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  * (c) Copyright 2003-2013 Datera, Inc.
   8  *
   9  * Nicholas A. Bellinger <nab@kernel.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  *
  25  ******************************************************************************/
  26
  27 #include <linux/string.h>
  28 #include <linux/parser.h>
  29 #include <linux/timer.h>
  30 #include <linux/fs.h>
  31 #include <linux/blkdev.h>
  32 #include <linux/slab.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/bio.h>
  35 #include <linux/genhd.h>
  36 #include <linux/file.h>
  37 #include <linux/module.h>
  38 #include <scsi/scsi_proto.h>
  39 #include <asm/unaligned.h>
  40
  41 #include <target/target_core_base.h>
  42 #include <target/target_core_backend.h>
  43
  44 #include "target_core_iblock.h"
  45
  46 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  47 #define IBLOCK_BIO_POOL_SIZE    128
  48
  49 static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
  50 {
  51         return container_of(dev, struct iblock_dev, dev);
  52 }
  53
  54
  55 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  56 {
  57         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  58                 " Generic Target Core Stack %s\n", hba->hba_id,
  59                 IBLOCK_VERSION, TARGET_CORE_VERSION);
  60         return 0;
  61 }
  62
  63 static void iblock_detach_hba(struct se_hba *hba)
  64 {
  65 }
  66
  67 static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
  68 {
  69         struct iblock_dev *ib_dev = NULL;
  70
  71         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  72         if (!ib_dev) {
  73                 pr_err("Unable to allocate struct iblock_dev\n");
  74                 return NULL;
  75         }
  76
  77         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  78
  79         return &ib_dev->dev;
  80 }
  81
  82 static int iblock_configure_device(struct se_device *dev)
  83 {
  84         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
  85         struct request_queue *q;
  86         struct block_device *bd = NULL;
  87         struct blk_integrity *bi;
  88         fmode_t mode;
  89         int ret = -ENOMEM;
  90
  91         if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
  92                 pr_err("Missing udev_path= parameters for IBLOCK\n");
  93                 return -EINVAL;
  94         }
  95
  96         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
  97         if (!ib_dev->ibd_bio_set) {
  98                 pr_err("IBLOCK: Unable to create bioset\n");
  99                 goto out;
 100         }
 101
 102         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 103                         ib_dev->ibd_udev_path);
 104
 105         mode = FMODE_READ|FMODE_EXCL;
 106         if (!ib_dev->ibd_readonly)
 107                 mode |= FMODE_WRITE;
 108         else
 109                 dev->dev_flags |= DF_READ_ONLY;
 110
 111         bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 112         if (IS_ERR(bd)) {
 113                 ret = PTR_ERR(bd);
 114                 goto out_free_bioset;
 115         }
 116         ib_dev->ibd_bd = bd;
 117
 118         q = bdev_get_queue(bd);
 119
 120         dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
 121         dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 122         dev->dev_attrib.hw_queue_depth = q->nr_requests;
 123
 124         if (target_configure_unmap_from_queue(&dev->dev_attrib, q))
 125                 pr_debug("IBLOCK: BLOCK Discard support available,"
 126                          " disabled by default\n");
 127
 128         /*
 129          * Enable write same emulation for IBLOCK and use 0xFFFF as
 130          * the smaller WRITE_SAME(10) only has a two-byte block count.
