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