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, int err)
 310 {
 311         struct se_cmd *cmd = bio->bi_private;
 312         struct iblock_req *ibr = cmd->priv;
 313
 314         /*
 315          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 316          */
 317         if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 318                 err = -EIO;
 319
 320         if (err != 0) {
 321                 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 322                         " err: %d\n", bio, err);
 323                 /*
 324                  * Bump the ib_bio_err_cnt and release bio.
 325                  */
 326                 atomic_inc(&ibr->ib_bio_err_cnt);
 327                 smp_mb__after_atomic();
 328         }
 329
 330         bio_put(bio);
 331
 332         iblock_complete_cmd(cmd);
 333 }
 334
 335 static struct bio *
 336 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 337 {
 338         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 339         struct bio *bio;
 340
 341         /*
 342          * Only allocate as many vector entries as the bio code allows us to,
 343          * we'll loop later on until we have handled the whole request.
 344          */
 345         if (sg_num > BIO_MAX_PAGES)
 346                 sg_num = BIO_MAX_PAGES;
 347
 348         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 349         if (!bio) {
 350                 pr_err("Unable to allocate memory for bio\n");
 351                 return NULL;
 352         }
 353
 354         bio->bi_bdev = ib_dev->ibd_bd;
 355         bio->bi_private = cmd;
 356         bio->bi_end_io = &iblock_bio_done;
 357         bio->bi_iter.bi_sector = lba;
 358
 359         return bio;
 360 }
 361
 362 static void iblock_submit_bios(struct bio_list *list, int rw)
 363 {
 364         struct blk_plug plug;
 365         struct bio *bio;
 366
 367         blk_start_plug(&plug);
 368         while ((bio = bio_list_pop(list)))
 369                 submit_bio(rw, bio);
 370         blk_finish_plug(&plug);
 371 }
 372
 373 static void iblock_end_io_flush(struct bio *bio, int err)
 374 {
 375         struct se_cmd *cmd = bio->bi_private;
 376
 377         if (err)
 378                 pr_err("IBLOCK: cache flush failed: %d\n", err);
 379
 380         if (cmd) {
 381                 if (err)
 382                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 383                 else
 384                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 385         }
 386
 387         bio_put(bio);
 388 }
 389
 390 /*
 391  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 392  * always flush the whole cache.
 393  */
 394 static sense_reason_t
 395 iblock_execute_sync_cache(struct se_cmd *cmd)
 396 {
 397         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 398         int immed = (cmd->t_task_cdb[1] & 0x2);
 399         struct bio *bio;
 400
 401         /*
 402          * If the Immediate bit is set, queue up the GOOD response
 403          * for this SYNCHRONIZE_CACHE op.
 404          */
 405         if (immed)
 406                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 407
 408         bio = bio_alloc(GFP_KERNEL, 0);
 409         bio->bi_end_io = iblock_end_io_flush;
 410         bio->bi_bdev = ib_dev->ibd_bd;
 411         if (!immed)
 412                 bio->bi_private = cmd;
 413         submit_bio(WRITE_FLUSH, bio);
 414         return 0;
 415 }
 416
 417 static sense_reason_t
 418 iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 419 {
 420         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 421         int ret;
 422
 423         ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
 424         if (ret < 0) {
 425                 pr_err("blkdev_issue_discard() failed: %d\n", ret);
 426                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 427         }
 428
 429         return 0;
 430 }
 431
 432 static sense_reason_t
 433 iblock_execute_write_same(struct se_cmd *cmd)
 434 {
 435         struct iblock_req *ibr;
 436         struct scatterlist *sg;
 437         struct bio *bio;
 438         struct bio_list list;
 439         sector_t block_lba = cmd->t_task_lba;
 440         sector_t sectors = sbc_get_write_same_sectors(cmd);
 441
 442         if (cmd->prot_op) {
 443                 pr_err("WRITE_SAME: Protection information with IBLOCK"
 444                        " backends not supported\n");
 445                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 446         }
 447         sg = &cmd->t_data_sg[0];
 448
 449         if (cmd->t_data_nents > 1 ||
 450             sg->length != cmd->se_dev->dev_attrib.block_size) {
 451                 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 452                         " block_size: %u\n", cmd->t_data_nents, sg->length,
 453                         cmd->se_dev->dev_attrib.block_size);
 454                 return TCM_INVALID_CDB_FIELD;
 455         }
 456
 457         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 458         if (!ibr)
 459                 goto fail;
 460         cmd->priv = ibr;
 461
