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 2003-2012 RisingTide Systems LLC.
   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.h>
  39#include <scsi/scsi_host.h>
  40#include <asm/unaligned.h>
  41
  42#include <target/target_core_base.h>
  43#include <target/target_core_backend.h>
  44
  45#include "target_core_iblock.h"
  46
  47#define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  48#define IBLOCK_BIO_POOL_SIZE    128
  49
  50static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
  51{
  52        return container_of(dev, struct iblock_dev, dev);
  53}
  54
  55
  56static struct se_subsystem_api iblock_template;
  57
  58/*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  59 *
  60 *
  61 */
  62static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  63{
  64        pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  65                " Generic Target Core Stack %s\n", hba->hba_id,
  66                IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  67        return 0;
  68}
  69
  70static void iblock_detach_hba(struct se_hba *hba)
  71{
  72}
  73
  74static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
  75{
  76        struct iblock_dev *ib_dev = NULL;
  77
  78        ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  79        if (!ib_dev) {
  80                pr_err("Unable to allocate struct iblock_dev\n");
  81                return NULL;
  82        }
  83
  84        pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  85
  86        return &ib_dev->dev;
  87}
  88
  89static int iblock_configure_device(struct se_device *dev)
  90{
  91        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
  92        struct request_queue *q;
  93        struct block_device *bd = NULL;
  94        fmode_t mode;
  95        int ret = -ENOMEM;
  96
  97        if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
  98                pr_err("Missing udev_path= parameters for IBLOCK\n");
  99                return -EINVAL;
 100        }
 101
 102        ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
 103        if (!ib_dev->ibd_bio_set) {
 104                pr_err("IBLOCK: Unable to create bioset\n");
 105                goto out;
 106        }
 107
 108        pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 109                        ib_dev->ibd_udev_path);
 110
 111        mode = FMODE_READ|FMODE_EXCL;
 112        if (!ib_dev->ibd_readonly)
 113                mode |= FMODE_WRITE;
 114
 115        bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 116        if (IS_ERR(bd)) {
 117                ret = PTR_ERR(bd);
 118                goto out_free_bioset;
 119        }
 120        ib_dev->ibd_bd = bd;
 121
 122        q = bdev_get_queue(bd);
 123
 124        dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
 125        dev->dev_attrib.hw_max_sectors = UINT_MAX;
 126        dev->dev_attrib.hw_queue_depth = q->nr_requests;
 127
 128        /*
 129         * Check if the underlying struct block_device request_queue supports
 130         * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 131         * in ATA and we need to set TPE=1
 132         */
 133        if (blk_queue_discard(q)) {
 134                dev->dev_attrib.max_unmap_lba_count =
 135                                q->limits.max_discard_sectors;
 136
 137                /*
 138                 * Currently hardcoded to 1 in Linux/SCSI code..
 139                 */
 140                dev->dev_attrib.max_unmap_block_desc_count = 1;
 141                dev->dev_attrib.unmap_granularity =
 142                                q->limits.discard_granularity >> 9;
 143                dev->dev_attrib.unmap_granularity_alignment =
 144                                q->limits.discard_alignment;
 145
 146                pr_debug("IBLOCK: BLOCK Discard support available,"
 147                                " disabled by default\n");
 148        }
 149        /*
 150         * Enable write same emulation for IBLOCK and use 0xFFFF as
 151         * the smaller WRITE_SAME(10) only has a two-byte block count.
