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
 109         bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 110         if (IS_ERR(bd)) {
 111                 ret = PTR_ERR(bd);
 112                 goto out_free_bioset;
 113         }
 114         ib_dev->ibd_bd = bd;
 115
 116         q = bdev_get_queue(bd);
 117
 118         dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
 119         dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 120         dev->dev_attrib.hw_queue_depth = q->nr_requests;
 121
 122         /*
 123          * Check if the underlying struct block_device request_queue supports
 124          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 125          * in ATA and we need to set TPE=1
 126          */
 127         if (blk_queue_discard(q)) {
 128                 dev->dev_attrib.max_unmap_lba_count =
 129                                 q->limits.max_discard_sectors;
 130
 131                 /*
 132                  * Currently hardcoded to 1 in Linux/SCSI code..
 133                  */
 134                 dev->dev_attrib.max_unmap_block_desc_count = 1;
 135                 dev->dev_attrib.unmap_granularity =
 136                                 q->limits.discard_granularity >> 9;
 137                 dev->dev_attrib.unmap_granularity_alignment =
 138                                 q->limits.discard_alignment;
 139
 140                 pr_debug("IBLOCK: BLOCK Discard support available,"
 141                                 " disabled by default\n");
 142         }
 143         /*
 144          * Enable write same emulation for IBLOCK and use 0xFFFF as
 145          * the smaller WRITE_SAME(10) only has a two-byte block count.
 146          */
 147         dev->dev_attrib.max_write_same_len = 0xFFFF;
 148
 149         if (blk_queue_nonrot(q))
 150                 dev->dev_attrib.is_nonrot = 1;
 151
 152         bi = bdev_get_integrity(bd);
 153         if (bi) {
 154                 struct bio_set *bs = ib_dev->ibd_bio_set;
 155
 156                 if (!strcmp(bi->name, "T10-DIF-TYPE3-IP") ||
 157                     !strcmp(bi->name, "T10-DIF-TYPE1-IP")) {
 158                         pr_err("IBLOCK export of blk_integrity: %s not"
 159                                " supported\n", bi->name);
 160                         ret = -ENOSYS;
 161                         goto out_blkdev_put;
 162                 }
 163
 164                 if (!strcmp(bi->name, "T10-DIF-TYPE3-CRC")) {
 165                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
 166                 } else if (!strcmp(bi->name, "T10-DIF-TYPE1-CRC")) {
 167                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
 168                 }
 169
 170                 if (dev->dev_attrib.pi_prot_type) {
 171                         if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
 172                                 pr_err("Unable to allocate bioset for PI\n");
 173                                 ret = -ENOMEM;
 174                                 goto out_blkdev_put;
 175                         }
 176                         pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
 177                                  bs->bio_integrity_pool);
 178                 }
 179                 dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
 180         }
 181
 182         return 0;
 183
 184 out_blkdev_put:
 185         blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 186 out_free_bioset:
 187         bioset_free(ib_dev->ibd_bio_set);
 188         ib_dev->ibd_bio_set = NULL;
 189 out:
 190         return ret;
 191 }
 192
 193 static void iblock_dev_call_rcu(struct rcu_head *p)
 194 {
 195         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 196         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 197
 198         kfree(ib_dev);
 199 }
 200
 201 static void iblock_free_device(struct se_device *dev)
 202 {
 203         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 204
 205         if (ib_dev->ibd_bd != NULL)
 206                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 207         if (ib_dev->ibd_bio_set != NULL)
 208                 bioset_free(ib_dev->ibd_bio_set);
 209
 210         call_rcu(&dev->rcu_head, iblock_dev_call_rcu);
