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  * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
   8  * Copyright (c) 2005, 2006, 2007 SBE, Inc.
   9  * Copyright (c) 2007-2010 Rising Tide Systems
  10  * Copyright (c) 2008-2010 Linux-iSCSI.org
  11  *
  12  * Nicholas A. Bellinger <nab@kernel.org>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  *
  28  ******************************************************************************/
  29
  30 #include <linux/version.h>
  31 #include <linux/string.h>
  32 #include <linux/parser.h>
  33 #include <linux/timer.h>
  34 #include <linux/fs.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/slab.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/bio.h>
  39 #include <linux/genhd.h>
  40 #include <linux/file.h>
  41 #include <scsi/scsi.h>
  42 #include <scsi/scsi_host.h>
  43
  44 #include <target/target_core_base.h>
  45 #include <target/target_core_device.h>
  46 #include <target/target_core_transport.h>
  47
  48 #include "target_core_iblock.h"
  49
  50 #if 0
  51 #define DEBUG_IBLOCK(x...) printk(x)
  52 #else
  53 #define DEBUG_IBLOCK(x...)
  54 #endif
  55
  56 static struct se_subsystem_api iblock_template;
  57
  58 static void iblock_bio_done(struct bio *, int);
  59
  60 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  61  *
  62  *
  63  */
  64 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  65 {
  66         struct iblock_hba *ib_host;
  67
  68         ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
  69         if (!(ib_host)) {
  70                 printk(KERN_ERR "Unable to allocate memory for"
  71                                 " struct iblock_hba\n");
  72                 return -ENOMEM;
  73         }
  74
  75         ib_host->iblock_host_id = host_id;
  76
  77         hba->hba_ptr = ib_host;
  78
  79         printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  80                 " Generic Target Core Stack %s\n", hba->hba_id,
  81                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  82
  83         printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic\n",
  84                 hba->hba_id, ib_host->iblock_host_id);
  85
  86         return 0;
  87 }
  88
  89 static void iblock_detach_hba(struct se_hba *hba)
  90 {
  91         struct iblock_hba *ib_host = hba->hba_ptr;
  92
  93         printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
  94                 " Target Core\n", hba->hba_id, ib_host->iblock_host_id);
  95
  96         kfree(ib_host);
  97         hba->hba_ptr = NULL;
  98 }
  99
 100 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
 101 {
 102         struct iblock_dev *ib_dev = NULL;
 103         struct iblock_hba *ib_host = hba->hba_ptr;
 104
 105         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
 106         if (!(ib_dev)) {
 107                 printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
 108                 return NULL;
 109         }
 110         ib_dev->ibd_host = ib_host;
 111
 112         printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);
 113
 114         return ib_dev;
 115 }
 116
 117 static struct se_device *iblock_create_virtdevice(
 118         struct se_hba *hba,
 119         struct se_subsystem_dev *se_dev,
 120         void *p)
 121 {
 122         struct iblock_dev *ib_dev = p;
 123         struct se_device *dev;
 124         struct se_dev_limits dev_limits;
 125         struct block_device *bd = NULL;
 126         struct request_queue *q;
 127         struct queue_limits *limits;
 128         u32 dev_flags = 0;
 129         int ret = -EINVAL;
 130
 131         if (!(ib_dev)) {
 132                 printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
 133                 return ERR_PTR(ret);
 134         }
 135         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 136         /*
 137          * These settings need to be made tunable..
 138          */
 139         ib_dev->ibd_bio_set = bioset_create(32, 64);
 140         if (!(ib_dev->ibd_bio_set)) {
 141                 printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
 142                 return ERR_PTR(-ENOMEM);
 143         }
 144         printk(KERN_INFO "IBLOCK: Created bio_set()\n");
 145         /*
 146          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 147          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 148          */
 149         printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
 150                         ib_dev->ibd_udev_path);
 151
 152         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
 153                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
 154         if (IS_ERR(bd)) {
 155                 ret = PTR_ERR(bd);
 156                 goto failed;
 157         }
 158         /*
 159          * Setup the local scope queue_limits from struct request_queue->limits
 160          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 161          */
 162         q = bdev_get_queue(bd);
 163         limits = &dev_limits.limits;
 164         limits->logical_block_size = bdev_logical_block_size(bd);
 165         limits->max_hw_sectors = queue_max_hw_sectors(q);
 166         limits->max_sectors = queue_max_sectors(q);
 167         dev_limits.hw_queue_depth = q->nr_requests;
 168         dev_limits.queue_depth = q->nr_requests;
 169
 170         ib_dev->ibd_bd = bd;
 171
 172         dev = transport_add_device_to_core_hba(hba,
 173                         &iblock_template, se_dev, dev_flags, ib_dev,
 174                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
 175         if (!(dev))
 176                 goto failed;
 177
 178         /*
 179          * Check if the underlying struct block_device request_queue supports
 180          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 181          * in ATA and we need to set TPE=1
 182          */
 183         if (blk_queue_discard(q)) {
 184                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 185                                 q->limits.max_discard_sectors;
 186                 /*
 187                  * Currently hardcoded to 1 in Linux/SCSI code..