 462         bio = iblock_get_bio(cmd, block_lba, 1);
 463         if (!bio)
 464                 goto fail_free_ibr;
 465
 466         bio_list_init(&list);
 467         bio_list_add(&list, bio);
 468
 469         atomic_set(&ibr->pending, 1);
 470
 471         while (sectors) {
 472                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 473                                 != sg->length) {
 474
 475                         bio = iblock_get_bio(cmd, block_lba, 1);
 476                         if (!bio)
 477                                 goto fail_put_bios;
 478
 479                         atomic_inc(&ibr->pending);
 480                         bio_list_add(&list, bio);
 481                 }
 482
 483                 /* Always in 512 byte units for Linux/Block */
 484                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 485                 sectors -= 1;
 486         }
 487
 488         iblock_submit_bios(&list, WRITE);
 489         return 0;
 490
 491 fail_put_bios:
 492         while ((bio = bio_list_pop(&list)))
 493                 bio_put(bio);
 494 fail_free_ibr:
 495         kfree(ibr);
 496 fail:
 497         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 498 }
 499
 500 enum {
 501         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 502 };
 503
 504 static match_table_t tokens = {
 505         {Opt_udev_path, "udev_path=%s"},
 506         {Opt_readonly, "readonly=%d"},
 507         {Opt_force, "force=%d"},
 508         {Opt_err, NULL}
 509 };
 510
 511 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 512                 const char *page, ssize_t count)
 513 {
 514         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 515         char *orig, *ptr, *arg_p, *opts;
 516         substring_t args[MAX_OPT_ARGS];
 517         int ret = 0, token;
 518         unsigned long tmp_readonly;
 519
 520         opts = kstrdup(page, GFP_KERNEL);
 521         if (!opts)
 522                 return -ENOMEM;
 523
 524         orig = opts;
 525
 526         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 527                 if (!*ptr)
 528                         continue;
 529
 530                 token = match_token(ptr, tokens, args);
 531                 switch (token) {
 532                 case Opt_udev_path:
 533                         if (ib_dev->ibd_bd) {
 534                                 pr_err("Unable to set udev_path= while"
 535                                         " ib_dev->ibd_bd exists\n");
 536                                 ret = -EEXIST;
 537                                 goto out;
 538                         }
 539                         if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 540                                 SE_UDEV_PATH_LEN) == 0) {
 541                                 ret = -EINVAL;
 542                                 break;
 543                         }
 544                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 545                                         ib_dev->ibd_udev_path);
 546                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 547                         break;
 548                 case Opt_readonly:
 549                         arg_p = match_strdup(&args[0]);
 550                         if (!arg_p) {
 551                                 ret = -ENOMEM;
 552                                 break;
 553                         }
 554                         ret = kstrtoul(arg_p, 0, &tmp_readonly);
 555                         kfree(arg_p);
 556                         if (ret < 0) {
 557                                 pr_err("kstrtoul() failed for"
 558                                                 " readonly=\n");
 559                                 goto out;
 560                         }
 561                         ib_dev->ibd_readonly = tmp_readonly;
 562                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 563                         break;
 564                 case Opt_force:
 565                         break;
 566                 default:
 567                         break;
 568                 }
 569         }
 570
 571 out:
 572         kfree(orig);
 573         return (!ret) ? count : ret;
 574 }
 575
 576 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 577 {
 578         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 579         struct block_device *bd = ib_dev->ibd_bd;
 580         char buf[BDEVNAME_SIZE];
 581         ssize_t bl = 0;
 582
 583         if (bd)
 584                 bl += sprintf(b + bl, "iBlock device: %s",
 585                                 bdevname(bd, buf));
 586         if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 587                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 588                                 ib_dev->ibd_udev_path);
 589         bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 590
 591         bl += sprintf(b + bl, "        ");
 592         if (bd) {
 593                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 594                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 595                         "" : (bd->bd_holder == ib_dev) ?