 131          */
 132         dev->dev_attrib.max_write_same_len = 0xFFFF;
 133
 134         if (blk_queue_nonrot(q))
 135                 dev->dev_attrib.is_nonrot = 1;
 136
 137         bi = bdev_get_integrity(bd);
 138         if (bi) {
 139                 struct bio_set *bs = ib_dev->ibd_bio_set;
 140
 141                 if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-IP") ||
 142                     !strcmp(bi->profile->name, "T10-DIF-TYPE1-IP")) {
 143                         pr_err("IBLOCK export of blk_integrity: %s not"
 144                                " supported\n", bi->profile->name);
 145                         ret = -ENOSYS;
 146                         goto out_blkdev_put;
 147                 }
 148
 149                 if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-CRC")) {
 150                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
 151                 } else if (!strcmp(bi->profile->name, "T10-DIF-TYPE1-CRC")) {
 152                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
 153                 }
 154
 155                 if (dev->dev_attrib.pi_prot_type) {
 156                         if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
 157                                 pr_err("Unable to allocate bioset for PI\n");
 158                                 ret = -ENOMEM;
 159                                 goto out_blkdev_put;
 160                         }
 161                         pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
 162                                  bs->bio_integrity_pool);
 163                 }
 164                 dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
 165         }
 166
 167         return 0;
 168
 169 out_blkdev_put:
 170         blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 171 out_free_bioset:
 172         bioset_free(ib_dev->ibd_bio_set);
 173         ib_dev->ibd_bio_set = NULL;
 174 out:
 175         return ret;
 176 }
 177
 178 static void iblock_dev_call_rcu(struct rcu_head *p)
 179 {
 180         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 181         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 182
 183         kfree(ib_dev);
 184 }
 185
 186 static void iblock_free_device(struct se_device *dev)
 187 {
 188         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 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
 195         call_rcu(&dev->rcu_head, iblock_dev_call_rcu);
 196 }
 197
 198 static unsigned long long iblock_emulate_read_cap_with_block_size(
 199         struct se_device *dev,
 200         struct block_device *bd,
 201         struct request_queue *q)
 202 {
 203         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 204                                         bdev_logical_block_size(bd)) - 1);
 205         u32 block_size = bdev_logical_block_size(bd);
 206
 207         if (block_size == dev->dev_attrib.block_size)
 208                 return blocks_long;
 209
 210         switch (block_size) {
 211         case 4096:
 212                 switch (dev->dev_attrib.block_size) {
 213                 case 2048:
 214                         blocks_long <<= 1;
 215                         break;
 216                 case 1024:
 217                         blocks_long <<= 2;
 218                         break;
 219                 case 512:
 220                         blocks_long <<= 3;
 221                 default:
 222                         break;
 223                 }
 224                 break;
 225         case 2048:
 226                 switch (dev->dev_attrib.block_size) {
 227                 case 4096:
 228                         blocks_long >>= 1;
 229                         break;
 230                 case 1024:
 231                         blocks_long <<= 1;
 232                         break;
 233                 case 512:
 234                         blocks_long <<= 2;
 235                         break;
 236                 default:
 237                         break;
 238                 }
 239                 break;
 240         case 1024:
 241                 switch (dev->dev_attrib.block_size) {
 242                 case 4096:
 243                         blocks_long >>= 2;
 244                         break;
 245                 case 2048:
 246                         blocks_long >>= 1;
 247                         break;
 248                 case 512:
 249                         blocks_long <<= 1;
 250                         break;
 251                 default:
 252                         break;
 253                 }
 254                 break;
 255         case 512:
 256                 switch (dev->dev_attrib.block_size) {
 257                 case 4096:
 258                         blocks_long >>= 3;
 259                         break;
 260                 case 2048:
 261                         blocks_long >>= 2;
 262                         break;
 263                 case 1024:
 264                         blocks_long >>= 1;
 265                         break;
 266                 default:
 267                         break;
 268                 }
 269                 break;
 270         default:
 271                 break;
 272         }
 273
 274         return blocks_long;
 275 }
 276
 277 static void iblock_complete_cmd(struct se_cmd *cmd)
 278 {
 279         struct iblock_req *ibr = cmd->priv;
 280         u8 status;
 281
 282         if (!atomic_dec_and_test(&ibr->pending))
 283                 return;
 284
 285         if (atomic_read(&ibr->ib_bio_err_cnt))
 286                 status = SAM_STAT_CHECK_CONDITION;
 287         else
 288                 status = SAM_STAT_GOOD;
 289
 290         target_complete_cmd(cmd, status);
 291         kfree(ibr);
 292 }
 293
 294 static void iblock_bio_done(struct bio *bio)
 295 {
 296         struct se_cmd *cmd = bio->bi_private;
 297         struct iblock_req *ibr = cmd->priv;
 298
 299         if (bio->bi_error) {
 300                 pr_err("bio error: %p,  err: %d\n", bio, bio->bi_error);
 301                 /*
 302                  * Bump the ib_bio_err_cnt and release bio.
