drivers/target/target_core_rd.c

   1 /*******************************************************************************
   2  * Filename:  target_core_rd.c
   3  *
   4  * This file contains the Storage Engine <-> Ramdisk 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/highmem.h>
  30 #include <linux/timer.h>
  31 #include <linux/scatterlist.h>
  32 #include <linux/slab.h>
  33 #include <linux/spinlock.h>
  34 #include <scsi/scsi_proto.h>
  35
  36 #include <target/target_core_base.h>
  37 #include <target/target_core_backend.h>
  38
  39 #include "target_core_rd.h"
  40
  41 static inline struct rd_dev *RD_DEV(struct se_device *dev)
  42 {
  43         return container_of(dev, struct rd_dev, dev);
  44 }
  45
  46 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
  47 {
  48         struct rd_host *rd_host;
  49
  50         rd_host = kzalloc(sizeof(*rd_host), GFP_KERNEL);
  51         if (!rd_host)
  52                 return -ENOMEM;
  53
  54         rd_host->rd_host_id = host_id;
  55
  56         hba->hba_ptr = rd_host;
  57
  58         pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
  59                 " Generic Target Core Stack %s\n", hba->hba_id,
  60                 RD_HBA_VERSION, TARGET_CORE_VERSION);
  61
  62         return 0;
  63 }
  64
  65 static void rd_detach_hba(struct se_hba *hba)
  66 {
  67         struct rd_host *rd_host = hba->hba_ptr;
  68
  69         pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
  70                 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
  71
  72         kfree(rd_host);
  73         hba->hba_ptr = NULL;
  74 }
  75
  76 static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
  77                                  u32 sg_table_count)
  78 {
  79         struct page *pg;
  80         struct scatterlist *sg;
  81         u32 i, j, page_count = 0, sg_per_table;
  82
  83         for (i = 0; i < sg_table_count; i++) {
  84                 sg = sg_table[i].sg_table;
  85                 sg_per_table = sg_table[i].rd_sg_count;
  86
  87                 for (j = 0; j < sg_per_table; j++) {
  88                         pg = sg_page(&sg[j]);
  89                         if (pg) {
  90                                 __free_page(pg);
  91                                 page_count++;
  92                         }
  93                 }
  94                 kfree(sg);
  95         }
  96
  97         kfree(sg_table);
  98         return page_count;
  99 }
 100
 101 static void rd_release_device_space(struct rd_dev *rd_dev)
 102 {
 103         u32 page_count;
 104
 105         if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
 106                 return;
 107
 108         page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
 109                                           rd_dev->sg_table_count);
 110
 111         pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
 112                 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
 113                 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
 114                 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 115
 116         rd_dev->sg_table_array = NULL;
 117         rd_dev->sg_table_count = 0;
 118 }
 119
 120
 121 /*      rd_build_device_space():
 122  *
 123  *
 124  */
 125 static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
 126                                  u32 total_sg_needed, unsigned char init_payload)
 127 {
 128         u32 i = 0, j, page_offset = 0, sg_per_table;
 129         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 130                                 sizeof(struct scatterlist));
 131         struct page *pg;
 132         struct scatterlist *sg;
 133         unsigned char *p;
 134
 135         while (total_sg_needed) {
 136                 unsigned int chain_entry = 0;
 137
 138                 sg_per_table = (total_sg_needed > max_sg_per_table) ?
