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