Pileus Git - ~andy/linux/blob - drivers/target/target_core_iblock.c

   1 /*******************************************************************************
   2  * Filename:  target_core_iblock.c
   3  *
   4  * This file contains the Storage Engine  <-> Linux BlockIO transport
   5  * specific functions.
   6  *
   7  * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
   8  * Copyright (c) 2005, 2006, 2007 SBE, Inc.
   9  * Copyright (c) 2007-2010 Rising Tide Systems
  10  * Copyright (c) 2008-2010 Linux-iSCSI.org
  11  *
  12  * Nicholas A. Bellinger <nab@kernel.org>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  *
  28  ******************************************************************************/
  29
  30 #include <linux/string.h>
  31 #include <linux/parser.h>
  32 #include <linux/timer.h>
  33 #include <linux/fs.h>
  34 #include <linux/blkdev.h>
  35 #include <linux/slab.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/bio.h>
  38 #include <linux/genhd.h>
  39 #include <linux/file.h>
  40 #include <linux/module.h>
  41 #include <scsi/scsi.h>
  42 #include <scsi/scsi_host.h>
  43 #include <asm/unaligned.h>
  44
  45 #include <target/target_core_base.h>
  46 #include <target/target_core_backend.h>
  47
  48 #include "target_core_iblock.h"
  49
  50 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  51 #define IBLOCK_BIO_POOL_SIZE    128
  52
  53 static struct se_subsystem_api iblock_template;
  54
  55 static void iblock_bio_done(struct bio *, int);
  56
  57 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  58  *
  59  *
  60  */
  61 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  62 {
  63         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  64                 " Generic Target Core Stack %s\n", hba->hba_id,
  65                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  66         return 0;
  67 }
  68
  69 static void iblock_detach_hba(struct se_hba *hba)
  70 {
  71 }
  72
  73 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
  74 {
  75         struct iblock_dev *ib_dev = NULL;
  76
  77         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  78         if (!ib_dev) {
  79                 pr_err("Unable to allocate struct iblock_dev\n");
  80                 return NULL;
  81         }
  82
  83         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  84
  85         return ib_dev;
  86 }
  87
  88 static struct se_device *iblock_create_virtdevice(
  89         struct se_hba *hba,
  90         struct se_subsystem_dev *se_dev,
  91         void *p)
  92 {
  93         struct iblock_dev *ib_dev = p;
  94         struct se_device *dev;
  95         struct se_dev_limits dev_limits;
  96         struct block_device *bd = NULL;
  97         struct request_queue *q;
  98         struct queue_limits *limits;
  99         u32 dev_flags = 0;
 100         fmode_t mode;
 101         int ret = -EINVAL;
 102
 103         if (!ib_dev) {
 104                 pr_err("Unable to locate struct iblock_dev parameter\n");
 105                 return ERR_PTR(ret);
 106         }
 107         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 108
 109         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
 110         if (!ib_dev->ibd_bio_set) {
 111                 pr_err("IBLOCK: Unable to create bioset()\n");
 112                 return ERR_PTR(-ENOMEM);
 113         }
 114         pr_debug("IBLOCK: Created bio_set()\n");
 115         /*
 116          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 117          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 118          */
 119         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 120                         ib_dev->ibd_udev_path);
 121
 122         mode = FMODE_READ|FMODE_EXCL;
 123         if (!ib_dev->ibd_readonly)
 124                 mode |= FMODE_WRITE;
 125
 126         bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 127         if (IS_ERR(bd)) {
 128                 ret = PTR_ERR(bd);
 129                 goto failed;
 130         }
 131         /*
 132          * Setup the local scope queue_limits from struct request_queue->limits
 133          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 134          */
 135         q = bdev_get_queue(bd);
 136         limits = &dev_limits.limits;
 137         limits->logical_block_size = bdev_logical_block_size(bd);
 138         limits->max_hw_sectors = UINT_MAX;
 139         limits->max_sectors = UINT_MAX;
 140         dev_limits.hw_queue_depth = q->nr_requests;
 141         dev_limits.queue_depth = q->nr_requests;
 142
 143         ib_dev->ibd_bd = bd;
 144
 145         dev = transport_add_device_to_core_hba(hba,
 146                         &iblock_template, se_dev, dev_flags, ib_dev,
 147                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
 148         if (!dev)
 149                 goto failed;
 150
 151         /*
 152          * Check if the underlying struct block_device request_queue supports
 153          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 154          * in ATA and we need to set TPE=1
 155          */
 156         if (blk_queue_discard(q)) {
 157                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 158                                 q->limits.max_discard_sectors;
 159                 /*
 160                  * Currently hardcoded to 1 in Linux/SCSI code..