 139                         max_sg_per_table : total_sg_needed;
 140
 141                 /*
 142                  * Reserve extra element for chain entry
 143                  */
 144                 if (sg_per_table < total_sg_needed)
 145                         chain_entry = 1;
 146
 147                 sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
 148                                 GFP_KERNEL);
 149                 if (!sg)
 150                         return -ENOMEM;
 151
 152                 sg_init_table(sg, sg_per_table + chain_entry);
 153
 154                 if (i > 0) {
 155                         sg_chain(sg_table[i - 1].sg_table,
 156                                  max_sg_per_table + 1, sg);
 157                 }
 158
 159                 sg_table[i].sg_table = sg;
 160                 sg_table[i].rd_sg_count = sg_per_table;
 161                 sg_table[i].page_start_offset = page_offset;
 162                 sg_table[i++].page_end_offset = (page_offset + sg_per_table)
 163                                                 - 1;
 164
 165                 for (j = 0; j < sg_per_table; j++) {
 166                         pg = alloc_pages(GFP_KERNEL, 0);
 167                         if (!pg) {
 168                                 pr_err("Unable to allocate scatterlist"
 169                                         " pages for struct rd_dev_sg_table\n");
 170                                 return -ENOMEM;
 171                         }
 172                         sg_assign_page(&sg[j], pg);
 173                         sg[j].length = PAGE_SIZE;
 174
 175                         p = kmap(pg);
 176                         memset(p, init_payload, PAGE_SIZE);
 177                         kunmap(pg);
 178                 }
 179
 180                 page_offset += sg_per_table;
 181                 total_sg_needed -= sg_per_table;
 182         }
 183
 184         return 0;
 185 }
 186
 187 static int rd_build_device_space(struct rd_dev *rd_dev)
 188 {
 189         struct rd_dev_sg_table *sg_table;
 190         u32 sg_tables, total_sg_needed;
 191         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 192                                 sizeof(struct scatterlist));
 193         int rc;
 194
 195         if (rd_dev->rd_page_count <= 0) {
 196                 pr_err("Illegal page count: %u for Ramdisk device\n",
 197                        rd_dev->rd_page_count);
 198                 return -EINVAL;
 199         }
 200
 201         /* Don't need backing pages for NULLIO */
 202         if (rd_dev->rd_flags & RDF_NULLIO)
 203                 return 0;
 204
 205         total_sg_needed = rd_dev->rd_page_count;
 206
 207         sg_tables = (total_sg_needed / max_sg_per_table) + 1;
 208         sg_table = kcalloc(sg_tables, sizeof(*sg_table), GFP_KERNEL);
 209         if (!sg_table)
 210                 return -ENOMEM;
 211
 212         rd_dev->sg_table_array = sg_table;
 213         rd_dev->sg_table_count = sg_tables;
 214
 215         rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
 216         if (rc)
 217                 return rc;
 218
 219         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
 220                  " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
 221                  rd_dev->rd_dev_id, rd_dev->rd_page_count,
 222                  rd_dev->sg_table_count);
 223
 224         return 0;
 225 }
 226
 227 static void rd_release_prot_space(struct rd_dev *rd_dev)
 228 {
 229         u32 page_count;
 230
 231         if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
 232                 return;
 233
 234         page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_prot_array,
 235                                           rd_dev->sg_prot_count);
 236
 237         pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
 238                  " Device ID: %u, pages %u in %u tables total bytes %lu\n",
 239                  rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
 240                  rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 241
 242         rd_dev->sg_prot_array = NULL;
 243         rd_dev->sg_prot_count = 0;
 244 }
 245
 246 static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
 247 {
 248         struct rd_dev_sg_table *sg_table;
 249         u32 total_sg_needed, sg_tables;
 250         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 251                                 sizeof(struct scatterlist));
 252         int rc;
 253
 254         if (rd_dev->rd_flags & RDF_NULLIO)
 255                 return 0;
 256         /*
 257          * prot_length=8byte dif data
 258          * tot sg needed = rd_page_count * (PGSZ/block_size) *
 259          *                 (prot_length/block_size) + pad
 260          * PGSZ canceled each other.
