drivers/target/target_core_rd.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*******************************************************************************
   3  * Filename:  target_core_rd.c
   4  *
   5  * This file contains the Storage Engine <-> Ramdisk transport
   6  * specific functions.
   7  *
   8  * (c) Copyright 2003-2013 Datera, Inc.
   9  *
  10  * Nicholas A. Bellinger <nab@kernel.org>
  11  *
  12  ******************************************************************************/
  13
  14 #include <linux/string.h>
  15 #include <linux/parser.h>
  16 #include <linux/highmem.h>
  17 #include <linux/timer.h>
  18 #include <linux/scatterlist.h>
  19 #include <linux/slab.h>
  20 #include <linux/spinlock.h>
  21 #include <scsi/scsi_proto.h>
  22
  23 #include <target/target_core_base.h>
  24 #include <target/target_core_backend.h>
  25
  26 #include "target_core_rd.h"
  27
  28 static inline struct rd_dev *RD_DEV(struct se_device *dev)
  29 {
  30         return container_of(dev, struct rd_dev, dev);
  31 }
  32
  33 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
  34 {
  35         struct rd_host *rd_host;
  36
  37         rd_host = kzalloc(sizeof(*rd_host), GFP_KERNEL);
  38         if (!rd_host)
  39                 return -ENOMEM;
  40
  41         rd_host->rd_host_id = host_id;
  42
  43         hba->hba_ptr = rd_host;
  44
  45         pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
  46                 " Generic Target Core Stack %s\n", hba->hba_id,
  47                 RD_HBA_VERSION, TARGET_CORE_VERSION);
  48
  49         return 0;
  50 }
  51
  52 static void rd_detach_hba(struct se_hba *hba)
  53 {
  54         struct rd_host *rd_host = hba->hba_ptr;
  55
  56         pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
  57                 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
  58
  59         kfree(rd_host);
  60         hba->hba_ptr = NULL;
  61 }
  62
  63 static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
  64                                  u32 sg_table_count)
  65 {
  66         struct page *pg;
  67         struct scatterlist *sg;
  68         u32 i, j, page_count = 0, sg_per_table;
  69
  70         for (i = 0; i < sg_table_count; i++) {
  71                 sg = sg_table[i].sg_table;
  72                 sg_per_table = sg_table[i].rd_sg_count;
  73
  74                 for (j = 0; j < sg_per_table; j++) {
  75                         pg = sg_page(&sg[j]);
  76                         if (pg) {
  77                                 __free_page(pg);
  78                                 page_count++;
  79                         }
  80                 }
  81                 kfree(sg);
  82         }
  83
  84         kfree(sg_table);
  85         return page_count;
  86 }
  87
  88 static void rd_release_device_space(struct rd_dev *rd_dev)
  89 {
  90         u32 page_count;
  91
  92         if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
  93                 return;
  94
  95         page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
  96                                           rd_dev->sg_table_count);
  97
  98         pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
  99                 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
 100                 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
 101                 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 102
 103         rd_dev->sg_table_array = NULL;
 104         rd_dev->sg_table_count = 0;
 105 }
 106
 107
 108 /*      rd_build_device_space():
 109  *
 110  *
 111  */
 112 static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
 113                                  u32 total_sg_needed, unsigned char init_payload)
 114 {
 115         u32 i = 0, j, page_offset = 0, sg_per_table;
 116         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 117                                 sizeof(struct scatterlist));
 118         struct page *pg;
 119         struct scatterlist *sg;
 120         unsigned char *p;
 121
 122         while (total_sg_needed) {
 123                 unsigned int chain_entry = 0;
 124
 125                 sg_per_table = (total_sg_needed > max_sg_per_table) ?