 152         */
 153        dev->dev_attrib.max_write_same_len = 0xFFFF;
 154
 155        if (blk_queue_nonrot(q))
 156                dev->dev_attrib.is_nonrot = 1;
 157
 158        return 0;
 159
 160out_free_bioset:
 161        bioset_free(ib_dev->ibd_bio_set);
 162        ib_dev->ibd_bio_set = NULL;
 163out:
 164        return ret;
 165}
 166
 167static void iblock_free_device(struct se_device *dev)
 168{
 169        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 170
 171        if (ib_dev->ibd_bd != NULL)
 172                blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 173        if (ib_dev->ibd_bio_set != NULL)
 174                bioset_free(ib_dev->ibd_bio_set);
 175        kfree(ib_dev);
 176}
 177
 178static unsigned long long iblock_emulate_read_cap_with_block_size(
 179        struct se_device *dev,
 180        struct block_device *bd,
 181        struct request_queue *q)
 182{
 183        unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 184                                        bdev_logical_block_size(bd)) - 1);
 185        u32 block_size = bdev_logical_block_size(bd);
 186
 187        if (block_size == dev->dev_attrib.block_size)
 188                return blocks_long;
 189
 190        switch (block_size) {
 191        case 4096:
 192                switch (dev->dev_attrib.block_size) {
 193                case 2048:
 194                        blocks_long <<= 1;
 195                        break;
 196                case 1024:
 197                        blocks_long <<= 2;
 198                        break;
 199                case 512:
 200                        blocks_long <<= 3;
 201                default:
 202                        break;
 203                }
 204                break;
 205        case 2048:
 206                switch (dev->dev_attrib.block_size) {
 207                case 4096:
 208                        blocks_long >>= 1;
 209                        break;
 210                case 1024:
 211                        blocks_long <<= 1;
 212                        break;
 213                case 512:
 214                        blocks_long <<= 2;
 215                        break;
 216                default:
 217                        break;
 218                }
 219                break;
 220        case 1024:
 221                switch (dev->dev_attrib.block_size) {
 222                case 4096:
 223                        blocks_long >>= 2;
 224                        break;
 225                case 2048:
 226                        blocks_long >>= 1;
 227                        break;
 228                case 512:
 229                        blocks_long <<= 1;
 230                        break;
 231                default:
 232                        break;
 233                }
 234                break;
 235        case 512:
 236                switch (dev->dev_attrib.block_size) {
 237                case 4096:
 238                        blocks_long >>= 3;
 239                        break;
 240                case 2048:
 241                        blocks_long >>= 2;
 242                        break;
 243                case 1024:
 244                        blocks_long >>= 1;
 245                        break;
 246                default:
 247                        break;
 248                }
 249                break;
 250        default:
 251                break;
 252        }
 253
 254        return blocks_long;
 255}
 256
 257static void iblock_complete_cmd(struct se_cmd *cmd)
 258{
 259        struct iblock_req *ibr = cmd->priv;
 260        u8 status;
 261
 262        if (!atomic_dec_and_test(&ibr->pending))
 263                return;
 264
 265        if (atomic_read(&ibr->ib_bio_err_cnt))
 266                status = SAM_STAT_CHECK_CONDITION;
 267        else
 268                status = SAM_STAT_GOOD;
 269
 270        target_complete_cmd(cmd, status);
 271        kfree(ibr);
 272}
 273
 274static void iblock_bio_done(struct bio *bio, int err)
 275{
 276        struct se_cmd *cmd = bio->bi_private;
 277        struct iblock_req *ibr = cmd->priv;
 278
 279        /*
 280         * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 281         */
 282        if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 283                err = -EIO;
 284
 285        if (err != 0) {
 286                pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 287                        " err: %d\n", bio, err);
 288                /*
 289                 * Bump the ib_bio_err_cnt and release bio.
 290                 */
 291                atomic_inc(&ibr->ib_bio_err_cnt);
 292                smp_mb__after_atomic_inc();
 293        }
 294
 295        bio_put(bio);
 296
 297        iblock_complete_cmd(cmd);
 298}
 299
 300static struct bio *
 301iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 302{
 303        struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 304        struct bio *bio;
 305
 306        /*
 307         * Only allocate as many vector entries as the bio code allows us to,
 308         * we'll loop later on until we have handled the whole request.