 211 }
 212
 213 static unsigned long long iblock_emulate_read_cap_with_block_size(
 214         struct se_device *dev,
 215         struct block_device *bd,
 216         struct request_queue *q)
 217 {
 218         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 219                                         bdev_logical_block_size(bd)) - 1);
 220         u32 block_size = bdev_logical_block_size(bd);
 221
 222         if (block_size == dev->dev_attrib.block_size)
 223                 return blocks_long;
 224
 225         switch (block_size) {
 226         case 4096:
 227                 switch (dev->dev_attrib.block_size) {
 228                 case 2048:
 229                         blocks_long <<= 1;
 230                         break;
 231                 case 1024:
 232                         blocks_long <<= 2;
 233                         break;
 234                 case 512:
 235                         blocks_long <<= 3;
 236                 default:
 237                         break;
 238                 }
 239                 break;
 240         case 2048:
 241                 switch (dev->dev_attrib.block_size) {
 242                 case 4096:
 243                         blocks_long >>= 1;
 244                         break;
 245                 case 1024:
 246                         blocks_long <<= 1;
 247                         break;
 248                 case 512:
 249                         blocks_long <<= 2;
 250                         break;
 251                 default:
 252                         break;
 253                 }
 254                 break;
 255         case 1024:
 256                 switch (dev->dev_attrib.block_size) {
 257                 case 4096:
 258                         blocks_long >>= 2;
 259                         break;
 260                 case 2048:
 261                         blocks_long >>= 1;
 262                         break;
 263                 case 512:
 264                         blocks_long <<= 1;
 265                         break;
 266                 default:
 267                         break;
 268                 }
 269                 break;
 270         case 512:
 271                 switch (dev->dev_attrib.block_size) {
 272                 case 4096:
 273                         blocks_long >>= 3;
 274                         break;
 275                 case 2048:
 276                         blocks_long >>= 2;
 277                         break;
 278                 case 1024:
 279                         blocks_long >>= 1;
 280                         break;
 281                 default:
 282                         break;
 283                 }
 284                 break;
 285         default:
 286                 break;
 287         }
 288
 289         return blocks_long;
 290 }
 291
 292 static void iblock_complete_cmd(struct se_cmd *cmd)
 293 {
 294         struct iblock_req *ibr = cmd->priv;
 295         u8 status;
 296
 297         if (!atomic_dec_and_test(&ibr->pending))
 298                 return;
 299
 300         if (atomic_read(&ibr->ib_bio_err_cnt))
 301                 status = SAM_STAT_CHECK_CONDITION;
 302         else
 303                 status = SAM_STAT_GOOD;
 304
 305         target_complete_cmd(cmd, status);
 306         kfree(ibr);
 307 }
 308
 309 static void iblock_bio_done(struct bio *bio)
 310 {
 311         struct se_cmd *cmd = bio->bi_private;
 312         struct iblock_req *ibr = cmd->priv;
 313
 314         if (bio->bi_error) {
 315                 pr_err("bio error: %p,  err: %d\n", bio, bio->bi_error);
 316                 /*
 317                  * Bump the ib_bio_err_cnt and release bio.
 318                  */
 319                 atomic_inc(&ibr->ib_bio_err_cnt);
 320                 smp_mb__after_atomic();
 321         }
 322
 323         bio_put(bio);
 324
 325         iblock_complete_cmd(cmd);
 326 }
 327
 328 static struct bio *
 329 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 330 {
 331         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 332         struct bio *bio;
 333
 334         /*
 335          * Only allocate as many vector entries as the bio code allows us to,
 336          * we'll loop later on until we have handled the whole request.