 126                         max_sg_per_table : total_sg_needed;
 127
 128                 /*
 129                  * Reserve extra element for chain entry
 130                  */
 131                 if (sg_per_table < total_sg_needed)
 132                         chain_entry = 1;
 133
 134                 sg = kmalloc_array(sg_per_table + chain_entry, sizeof(*sg),
 135                                 GFP_KERNEL);
 136                 if (!sg)
 137                         return -ENOMEM;
 138
 139                 sg_init_table(sg, sg_per_table + chain_entry);
 140
 141                 if (i > 0) {
 142                         sg_chain(sg_table[i - 1].sg_table,
 143                                  max_sg_per_table + 1, sg);
 144                 }
 145
 146                 sg_table[i].sg_table = sg;
 147                 sg_table[i].rd_sg_count = sg_per_table;
 148                 sg_table[i].page_start_offset = page_offset;
 149                 sg_table[i++].page_end_offset = (page_offset + sg_per_table)
 150                                                 - 1;
 151
 152                 for (j = 0; j < sg_per_table; j++) {
 153                         pg = alloc_pages(GFP_KERNEL, 0);
 154                         if (!pg) {
 155                                 pr_err("Unable to allocate scatterlist"
 156                                         " pages for struct rd_dev_sg_table\n");
 157                                 return -ENOMEM;
 158                         }
 159                         sg_assign_page(&sg[j], pg);
 160                         sg[j].length = PAGE_SIZE;
 161
 162                         p = kmap(pg);
 163                         memset(p, init_payload, PAGE_SIZE);
 164                         kunmap(pg);
 165                 }
 166
 167                 page_offset += sg_per_table;
 168                 total_sg_needed -= sg_per_table;
 169         }
 170
 171         return 0;
 172 }
 173
 174 static int rd_build_device_space(struct rd_dev *rd_dev)
 175 {
 176         struct rd_dev_sg_table *sg_table;
 177         u32 sg_tables, total_sg_needed;
 178         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 179                                 sizeof(struct scatterlist));
 180         int rc;
 181
 182         if (rd_dev->rd_page_count <= 0) {
 183                 pr_err("Illegal page count: %u for Ramdisk device\n",
 184                        rd_dev->rd_page_count);
 185                 return -EINVAL;
 186         }
 187
 188         /* Don't need backing pages for NULLIO */
 189         if (rd_dev->rd_flags & RDF_NULLIO)
 190                 return 0;
 191
 192         total_sg_needed = rd_dev->rd_page_count;
 193
 194         sg_tables = (total_sg_needed / max_sg_per_table) + 1;
 195         sg_table = kcalloc(sg_tables, sizeof(*sg_table), GFP_KERNEL);
 196         if (!sg_table)
 197                 return -ENOMEM;
 198
 199         rd_dev->sg_table_array = sg_table;
 200         rd_dev->sg_table_count = sg_tables;
 201
 202         rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
 203         if (rc)
 204                 return rc;
 205
 206         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
 207                  " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
 208                  rd_dev->rd_dev_id, rd_dev->rd_page_count,
 209                  rd_dev->sg_table_count);
 210
 211         return 0;
 212 }
 213
 214 static void rd_release_prot_space(struct rd_dev *rd_dev)
 215 {
 216         u32 page_count;
 217
 218         if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
 219                 return;
 220
 221         page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_prot_array,
 222                                           rd_dev->sg_prot_count);
 223
 224         pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
 225                  " Device ID: %u, pages %u in %u tables total bytes %lu\n",
 226                  rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
 227                  rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 228
 229         rd_dev->sg_prot_array = NULL;
 230         rd_dev->sg_prot_count = 0;
 231 }
 232
 233 static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
 234 {
 235         struct rd_dev_sg_table *sg_table;
 236         u32 total_sg_needed, sg_tables;
 237         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 238                                 sizeof(struct scatterlist));
 239         int rc;
 240
 241         if (rd_dev->rd_flags & RDF_NULLIO)
 242                 return 0;
 243         /*
 244          * prot_length=8byte dif data
 245          * tot sg needed = rd_page_count * (PGSZ/block_size) *
 246          *                 (prot_length/block_size) + pad
 247          * PGSZ canceled each other.