 161                  */
 162                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 163                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 164                                 q->limits.discard_granularity >> 9;
 165                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 166                                 q->limits.discard_alignment;
 167
 168                 pr_debug("IBLOCK: BLOCK Discard support available,"
 169                                 " disabled by default\n");
 170         }
 171
 172         if (blk_queue_nonrot(q))
 173                 dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
 174
 175         return dev;
 176
 177 failed:
 178         if (ib_dev->ibd_bio_set) {
 179                 bioset_free(ib_dev->ibd_bio_set);
 180                 ib_dev->ibd_bio_set = NULL;
 181         }
 182         ib_dev->ibd_bd = NULL;
 183         return ERR_PTR(ret);
 184 }
 185
 186 static void iblock_free_device(void *p)
 187 {
 188         struct iblock_dev *ib_dev = p;
 189
 190         if (ib_dev->ibd_bd != NULL)
 191                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 192         if (ib_dev->ibd_bio_set != NULL)
 193                 bioset_free(ib_dev->ibd_bio_set);
 194         kfree(ib_dev);
 195 }
 196
 197 static unsigned long long iblock_emulate_read_cap_with_block_size(
 198         struct se_device *dev,
 199         struct block_device *bd,
 200         struct request_queue *q)
 201 {
 202         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 203                                         bdev_logical_block_size(bd)) - 1);
 204         u32 block_size = bdev_logical_block_size(bd);
 205
 206         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 207                 return blocks_long;
 208
 209         switch (block_size) {
 210         case 4096:
 211                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 212                 case 2048:
 213                         blocks_long <<= 1;
 214                         break;
 215                 case 1024:
 216                         blocks_long <<= 2;
 217                         break;
 218                 case 512:
 219                         blocks_long <<= 3;
 220                 default:
 221                         break;
 222                 }
 223                 break;
 224         case 2048:
 225                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 226                 case 4096:
 227                         blocks_long >>= 1;
 228                         break;
 229                 case 1024:
 230                         blocks_long <<= 1;
 231                         break;
 232                 case 512:
 233                         blocks_long <<= 2;
 234                         break;
 235                 default:
 236                         break;
 237                 }
 238                 break;
 239         case 1024:
 240                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 241                 case 4096:
 242                         blocks_long >>= 2;
 243                         break;
 244                 case 2048:
 245                         blocks_long >>= 1;
 246                         break;
 247                 case 512:
 248                         blocks_long <<= 1;
 249                         break;
 250                 default:
 251                         break;
 252                 }
 253                 break;
 254         case 512:
 255                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 256                 case 4096:
 257                         blocks_long >>= 3;
 258                         break;
 259                 case 2048:
 260                         blocks_long >>= 2;
 261                         break;
 262                 case 1024:
 263                         blocks_long >>= 1;
 264                         break;
 265                 default:
 266                         break;
 267                 }
 268                 break;
 269         default:
 270                 break;
 271         }
 272
 273         return blocks_long;
 274 }
 275
 276 static void iblock_end_io_flush(struct bio *bio, int err)
 277 {
 278         struct se_cmd *cmd = bio->bi_private;
 279
 280         if (err)
 281                 pr_err("IBLOCK: cache flush failed: %d\n", err);
 282
 283         if (cmd) {
 284                 if (err) {
 285                         cmd->scsi_sense_reason =
 286                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 287                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 288                 } else {
 289                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 290                 }
 291         }
 292
 293         bio_put(bio);
 294 }
 295
 296 /*
 297  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 298  * always flush the whole cache.
