linux/drivers/target/target_core_iblock.c
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   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
  49static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
  50{
  51        return container_of(dev, struct iblock_dev, dev);
  52}
  53
  54
  55static 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
  63static void iblock_detach_hba(struct se_hba *hba)
  64{
  65}
  66
  67static 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
  82static 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
 186out_blkdev_put:
 187        blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 188out_free_bioset:
 189        bioset_free(ib_dev->ibd_bio_set);
 190        ib_dev->ibd_bio_set = NULL;
 191out:
 192        return ret;
 193}
 194
 195static 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
 203static 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
 215static 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
 294static 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
 311static 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
 330static struct bio *
 331iblock_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
 357static 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
 368static 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 */
 389static sense_reason_t
 390iblock_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
 412static sense_reason_t
 413iblock_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
 427static sense_reason_t
 428iblock_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
 486fail_put_bios:
 487        while ((bio = bio_list_pop(&list)))
 488                bio_put(bio);
 489fail_free_ibr:
 490        kfree(ibr);
 491fail:
 492        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 493}
 494
 495enum {
 496        Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 497};
 498
 499static 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
 506static 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
 566out:
 567        kfree(orig);
 568        return (!ret) ? count : ret;
 569}
 570
 571static 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
 599static int
 600iblock_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
 644static sense_reason_t
 645iblock_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
 757fail_put_bios:
 758        while ((bio = bio_list_pop(&list)))
 759                bio_put(bio);
 760fail_free_ibr:
 761        kfree(ibr);
 762fail:
 763        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 764}
 765
 766static 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
 775static 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
 789static 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
 798static 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
 806static 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
 814static 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
 821static sense_reason_t
 822iblock_parse_cdb(struct se_cmd *cmd)
 823{
 824        return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 825}
 826
 827static 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
 836static 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
 859static int __init iblock_module_init(void)
 860{
 861        return transport_backend_register(&iblock_ops);
 862}
 863
 864static void __exit iblock_module_exit(void)
 865{
 866        target_backend_unregister(&iblock_ops);
 867}
 868
 869MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 870MODULE_AUTHOR("nab@Linux-iSCSI.org");
 871MODULE_LICENSE("GPL");
 872
 873module_init(iblock_module_init);
 874module_exit(iblock_module_exit);
 875