 261          */
 262         total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
 263
 264         sg_tables = (total_sg_needed / max_sg_per_table) + 1;
 265         sg_table = kcalloc(sg_tables, sizeof(*sg_table), GFP_KERNEL);
 266         if (!sg_table)
 267                 return -ENOMEM;
 268
 269         rd_dev->sg_prot_array = sg_table;
 270         rd_dev->sg_prot_count = sg_tables;
 271
 272         rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0xff);
 273         if (rc)
 274                 return rc;
 275
 276         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
 277                  " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
 278                  rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
 279
 280         return 0;
 281 }
 282
 283 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
 284 {
 285         struct rd_dev *rd_dev;
 286         struct rd_host *rd_host = hba->hba_ptr;
 287
 288         rd_dev = kzalloc(sizeof(*rd_dev), GFP_KERNEL);
 289         if (!rd_dev)
 290                 return NULL;
 291
 292         rd_dev->rd_host = rd_host;
 293
 294         return &rd_dev->dev;
 295 }
 296
 297 static int rd_configure_device(struct se_device *dev)
 298 {
 299         struct rd_dev *rd_dev = RD_DEV(dev);
 300         struct rd_host *rd_host = dev->se_hba->hba_ptr;
 301         int ret;
 302
 303         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 304                 pr_debug("Missing rd_pages= parameter\n");
 305                 return -EINVAL;
 306         }
 307
 308         ret = rd_build_device_space(rd_dev);
 309         if (ret < 0)
 310                 goto fail;
 311
 312         dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
 313         dev->dev_attrib.hw_max_sectors = UINT_MAX;
 314         dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 315         dev->dev_attrib.is_nonrot = 1;
 316
 317         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 318
 319         pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
 320                 " %u pages in %u tables, %lu total bytes\n",
 321                 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
 322                 rd_dev->sg_table_count,
 323                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 324
 325         return 0;
 326
 327 fail:
 328         rd_release_device_space(rd_dev);
 329         return ret;
 330 }
 331
 332 static void rd_dev_call_rcu(struct rcu_head *p)
 333 {
 334         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 335         struct rd_dev *rd_dev = RD_DEV(dev);
 336
 337         kfree(rd_dev);
 338 }
 339
 340 static void rd_free_device(struct se_device *dev)
 341 {
 342         call_rcu(&dev->rcu_head, rd_dev_call_rcu);
 343 }
 344
 345 static void rd_destroy_device(struct se_device *dev)
 346 {
 347         struct rd_dev *rd_dev = RD_DEV(dev);
 348
 349         rd_release_device_space(rd_dev);
 350 }
 351
 352 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 353 {
 354         struct rd_dev_sg_table *sg_table;
 355         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 356                                 sizeof(struct scatterlist));
 357
 358         i = page / sg_per_table;
 359         if (i < rd_dev->sg_table_count) {
 360                 sg_table = &rd_dev->sg_table_array[i];
 361                 if ((sg_table->page_start_offset <= page) &&
 362                     (sg_table->page_end_offset >= page))
 363                         return sg_table;
 364         }
 365
 366         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 367                         page);
 368
 369         return NULL;
 370 }
 371
 372 static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
 373 {
 374         struct rd_dev_sg_table *sg_table;
 375         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 376                                 sizeof(struct scatterlist));
 377
 378         i = page / sg_per_table;
 379         if (i < rd_dev->sg_prot_count) {
 380                 sg_table = &rd_dev->sg_prot_array[i];
 381                 if ((sg_table->page_start_offset <= page) &&
 382                      (sg_table->page_end_offset >= page))
 383                         return sg_table;
 384         }
 385
 386         pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
 387                         page);
 388
 389         return NULL;
 390 }
 391
 392 static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
 393 {
 394         struct se_device *se_dev = cmd->se_dev;
 395         struct rd_dev *dev = RD_DEV(se_dev);
 396         struct rd_dev_sg_table *prot_table;
 397         struct scatterlist *prot_sg;
 398         u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
 399         u32 prot_offset, prot_page;
 400         u32 prot_npages __maybe_unused;
 401         u64 tmp;
 402         sense_reason_t rc = 0;
 403
 404         tmp = cmd->t_task_lba * se_dev->prot_length;
 405         prot_offset = do_div(tmp, PAGE_SIZE);
 406         prot_page = tmp;