 248          */
 249         total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
 250
 251         sg_tables = (total_sg_needed / max_sg_per_table) + 1;
 252         sg_table = kcalloc(sg_tables, sizeof(*sg_table), GFP_KERNEL);
 253         if (!sg_table)
 254                 return -ENOMEM;
 255
 256         rd_dev->sg_prot_array = sg_table;
 257         rd_dev->sg_prot_count = sg_tables;
 258
 259         rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0xff);
 260         if (rc)
 261                 return rc;
 262
 263         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
 264                  " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
 265                  rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
 266
 267         return 0;
 268 }
 269
 270 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
 271 {
 272         struct rd_dev *rd_dev;
 273         struct rd_host *rd_host = hba->hba_ptr;
 274
 275         rd_dev = kzalloc(sizeof(*rd_dev), GFP_KERNEL);
 276         if (!rd_dev)
 277                 return NULL;
 278
 279         rd_dev->rd_host = rd_host;
 280
 281         return &rd_dev->dev;
 282 }
 283
 284 static int rd_configure_device(struct se_device *dev)
 285 {
 286         struct rd_dev *rd_dev = RD_DEV(dev);
 287         struct rd_host *rd_host = dev->se_hba->hba_ptr;
 288         int ret;
 289
 290         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 291                 pr_debug("Missing rd_pages= parameter\n");
 292                 return -EINVAL;
 293         }
 294
 295         ret = rd_build_device_space(rd_dev);
 296         if (ret < 0)
 297                 goto fail;
 298
 299         dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
 300         dev->dev_attrib.hw_max_sectors = UINT_MAX;
 301         dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 302         dev->dev_attrib.is_nonrot = 1;
 303
 304         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 305
 306         pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
 307                 " %u pages in %u tables, %lu total bytes\n",
 308                 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
 309                 rd_dev->sg_table_count,
 310                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 311
 312         return 0;
 313
 314 fail:
 315         rd_release_device_space(rd_dev);
 316         return ret;
 317 }
 318
 319 static void rd_dev_call_rcu(struct rcu_head *p)
 320 {
 321         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 322         struct rd_dev *rd_dev = RD_DEV(dev);
 323
 324         kfree(rd_dev);
 325 }
 326
 327 static void rd_free_device(struct se_device *dev)
 328 {
 329         call_rcu(&dev->rcu_head, rd_dev_call_rcu);
 330 }
 331
 332 static void rd_destroy_device(struct se_device *dev)
 333 {
 334         struct rd_dev *rd_dev = RD_DEV(dev);
 335
 336         rd_release_device_space(rd_dev);
 337 }
 338
 339 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 340 {
 341         struct rd_dev_sg_table *sg_table;
 342         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 343                                 sizeof(struct scatterlist));
 344
 345         i = page / sg_per_table;
 346         if (i < rd_dev->sg_table_count) {
 347                 sg_table = &rd_dev->sg_table_array[i];
 348                 if ((sg_table->page_start_offset <= page) &&
 349                     (sg_table->page_end_offset >= page))
 350                         return sg_table;
 351         }
 352
 353         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 354                         page);
 355
 356         return NULL;
 357 }
 358
 359 static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
 360 {
 361         struct rd_dev_sg_table *sg_table;
 362         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 363                                 sizeof(struct scatterlist));
 364
 365         i = page / sg_per_table;
 366         if (i < rd_dev->sg_prot_count) {
 367                 sg_table = &rd_dev->sg_prot_array[i];
 368                 if ((sg_table->page_start_offset <= page) &&
 369                      (sg_table->page_end_offset >= page))
 370                         return sg_table;
 371         }
 372
 373         pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
 374                         page);
 375
 376         return NULL;
 377 }
 378
 379 static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
 380 {
 381         struct se_device *se_dev = cmd->se_dev;
 382         struct rd_dev *dev = RD_DEV(se_dev);
 383         struct rd_dev_sg_table *prot_table;
 384         struct scatterlist *prot_sg;
 385         u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
 386         u32 prot_offset, prot_page;
 387         u32 prot_npages __maybe_unused;
 388         u64 tmp;
 389         sense_reason_t rc = 0;
 390
 391         tmp = cmd->t_task_lba * se_dev->prot_length;
 392         prot_offset = do_div(tmp, PAGE_SIZE);
 393         prot_page = tmp;
 394
 395         prot_table = rd_get_prot_table(dev, prot_page);
 396         if (!prot_table)
 397                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 398
 399         prot_sg = &prot_table->sg_table[prot_page -
 400                                         prot_table->page_start_offset];
 401
 402         if (se_dev->dev_attrib.pi_prot_verify) {
 403                 if (is_read)
 404                         rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
 405                                             prot_sg, prot_offset);
 406                 else
 407                         rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
 408                                             cmd->t_prot_sg, 0);
 409         }
 410         if (!rc)
 411                 sbc_dif_copy_prot(cmd, sectors, is_read, prot_sg, prot_offset);
 412
 413         return rc;
 414 }
 415
 416 static sense_reason_t
 417 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 418               enum dma_data_direction data_direction)
 419 {
 420         struct se_device *se_dev = cmd->se_dev;
 421         struct rd_dev *dev = RD_DEV(se_dev);
 422         struct rd_dev_sg_table *table;
 423         struct scatterlist *rd_sg;
 424         struct sg_mapping_iter m;
 425         u32 rd_offset;
 426         u32 rd_size;
 427         u32 rd_page;
 428         u32 src_len;
 429         u64 tmp;
 430         sense_reason_t rc;
 431
 432         if (dev->rd_flags & RDF_NULLIO) {
 433                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 434                 return 0;
 435         }
 436
 437         tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
 438         rd_offset = do_div(tmp, PAGE_SIZE);
 439         rd_page = tmp;
 440         rd_size = cmd->data_length;
 441
 442         table = rd_get_sg_table(dev, rd_page);
 443         if (!table)
 444                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 445
 446         rd_sg = &table->sg_table[rd_page - table->page_start_offset];
 447
 448         pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
 449                         dev->rd_dev_id,
 450                         data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
 451                         cmd->t_task_lba, rd_size, rd_page, rd_offset);
 452
 453         if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
 454             data_direction == DMA_TO_DEVICE) {
 455                 rc = rd_do_prot_rw(cmd, false);
 456                 if (rc)
 457                         return rc;
 458         }
 459
 460         src_len = PAGE_SIZE - rd_offset;
 461         sg_miter_start(&m, sgl, sgl_nents,
 462                         data_direction == DMA_FROM_DEVICE ?