 303                  */
 304                 atomic_inc(&ibr->ib_bio_err_cnt);
 305                 smp_mb__after_atomic();
 306         }
 307
 308         bio_put(bio);
 309
 310         iblock_complete_cmd(cmd);
 311 }
 312
 313 static struct bio *
 314 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 315 {
 316         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 317         struct bio *bio;
 318
 319         /*
 320          * Only allocate as many vector entries as the bio code allows us to,
 321          * we'll loop later on until we have handled the whole request.
 322          */
 323         if (sg_num > BIO_MAX_PAGES)
 324                 sg_num = BIO_MAX_PAGES;
 325
 326         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 327         if (!bio) {
 328                 pr_err("Unable to allocate memory for bio\n");
 329                 return NULL;
 330         }
 331
 332         bio->bi_bdev = ib_dev->ibd_bd;
 333         bio->bi_private = cmd;
 334         bio->bi_end_io = &iblock_bio_done;
 335         bio->bi_iter.bi_sector = lba;
 336
 337         return bio;
 338 }
 339
 340 static void iblock_submit_bios(struct bio_list *list, int rw)
 341 {
 342         struct blk_plug plug;
 343         struct bio *bio;
 344
 345         blk_start_plug(&plug);
 346         while ((bio = bio_list_pop(list)))
 347                 submit_bio(rw, bio);
 348         blk_finish_plug(&plug);
 349 }
 350
 351 static void iblock_end_io_flush(struct bio *bio)
 352 {
 353         struct se_cmd *cmd = bio->bi_private;
 354
 355         if (bio->bi_error)
 356                 pr_err("IBLOCK: cache flush failed: %d\n", bio->bi_error);
 357
 358         if (cmd) {
 359                 if (bio->bi_error)
 360                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 361                 else
 362                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 363         }
 364
 365         bio_put(bio);
 366 }
 367
 368 /*
 369  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 370  * always flush the whole cache.
 371  */
 372 static sense_reason_t
 373 iblock_execute_sync_cache(struct se_cmd *cmd)
 374 {
 375         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 376         int immed = (cmd->t_task_cdb[1] & 0x2);
 377         struct bio *bio;
 378
 379         /*
 380          * If the Immediate bit is set, queue up the GOOD response
 381          * for this SYNCHRONIZE_CACHE op.
 382          */
 383         if (immed)
 384                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 385
 386         bio = bio_alloc(GFP_KERNEL, 0);
 387         bio->bi_end_io = iblock_end_io_flush;
 388         bio->bi_bdev = ib_dev->ibd_bd;
 389         if (!immed)
 390                 bio->bi_private = cmd;
 391         submit_bio(WRITE_FLUSH, bio);
 392         return 0;
 393 }
 394
 395 static sense_reason_t
 396 iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 397 {
 398         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 399         struct se_device *dev = cmd->se_dev;
 400         int ret;
 401
 402         ret = blkdev_issue_discard(bdev,
 403                                    target_to_linux_sector(dev, lba),
 404                                    target_to_linux_sector(dev,  nolb),
 405                                    GFP_KERNEL, 0);
 406         if (ret < 0) {
 407                 pr_err("blkdev_issue_discard() failed: %d\n", ret);
 408                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 409         }
 410
 411         return 0;
 412 }
 413
 414 static sense_reason_t
 415 iblock_execute_write_same(struct se_cmd *cmd)
 416 {
 417         struct iblock_req *ibr;
 418         struct scatterlist *sg;
 419         struct bio *bio;
 420         struct bio_list list;
 421         struct se_device *dev = cmd->se_dev;
 422         sector_t block_lba = target_to_linux_sector(dev, cmd->t_task_lba);
 423         sector_t sectors = target_to_linux_sector(dev,
 424                                         sbc_get_write_same_sectors(cmd));
 425
 426         if (cmd->prot_op) {
 427                 pr_err("WRITE_SAME: Protection information with IBLOCK"
 428                        " backends not supported\n");
 429                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 430         }
 431         sg = &cmd->t_data_sg[0];
 432
 433         if (cmd->t_data_nents > 1 ||
 434             sg->length != cmd->se_dev->dev_attrib.block_size) {
 435                 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 436                         " block_size: %u\n", cmd->t_data_nents, sg->length,
 437                         cmd->se_dev->dev_attrib.block_size);
 438                 return TCM_INVALID_CDB_FIELD;
 439         }
 440
 441         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 442         if (!ibr)
 443                 goto fail;
 444         cmd->priv = ibr;
 445
 446         bio = iblock_get_bio(cmd, block_lba, 1);
 447         if (!bio)
 448                 goto fail_free_ibr;
 449