 188                  */
 189                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 190                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 191                                 q->limits.discard_granularity;
 192                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 193                                 q->limits.discard_alignment;
 194
 195                 printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
 196                                 " disabled by default\n");
 197         }
 198
 199         if (blk_queue_nonrot(q))
 200                 dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
 201
 202         return dev;
 203
 204 failed:
 205         if (ib_dev->ibd_bio_set) {
 206                 bioset_free(ib_dev->ibd_bio_set);
 207                 ib_dev->ibd_bio_set = NULL;
 208         }
 209         ib_dev->ibd_bd = NULL;
 210         return ERR_PTR(ret);
 211 }
 212
 213 static void iblock_free_device(void *p)
 214 {
 215         struct iblock_dev *ib_dev = p;
 216
 217         if (ib_dev->ibd_bd != NULL)
 218                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 219         if (ib_dev->ibd_bio_set != NULL)
 220                 bioset_free(ib_dev->ibd_bio_set);
 221         kfree(ib_dev);
 222 }
 223
 224 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
 225 {
 226         return container_of(task, struct iblock_req, ib_task);
 227 }
 228
 229 static struct se_task *
 230 iblock_alloc_task(struct se_cmd *cmd)
 231 {
 232         struct iblock_req *ib_req;
 233
 234         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 235         if (!(ib_req)) {
 236                 printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
 237                 return NULL;
 238         }
 239
 240         ib_req->ib_dev = cmd->se_dev->dev_ptr;
 241         atomic_set(&ib_req->ib_bio_cnt, 0);
 242         return &ib_req->ib_task;
 243 }
 244
 245 static unsigned long long iblock_emulate_read_cap_with_block_size(
 246         struct se_device *dev,
 247         struct block_device *bd,
 248         struct request_queue *q)
 249 {
 250         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 251                                         bdev_logical_block_size(bd)) - 1);
 252         u32 block_size = bdev_logical_block_size(bd);
 253
 254         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 255                 return blocks_long;
 256
 257         switch (block_size) {
 258         case 4096:
 259                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 260                 case 2048:
 261                         blocks_long <<= 1;
 262                         break;
 263                 case 1024:
 264                         blocks_long <<= 2;
 265                         break;
 266                 case 512:
 267                         blocks_long <<= 3;
 268                 default:
 269                         break;
 270                 }
 271                 break;
 272         case 2048:
 273                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 274                 case 4096:
 275                         blocks_long >>= 1;
 276                         break;
 277                 case 1024:
 278                         blocks_long <<= 1;
 279                         break;
 280                 case 512:
 281                         blocks_long <<= 2;
 282                         break;
 283                 default:
 284                         break;
 285                 }
 286                 break;
 287         case 1024:
 288                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 289                 case 4096:
 290                         blocks_long >>= 2;
 291                         break;
 292                 case 2048:
 293                         blocks_long >>= 1;
 294                         break;
 295                 case 512:
 296                         blocks_long <<= 1;
 297                         break;
 298                 default:
 299                         break;
 300                 }
 301                 break;
 302         case 512:
 303                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 304                 case 4096:
 305                         blocks_long >>= 3;
 306                         break;
 307                 case 2048:
 308                         blocks_long >>= 2;
 309                         break;
 310                 case 1024:
 311                         blocks_long >>= 1;
 312                         break;
 313                 default:
 314                         break;
 315                 }
 316                 break;
 317         default:
 318                 break;
 319         }
 320
 321         return blocks_long;
 322 }
 323
 324 /*
 325  * Emulate SYCHRONIZE_CACHE_*
 326  */
 327 static void iblock_emulate_sync_cache(struct se_task *task)
 328 {
 329         struct se_cmd *cmd = task->task_se_cmd;
 330         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 331         int immed = (cmd->t_task_cdb[1] & 0x2);
 332         sector_t error_sector;
 333         int ret;
 334
 335         /*
 336          * If the Immediate bit is set, queue up the GOOD response
 337          * for this SYNCHRONIZE_CACHE op
 338          */
 339         if (immed)
 340                 transport_complete_sync_cache(cmd, 1);
 341
 342         /*
 343          * blkdev_issue_flush() does not support a specifying a range, so
 344          * we have to flush the entire cache.