 337          */
 338         if (sg_num > BIO_MAX_PAGES)
 339                 sg_num = BIO_MAX_PAGES;
 340
 341         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 342         if (!bio) {
 343                 pr_err("Unable to allocate memory for bio\n");
 344                 return NULL;
 345         }
 346
 347         bio->bi_bdev = ib_dev->ibd_bd;
 348         bio->bi_private = cmd;
 349         bio->bi_end_io = &iblock_bio_done;
 350         bio->bi_iter.bi_sector = lba;
 351
 352         return bio;
 353 }
 354
 355 static void iblock_submit_bios(struct bio_list *list, int rw)
 356 {
 357         struct blk_plug plug;
 358         struct bio *bio;
 359
 360         blk_start_plug(&plug);
 361         while ((bio = bio_list_pop(list)))
 362                 submit_bio(rw, bio);
 363         blk_finish_plug(&plug);
 364 }
 365
 366 static void iblock_end_io_flush(struct bio *bio)
 367 {
 368         struct se_cmd *cmd = bio->bi_private;
 369
 370         if (bio->bi_error)
 371                 pr_err("IBLOCK: cache flush failed: %d\n", bio->bi_error);
 372
 373         if (cmd) {
 374                 if (bio->bi_error)
 375                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 376                 else
 377                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 378         }
 379
 380         bio_put(bio);
 381 }
 382
 383 /*
 384  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 385  * always flush the whole cache.
 386  */
 387 static sense_reason_t
 388 iblock_execute_sync_cache(struct se_cmd *cmd)
 389 {
 390         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 391         int immed = (cmd->t_task_cdb[1] & 0x2);
 392         struct bio *bio;
 393
 394         /*
 395          * If the Immediate bit is set, queue up the GOOD response
 396          * for this SYNCHRONIZE_CACHE op.
 397          */
 398         if (immed)
 399                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 400
 401         bio = bio_alloc(GFP_KERNEL, 0);
 402         bio->bi_end_io = iblock_end_io_flush;
 403         bio->bi_bdev = ib_dev->ibd_bd;
 404         if (!immed)
 405                 bio->bi_private = cmd;
 406         submit_bio(WRITE_FLUSH, bio);
 407         return 0;
 408 }
 409
 410 static sense_reason_t
 411 iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 412 {
 413         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 414         int ret;
 415
 416         ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
 417         if (ret < 0) {
 418                 pr_err("blkdev_issue_discard() failed: %d\n", ret);
 419                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 420         }
 421
 422         return 0;
 423 }
 424
 425 static sense_reason_t
 426 iblock_execute_write_same(struct se_cmd *cmd)
 427 {
 428         struct iblock_req *ibr;
 429         struct scatterlist *sg;
 430         struct bio *bio;
 431         struct bio_list list;
 432         sector_t block_lba = cmd->t_task_lba;
 433         sector_t sectors = sbc_get_write_same_sectors(cmd);
 434
 435         if (cmd->prot_op) {
 436                 pr_err("WRITE_SAME: Protection information with IBLOCK"
 437                        " backends not supported\n");
 438                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 439         }
 440         sg = &cmd->t_data_sg[0];
 441
 442         if (cmd->t_data_nents > 1 ||
 443             sg->length != cmd->se_dev->dev_attrib.block_size) {
 444                 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 445                         " block_size: %u\n", cmd->t_data_nents, sg->length,
 446                         cmd->se_dev->dev_attrib.block_size);
 447                 return TCM_INVALID_CDB_FIELD;
 448         }
 449
 450         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 451         if (!ibr)
 452                 goto fail;
 453         cmd->priv = ibr;
 454
 455         bio = iblock_get_bio(cmd, block_lba, 1);
 456         if (!bio)
 457                 goto fail_free_ibr;
 458
 459         bio_list_init(&list);
 460         bio_list_add(&list, bio);
 461
 462         atomic_set(&ibr->pending, 1);
 463
 464         while (sectors) {
 465                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 466                                 != sg->length) {
 467
 468                         bio = iblock_get_bio(cmd, block_lba, 1);
 469                         if (!bio)
 470                                 goto fail_put_bios;
 471
 472                         atomic_inc(&ibr->pending);