 407
 408         prot_table = rd_get_prot_table(dev, prot_page);
 409         if (!prot_table)
 410                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 411
 412         prot_sg = &prot_table->sg_table[prot_page -
 413                                         prot_table->page_start_offset];
 414
 415         if (se_dev->dev_attrib.pi_prot_verify) {
 416                 if (is_read)
 417                         rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
 418                                             prot_sg, prot_offset);
 419                 else
 420                         rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
 421                                             cmd->t_prot_sg, 0);
 422         }
 423         if (!rc)
 424                 sbc_dif_copy_prot(cmd, sectors, is_read, prot_sg, prot_offset);
 425
 426         return rc;
 427 }
 428
 429 static sense_reason_t
 430 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 431               enum dma_data_direction data_direction)
 432 {
 433         struct se_device *se_dev = cmd->se_dev;
 434         struct rd_dev *dev = RD_DEV(se_dev);
 435         struct rd_dev_sg_table *table;
 436         struct scatterlist *rd_sg;
 437         struct sg_mapping_iter m;
 438         u32 rd_offset;
 439         u32 rd_size;
 440         u32 rd_page;
 441         u32 src_len;
 442         u64 tmp;
 443         sense_reason_t rc;
 444
 445         if (dev->rd_flags & RDF_NULLIO) {
 446                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 447                 return 0;
 448         }
 449
 450         tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
 451         rd_offset = do_div(tmp, PAGE_SIZE);
 452         rd_page = tmp;
 453         rd_size = cmd->data_length;
 454
 455         table = rd_get_sg_table(dev, rd_page);
 456         if (!table)
 457                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 458
 459         rd_sg = &table->sg_table[rd_page - table->page_start_offset];
 460
 461         pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
 462                         dev->rd_dev_id,
 463                         data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
 464                         cmd->t_task_lba, rd_size, rd_page, rd_offset);
 465
 466         if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
 467             data_direction == DMA_TO_DEVICE) {
 468                 rc = rd_do_prot_rw(cmd, false);
 469                 if (rc)
 470                         return rc;
 471         }
 472
 473         src_len = PAGE_SIZE - rd_offset;
 474         sg_miter_start(&m, sgl, sgl_nents,
 475                         data_direction == DMA_FROM_DEVICE ?
 476                                 SG_MITER_TO_SG : SG_MITER_FROM_SG);
 477         while (rd_size) {
 478                 u32 len;
 479                 void *rd_addr;
 480
 481                 sg_miter_next(&m);
 482                 if (!(u32)m.length) {
 483                         pr_debug("RD[%u]: invalid sgl %p len %zu\n",
 484                                  dev->rd_dev_id, m.addr, m.length);
 485                         sg_miter_stop(&m);
 486                         return TCM_INCORRECT_AMOUNT_OF_DATA;
 487                 }
 488                 len = min((u32)m.length, src_len);
 489                 if (len > rd_size) {
 490                         pr_debug("RD[%u]: size underrun page %d offset %d "
 491                                  "size %d\n", dev->rd_dev_id,
 492                                  rd_page, rd_offset, rd_size);
 493                         len = rd_size;
 494                 }
 495                 m.consumed = len;
 496
 497                 rd_addr = sg_virt(rd_sg) + rd_offset;
 498
 499                 if (data_direction == DMA_FROM_DEVICE)
 500                         memcpy(m.addr, rd_addr, len);
 501                 else
 502                         memcpy(rd_addr, m.addr, len);
 503
 504                 rd_size -= len;
 505                 if (!rd_size)
 506                         continue;
 507
 508                 src_len -= len;
 509                 if (src_len) {
 510                         rd_offset += len;
 511                         continue;
 512                 }
 513
 514                 /* rd page completed, next one please */
 515                 rd_page++;
 516                 rd_offset = 0;
 517                 src_len = PAGE_SIZE;
 518                 if (rd_page <= table->page_end_offset) {
 519                         rd_sg++;
 520                         continue;
 521                 }
 522
 523                 table = rd_get_sg_table(dev, rd_page);
 524                 if (!table) {
 525                         sg_miter_stop(&m);
 526                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 527                 }
 528
 529                 /* since we increment, the first sg entry is correct */
 530                 rd_sg = table->sg_table;
 531         }
 532         sg_miter_stop(&m);
 533