 345          */
 346         ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
 347         if (ret != 0) {
 348                 printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
 349                         " error_sector: %llu\n", ret,
 350                         (unsigned long long)error_sector);
 351         }
 352
 353         if (!immed)
 354                 transport_complete_sync_cache(cmd, ret == 0);
 355 }
 356
 357 /*
 358  * Tell TCM Core that we are capable of WriteCache emulation for
 359  * an underlying struct se_device.
 360  */
 361 static int iblock_emulated_write_cache(struct se_device *dev)
 362 {
 363         return 1;
 364 }
 365
 366 static int iblock_emulated_dpo(struct se_device *dev)
 367 {
 368         return 0;
 369 }
 370
 371 /*
 372  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
 373  * for TYPE_DISK.
 374  */
 375 static int iblock_emulated_fua_write(struct se_device *dev)
 376 {
 377         return 1;
 378 }
 379
 380 static int iblock_emulated_fua_read(struct se_device *dev)
 381 {
 382         return 0;
 383 }
 384
 385 static int iblock_do_task(struct se_task *task)
 386 {
 387         struct se_device *dev = task->task_se_cmd->se_dev;
 388         struct iblock_req *req = IBLOCK_REQ(task);
 389         struct bio *bio = req->ib_bio, *nbio = NULL;
 390         struct blk_plug plug;
 391         int rw;
 392
 393         if (task->task_data_direction == DMA_TO_DEVICE) {
 394                 /*
 395                  * Force data to disk if we pretend to not have a volatile
 396                  * write cache, or the initiator set the Force Unit Access bit.
 397                  */
 398                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 399                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 400                      task->task_se_cmd->t_tasks_fua))
 401                         rw = WRITE_FUA;
 402                 else
 403                         rw = WRITE;
 404         } else {
 405                 rw = READ;
 406         }
 407
 408         blk_start_plug(&plug);
 409         while (bio) {
 410                 nbio = bio->bi_next;
 411                 bio->bi_next = NULL;
 412                 DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
 413                         " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
 414
 415                 submit_bio(rw, bio);
 416                 bio = nbio;
 417         }
 418         blk_finish_plug(&plug);
 419
 420         return PYX_TRANSPORT_SENT_TO_TRANSPORT;
 421 }
 422
 423 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
 424 {
 425         struct iblock_dev *ibd = dev->dev_ptr;
 426         struct block_device *bd = ibd->ibd_bd;
 427         int barrier = 0;
 428
 429         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
 430 }
 431
 432 static void iblock_free_task(struct se_task *task)
 433 {
 434         struct iblock_req *req = IBLOCK_REQ(task);
 435         struct bio *bio, *hbio = req->ib_bio;
 436         /*
 437          * We only release the bio(s) here if iblock_bio_done() has not called
 438          * bio_put() -> iblock_bio_destructor().
 439          */
 440         while (hbio != NULL) {
 441                 bio = hbio;
 442                 hbio = hbio->bi_next;
 443                 bio->bi_next = NULL;
 444                 bio_put(bio);
 445         }
 446
 447         kfree(req);
 448 }
 449
 450 enum {
 451         Opt_udev_path, Opt_force, Opt_err
 452 };
 453
 454 static match_table_t tokens = {
 455         {Opt_udev_path, "udev_path=%s"},
 456         {Opt_force, "force=%d"},
 457         {Opt_err, NULL}
 458 };
 459
 460 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 461                                                struct se_subsystem_dev *se_dev,
 462                                                const char *page, ssize_t count)
 463 {
 464         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 465         char *orig, *ptr, *arg_p, *opts;
 466         substring_t args[MAX_OPT_ARGS];
 467         int ret = 0, token;
 468
 469         opts = kstrdup(page, GFP_KERNEL);
 470         if (!opts)
 471                 return -ENOMEM;
 472
 473         orig = opts;
 474
 475         while ((ptr = strsep(&opts, ",")) != NULL) {
 476                 if (!*ptr)
 477                         continue;
 478
 479                 token = match_token(ptr, tokens, args);
 480                 switch (token) {
 481                 case Opt_udev_path:
 482                         if (ib_dev->ibd_bd) {
 483                                 printk(KERN_ERR "Unable to set udev_path= while"
 484                                         " ib_dev->ibd_bd exists\n");
 485                                 ret = -EEXIST;
 486                                 goto out;
 487                         }
 488                         arg_p = match_strdup(&args[0]);
 489                         if (!arg_p) {
 490                                 ret = -ENOMEM;
 491                                 break;
 492                         }
 493                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
 494                                         "%s", arg_p);
 495                         kfree(arg_p);
 496                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
 497                                         ib_dev->ibd_udev_path);
 498                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 499                         break;
 500                 case Opt_force:
 501                         break;
 502                 default:
 503                         break;
 504                 }
 505         }
 506
 507 out:
 508         kfree(orig);
 509         return (!ret) ? count : ret;
 510 }
 511
 512 static ssize_t iblock_check_configfs_dev_params(
 513         struct se_hba *hba,
 514         struct se_subsystem_dev *se_dev)
 515 {