 299  */
 300 static int iblock_execute_sync_cache(struct se_cmd *cmd)
 301 {
 302         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 303         int immed = (cmd->t_task_cdb[1] & 0x2);
 304         struct bio *bio;
 305
 306         /*
 307          * If the Immediate bit is set, queue up the GOOD response
 308          * for this SYNCHRONIZE_CACHE op.
 309          */
 310         if (immed)
 311                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 312
 313         bio = bio_alloc(GFP_KERNEL, 0);
 314         bio->bi_end_io = iblock_end_io_flush;
 315         bio->bi_bdev = ib_dev->ibd_bd;
 316         if (!immed)
 317                 bio->bi_private = cmd;
 318         submit_bio(WRITE_FLUSH, bio);
 319         return 0;
 320 }
 321
 322 static int iblock_execute_unmap(struct se_cmd *cmd)
 323 {
 324         struct se_device *dev = cmd->se_dev;
 325         struct iblock_dev *ibd = dev->dev_ptr;
 326         unsigned char *buf, *ptr = NULL;
 327         sector_t lba;
 328         int size = cmd->data_length;
 329         u32 range;
 330         int ret = 0;
 331         int dl, bd_dl;
 332
 333         buf = transport_kmap_data_sg(cmd);
 334
 335         dl = get_unaligned_be16(&buf[0]);
 336         bd_dl = get_unaligned_be16(&buf[2]);
 337
 338         size = min(size - 8, bd_dl);
 339         if (size / 16 > dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count) {
 340                 cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 341                 ret = -EINVAL;
 342                 goto err;
 343         }
 344
 345         /* First UNMAP block descriptor starts at 8 byte offset */
 346         ptr = &buf[8];
 347         pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
 348                 " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
 349
 350         while (size >= 16) {
 351                 lba = get_unaligned_be64(&ptr[0]);
 352                 range = get_unaligned_be32(&ptr[8]);
 353                 pr_debug("UNMAP: Using lba: %llu and range: %u\n",
 354                                  (unsigned long long)lba, range);
 355
 356                 if (range > dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count) {
 357                         cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 358                         ret = -EINVAL;
 359                         goto err;
 360                 }
 361
 362                 if (lba + range > dev->transport->get_blocks(dev) + 1) {
 363                         cmd->scsi_sense_reason = TCM_ADDRESS_OUT_OF_RANGE;
 364                         ret = -EINVAL;
 365                         goto err;
 366                 }
 367
 368                 ret = blkdev_issue_discard(ibd->ibd_bd, lba, range,
 369                                            GFP_KERNEL, 0);
 370                 if (ret < 0) {
 371                         pr_err("blkdev_issue_discard() failed: %d\n",
 372                                         ret);
 373                         goto err;
 374                 }
 375
 376                 ptr += 16;
 377                 size -= 16;
 378         }
 379
 380 err:
 381         transport_kunmap_data_sg(cmd);
 382         if (!ret)
 383                 target_complete_cmd(cmd, GOOD);
 384         return ret;
 385 }
 386
 387 static int iblock_execute_write_same(struct se_cmd *cmd)
 388 {
 389         struct iblock_dev *ibd = cmd->se_dev->dev_ptr;
 390         int ret;
 391
 392         ret = blkdev_issue_discard(ibd->ibd_bd, cmd->t_task_lba,
 393                                    spc_get_write_same_sectors(cmd), GFP_KERNEL,
 394                                    0);
 395         if (ret < 0) {
 396                 pr_debug("blkdev_issue_discard() failed for WRITE_SAME\n");
 397                 return ret;
 398         }
 399
 400         target_complete_cmd(cmd, GOOD);
 401         return 0;
 402 }
 403
 404 enum {
 405         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 406 };
 407
 408 static match_table_t tokens = {
 409         {Opt_udev_path, "udev_path=%s"},
 410         {Opt_readonly, "readonly=%d"},
 411         {Opt_force, "force=%d"},
 412         {Opt_err, NULL}
 413 };
 414
 415 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 416                                                struct se_subsystem_dev *se_dev,