 450         bio_list_init(&list);
 451         bio_list_add(&list, bio);
 452
 453         atomic_set(&ibr->pending, 1);
 454
 455         while (sectors) {
 456                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 457                                 != sg->length) {
 458
 459                         bio = iblock_get_bio(cmd, block_lba, 1);
 460                         if (!bio)
 461                                 goto fail_put_bios;
 462
 463                         atomic_inc(&ibr->pending);
 464                         bio_list_add(&list, bio);
 465                 }
 466
 467                 /* Always in 512 byte units for Linux/Block */
 468                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 469                 sectors -= 1;
 470         }
 471
 472         iblock_submit_bios(&list, WRITE);
 473         return 0;
 474
 475 fail_put_bios:
 476         while ((bio = bio_list_pop(&list)))
 477                 bio_put(bio);
 478 fail_free_ibr:
 479         kfree(ibr);
 480 fail:
 481         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 482 }
 483
 484 enum {
 485         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 486 };
 487
 488 static match_table_t tokens = {
 489         {Opt_udev_path, "udev_path=%s"},
 490         {Opt_readonly, "readonly=%d"},
 491         {Opt_force, "force=%d"},
 492         {Opt_err, NULL}
 493 };
 494
 495 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 496                 const char *page, ssize_t count)
 497 {
 498         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 499         char *orig, *ptr, *arg_p, *opts;
 500         substring_t args[MAX_OPT_ARGS];
 501         int ret = 0, token;
 502         unsigned long tmp_readonly;
 503
 504         opts = kstrdup(page, GFP_KERNEL);
 505         if (!opts)
 506                 return -ENOMEM;
 507
 508         orig = opts;
 509
 510         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 511                 if (!*ptr)
 512                         continue;
 513
 514                 token = match_token(ptr, tokens, args);
 515                 switch (token) {
 516                 case Opt_udev_path:
 517                         if (ib_dev->ibd_bd) {
 518                                 pr_err("Unable to set udev_path= while"
 519                                         " ib_dev->ibd_bd exists\n");
 520                                 ret = -EEXIST;
 521                                 goto out;
 522                         }
 523                         if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 524                                 SE_UDEV_PATH_LEN) == 0) {
 525                                 ret = -EINVAL;
 526                                 break;
 527                         }
 528                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 529                                         ib_dev->ibd_udev_path);
 530                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 531                         break;
 532                 case Opt_readonly:
 533                         arg_p = match_strdup(&args[0]);
 534                         if (!arg_p) {
 535                                 ret = -ENOMEM;
 536                                 break;
 537                         }
 538                         ret = kstrtoul(arg_p, 0, &tmp_readonly);
 539                         kfree(arg_p);
 540                         if (ret < 0) {
 541                                 pr_err("kstrtoul() failed for"
 542                                                 " readonly=\n");
 543                                 goto out;
 544                         }
 545                         ib_dev->ibd_readonly = tmp_readonly;
 546                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 547                         break;
 548                 case Opt_force:
 549                         break;
 550                 default:
 551                         break;
 552                 }
 553         }
 554
 555 out:
 556         kfree(orig);
 557         return (!ret) ? count : ret;
 558 }
 559
 560 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 561 {
 562         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 563         struct block_device *bd = ib_dev->ibd_bd;
 564         char buf[BDEVNAME_SIZE];
 565         ssize_t bl = 0;
 566
 567         if (bd)
 568                 bl += sprintf(b + bl, "iBlock device: %s",
 569                                 bdevname(bd, buf));
 570         if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 571                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 572                                 ib_dev->ibd_udev_path);
 573         bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 574
 575         bl += sprintf(b + bl, "        ");
 576         if (bd) {
 577                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 578                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 579                         "" : (bd->bd_holder == ib_dev) ?