 516         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 517
 518         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 519                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
 520                 return -EINVAL;
 521         }
 522
 523         return 0;
 524 }
 525
 526 static ssize_t iblock_show_configfs_dev_params(
 527         struct se_hba *hba,
 528         struct se_subsystem_dev *se_dev,
 529         char *b)
 530 {
 531         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 532         struct block_device *bd = ibd->ibd_bd;
 533         char buf[BDEVNAME_SIZE];
 534         ssize_t bl = 0;
 535
 536         if (bd)
 537                 bl += sprintf(b + bl, "iBlock device: %s",
 538                                 bdevname(bd, buf));
 539         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
 540                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
 541                                 ibd->ibd_udev_path);
 542         } else
 543                 bl += sprintf(b + bl, "\n");
 544
 545         bl += sprintf(b + bl, "        ");
 546         if (bd) {
 547                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 548                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 549                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
 550                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 551         } else {
 552                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 553         }
 554
 555         return bl;
 556 }
 557
 558 static void iblock_bio_destructor(struct bio *bio)
 559 {
 560         struct se_task *task = bio->bi_private;
 561         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
 562
 563         bio_free(bio, ib_dev->ibd_bio_set);
 564 }
 565
 566 static struct bio *iblock_get_bio(
 567         struct se_task *task,
 568         struct iblock_req *ib_req,
 569         struct iblock_dev *ib_dev,
 570         int *ret,
 571         sector_t lba,
 572         u32 sg_num)
 573 {
 574         struct bio *bio;
 575
 576         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 577         if (!(bio)) {
 578                 printk(KERN_ERR "Unable to allocate memory for bio\n");
 579                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
 580                 return NULL;
 581         }
 582
 583         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
 584                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
 585         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
 586
 587         bio->bi_bdev = ib_dev->ibd_bd;
 588         bio->bi_private = task;
 589         bio->bi_destructor = iblock_bio_destructor;
 590         bio->bi_end_io = &iblock_bio_done;
 591         bio->bi_sector = lba;
 592         atomic_inc(&ib_req->ib_bio_cnt);
 593
 594         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
 595         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
 596                         atomic_read(&ib_req->ib_bio_cnt));
 597         return bio;
 598 }
 599
 600 static int iblock_map_task_SG(struct se_task *task)
 601 {
 602         struct se_cmd *cmd = task->task_se_cmd;
 603         struct se_device *dev = cmd->se_dev;
 604         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
 605         struct iblock_req *ib_req = IBLOCK_REQ(task);
 606         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
 607         struct scatterlist *sg;
 608         int ret = 0;
 609         u32 i, sg_num = task->task_sg_num;
 610         sector_t block_lba;
 611         /*
 612          * Do starting conversion up from non 512-byte blocksize with
 613          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
 614          */
 615         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 616                 block_lba = (task->task_lba << 3);
 617         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 618                 block_lba = (task->task_lba << 2);
 619         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 620                 block_lba = (task->task_lba << 1);
 621         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 622                 block_lba = task->task_lba;
 623         else {
 624                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
 625                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 626                 return PYX_TRANSPORT_LU_COMM_FAILURE;
 627         }
 628
 629         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
 630         if (!(bio))
 631                 return ret;
 632
 633         ib_req->ib_bio = bio;
 634         hbio = tbio = bio;
 635         /*
 636          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
 637          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
 638          */
 639         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
 640                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
 641                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
 642                                 sg->length, sg->offset);
 643 again:
 644                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
 645                 if (ret != sg->length) {
 646
 647                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
 648                                         bio->bi_sector);
 649                         DEBUG_IBLOCK("** task->task_size: %u\n",
 650                                         task->task_size);
 651                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
 652                                         bio->bi_max_vecs);
 653                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
 654                                         bio->bi_vcnt);
 655
 656                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
 657                                                 block_lba, sg_num);