 417                                                const char *page, ssize_t count)
 418 {
 419         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 420         char *orig, *ptr, *arg_p, *opts;
 421         substring_t args[MAX_OPT_ARGS];
 422         int ret = 0, token;
 423         unsigned long tmp_readonly;
 424
 425         opts = kstrdup(page, GFP_KERNEL);
 426         if (!opts)
 427                 return -ENOMEM;
 428
 429         orig = opts;
 430
 431         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 432                 if (!*ptr)
 433                         continue;
 434
 435                 token = match_token(ptr, tokens, args);
 436                 switch (token) {
 437                 case Opt_udev_path:
 438                         if (ib_dev->ibd_bd) {
 439                                 pr_err("Unable to set udev_path= while"
 440                                         " ib_dev->ibd_bd exists\n");
 441                                 ret = -EEXIST;
 442                                 goto out;
 443                         }
 444                         arg_p = match_strdup(&args[0]);
 445                         if (!arg_p) {
 446                                 ret = -ENOMEM;
 447                                 break;
 448                         }
 449                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
 450                                         "%s", arg_p);
 451                         kfree(arg_p);
 452                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 453                                         ib_dev->ibd_udev_path);
 454                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 455                         break;
 456                 case Opt_readonly:
 457                         arg_p = match_strdup(&args[0]);
 458                         if (!arg_p) {
 459                                 ret = -ENOMEM;
 460                                 break;
 461                         }
 462                         ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 463                         kfree(arg_p);
 464                         if (ret < 0) {
 465                                 pr_err("strict_strtoul() failed for"
 466                                                 " readonly=\n");
 467                                 goto out;
 468                         }
 469                         ib_dev->ibd_readonly = tmp_readonly;
 470                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 471                         break;
 472                 case Opt_force:
 473                         break;
 474                 default:
 475                         break;
 476                 }
 477         }
 478
 479 out:
 480         kfree(orig);
 481         return (!ret) ? count : ret;
 482 }
 483
 484 static ssize_t iblock_check_configfs_dev_params(
 485         struct se_hba *hba,
 486         struct se_subsystem_dev *se_dev)
 487 {
 488         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 489
 490         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 491                 pr_err("Missing udev_path= parameters for IBLOCK\n");
 492                 return -EINVAL;
 493         }
 494
 495         return 0;
 496 }
 497
 498 static ssize_t iblock_show_configfs_dev_params(
 499         struct se_hba *hba,
 500         struct se_subsystem_dev *se_dev,
 501         char *b)
 502 {
 503         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 504         struct block_device *bd = ibd->ibd_bd;
 505         char buf[BDEVNAME_SIZE];
 506         ssize_t bl = 0;
 507
 508         if (bd)
 509                 bl += sprintf(b + bl, "iBlock device: %s",
 510                                 bdevname(bd, buf));
 511         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH)
 512                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 513                                 ibd->ibd_udev_path);
 514         bl += sprintf(b + bl, "  readonly: %d\n", ibd->ibd_readonly);
 515
 516         bl += sprintf(b + bl, "        ");
 517         if (bd) {
 518                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 519                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 520                         "" : (bd->bd_holder == ibd) ?