 309         */
 310        if (sg_num > BIO_MAX_PAGES)
 311                sg_num = BIO_MAX_PAGES;
 312
 313        bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 314        if (!bio) {
 315                pr_err("Unable to allocate memory for bio\n");
 316                return NULL;
 317        }
 318
 319        bio->bi_bdev = ib_dev->ibd_bd;
 320        bio->bi_private = cmd;
 321        bio->bi_end_io = &iblock_bio_done;
 322        bio->bi_sector = lba;
 323
 324        return bio;
 325}
 326
 327static void iblock_submit_bios(struct bio_list *list, int rw)
 328{
 329        struct blk_plug plug;
 330        struct bio *bio;
 331
 332        blk_start_plug(&plug);
 333        while ((bio = bio_list_pop(list)))
 334                submit_bio(rw, bio);
 335        blk_finish_plug(&plug);
 336}
 337
 338static void iblock_end_io_flush(struct bio *bio, int err)
 339{
 340        struct se_cmd *cmd = bio->bi_private;
 341
 342        if (err)
 343                pr_err("IBLOCK: cache flush failed: %d\n", err);
 344
 345        if (cmd) {
 346                if (err)
 347                        target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 348                else
 349                        target_complete_cmd(cmd, SAM_STAT_GOOD);
 350        }
 351
 352        bio_put(bio);
 353}
 354
 355/*
 356 * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 357 * always flush the whole cache.
 358 */
 359static sense_reason_t
 360iblock_execute_sync_cache(struct se_cmd *cmd)
 361{
 362        struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 363        int immed = (cmd->t_task_cdb[1] & 0x2);
 364        struct bio *bio;
 365
 366        /*
 367         * If the Immediate bit is set, queue up the GOOD response
 368         * for this SYNCHRONIZE_CACHE op.
 369         */
 370        if (immed)
 371                target_complete_cmd(cmd, SAM_STAT_GOOD);
 372
 373        bio = bio_alloc(GFP_KERNEL, 0);
 374        bio->bi_end_io = iblock_end_io_flush;
 375        bio->bi_bdev = ib_dev->ibd_bd;
 376        if (!immed)
 377                bio->bi_private = cmd;
 378        submit_bio(WRITE_FLUSH, bio);
 379        return 0;
 380}
 381
 382static sense_reason_t
 383iblock_execute_unmap(struct se_cmd *cmd)
 384{
 385        struct se_device *dev = cmd->se_dev;
 386        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 387        unsigned char *buf, *ptr = NULL;
 388        sector_t lba;
 389        int size;
 390        u32 range;
 391        sense_reason_t ret = 0;
 392        int dl, bd_dl, err;
 393
 394        /* We never set ANC_SUP */
 395        if (cmd->t_task_cdb[1])
 396                return TCM_INVALID_CDB_FIELD;
 397
 398        if (cmd->data_length == 0) {
 399                target_complete_cmd(cmd, SAM_STAT_GOOD);
 400                return 0;
 401        }
 402
 403        if (cmd->data_length < 8) {
 404                pr_warn("UNMAP parameter list length %u too small\n",
 405                        cmd->data_length);
 406                return TCM_PARAMETER_LIST_LENGTH_ERROR;
 407        }
 408
 409        buf = transport_kmap_data_sg(cmd);
 410        if (!buf)
 411                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 412
 413        dl = get_unaligned_be16(&buf[0]);
 414        bd_dl = get_unaligned_be16(&buf[2]);
 415
 416        size = cmd->data_length - 8;
 417        if (bd_dl > size)
 418                pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
 419                        cmd->data_length, bd_dl);
 420        else
 421                size = bd_dl;
 422
 423        if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
 424                ret = TCM_INVALID_PARAMETER_LIST;
 425                goto err;
 426        }
 427
 428        /* First UNMAP block descriptor starts at 8 byte offset */
 429        ptr = &buf[8];
 430        pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
 431                " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
 432
 433        while (size >= 16) {
 434                lba = get_unaligned_be64(&ptr[0]);
 435                range = get_unaligned_be32(&ptr[8]);
 436                pr_debug("UNMAP: Using lba: %llu and range: %u\n",
 437                                 (unsigned long long)lba, range);
 438
 439                if (range > dev->dev_attrib.max_unmap_lba_count) {
 440                        ret = TCM_INVALID_PARAMETER_LIST;
 441                        goto err;
 442                }
 443
 444                if (lba + range > dev->transport->get_blocks(dev) + 1) {
 445                        ret = TCM_ADDRESS_OUT_OF_RANGE;
 446                        goto err;
 447                }
 448
 449                err = blkdev_issue_discard(ib_dev->ibd_bd, lba, range,
 450                                           GFP_KERNEL, 0);
 451                if (err < 0) {
 452                        pr_err("blkdev_issue_discard() failed: %d\n",
 453                                        err);
 454                        ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 455                        goto err;
 456                }
 457
 458                ptr += 16;
 459                size -= 16;