 658                         if (!(bio))
 659                                 goto fail;
 660
 661                         tbio = tbio->bi_next = bio;
 662                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
 663                                 " list, Going to again\n", bio);
 664                         goto again;
 665                 }
 666                 /* Always in 512 byte units for Linux/Block */
 667                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 668                 sg_num--;
 669                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
 670                         " sg_num to %u\n", task, sg_num);
 671                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
 672                                 " to %llu\n", task, block_lba);
 673                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
 674                                 " %u\n", task, bio->bi_vcnt);
 675         }
 676
 677         return 0;
 678 fail:
 679         while (hbio) {
 680                 bio = hbio;
 681                 hbio = hbio->bi_next;
 682                 bio->bi_next = NULL;
 683                 bio_put(bio);
 684         }
 685         return ret;
 686 }
 687
 688 static unsigned char *iblock_get_cdb(struct se_task *task)
 689 {
 690         return IBLOCK_REQ(task)->ib_scsi_cdb;
 691 }
 692
 693 static u32 iblock_get_device_rev(struct se_device *dev)
 694 {
 695         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 696 }
 697
 698 static u32 iblock_get_device_type(struct se_device *dev)
 699 {
 700         return TYPE_DISK;
 701 }
 702
 703 static sector_t iblock_get_blocks(struct se_device *dev)
 704 {
 705         struct iblock_dev *ibd = dev->dev_ptr;
 706         struct block_device *bd = ibd->ibd_bd;
 707         struct request_queue *q = bdev_get_queue(bd);
 708
 709         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 710 }
 711
 712 static void iblock_bio_done(struct bio *bio, int err)
 713 {
 714         struct se_task *task = bio->bi_private;
 715         struct iblock_req *ibr = IBLOCK_REQ(task);
 716         /*
 717          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 718          */
 719         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
 720                 err = -EIO;
 721
 722         if (err != 0) {
 723                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
 724                         " err: %d\n", bio, err);
 725                 /*
 726                  * Bump the ib_bio_err_cnt and release bio.
 727                  */
 728                 atomic_inc(&ibr->ib_bio_err_cnt);
 729                 smp_mb__after_atomic_inc();
 730                 bio_put(bio);
 731                 /*
 732                  * Wait to complete the task until the last bio as completed.
 733                  */
 734                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
 735                         return;
 736
 737                 ibr->ib_bio = NULL;
 738                 transport_complete_task(task, 0);
 739                 return;
 740         }
 741         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
 742                 task, bio, task->task_lba, bio->bi_sector, err);
 743         /*
 744          * bio_put() will call iblock_bio_destructor() to release the bio back
 745          * to ibr->ib_bio_set.
 746          */
 747         bio_put(bio);
 748         /*
 749          * Wait to complete the task until the last bio as completed.
 750          */
 751         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
 752                 return;
 753         /*
 754          * Return GOOD status for task if zero ib_bio_err_cnt exists.
 755          */
 756         ibr->ib_bio = NULL;
 757         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
 758 }
 759
 760 static struct se_subsystem_api iblock_template = {
 761         .name                   = "iblock",
 762         .owner                  = THIS_MODULE,
 763         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 764         .map_task_SG            = iblock_map_task_SG,
 765         .attach_hba             = iblock_attach_hba,
 766         .detach_hba             = iblock_detach_hba,
 767         .allocate_virtdevice    = iblock_allocate_virtdevice,
 768         .create_virtdevice      = iblock_create_virtdevice,
 769         .free_device            = iblock_free_device,
 770         .dpo_emulated           = iblock_emulated_dpo,
 771         .fua_write_emulated     = iblock_emulated_fua_write,
 772         .fua_read_emulated      = iblock_emulated_fua_read,
 773         .write_cache_emulated   = iblock_emulated_write_cache,
 774         .alloc_task             = iblock_alloc_task,
 775         .do_task                = iblock_do_task,
 776         .do_discard             = iblock_do_discard,
 777         .do_sync_cache          = iblock_emulate_sync_cache,
 778         .free_task              = iblock_free_task,
 779         .check_configfs_dev_params = iblock_check_configfs_dev_params,
 780         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 781         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 782         .get_cdb                = iblock_get_cdb,
 783         .get_device_rev         = iblock_get_device_rev,
 784         .get_device_type        = iblock_get_device_type,
 785         .get_blocks             = iblock_get_blocks,
 786 };
 787
 788 static int __init iblock_module_init(void)
 789 {
 790         return transport_subsystem_register(&iblock_template);
 791 }
 792
 793 static void iblock_module_exit(void)
 794 {
 795         transport_subsystem_release(&iblock_template);
 796 }
 797
 798 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 799 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 800 MODULE_LICENSE("GPL");
 801
 802 module_init(iblock_module_init);
 803 module_exit(iblock_module_exit);