 521                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 522         } else {
 523                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 524         }
 525
 526         return bl;
 527 }
 528
 529 static void iblock_complete_cmd(struct se_cmd *cmd)
 530 {
 531         struct iblock_req *ibr = cmd->priv;
 532         u8 status;
 533
 534         if (!atomic_dec_and_test(&ibr->pending))
 535                 return;
 536
 537         if (atomic_read(&ibr->ib_bio_err_cnt))
 538                 status = SAM_STAT_CHECK_CONDITION;
 539         else
 540                 status = SAM_STAT_GOOD;
 541
 542         target_complete_cmd(cmd, status);
 543         kfree(ibr);
 544 }
 545
 546 static void iblock_bio_destructor(struct bio *bio)
 547 {
 548         struct se_cmd *cmd = bio->bi_private;
 549         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 550
 551         bio_free(bio, ib_dev->ibd_bio_set);
 552 }
 553
 554 static struct bio *
 555 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 556 {
 557         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 558         struct bio *bio;
 559
 560         /*
 561          * Only allocate as many vector entries as the bio code allows us to,
 562          * we'll loop later on until we have handled the whole request.
 563          */
 564         if (sg_num > BIO_MAX_PAGES)
 565                 sg_num = BIO_MAX_PAGES;
 566
 567         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 568         if (!bio) {
 569                 pr_err("Unable to allocate memory for bio\n");
 570                 return NULL;
 571         }
 572
 573         bio->bi_bdev = ib_dev->ibd_bd;
 574         bio->bi_private = cmd;
 575         bio->bi_destructor = iblock_bio_destructor;
 576         bio->bi_end_io = &iblock_bio_done;
 577         bio->bi_sector = lba;
 578         return bio;
 579 }
 580
 581 static void iblock_submit_bios(struct bio_list *list, int rw)
 582 {
 583         struct blk_plug plug;
 584         struct bio *bio;
 585
 586         blk_start_plug(&plug);
 587         while ((bio = bio_list_pop(list)))
 588                 submit_bio(rw, bio);
 589         blk_finish_plug(&plug);
 590 }
 591
 592 static int iblock_execute_rw(struct se_cmd *cmd)
 593 {
 594         struct scatterlist *sgl = cmd->t_data_sg;
 595         u32 sgl_nents = cmd->t_data_nents;
 596         enum dma_data_direction data_direction = cmd->data_direction;
 597         struct se_device *dev = cmd->se_dev;
 598         struct iblock_req *ibr;
 599         struct bio *bio;
 600         struct bio_list list;
 601         struct scatterlist *sg;
 602         u32 sg_num = sgl_nents;
 603         sector_t block_lba;
 604         unsigned bio_cnt;
 605         int rw;
 606         int i;
 607
 608         if (data_direction == DMA_TO_DEVICE) {
 609                 /*
 610                  * Force data to disk if we pretend to not have a volatile
 611                  * write cache, or the initiator set the Force Unit Access bit.
 612                  */
 613                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 614                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 615                      (cmd->se_cmd_flags & SCF_FUA)))
 616                         rw = WRITE_FUA;
 617                 else
 618                         rw = WRITE;
 619         } else {
 620                 rw = READ;
 621         }
 622
 623         /*
 624          * Convert the blocksize advertised to the initiator to the 512 byte
 625          * units unconditionally used by the Linux block layer.
 626          */
 627         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 628                 block_lba = (cmd->t_task_lba << 3);
 629         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 630                 block_lba = (cmd->t_task_lba << 2);
 631         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 632                 block_lba = (cmd->t_task_lba << 1);
 633         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 634                 block_lba = cmd->t_task_lba;
 635         else {
 636                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 637                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 638                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 639                 return -ENOSYS;
 640         }
 641
 642         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 643         if (!ibr)
 644                 goto fail;
 645         cmd->priv = ibr;
 646
 647         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 648         if (!bio)
 649                 goto fail_free_ibr;
 650
 651         bio_list_init(&list);
 652         bio_list_add(&list, bio);
 653
 654         atomic_set(&ibr->pending, 2);
 655         bio_cnt = 1;
 656
 657         for_each_sg(sgl, sg, sgl_nents, i) {
 658                 /*
 659                  * XXX: if the length the device accepts is shorter than the
 660                  *      length of the S/G list entry this will cause and
 661                  *      endless loop.  Better hope no driver uses huge pages.