 460        }
 461
 462err:
 463        transport_kunmap_data_sg(cmd);
 464        if (!ret)
 465                target_complete_cmd(cmd, GOOD);
 466        return ret;
 467}
 468
 469static sense_reason_t
 470iblock_execute_write_same_unmap(struct se_cmd *cmd)
 471{
 472        struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 473        int rc;
 474
 475        rc = blkdev_issue_discard(ib_dev->ibd_bd, cmd->t_task_lba,
 476                        sbc_get_write_same_sectors(cmd), GFP_KERNEL, 0);
 477        if (rc < 0) {
 478                pr_warn("blkdev_issue_discard() failed: %d\n", rc);
 479                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 480        }
 481
 482        target_complete_cmd(cmd, GOOD);
 483        return 0;
 484}
 485
 486static sense_reason_t
 487iblock_execute_write_same(struct se_cmd *cmd)
 488{
 489        struct iblock_req *ibr;
 490        struct scatterlist *sg;
 491        struct bio *bio;
 492        struct bio_list list;
 493        sector_t block_lba = cmd->t_task_lba;
 494        sector_t sectors = sbc_get_write_same_sectors(cmd);
 495
 496        sg = &cmd->t_data_sg[0];
 497
 498        if (cmd->t_data_nents > 1 ||
 499            sg->length != cmd->se_dev->dev_attrib.block_size) {
 500                pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 501                        " block_size: %u\n", cmd->t_data_nents, sg->length,
 502                        cmd->se_dev->dev_attrib.block_size);
 503                return TCM_INVALID_CDB_FIELD;
 504        }
 505
 506        ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 507        if (!ibr)
 508                goto fail;
 509        cmd->priv = ibr;
 510
 511        bio = iblock_get_bio(cmd, block_lba, 1);
 512        if (!bio)
 513                goto fail_free_ibr;
 514
 515        bio_list_init(&list);
 516        bio_list_add(&list, bio);
 517
 518        atomic_set(&ibr->pending, 1);
 519
 520        while (sectors) {
 521                while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 522                                != sg->length) {
 523
 524                        bio = iblock_get_bio(cmd, block_lba, 1);
 525                        if (!bio)
 526                                goto fail_put_bios;
 527
 528                        atomic_inc(&ibr->pending);
 529                        bio_list_add(&list, bio);
 530                }
 531
 532                /* Always in 512 byte units for Linux/Block */
 533                block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 534                sectors -= 1;
 535        }
 536
 537        iblock_submit_bios(&list, WRITE);
 538        return 0;
 539
 540fail_put_bios:
 541        while ((bio = bio_list_pop(&list)))
 542                bio_put(bio);
 543fail_free_ibr:
 544        kfree(ibr);
 545fail:
 546        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 547}
 548
 549enum {
 550        Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 551};
 552
 553static match_table_t tokens = {
 554        {Opt_udev_path, "udev_path=%s"},
 555        {Opt_readonly, "readonly=%d"},
 556        {Opt_force, "force=%d"},
 557        {Opt_err, NULL}
 558};
 559
 560static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 561                const char *page, ssize_t count)
 562{
 563        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 564        char *orig, *ptr, *arg_p, *opts;
 565        substring_t args[MAX_OPT_ARGS];
 566        int ret = 0, token;
 567        unsigned long tmp_readonly;
 568
 569        opts = kstrdup(page, GFP_KERNEL);
 570        if (!opts)
 571                return -ENOMEM;
 572
 573        orig = opts;
 574
 575        while ((ptr = strsep(&opts, ",\n")) != NULL) {
 576                if (!*ptr)
 577                        continue;
 578
 579                token = match_token(ptr, tokens, args);
 580                switch (token) {
 581                case Opt_udev_path:
 582                        if (ib_dev->ibd_bd) {
 583                                pr_err("Unable to set udev_path= while"
 584                                        " ib_dev->ibd_bd exists\n");
 585                                ret = -EEXIST;
 586                                goto out;
 587                        }
 588                        if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 589                                SE_UDEV_PATH_LEN) == 0) {
 590                                ret = -EINVAL;
 591                                break;
 592                        }
 593                        pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 594                                        ib_dev->ibd_udev_path);
 595                        ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 596                        break;
 597                case Opt_readonly:
 598                        arg_p = match_strdup(&args[0]);
 599                        if (!arg_p) {
 600                                ret = -ENOMEM;
 601                                break;
 602                        }
 603                        ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 604                        kfree(arg_p);