 596                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 597         } else {
 598                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 599         }
 600
 601         return bl;
 602 }
 603
 604 static int
 605 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
 606 {
 607         struct se_device *dev = cmd->se_dev;
 608         struct blk_integrity *bi;
 609         struct bio_integrity_payload *bip;
 610         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 611         struct scatterlist *sg;
 612         int i, rc;
 613
 614         bi = bdev_get_integrity(ib_dev->ibd_bd);
 615         if (!bi) {
 616                 pr_err("Unable to locate bio_integrity\n");
 617                 return -ENODEV;
 618         }
 619
 620         bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
 621         if (!bip) {
 622                 pr_err("Unable to allocate bio_integrity_payload\n");
 623                 return -ENOMEM;
 624         }
 625
 626         bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
 627                          dev->prot_length;
 628         bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
 629
 630         pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
 631                  (unsigned long long)bip->bip_iter.bi_sector);
 632
 633         for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
 634
 635                 rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
 636                                             sg->offset);
 637                 if (rc != sg->length) {
 638                         pr_err("bio_integrity_add_page() failed; %d\n", rc);
 639                         return -ENOMEM;
 640                 }
 641
 642                 pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
 643                          sg_page(sg), sg->length, sg->offset);
 644         }
 645
 646         return 0;
 647 }
 648
 649 static sense_reason_t
 650 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 651                   enum dma_data_direction data_direction)
 652 {
 653         struct se_device *dev = cmd->se_dev;
 654         struct iblock_req *ibr;
 655         struct bio *bio, *bio_start;
 656         struct bio_list list;
 657         struct scatterlist *sg;
 658         u32 sg_num = sgl_nents;
 659         sector_t block_lba;
 660         unsigned bio_cnt;
 661         int rw = 0;
 662         int i;
 663
 664         if (data_direction == DMA_TO_DEVICE) {
 665                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 666                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 667                 /*
 668                  * Force writethrough using WRITE_FUA if a volatile write cache
 669                  * is not enabled, or if initiator set the Force Unit Access bit.
 670                  */
 671                 if (q->flush_flags & REQ_FUA) {
 672                         if (cmd->se_cmd_flags & SCF_FUA)
 673                                 rw = WRITE_FUA;
 674                         else if (!(q->flush_flags & REQ_FLUSH))
 675                                 rw = WRITE_FUA;
 676                         else
 677                                 rw = WRITE;
 678                 } else {
 679                         rw = WRITE;
 680                 }
 681         } else {
 682                 rw = READ;
 683         }
 684
 685         /*
 686          * Convert the blocksize advertised to the initiator to the 512 byte
 687          * units unconditionally used by the Linux block layer.
 688          */
 689         if (dev->dev_attrib.block_size == 4096)
 690                 block_lba = (cmd->t_task_lba << 3);
 691         else if (dev->dev_attrib.block_size == 2048)
 692                 block_lba = (cmd->t_task_lba << 2);
 693         else if (dev->dev_attrib.block_size == 1024)
 694                 block_lba = (cmd->t_task_lba << 1);
 695         else if (dev->dev_attrib.block_size == 512)
 696                 block_lba = cmd->t_task_lba;
 697         else {
 698                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 699                                 " %u\n", dev->dev_attrib.block_size);
 700                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 701         }
 702
 703         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 704         if (!ibr)
 705                 goto fail;
 706         cmd->priv = ibr;
 707
 708         if (!sgl_nents) {
 709                 atomic_set(&ibr->pending, 1);
 710                 iblock_complete_cmd(cmd);
 711                 return 0;
 712         }
 713
 714         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 715         if (!bio)
 716                 goto fail_free_ibr;
 717
 718         bio_start = bio;
 719         bio_list_init(&list);
 720         bio_list_add(&list, bio);
 721
 722         atomic_set(&ibr->pending, 2);
 723         bio_cnt = 1;
 724
 725         for_each_sg(sgl, sg, sgl_nents, i) {
 726                 /*
 727                  * XXX: if the length the device accepts is shorter than the
 728                  *      length of the S/G list entry this will cause and
 729                  *      endless loop.  Better hope no driver uses huge pages.