 580                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 581         } else {
 582                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 583         }
 584
 585         return bl;
 586 }
 587
 588 static int
 589 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
 590 {
 591         struct se_device *dev = cmd->se_dev;
 592         struct blk_integrity *bi;
 593         struct bio_integrity_payload *bip;
 594         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 595         struct scatterlist *sg;
 596         int i, rc;
 597
 598         bi = bdev_get_integrity(ib_dev->ibd_bd);
 599         if (!bi) {
 600                 pr_err("Unable to locate bio_integrity\n");
 601                 return -ENODEV;
 602         }
 603
 604         bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
 605         if (!bip) {
 606                 pr_err("Unable to allocate bio_integrity_payload\n");
 607                 return -ENOMEM;
 608         }
 609
 610         bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
 611                          dev->prot_length;
 612         bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
 613
 614         pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
 615                  (unsigned long long)bip->bip_iter.bi_sector);
 616
 617         for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
 618
 619                 rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
 620                                             sg->offset);
 621                 if (rc != sg->length) {
 622                         pr_err("bio_integrity_add_page() failed; %d\n", rc);
 623                         return -ENOMEM;
 624                 }
 625
 626                 pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
 627                          sg_page(sg), sg->length, sg->offset);
 628         }
 629
 630         return 0;
 631 }
 632
 633 static sense_reason_t
 634 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 635                   enum dma_data_direction data_direction)
 636 {
 637         struct se_device *dev = cmd->se_dev;
 638         sector_t block_lba = target_to_linux_sector(dev, cmd->t_task_lba);
 639         struct iblock_req *ibr;
 640         struct bio *bio, *bio_start;
 641         struct bio_list list;
 642         struct scatterlist *sg;
 643         u32 sg_num = sgl_nents;
 644         unsigned bio_cnt;
 645         int rw = 0;
 646         int i;
 647
 648         if (data_direction == DMA_TO_DEVICE) {
 649                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 650                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 651                 /*
 652                  * Force writethrough using WRITE_FUA if a volatile write cache
 653                  * is not enabled, or if initiator set the Force Unit Access bit.
 654                  */
 655                 if (q->flush_flags & REQ_FUA) {
 656                         if (cmd->se_cmd_flags & SCF_FUA)
 657                                 rw = WRITE_FUA;
 658                         else if (!(q->flush_flags & REQ_FLUSH))
 659                                 rw = WRITE_FUA;
 660                         else
 661                                 rw = WRITE;
 662                 } else {
 663                         rw = WRITE;
 664                 }
 665         } else {
 666                 rw = READ;
 667         }
 668
 669         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 670         if (!ibr)
 671                 goto fail;
 672         cmd->priv = ibr;
 673
 674         if (!sgl_nents) {
 675                 atomic_set(&ibr->pending, 1);
 676                 iblock_complete_cmd(cmd);
 677                 return 0;
 678         }
 679
 680         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 681         if (!bio)
 682                 goto fail_free_ibr;
 683
 684         bio_start = bio;
 685         bio_list_init(&list);
 686         bio_list_add(&list, bio);
 687
 688         atomic_set(&ibr->pending, 2);
 689         bio_cnt = 1;
 690
 691         for_each_sg(sgl, sg, sgl_nents, i) {
 692                 /*
 693                  * XXX: if the length the device accepts is shorter than the
 694                  *      length of the S/G list entry this will cause and
 695                  *      endless loop.  Better hope no driver uses huge pages.