 605                        if (ret < 0) {
 606                                pr_err("strict_strtoul() failed for"
 607                                                " readonly=\n");
 608                                goto out;
 609                        }
 610                        ib_dev->ibd_readonly = tmp_readonly;
 611                        pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 612                        break;
 613                case Opt_force:
 614                        break;
 615                default:
 616                        break;
 617                }
 618        }
 619
 620out:
 621        kfree(orig);
 622        return (!ret) ? count : ret;
 623}
 624
 625static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 626{
 627        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 628        struct block_device *bd = ib_dev->ibd_bd;
 629        char buf[BDEVNAME_SIZE];
 630        ssize_t bl = 0;
 631
 632        if (bd)
 633                bl += sprintf(b + bl, "iBlock device: %s",
 634                                bdevname(bd, buf));
 635        if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 636                bl += sprintf(b + bl, "  UDEV PATH: %s",
 637                                ib_dev->ibd_udev_path);
 638        bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 639
 640        bl += sprintf(b + bl, "        ");
 641        if (bd) {
 642                bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 643                        MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 644                        "" : (bd->bd_holder == ib_dev) ?
 645                        "CLAIMED: IBLOCK" : "CLAIMED: OS");
 646        } else {
 647                bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 648        }
 649
 650        return bl;
 651}
 652
 653static sense_reason_t
 654iblock_execute_rw(struct se_cmd *cmd)
 655{
 656        struct scatterlist *sgl = cmd->t_data_sg;
 657        u32 sgl_nents = cmd->t_data_nents;
 658        enum dma_data_direction data_direction = cmd->data_direction;
 659        struct se_device *dev = cmd->se_dev;
 660        struct iblock_req *ibr;
 661        struct bio *bio;
 662        struct bio_list list;
 663        struct scatterlist *sg;
 664        u32 sg_num = sgl_nents;
 665        sector_t block_lba;
 666        unsigned bio_cnt;
 667        int rw = 0;
 668        int i;
 669
 670        if (data_direction == DMA_TO_DEVICE) {
 671                struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 672                struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 673                /*
 674                 * Force writethrough using WRITE_FUA if a volatile write cache
 675                 * is not enabled, or if initiator set the Force Unit Access bit.
 676                 */
 677                if (q->flush_flags & REQ_FUA) {
 678                        if (cmd->se_cmd_flags & SCF_FUA)
 679                                rw = WRITE_FUA;
 680                        else if (!(q->flush_flags & REQ_FLUSH))
 681                                rw = WRITE_FUA;
 682                        else
 683                                rw = WRITE;
 684                } else {
 685                        rw = WRITE;
 686                }
 687        } else {
 688                rw = READ;
 689        }
 690
 691        /*
 692         * Convert the blocksize advertised to the initiator to the 512 byte
 693         * units unconditionally used by the Linux block layer.
 694         */
 695        if (dev->dev_attrib.block_size == 4096)
 696                block_lba = (cmd->t_task_lba << 3);
 697        else if (dev->dev_attrib.block_size == 2048)
 698                block_lba = (cmd->t_task_lba << 2);
 699        else if (dev->dev_attrib.block_size == 1024)
 700                block_lba = (cmd->t_task_lba << 1);
 701        else if (dev->dev_attrib.block_size == 512)
 702                block_lba = cmd->t_task_lba;
 703        else {
 704                pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 705                                " %u\n", dev->dev_attrib.block_size);
 706                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 707        }
 708
 709        ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 710        if (!ibr)
 711                goto fail;
 712        cmd->priv = ibr;
 713
 714        if (!sgl_nents) {
 715                atomic_set(&ibr->pending, 1);
 716                iblock_complete_cmd(cmd);
 717                return 0;
 718        }
 719
 720        bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 721        if (!bio)
 722                goto fail_free_ibr;
 723
 724        bio_list_init(&list);
 725        bio_list_add(&list, bio);
 726
 727        atomic_set(&ibr->pending, 2);
 728        bio_cnt = 1;
 729
 730        for_each_sg(sgl, sg, sgl_nents, i) {
 731                /*
 732                 * XXX: if the length the device accepts is shorter than the
 733                 *      length of the S/G list entry this will cause and
 734                 *      endless loop.  Better hope no driver uses huge pages.
