPT_ARGS];
1103         int ret = 0, token;
1104
1105         opts = kstrdup(page, GFP_KERNEL);
1106         if (!opts)
1107                 return -ENOMEM;
1108
1109         orig = opts;
1110
1111         while ((ptr = strsep(&opts, ",\n")) != NULL) {
1112                 if (!*ptr)
1113                         continue;
1114
1115                 token = match_token(ptr, tokens, args);
1116                 switch (token) {
1117                 case Opt_dev_config:
1118                         if (match_strlcpy(udev->dev_config, &args[0],
1119                                           TCMU_CONFIG_LEN) == 0) {
1120                                 ret = -EINVAL;
1121                                 break;
1122                         }
1123                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1124                         break;
1125                 case Opt_dev_size:
1126                         arg_p = match_strdup(&args[0]);
1127                         if (!arg_p) {
1128                                 ret = -ENOMEM;
1129                                 break;
1130                         }
1131                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1132                         kfree(arg_p);
1133                         if (ret < 0)
1134                                 pr_err("kstrtoul() failed for dev_size=\n");
1135                         break;
1136                 case Opt_hw_block_size:
1137                         ret = tcmu_set_dev_attrib(&args[0],
1138                                         &(dev->dev_attrib.hw_block_size));
1139                         break;
1140                 case Opt_hw_max_sectors:
1141                         ret = tcmu_set_dev_attrib(&args[0],
1142                                         &(dev->dev_attrib.hw_max_sectors));
1143                         break;
1144                 default:
1145                         break;
1146                 }
1147
1148                 if (ret)
1149                         break;
1150         }
1151
1152         kfree(orig);
1153         return (!ret) ? count : ret;
1154 }
1155
1156 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1157 {
1158         struct tcmu_dev *udev = TCMU_DEV(dev);
1159         ssize_t bl = 0;
1160
1161         bl = sprintf(b + bl, "Config: %s ",
1162                      udev->dev_config[0] ? udev->dev_config : "NULL");
1163         bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1164
1165         return bl;
1166 }
1167
1168 static sector_t tcmu_get_blocks(struct se_device *dev)
1169 {
1170         struct tcmu_dev *udev = TCMU_DEV(dev);
1171
1172         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1173                        dev->dev_attrib.block_size);
1174 }
1175
1176 static sense_reason_t
1177 tcmu_parse_cdb(struct se_cmd *cmd)
1178 {
1179         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
1180 }
1181
1182 static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
1183 {
1184         struct se_dev_attrib *da = container_of(to_config_group(item),
1185                                         struct se_dev_attrib, da_group);
1186         struct tcmu_dev *udev = container_of(da->da_dev,
1187                                         struct tcmu_dev, se_dev);
1188
1189         return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
1190 }
1191
1192 static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
1193                                        size_t count)
1194 {
1195         struct se_dev_attrib *da = container_of(to_config_group(item),
1196                                         struct se_dev_attrib, da_group);
1197         struct tcmu_dev *udev = container_of(da->da_dev,
1198                                         struct tcmu_dev, se_dev);
1199         u32 val;
1200         int ret;
1201
1202         if (da->da_dev->export_count) {
1203                 pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
1204                 return -EINVAL;
1205         }
1206
1207         ret = kstrtou32(page, 0, &val);
1208         if (ret < 0)
1209                 return ret;
1210
1211         udev->cmd_time_out = val * MSEC_PER_SEC;
1212         return count;
1213 }
1214 CONFIGFS_ATTR(tcmu_, cmd_time_out);
1215
1216 static struct configfs_attribute **tcmu_attrs;
1217
1218 static struct target_backend_ops tcmu_ops = {
1219         .name                   = "user",
1220         .owner                  = THIS_MODULE,
1221         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1222         .attach_hba             = tcmu_attach_hba,
1223         .detach_hba             = tcmu_detach_hba,
1224         .alloc_device           = tcmu_alloc_device,
1225         .configure_device       = tcmu_configure_device,
1226         .free_device            = tcmu_free_device,
1227         .parse_cdb              = tcmu_parse_cdb,
1228         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1229         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1230         .get_device_type        = sbc_get_device_type,
1231         .get_blocks             = tcmu_get_blocks,
1232         .tb_dev_attrib_attrs    = NULL,
1233 };
1234
1235 static int __init tcmu_module_init(void)
1236 {
1237         int ret, i, len = 0;
1238
1239         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1240
1241         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1242                                 sizeof(struct tcmu_cmd),
1243                                 __alignof__(struct tcmu_cmd),
1244                                 0, NULL);
1245         if (!tcmu_cmd_cache)
1246                 return -ENOMEM;
1247
1248         tcmu_root_device = root_device_register("tcm_user");
1249         if (IS_ERR(tcmu_root_device)) {
1250                 ret = PTR_ERR(tcmu_root_device);
1251                 goto out_free_cache;
1252         }
1253
1254         ret = genl_register_family(&tcmu_genl_family);
1255         if (ret < 0) {
1256                 goto out_unreg_device;
1257         }
1258
1259         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
1260                 len += sizeof(struct configfs_attribute *);
1261         }
1262         len += sizeof(struct configfs_attribute *) * 2;
1263
1264         tcmu_attrs = kzalloc(len, GFP_KERNEL);
1265         if (!tcmu_attrs) {
1266                 ret = -ENOMEM;
1267                 goto out_unreg_genl;
1268         }
1269
1270         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
1271                 tcmu_attrs[i] = passthrough_attrib_attrs[i];
1272         }
1273         tcmu_attrs[i] = &tcmu_attr_cmd_time_out;
1274         tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
1275
1276         ret = transport_backend_register(&tcmu_ops);
1277         if (ret)
1278                 goto out_attrs;
1279
1280         return 0;
1281
1282 out_attrs:
1283         kfree(tcmu_attrs);
1284 out_unreg_genl:
1285         genl_unregister_family(&tcmu_genl_family);
1286 out_unreg_device:
1287         root_device_unregister(tcmu_root_device);
1288 out_free_cache:
1289         kmem_cache_destroy(tcmu_cmd_cache);
1290
1291         return ret;
1292 }
1293
1294 static void __exit tcmu_module_exit(void)
1295 {
1296         target_backend_unregister(&tcmu_ops);
1297         kfree(tcmu_attrs);
1298         genl_unregister_family(&tcmu_genl_family);
1299         root_device_unregister(tcmu_root_device);
1300         kmem_cache_destroy(tcmu_cmd_cache);
1301 }
1302
1303 MODULE_DESCRIPTION("TCM USER subsystem plugin");
1304 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1305 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1306 MODULE_LICENSE("GPL");
1307
1308 module_init(tcmu_module_init);
1309 module_exit(tcmu_module_exit);