 473                         bio_list_add(&list, bio);
 474                 }
 475
 476                 /* Always in 512 byte units for Linux/Block */
 477                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 478                 sectors -= 1;
 479         }
 480
 481         iblock_submit_bios(&list, WRITE);
 482         return 0;
 483
 484 fail_put_bios:
 485         while ((bio = bio_list_pop(&list)))
 486                 bio_put(bio);
 487 fail_free_ibr:
 488         kfree(ibr);
 489 fail:
 490         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 491 }
 492
 493 enum {
 494         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 495 };
 496
 497 static match_table_t tokens = {
 498         {Opt_udev_path, "udev_path=%s"},
 499         {Opt_readonly, "readonly=%d"},
 500         {Opt_force, "force=%d"},
 501         {Opt_err, NULL}
 502 };
 503
 504 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 505                 const char *page, ssize_t count)
 506 {
 507         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 508         char *orig, *ptr, *arg_p, *opts;
 509         substring_t args[MAX_OPT_ARGS];
 510         int ret = 0, token;
 511         unsigned long tmp_readonly;
 512
 513         opts = kstrdup(page, GFP_KERNEL);
 514         if (!opts)
 515                 return -ENOMEM;
 516
 517         orig = opts;
 518
 519         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 520                 if (!*ptr)
 521                         continue;
 522
 523                 token = match_token(ptr, tokens, args);
 524                 switch (token) {
 525                 case Opt_udev_path:
 526                         if (ib_dev->ibd_bd) {
 527                                 pr_err("Unable to set udev_path= while"
 528                                         " ib_dev->ibd_bd exists\n");
 529                                 ret = -EEXIST;
 530                                 goto out;
 531                         }
 532                         if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 533                                 SE_UDEV_PATH_LEN) == 0) {
 534                                 ret = -EINVAL;
 535                                 break;
 536                         }
 537                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 538                                         ib_dev->ibd_udev_path);
 539                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 540                         break;
 541                 case Opt_readonly:
 542                         arg_p = match_strdup(&args[0]);
 543                         if (!arg_p) {
 544                                 ret = -ENOMEM;
 545                                 break;
 546                         }
 547                         ret = kstrtoul(arg_p, 0, &tmp_readonly);
 548                         kfree(arg_p);
 549                         if (ret < 0) {
 550                                 pr_err("kstrtoul() failed for"
 551                                                 " readonly=\n");
 552                                 goto out;
 553                         }
 554                         ib_dev->ibd_readonly = tmp_readonly;
 555                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 556                         break;
 557                 case Opt_force:
 558                         break;
 559                 default:
 560                         break;
 561                 }
 562         }
 563
 564 out:
 565         kfree(orig);
 566         return (!ret) ? count : ret;
 567 }
 568
 569 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 570 {
 571         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 572         struct block_device *bd = ib_dev->ibd_bd;
 573         char buf[BDEVNAME_SIZE];
 574         ssize_t bl = 0;
 575
 576         if (bd)
 577                 bl += sprintf(b + bl, "iBlock device: %s",
 578                                 bdevname(bd, buf));
 579         if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 580                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 581                                 ib_dev->ibd_udev_path);
 582         bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 583
 584         bl += sprintf(b + bl, "        ");
 585         if (bd) {
 586                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 587                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 588                         "" : (bd->bd_holder == ib_dev) ?