 463                                 SG_MITER_TO_SG : SG_MITER_FROM_SG);
 464         while (rd_size) {
 465                 u32 len;
 466                 void *rd_addr;
 467
 468                 sg_miter_next(&m);
 469                 if (!(u32)m.length) {
 470                         pr_debug("RD[%u]: invalid sgl %p len %zu\n",
 471                                  dev->rd_dev_id, m.addr, m.length);
 472                         sg_miter_stop(&m);
 473                         return TCM_INCORRECT_AMOUNT_OF_DATA;
 474                 }
 475                 len = min((u32)m.length, src_len);
 476                 if (len > rd_size) {
 477                         pr_debug("RD[%u]: size underrun page %d offset %d "
 478                                  "size %d\n", dev->rd_dev_id,
 479                                  rd_page, rd_offset, rd_size);
 480                         len = rd_size;
 481                 }
 482                 m.consumed = len;
 483
 484                 rd_addr = sg_virt(rd_sg) + rd_offset;
 485
 486                 if (data_direction == DMA_FROM_DEVICE)
 487                         memcpy(m.addr, rd_addr, len);
 488                 else
 489                         memcpy(rd_addr, m.addr, len);
 490
 491                 rd_size -= len;
 492                 if (!rd_size)
 493                         continue;
 494
 495                 src_len -= len;
 496                 if (src_len) {
 497                         rd_offset += len;
 498                         continue;
 499                 }
 500
 501                 /* rd page completed, next one please */
 502                 rd_page++;
 503                 rd_offset = 0;
 504                 src_len = PAGE_SIZE;
 505                 if (rd_page <= table->page_end_offset) {
 506                         rd_sg++;
 507                         continue;
 508                 }
 509
 510                 table = rd_get_sg_table(dev, rd_page);
 511                 if (!table) {
 512                         sg_miter_stop(&m);
 513                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 514                 }
 515
 516                 /* since we increment, the first sg entry is correct */
 517                 rd_sg = table->sg_table;
 518         }
 519         sg_miter_stop(&m);
 520
 521         if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
 522             data_direction == DMA_FROM_DEVICE) {
 523                 rc = rd_do_prot_rw(cmd, true);
 524                 if (rc)
 525                         return rc;
 526         }
 527
 528         target_complete_cmd(cmd, SAM_STAT_GOOD);
 529         return 0;
 530 }
 531
 532 enum {
 533         Opt_rd_pages, Opt_rd_nullio, Opt_rd_dummy, Opt_err
 534 };
 535
 536 static match_table_t tokens = {
 537         {Opt_rd_pages, "rd_pages=%d"},
 538         {Opt_rd_nullio, "rd_nullio=%d"},
 539         {Opt_rd_dummy, "rd_dummy=%d"},
 540         {Opt_err, NULL}
 541 };
 542
 543 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
 544                 const char *page, ssize_t count)
 545 {
 546         struct rd_dev *rd_dev = RD_DEV(dev);
 547         char *orig, *ptr, *opts;
 548         substring_t args[MAX_OPT_ARGS];
 549         int arg, token;
 550
 551         opts = kstrdup(page, GFP_KERNEL);
 552         if (!opts)
 553                 return -ENOMEM;
 554
 555         orig = opts;
 556
 557         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 558                 if (!*ptr)
 559                         continue;
 560
 561                 token = match_token(ptr, tokens, args);
 562                 switch (token) {
 563                 case Opt_rd_pages:
 564                         match_int(args, &arg);
 565                         rd_dev->rd_page_count = arg;
 566                         pr_debug("RAMDISK: Referencing Page"
 567                                 " Count: %u\n", rd_dev->rd_page_count);
 568                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 569                         break;
 570                 case Opt_rd_nullio:
 571                         match_int(args, &arg);
 572                         if (arg != 1)
 573                                 break;
 574
 575                         pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
 576                         rd_dev->rd_flags |= RDF_NULLIO;
 577                         break;
 578                 case Opt_rd_dummy:
 579                         match_int(args, &arg);
 580                         if (arg != 1)
 581                                 break;
 582
 583                         pr_debug("RAMDISK: Setting DUMMY flag: %d\n", arg);
 584                         rd_dev->rd_flags |= RDF_DUMMY;
 585                         break;
 586                 default:
 587                         break;
 588                 }
 589         }
 590
 591         kfree(orig);
 592         return count;
 593 }
 594
 595 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
 596 {
 597         struct rd_dev *rd_dev = RD_DEV(dev);
 598
 599         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
 600                         rd_dev->rd_dev_id);
 601         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 602                         "  SG_table_count: %u  nullio: %d dummy: %d\n",
 603                         rd_dev->rd_page_count,
 604                         PAGE_SIZE, rd_dev->sg_table_count,
 605                         !!(rd_dev->rd_flags & RDF_NULLIO),
 606                         !!(rd_dev->rd_flags & RDF_DUMMY));
 607         return bl;
 608 }
 609
 610 static u32 rd_get_device_type(struct se_device *dev)
 611 {
 612         if (RD_DEV(dev)->rd_flags & RDF_DUMMY)
 613                 return 0x3f; /* Unknown device type, not connected */
 614         else
 615                 return sbc_get_device_type(dev);
 616 }
 617
 618 static sector_t rd_get_blocks(struct se_device *dev)
 619 {
 620         struct rd_dev *rd_dev = RD_DEV(dev);
 621
 622         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 623                         dev->dev_attrib.block_size) - 1;
 624
 625         return blocks_long;
 626 }
 627
 628 static int rd_init_prot(struct se_device *dev)
 629 {
 630         struct rd_dev *rd_dev = RD_DEV(dev);
 631
 632         if (!dev->dev_attrib.pi_prot_type)
 633                 return 0;
 634
 635         return rd_build_prot_space(rd_dev, dev->prot_length,
 636                                    dev->dev_attrib.block_size);
 637 }
 638
 639 static void rd_free_prot(struct se_device *dev)
 640 {
 641         struct rd_dev *rd_dev = RD_DEV(dev);
 642
 643         rd_release_prot_space(rd_dev);
 644 }
 645
 646 static struct sbc_ops rd_sbc_ops = {
 647         .execute_rw             = rd_execute_rw,
 648 };
 649
 650 static sense_reason_t
 651 rd_parse_cdb(struct se_cmd *cmd)
 652 {
 653         return sbc_parse_cdb(cmd, &rd_sbc_ops);
 654 }
 655
 656 static const struct target_backend_ops rd_mcp_ops = {
 657         .name                   = "rd_mcp",
 658         .inquiry_prod           = "RAMDISK-MCP",
 659         .inquiry_rev            = RD_MCP_VERSION,
 660         .attach_hba             = rd_attach_hba,
 661         .detach_hba             = rd_detach_hba,
 662         .alloc_device           = rd_alloc_device,
 663         .configure_device       = rd_configure_device,
 664         .destroy_device         = rd_destroy_device,
 665         .free_device            = rd_free_device,
 666         .parse_cdb              = rd_parse_cdb,
 667         .set_configfs_dev_params = rd_set_configfs_dev_params,
 668         .show_configfs_dev_params = rd_show_configfs_dev_params,
 669         .get_device_type        = rd_get_device_type,
 670         .get_blocks             = rd_get_blocks,
 671         .init_prot              = rd_init_prot,
 672         .free_prot              = rd_free_prot,
 673         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 674 };
 675
 676 int __init rd_module_init(void)
 677 {
 678         return transport_backend_register(&rd_mcp_ops);
 679 }
 680
 681 void rd_module_exit(void)
 682 {
 683         target_backend_unregister(&rd_mcp_ops);
 684 }