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