 589                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 590         } else {
 591                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 592         }
 593
 594         return bl;
 595 }
 596
 597 static int
 598 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
 599 {
 600         struct se_device *dev = cmd->se_dev;
 601         struct blk_integrity *bi;
 602         struct bio_integrity_payload *bip;
 603         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 604         struct scatterlist *sg;
 605         int i, rc;
 606
 607         bi = bdev_get_integrity(ib_dev->ibd_bd);
 608         if (!bi) {
 609                 pr_err("Unable to locate bio_integrity\n");
 610                 return -ENODEV;
 611         }
 612
 613         bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
 614         if (!bip) {
 615                 pr_err("Unable to allocate bio_integrity_payload\n");
 616                 return -ENOMEM;
 617         }
 618
 619         bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
 620                          dev->prot_length;
 621         bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
 622
 623         pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
 624                  (unsigned long long)bip->bip_iter.bi_sector);
 625
 626         for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
 627
 628                 rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
 629                                             sg->offset);
 630                 if (rc != sg->length) {
 631                         pr_err("bio_integrity_add_page() failed; %d\n", rc);
 632                         return -ENOMEM;
 633                 }
 634
 635                 pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
 636                          sg_page(sg), sg->length, sg->offset);
 637         }
 638
 639         return 0;
 640 }
 641
 642 static sense_reason_t
 643 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 644                   enum dma_data_direction data_direction)
 645 {
 646         struct se_device *dev = cmd->se_dev;
 647         struct iblock_req *ibr;
 648         struct bio *bio, *bio_start;
 649         struct bio_list list;
 650         struct scatterlist *sg;
 651         u32 sg_num = sgl_nents;
 652         sector_t block_lba;
 653         unsigned bio_cnt;
 654         int rw = 0;
 655         int i;
 656
 657         if (data_direction == DMA_TO_DEVICE) {
 658                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 659                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 660                 /*
 661                  * Force writethrough using WRITE_FUA if a volatile write cache
 662                  * is not enabled, or if initiator set the Force Unit Access bit.
 663                  */
 664                 if (q->flush_flags & REQ_FUA) {
 665                         if (cmd->se_cmd_flags & SCF_FUA)
 666                                 rw = WRITE_FUA;
 667                         else if (!(q->flush_flags & REQ_FLUSH))
 668                                 rw = WRITE_FUA;
 669                         else
 670                                 rw = WRITE;
 671                 } else {
 672                         rw = WRITE;
 673                 }
 674         } else {
 675                 rw = READ;
 676         }
 677
 678         /*
 679          * Convert the blocksize advertised to the initiator to the 512 byte
 680          * units unconditionally used by the Linux block layer.
 681          */
 682         if (dev->dev_attrib.block_size == 4096)
 683                 block_lba = (cmd->t_task_lba << 3);
 684         else if (dev->dev_attrib.block_size == 2048)
 685                 block_lba = (cmd->t_task_lba << 2);
 686         else if (dev->dev_attrib.block_size == 1024)
 687                 block_lba = (cmd->t_task_lba << 1);
 688         else if (dev->dev_attrib.block_size == 512)
 689                 block_lba = cmd->t_task_lba;
 690         else {
 691                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 692                                 " %u\n", dev->dev_attrib.block_size);
 693                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 694         }
 695
 696         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 697         if (!ibr)
 698                 goto fail;
 699         cmd->priv = ibr;
 700
 701         if (!sgl_nents) {
 702                 atomic_set(&ibr->pending, 1);
 703                 iblock_complete_cmd(cmd);
 704                 return 0;
 705         }
 706
 707         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 708         if (!bio)
 709                 goto fail_free_ibr;
 710
 711         bio_start = bio;
 712         bio_list_init(&list);
 713         bio_list_add(&list, bio);
 714
 715         atomic_set(&ibr->pending, 2);
 716         bio_cnt = 1;
 717
 718         for_each_sg(sgl, sg, sgl_nents, i) {
 719                 /*
 720                  * XXX: if the length the device accepts is shorter than the
 721                  *      length of the S/G list entry this will cause and
 722                  *      endless loop.  Better hope no driver uses huge pages.
