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/timer.h> 30 #include <linux/slab.h> 31 #include <linux/spinlock.h> 32 #include <scsi/scsi.h> 33 #include <scsi/scsi_host.h> 34 35 #include <target/target_core_base.h> 36 #include <target/target_core_backend.h> 37 38 #include "target_core_rd.h" 39 40 static inline struct rd_dev *RD_DEV(struct se_device *dev) 41 { 42 return container_of(dev, struct rd_dev, dev); 43 } 44 45 /* rd_attach_hba(): (Part of se_subsystem_api_t template) 46 * 47 * 48 */ 49 static int rd_attach_hba(struct se_hba *hba, u32 host_id) 50 { 51 struct rd_host *rd_host; 52 53 rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL); 54 if (!rd_host) { 55 pr_err("Unable to allocate memory for struct rd_host\n"); 56 return -ENOMEM; 57 } 58 59 rd_host->rd_host_id = host_id; 60 61 hba->hba_ptr = rd_host; 62 63 pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on" 64 " Generic Target Core Stack %s\n", hba->hba_id, 65 RD_HBA_VERSION, TARGET_CORE_MOD_VERSION); 66 67 return 0; 68 } 69 70 static void rd_detach_hba(struct se_hba *hba) 71 { 72 struct rd_host *rd_host = hba->hba_ptr; 73 74 pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from" 75 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id); 76 77 kfree(rd_host); 78 hba->hba_ptr = NULL; 79 } 80 81 static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table, 82 u32 sg_table_count) 83 { 84 struct page *pg; 85 struct scatterlist *sg; 86 u32 i, j, page_count = 0, sg_per_table; 87 88 for (i = 0; i < sg_table_count; i++) { 89 sg = sg_table[i].sg_table; 90 sg_per_table = sg_table[i].rd_sg_count; 91 92 for (j = 0; j < sg_per_table; j++) { 93 pg = sg_page(&sg[j]); 94 if (pg) { 95 __free_page(pg); 96 page_count++; 97 } 98 } 99 kfree(sg); 100 } 101 102 kfree(sg_table); 103 return page_count; 104 } 105 106 static void rd_release_device_space(struct rd_dev *rd_dev) 107 { 108 u32 page_count; 109 110 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count) 111 return; 112 113 page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array, 114 rd_dev->sg_table_count); 115 116 pr_debug("CORE_RD[%u] - Released device space for Ramdisk" 117 " Device ID: %u, pages %u in %u tables total bytes %lu\n", 118 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count, 119 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE); 120 121 rd_dev->sg_table_array = NULL; 122 rd_dev->sg_table_count = 0; 123 } 124 125 126 /* rd_build_device_space(): 127 * 128 * 129 */ 130 static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table, 131 u32 total_sg_needed, unsigned char init_payload) 132 { 133 u32 i = 0, j, page_offset = 0, sg_per_table; 134 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE / 135 sizeof(struct scatterlist)); 136 struct page *pg; 137 struct scatterlist *sg; 138 unsigned char *p; 139 140 while (total_sg_needed) { 141 sg_per_table = (total_sg_needed > max_sg_per_table) ? 142 max_sg_per_table : total_sg_needed; 143 144 sg = kzalloc(sg_per_table * sizeof(struct scatterlist), 145 GFP_KERNEL); 146 if (!sg) { 147 pr_err("Unable to allocate scatterlist array" 148 " for struct rd_dev\n"); 149 return -ENOMEM; 150 } 151 152 sg_init_table(sg, sg_per_table); 153 154 sg_table[i].sg_table = sg; 155 sg_table[i].rd_sg_count = sg_per_table; 156 sg_table[i].page_start_offset = page_offset; 157 sg_table[i++].page_end_offset = (page_offset + sg_per_table) 158 - 1; 159 160 for (j = 0; j < sg_per_table; j++) { 161 pg = alloc_pages(GFP_KERNEL, 0); 162 if (!pg) { 163 pr_err("Unable to allocate scatterlist" 164 " pages for struct rd_dev_sg_table\n"); 165 return -ENOMEM; 166 } 167 sg_assign_page(&sg[j], pg); 168 sg[j].length = PAGE_SIZE; 169 170 p = kmap(pg); 171 memset(p, init_payload, PAGE_SIZE); 172 kunmap(pg); 173 } 174 175 page_offset += sg_per_table; 176 total_sg_needed -= sg_per_table; 177 } 178 179 return 0; 180 } 181 182 static int rd_build_device_space(struct rd_dev *rd_dev) 183 { 184 struct rd_dev_sg_table *sg_table; 185 u32 sg_tables, total_sg_needed; 186 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE / 187 sizeof(struct scatterlist)); 188 int rc; 189 190 if (rd_dev->rd_page_count <= 0) { 191 pr_err("Illegal page count: %u for Ramdisk device\n", 192 rd_dev->rd_page_count); 193 return -EINVAL; 194 } 195 196 /* Don't need backing pages for NULLIO */ 197 if (rd_dev->rd_flags & RDF_NULLIO) 198 return 0; 199 200 total_sg_needed = rd_dev->rd_page_count; 201 202 sg_tables = (total_sg_needed / max_sg_per_table) + 1; 203 204 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL); 205 if (!sg_table) { 206 pr_err("Unable to allocate memory for Ramdisk" 207 " scatterlist tables\n"); 208 return -ENOMEM; 209 } 210 211 rd_dev->sg_table_array = sg_table; 212 rd_dev->sg_table_count = sg_tables; 213 214 rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00); 215 if (rc) 216 return rc; 217 218 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of" 219 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id, 220 rd_dev->rd_dev_id, rd_dev->rd_page_count, 221 rd_dev->sg_table_count); 222 223 return 0; 224 } 225 226 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name) 227 { 228 struct rd_dev *rd_dev; 229 struct rd_host *rd_host = hba->hba_ptr; 230 231 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL); 232 if (!rd_dev) { 233 pr_err("Unable to allocate memory for struct rd_dev\n"); 234 return NULL; 235 } 236 237 rd_dev->rd_host = rd_host; 238 239 return &rd_dev->dev; 240 } 241 242 static int rd_configure_device(struct se_device *dev) 243 { 244 struct rd_dev *rd_dev = RD_DEV(dev); 245 struct rd_host *rd_host = dev->se_hba->hba_ptr; 246 int ret; 247 248 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) { 249 pr_debug("Missing rd_pages= parameter\n"); 250 return -EINVAL; 251 } 252 253 ret = rd_build_device_space(rd_dev); 254 if (ret < 0) 255 goto fail; 256 257 dev->dev_attrib.hw_block_size = RD_BLOCKSIZE; 258 dev->dev_attrib.hw_max_sectors = UINT_MAX; 259 dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH; 260 261 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++; 262 263 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of" 264 " %u pages in %u tables, %lu total bytes\n", 265 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count, 266 rd_dev->sg_table_count, 267 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE)); 268 269 return 0; 270 271 fail: 272 rd_release_device_space(rd_dev); 273 return ret; 274 } 275 276 static void rd_free_device(struct se_device *dev) 277 { 278 struct rd_dev *rd_dev = RD_DEV(dev); 279 280 rd_release_device_space(rd_dev); 281 kfree(rd_dev); 282 } 283 284 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page) 285 { 286 struct rd_dev_sg_table *sg_table; 287 u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE / 288 sizeof(struct scatterlist)); 289 290 i = page / sg_per_table; 291 if (i < rd_dev->sg_table_count) { 292 sg_table = &rd_dev->sg_table_array[i]; 293 if ((sg_table->page_start_offset <= page) && 294 (sg_table->page_end_offset >= page)) 295 return sg_table; 296 } 297 298 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n", 299 page); 300 301 return NULL; 302 } 303 304 static sense_reason_t 305 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, 306 enum dma_data_direction data_direction) 307 { 308 struct se_device *se_dev = cmd->se_dev; 309 struct rd_dev *dev = RD_DEV(se_dev); 310 struct rd_dev_sg_table *table; 311 struct scatterlist *rd_sg; 312 struct sg_mapping_iter m; 313 u32 rd_offset; 314 u32 rd_size; 315 u32 rd_page; 316 u32 src_len; 317 u64 tmp; 318 319 if (dev->rd_flags & RDF_NULLIO) { 320 target_complete_cmd(cmd, SAM_STAT_GOOD); 321 return 0; 322 } 323 324 tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size; 325 rd_offset = do_div(tmp, PAGE_SIZE); 326 rd_page = tmp; 327 rd_size = cmd->data_length; 328 329 table = rd_get_sg_table(dev, rd_page); 330 if (!table) 331 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 332 333 rd_sg = &table->sg_table[rd_page - table->page_start_offset]; 334 335 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n", 336 dev->rd_dev_id, 337 data_direction == DMA_FROM_DEVICE ? "Read" : "Write", 338 cmd->t_task_lba, rd_size, rd_page, rd_offset); 339 340 src_len = PAGE_SIZE - rd_offset; 341 sg_miter_start(&m, sgl, sgl_nents, 342 data_direction == DMA_FROM_DEVICE ? 343 SG_MITER_TO_SG : SG_MITER_FROM_SG); 344 while (rd_size) { 345 u32 len; 346 void *rd_addr; 347 348 sg_miter_next(&m); 349 if (!