 696                  */
 697                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 698                                 != sg->length) {
 699                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 700                                 iblock_submit_bios(&list, rw);
 701                                 bio_cnt = 0;
 702                         }
 703
 704                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 705                         if (!bio)
 706                                 goto fail_put_bios;
 707
 708                         atomic_inc(&ibr->pending);
 709                         bio_list_add(&list, bio);
 710                         bio_cnt++;
 711                 }
 712
 713                 /* Always in 512 byte units for Linux/Block */
 714                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 715                 sg_num--;
 716         }
 717
 718         if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
 719                 int rc = iblock_alloc_bip(cmd, bio_start);
 720                 if (rc)
 721                         goto fail_put_bios;
 722         }
 723
 724         iblock_submit_bios(&list, rw);
 725         iblock_complete_cmd(cmd);
 726         return 0;
 727
 728 fail_put_bios:
 729         while ((bio = bio_list_pop(&list)))
 730                 bio_put(bio);
 731 fail_free_ibr:
 732         kfree(ibr);
 733 fail:
 734         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 735 }
 736
 737 static sector_t iblock_get_blocks(struct se_device *dev)
 738 {
 739         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 740         struct block_device *bd = ib_dev->ibd_bd;
 741         struct request_queue *q = bdev_get_queue(bd);
 742
 743         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 744 }
 745
 746 static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
 747 {
 748         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 749         struct block_device *bd = ib_dev->ibd_bd;
 750         int ret;
 751
 752         ret = bdev_alignment_offset(bd);
 753         if (ret == -1)
 754                 return 0;
 755
 756         /* convert offset-bytes to offset-lbas */
 757         return ret / bdev_logical_block_size(bd);
 758 }
 759
 760 static unsigned int iblock_get_lbppbe(struct se_device *dev)
 761 {
 762         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 763         struct block_device *bd = ib_dev->ibd_bd;
 764         int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
 765
 766         return ilog2(logs_per_phys);
 767 }
 768
 769 static unsigned int iblock_get_io_min(struct se_device *dev)
 770 {
 771         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 772         struct block_device *bd = ib_dev->ibd_bd;
 773
 774         return bdev_io_min(bd);
 775 }
 776
 777 static unsigned int iblock_get_io_opt(struct se_device *dev)
 778 {
 779         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 780         struct block_device *bd = ib_dev->ibd_bd;
 781
 782         return bdev_io_opt(bd);
 783 }
 784
 785 static struct sbc_ops iblock_sbc_ops = {
 786         .execute_rw             = iblock_execute_rw,
 787         .execute_sync_cache     = iblock_execute_sync_cache,
 788         .execute_write_same     = iblock_execute_write_same,
 789         .execute_unmap          = iblock_execute_unmap,
 790 };
 791
 792 static sense_reason_t
 793 iblock_parse_cdb(struct se_cmd *cmd)
 794 {
 795         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 796 }
 797
 798 static bool iblock_get_write_cache(struct se_device *dev)
 799 {
 800         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 801         struct block_device *bd = ib_dev->ibd_bd;
 802         struct request_queue *q = bdev_get_queue(bd);
 803
 804         return q->flush_flags & REQ_FLUSH;
 805 }
 806
 807 static const struct target_backend_ops iblock_ops = {
 808         .name                   = "iblock",
 809         .inquiry_prod           = "IBLOCK",
 810         .inquiry_rev            = IBLOCK_VERSION,
 811         .owner                  = THIS_MODULE,
 812         .attach_hba             = iblock_attach_hba,
 813         .detach_hba             = iblock_detach_hba,
 814         .alloc_device           = iblock_alloc_device,
 815         .configure_device       = iblock_configure_device,
 816         .free_device            = iblock_free_device,
 817         .parse_cdb              = iblock_parse_cdb,
 818         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 819         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 820         .get_device_type        = sbc_get_device_type,
 821         .get_blocks             = iblock_get_blocks,
 822         .get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
 823         .get_lbppbe             = iblock_get_lbppbe,
 824         .get_io_min             = iblock_get_io_min,
 825         .get_io_opt             = iblock_get_io_opt,
 826         .get_write_cache        = iblock_get_write_cache,
 827         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 828 };
 829
 830 static int __init iblock_module_init(void)
 831 {
 832         return transport_backend_register(&iblock_ops);
 833 }
 834
 835 static void __exit iblock_module_exit(void)
 836 {
 837         target_backend_unregister(&iblock_ops);
 838 }
 839
 840 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 841 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 842 MODULE_LICENSE("GPL");
 843
 844 module_init(iblock_module_init);
 845 module_exit(iblock_module_exit);