 723                  */
 724                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 725                                 != sg->length) {
 726                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 727                                 iblock_submit_bios(&list, rw);
 728                                 bio_cnt = 0;
 729                         }
 730
 731                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 732                         if (!bio)
 733                                 goto fail_put_bios;
 734
 735                         atomic_inc(&ibr->pending);
 736                         bio_list_add(&list, bio);
 737                         bio_cnt++;
 738                 }
 739
 740                 /* Always in 512 byte units for Linux/Block */
 741                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 742                 sg_num--;
 743         }
 744
 745         if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
 746                 int rc = iblock_alloc_bip(cmd, bio_start);
 747                 if (rc)
 748                         goto fail_put_bios;
 749         }
 750
 751         iblock_submit_bios(&list, rw);
 752         iblock_complete_cmd(cmd);
 753         return 0;
 754
 755 fail_put_bios:
 756         while ((bio = bio_list_pop(&list)))
 757                 bio_put(bio);
 758 fail_free_ibr:
 759         kfree(ibr);
 760 fail:
 761         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 762 }
 763
 764 static sector_t iblock_get_blocks(struct se_device *dev)
 765 {
 766         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 767         struct block_device *bd = ib_dev->ibd_bd;
 768         struct request_queue *q = bdev_get_queue(bd);
 769
 770         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 771 }
 772
 773 static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
 774 {
 775         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 776         struct block_device *bd = ib_dev->ibd_bd;
 777         int ret;
 778
 779         ret = bdev_alignment_offset(bd);
 780         if (ret == -1)
 781                 return 0;
 782
 783         /* convert offset-bytes to offset-lbas */
 784         return ret / bdev_logical_block_size(bd);
 785 }
 786
 787 static unsigned int iblock_get_lbppbe(struct se_device *dev)
 788 {
 789         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 790         struct block_device *bd = ib_dev->ibd_bd;
 791         int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
 792
 793         return ilog2(logs_per_phys);
 794 }
 795
 796 static unsigned int iblock_get_io_min(struct se_device *dev)
 797 {
 798         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 799         struct block_device *bd = ib_dev->ibd_bd;
 800
 801         return bdev_io_min(bd);
 802 }
 803
 804 static unsigned int iblock_get_io_opt(struct se_device *dev)
 805 {
 806         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 807         struct block_device *bd = ib_dev->ibd_bd;
 808
 809         return bdev_io_opt(bd);
 810 }
 811
 812 static struct sbc_ops iblock_sbc_ops = {
 813         .execute_rw             = iblock_execute_rw,
 814         .execute_sync_cache     = iblock_execute_sync_cache,
 815         .execute_write_same     = iblock_execute_write_same,
 816         .execute_unmap          = iblock_execute_unmap,
 817 };
 818
 819 static sense_reason_t
 820 iblock_parse_cdb(struct se_cmd *cmd)
 821 {
 822         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 823 }
 824
 825 static bool iblock_get_write_cache(struct se_device *dev)
 826 {
 827         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 828         struct block_device *bd = ib_dev->ibd_bd;
 829         struct request_queue *q = bdev_get_queue(bd);
 830
 831         return q->flush_flags & REQ_FLUSH;
 832 }
 833
 834 static const struct target_backend_ops iblock_ops = {
 835         .name                   = "iblock",
 836         .inquiry_prod           = "IBLOCK",
 837         .inquiry_rev            = IBLOCK_VERSION,
 838         .owner                  = THIS_MODULE,
 839         .attach_hba             = iblock_attach_hba,
 840         .detach_hba             = iblock_detach_hba,
 841         .alloc_device           = iblock_alloc_device,
 842         .configure_device       = iblock_configure_device,
 843         .free_device            = iblock_free_device,
 844         .parse_cdb              = iblock_parse_cdb,
 845         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 846         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 847         .get_device_type        = sbc_get_device_type,
 848         .get_blocks             = iblock_get_blocks,
 849         .get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
 850         .get_lbppbe             = iblock_get_lbppbe,
 851         .get_io_min             = iblock_get_io_min,
 852         .get_io_opt             = iblock_get_io_opt,
 853         .get_write_cache        = iblock_get_write_cache,
 854         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 855 };
 856
 857 static int __init iblock_module_init(void)
 858 {
 859         return transport_backend_register(&iblock_ops);
 860 }
 861
 862 static void __exit iblock_module_exit(void)
 863 {
 864         target_backend_unregister(&iblock_ops);
 865 }
 866
 867 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 868 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 869 MODULE_LICENSE("GPL");
 870
 871 module_init(iblock_module_init);
 872 module_exit(iblock_module_exit);