 735                 */
 736                while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 737                                != sg->length) {
 738                        if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 739                                iblock_submit_bios(&list, rw);
 740                                bio_cnt = 0;
 741                        }
 742
 743                        bio = iblock_get_bio(cmd, block_lba, sg_num);
 744                        if (!bio)
 745                                goto fail_put_bios;
 746
 747                        atomic_inc(&ibr->pending);
 748                        bio_list_add(&list, bio);
 749                        bio_cnt++;
 750                }
 751
 752                /* Always in 512 byte units for Linux/Block */
 753                block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 754                sg_num--;
 755        }
 756
 757        iblock_submit_bios(&list, rw);
 758        iblock_complete_cmd(cmd);
 759        return 0;
 760
 761fail_put_bios:
 762        while ((bio = bio_list_pop(&list)))
 763                bio_put(bio);
 764fail_free_ibr:
 765        kfree(ibr);
 766fail:
 767        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 768}
 769
 770static sector_t iblock_get_blocks(struct se_device *dev)
 771{
 772        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 773        struct block_device *bd = ib_dev->ibd_bd;
 774        struct request_queue *q = bdev_get_queue(bd);
 775
 776        return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 777}
 778
 779static struct sbc_ops iblock_sbc_ops = {
 780        .execute_rw             = iblock_execute_rw,
 781        .execute_sync_cache     = iblock_execute_sync_cache,
 782        .execute_write_same     = iblock_execute_write_same,
 783        .execute_write_same_unmap = iblock_execute_write_same_unmap,
 784        .execute_unmap          = iblock_execute_unmap,
 785};
 786
 787static sense_reason_t
 788iblock_parse_cdb(struct se_cmd *cmd)
 789{
 790        return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 791}
 792
 793bool iblock_get_write_cache(struct se_device *dev)
 794{
 795        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 796        struct block_device *bd = ib_dev->ibd_bd;
 797        struct request_queue *q = bdev_get_queue(bd);
 798
 799        return q->flush_flags & REQ_FLUSH;
 800}
 801
 802static struct se_subsystem_api iblock_template = {
 803        .name                   = "iblock",
 804        .inquiry_prod           = "IBLOCK",
 805        .inquiry_rev            = IBLOCK_VERSION,
 806        .owner                  = THIS_MODULE,
 807        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 808        .attach_hba             = iblock_attach_hba,
 809        .detach_hba             = iblock_detach_hba,
 810        .alloc_device           = iblock_alloc_device,
 811        .configure_device       = iblock_configure_device,
 812        .free_device            = iblock_free_device,
 813        .parse_cdb              = iblock_parse_cdb,
 814        .set_configfs_dev_params = iblock_set_configfs_dev_params,
 815        .show_configfs_dev_params = iblock_show_configfs_dev_params,
 816        .get_device_type        = sbc_get_device_type,
 817        .get_blocks             = iblock_get_blocks,
 818        .get_write_cache        = iblock_get_write_cache,
 819};
 820
 821static int __init iblock_module_init(void)
 822{
 823        return transport_subsystem_register(&iblock_template);
 824}
 825
 826static void __exit iblock_module_exit(void)
 827{
 828        transport_subsystem_release(&iblock_template);
 829}
 830
 831MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 832MODULE_AUTHOR("nab@Linux-iSCSI.org");
 833MODULE_LICENSE("GPL");
 834
 835module_init(iblock_module_init);
 836module_exit(iblock_module_exit);
 837
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