(u32)m.length) { 350 pr_debug("RD[%u]: invalid sgl %p len %zu\n", 351 dev->rd_dev_id, m.addr, m.length); 352 sg_miter_stop(&m); 353 return TCM_INCORRECT_AMOUNT_OF_DATA; 354 } 355 len = min((u32)m.length, src_len); 356 if (len > rd_size) { 357 pr_debug("RD[%u]: size underrun page %d offset %d " 358 "size %d\n", dev->rd_dev_id, 359 rd_page, rd_offset, rd_size); 360 len = rd_size; 361 } 362 m.consumed = len; 363 364 rd_addr = sg_virt(rd_sg) + rd_offset; 365 366 if (data_direction == DMA_FROM_DEVICE) 367 memcpy(m.addr, rd_addr, len); 368 else 369 memcpy(rd_addr, m.addr, len); 370 371 rd_size -= len; 372 if (!rd_size) 373 continue; 374 375 src_len -= len; 376 if (src_len) { 377 rd_offset += len; 378 continue; 379 } 380 381 /* rd page completed, next one please */ 382 rd_page++; 383 rd_offset = 0; 384 src_len = PAGE_SIZE; 385 if (rd_page <= table->page_end_offset) { 386 rd_sg++; 387 continue; 388 } 389 390 table = rd_get_sg_table(dev, rd_page); 391 if (!table) { 392 sg_miter_stop(&m); 393 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 394 } 395 396 /* since we increment, the first sg entry is correct */ 397 rd_sg = table->sg_table; 398 } 399 sg_miter_stop(&m); 400 401 target_complete_cmd(cmd, SAM_STAT_GOOD); 402 return 0; 403 } 404 405 enum { 406 Opt_rd_pages, Opt_rd_nullio, Opt_err 407 }; 408 409 static match_table_t tokens = { 410 {Opt_rd_pages, "rd_pages=%d"}, 411 {Opt_rd_nullio, "rd_nullio=%d"}, 412 {Opt_err, NULL} 413 }; 414 415 static ssize_t rd_set_configfs_dev_params(struct se_device *dev, 416 const char *page, ssize_t count) 417 { 418 struct rd_dev *rd_dev = RD_DEV(dev); 419 char *orig, *ptr, *opts; 420 substring_t args[MAX_OPT_ARGS]; 421 int ret = 0, arg, token; 422 423 opts = kstrdup(page, GFP_KERNEL); 424 if (!opts) 425 return -ENOMEM; 426 427 orig = opts; 428 429 while ((ptr = strsep(&opts, ",\n")) != NULL) { 430 if (!*ptr) 431 continue; 432 433 token = match_token(ptr, tokens, args); 434 switch (token) { 435 case Opt_rd_pages: 436 match_int(args, &arg); 437 rd_dev->rd_page_count = arg; 438 pr_debug("RAMDISK: Referencing Page" 439 " Count: %u\n", rd_dev->rd_page_count); 440 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT; 441 break; 442 case Opt_rd_nullio: 443 match_int(args, &arg); 444 if (arg != 1) 445 break; 446 447 pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg); 448 rd_dev->rd_flags |= RDF_NULLIO; 449 break; 450 default: 451 break; 452 } 453 } 454 455 kfree(orig); 456 return (!ret) ? count : ret; 457 } 458 459 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b) 460 { 461 struct rd_dev *rd_dev = RD_DEV(dev); 462 463 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n", 464 rd_dev->rd_dev_id); 465 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu" 466 " SG_table_count: %u nullio: %d\n", rd_dev->rd_page_count, 467 PAGE_SIZE, rd_dev->sg_table_count, 468 !!(rd_dev->rd_flags & RDF_NULLIO)); 469 return bl; 470 } 471 472 static sector_t rd_get_blocks(struct se_device *dev) 473 { 474 struct rd_dev *rd_dev = RD_DEV(dev); 475 476 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) / 477 dev->dev_attrib.block_size) - 1; 478 479 return blocks_long; 480 } 481 482 static struct sbc_ops rd_sbc_ops = { 483 .execute_rw = rd_execute_rw, 484 }; 485 486 static sense_reason_t 487 rd_parse_cdb(struct se_cmd *cmd) 488 { 489 return sbc_parse_cdb(cmd, &rd_sbc_ops); 490 } 491 492 static struct se_subsystem_api rd_mcp_template = { 493 .name = "rd_mcp", 494 .inquiry_prod = "RAMDISK-MCP", 495 .inquiry_rev = RD_MCP_VERSION, 496 .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV, 497 .attach_hba = rd_attach_hba, 498 .detach_hba = rd_detach_hba, 499 .alloc_device = rd_alloc_device, 500 .configure_device = rd_configure_device, 501 .free_device = rd_free_device, 502 .parse_cdb = rd_parse_cdb, 503 .set_configfs_dev_params = rd_set_configfs_dev_params, 504 .show_configfs_dev_params = rd_show_configfs_dev_params, 505 .get_device_type = sbc_get_device_type, 506 .get_blocks = rd_get_blocks, 507 }; 508 509 int __init rd_module_init(void) 510 { 511 int ret; 512 513 ret = transport_subsystem_register(&rd_mcp_template); 514 if (ret < 0) { 515 return ret; 516 } 517 518 return 0; 519 } 520 521 void rd_module_exit(void) 522 { 523 transport_subsystem_release(&rd_mcp_template); 524 } 525