 534         if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
 535             data_direction == DMA_FROM_DEVICE) {
 536                 rc = rd_do_prot_rw(cmd, true);
 537                 if (rc)
 538                         return rc;
 539         }
 540
 541         target_complete_cmd(cmd, SAM_STAT_GOOD);
 542         return 0;
 543 }
 544
 545 enum {
 546         Opt_rd_pages, Opt_rd_nullio, Opt_err
 547 };
 548
 549 static match_table_t tokens = {
 550         {Opt_rd_pages, "rd_pages=%d"},
 551         {Opt_rd_nullio, "rd_nullio=%d"},
 552         {Opt_err, NULL}
 553 };
 554
 555 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
 556                 const char *page, ssize_t count)
 557 {
 558         struct rd_dev *rd_dev = RD_DEV(dev);
 559         char *orig, *ptr, *opts;
 560         substring_t args[MAX_OPT_ARGS];
 561         int arg, token;
 562
 563         opts = kstrdup(page, GFP_KERNEL);
 564         if (!opts)
 565                 return -ENOMEM;
 566
 567         orig = opts;
 568
 569         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 570                 if (!*ptr)
 571                         continue;
 572
 573                 token = match_token(ptr, tokens, args);
 574                 switch (token) {
 575                 case Opt_rd_pages:
 576                         match_int(args, &arg);
 577                         rd_dev->rd_page_count = arg;
 578                         pr_debug("RAMDISK: Referencing Page"
 579                                 " Count: %u\n", rd_dev->rd_page_count);
 580                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 581                         break;
 582                 case Opt_rd_nullio:
 583                         match_int(args, &arg);
 584                         if (arg != 1)
 585                                 break;
 586
 587                         pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
 588                         rd_dev->rd_flags |= RDF_NULLIO;
 589                         break;
 590                 default:
 591                         break;
 592                 }
 593         }
 594
 595         kfree(orig);
 596         return count;
 597 }
 598
 599 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
 600 {
 601         struct rd_dev *rd_dev = RD_DEV(dev);
 602
 603         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
 604                         rd_dev->rd_dev_id);
 605         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 606                         "  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
 607                         PAGE_SIZE, rd_dev->sg_table_count,
 608                         !!(rd_dev->rd_flags & RDF_NULLIO));
 609         return bl;
 610 }
 611
 612 static sector_t rd_get_blocks(struct se_device *dev)
 613 {
 614         struct rd_dev *rd_dev = RD_DEV(dev);
 615
 616         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 617                         dev->dev_attrib.block_size) - 1;
 618
 619         return blocks_long;
 620 }
 621
 622 static int rd_init_prot(struct se_device *dev)
 623 {
 624         struct rd_dev *rd_dev = RD_DEV(dev);
 625
 626         if (!dev->dev_attrib.pi_prot_type)
 627                 return 0;
 628
 629         return rd_build_prot_space(rd_dev, dev->prot_length,
 630                                    dev->dev_attrib.block_size);
 631 }
 632
 633 static void rd_free_prot(struct se_device *dev)
 634 {
 635         struct rd_dev *rd_dev = RD_DEV(dev);
 636
 637         rd_release_prot_space(rd_dev);
 638 }
 639
 640 static struct sbc_ops rd_sbc_ops = {
 641         .execute_rw             = rd_execute_rw,
 642 };
 643
 644 static sense_reason_t
 645 rd_parse_cdb(struct se_cmd *cmd)
 646 {
 647         return sbc_parse_cdb(cmd, &rd_sbc_ops);
 648 }
 649
 650 static const struct target_backend_ops rd_mcp_ops = {
 651         .name                   = "rd_mcp",
 652         .inquiry_prod           = "RAMDISK-MCP",
 653         .inquiry_rev            = RD_MCP_VERSION,
 654         .attach_hba             = rd_attach_hba,
 655         .detach_hba             = rd_detach_hba,
 656         .alloc_device           = rd_alloc_device,
 657         .configure_device       = rd_configure_device,
 658         .destroy_device         = rd_destroy_device,
 659         .free_device            = rd_free_device,
 660         .parse_cdb              = rd_parse_cdb,
 661         .set_configfs_dev_params = rd_set_configfs_dev_params,
 662         .show_configfs_dev_params = rd_show_configfs_dev_params,
 663         .get_device_type        = sbc_get_device_type,
 664         .get_blocks             = rd_get_blocks,
 665         .init_prot              = rd_init_prot,
 666         .free_prot              = rd_free_prot,
 667         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 668 };
 669
 670 int __init rd_module_init(void)
 671 {
 672         return transport_backend_register(&rd_mcp_ops);
 673 }
 674
 675 void rd_module_exit(void)
 676 {
 677         target_backend_unregister(&rd_mcp_ops);
 678 }