 662                  */
 663                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 664                                 != sg->length) {
 665                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 666                                 iblock_submit_bios(&list, rw);
 667                                 bio_cnt = 0;
 668                         }
 669
 670                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 671                         if (!bio)
 672                                 goto fail_put_bios;
 673
 674                         atomic_inc(&ibr->pending);
 675                         bio_list_add(&list, bio);
 676                         bio_cnt++;
 677                 }
 678
 679                 /* Always in 512 byte units for Linux/Block */
 680                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 681                 sg_num--;
 682         }
 683
 684         iblock_submit_bios(&list, rw);
 685         iblock_complete_cmd(cmd);
 686         return 0;
 687
 688 fail_put_bios:
 689         while ((bio = bio_list_pop(&list)))
 690                 bio_put(bio);
 691 fail_free_ibr:
 692         kfree(ibr);
 693         cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 694 fail:
 695         return -ENOMEM;
 696 }
 697
 698 static u32 iblock_get_device_rev(struct se_device *dev)
 699 {
 700         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 701 }
 702
 703 static u32 iblock_get_device_type(struct se_device *dev)
 704 {
 705         return TYPE_DISK;
 706 }
 707
 708 static sector_t iblock_get_blocks(struct se_device *dev)
 709 {
 710         struct iblock_dev *ibd = dev->dev_ptr;
 711         struct block_device *bd = ibd->ibd_bd;
 712         struct request_queue *q = bdev_get_queue(bd);
 713
 714         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 715 }
 716
 717 static void iblock_bio_done(struct bio *bio, int err)
 718 {
 719         struct se_cmd *cmd = bio->bi_private;
 720         struct iblock_req *ibr = cmd->priv;
 721
 722         /*
 723          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 724          */
 725         if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 726                 err = -EIO;
 727
 728         if (err != 0) {
 729                 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 730                         " err: %d\n", bio, err);
 731                 /*
 732                  * Bump the ib_bio_err_cnt and release bio.
 733                  */
 734                 atomic_inc(&ibr->ib_bio_err_cnt);
 735                 smp_mb__after_atomic_inc();
 736         }
 737
 738         bio_put(bio);
 739
 740         iblock_complete_cmd(cmd);
 741 }
 742
 743 static struct spc_ops iblock_spc_ops = {
 744         .execute_rw             = iblock_execute_rw,
 745         .execute_sync_cache     = iblock_execute_sync_cache,
 746         .execute_write_same     = iblock_execute_write_same,
 747         .execute_unmap          = iblock_execute_unmap,
 748 };
 749
 750 static int iblock_parse_cdb(struct se_cmd *cmd)
 751 {
 752         return sbc_parse_cdb(cmd, &iblock_spc_ops);
 753 }
 754
 755 static struct se_subsystem_api iblock_template = {
 756         .name                   = "iblock",
 757         .owner                  = THIS_MODULE,
 758         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 759         .write_cache_emulated   = 1,
 760         .fua_write_emulated     = 1,
 761         .attach_hba             = iblock_attach_hba,
 762         .detach_hba             = iblock_detach_hba,
 763         .allocate_virtdevice    = iblock_allocate_virtdevice,
 764         .create_virtdevice      = iblock_create_virtdevice,
 765         .free_device            = iblock_free_device,
 766         .parse_cdb              = iblock_parse_cdb,
 767         .check_configfs_dev_params = iblock_check_configfs_dev_params,
 768         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 769         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 770         .get_device_rev         = iblock_get_device_rev,
 771         .get_device_type        = iblock_get_device_type,
 772         .get_blocks             = iblock_get_blocks,
 773 };
 774
 775 static int __init iblock_module_init(void)
 776 {
 777         return transport_subsystem_register(&iblock_template);
 778 }
 779
 780 static void iblock_module_exit(void)
 781 {
 782         transport_subsystem_release(&iblock_template);
 783 }
 784
 785 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 786 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 787 MODULE_LICENSE("GPL");
 788
 789 module_init(iblock_module_init);
 790 module_exit(iblock_module_exit);