 730                  */
 731                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 732                                 != sg->length) {
 733                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 734                                 iblock_submit_bios(&list, rw);
 735                                 bio_cnt = 0;
 736                         }
 737
 738                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 739                         if (!bio)
 740                                 goto fail_put_bios;
 741
 742                         atomic_inc(&ibr->pending);
 743                         bio_list_add(&list, bio);
 744                         bio_cnt++;
 745                 }
 746
 747                 /* Always in 512 byte units for Linux/Block */
 748                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 749                 sg_num--;
 750         }
 751
 752         if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
 753                 int rc = iblock_alloc_bip(cmd, bio_start);
 754                 if (rc)
 755                         goto fail_put_bios;
 756         }
 757
 758         iblock_submit_bios(&list, rw);
 759         iblock_complete_cmd(cmd);
 760         return 0;
 761
 762 fail_put_bios:
 763         while ((bio = bio_list_pop(&list)))
 764                 bio_put(bio);
 765 fail_free_ibr:
 766         kfree(ibr);
 767 fail:
 768         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 769 }
 770
 771 static sector_t iblock_get_blocks(struct se_device *dev)
 772 {
 773         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 774         struct block_device *bd = ib_dev->ibd_bd;
 775         struct request_queue *q = bdev_get_queue(bd);
 776
 777         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 778 }
 779
 780 static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
 781 {
 782         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 783         struct block_device *bd = ib_dev->ibd_bd;
 784         int ret;
 785
 786         ret = bdev_alignment_offset(bd);
 787         if (ret == -1)
 788                 return 0;
 789
 790         /* convert offset-bytes to offset-lbas */
 791         return ret / bdev_logical_block_size(bd);
 792 }
 793
 794 static unsigned int iblock_get_lbppbe(struct se_device *dev)
 795 {
 796         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 797         struct block_device *bd = ib_dev->ibd_bd;
 798         int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
 799
 800         return ilog2(logs_per_phys);
 801 }
 802
 803 static unsigned int iblock_get_io_min(struct se_device *dev)
 804 {
 805         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 806         struct block_device *bd = ib_dev->ibd_bd;
 807
 808         return bdev_io_min(bd);
 809 }
 810
 811 static unsigned int iblock_get_io_opt(struct se_device *dev)
 812 {
 813         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 814         struct block_device *bd = ib_dev->ibd_bd;
 815
 816         return bdev_io_opt(bd);
 817 }
 818
 819 static struct sbc_ops iblock_sbc_ops = {
 820         .execute_rw             = iblock_execute_rw,
 821         .execute_sync_cache     = iblock_execute_sync_cache,
 822         .execute_write_same     = iblock_execute_write_same,
 823         .execute_unmap          = iblock_execute_unmap,
 824 };
 825
 826 static sense_reason_t
 827 iblock_parse_cdb(struct se_cmd *cmd)
 828 {
 829         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 830 }
 831
 832 static bool iblock_get_write_cache(struct se_device *dev)
 833 {
 834         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 835         struct block_device *bd = ib_dev->ibd_bd;
 836         struct request_queue *q = bdev_get_queue(bd);
 837
 838         return q->flush_flags & REQ_FLUSH;
 839 }
 840
 841 static const struct target_backend_ops iblock_ops = {
 842         .name                   = "iblock",
 843         .inquiry_prod           = "IBLOCK",
 844         .inquiry_rev            = IBLOCK_VERSION,
 845         .owner                  = THIS_MODULE,
 846         .attach_hba             = iblock_attach_hba,
 847         .detach_hba             = iblock_detach_hba,
 848         .alloc_device           = iblock_alloc_device,
 849         .configure_device       = iblock_configure_device,
 850         .free_device            = iblock_free_device,
 851         .parse_cdb              = iblock_parse_cdb,
 852         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 853         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 854         .get_device_type        = sbc_get_device_type,
 855         .get_blocks             = iblock_get_blocks,
 856         .get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
 857         .get_lbppbe             = iblock_get_lbppbe,
 858         .get_io_min             = iblock_get_io_min,
 859         .get_io_opt             = iblock_get_io_opt,
 860         .get_write_cache        = iblock_get_write_cache,
 861         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 862 };
 863
 864 static int __init iblock_module_init(void)
 865 {
 866         return transport_backend_register(&iblock_ops);
 867 }
 868
 869 static void __exit iblock_module_exit(void)
 870 {
 871         target_backend_unregister(&iblock_ops);
 872 }
 873
 874 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 875 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 876 MODULE_LICENSE("GPL");
 877
 878 module_init(iblock_module_init);
 879 module_exit(iblock_module_exit);