1 /******************************************************************************* 2 * Filename: target_core_rd.c 3 * 4 * This file contains the Storage Engine <-> Ramdisk transport 5 * specific functions. 6 * 7 * (c) Copyright 2003-2012 RisingTide Systems LLC. 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/blkdev.h> 31 #include <linux/slab.h> 32 #include <linux/spinlock.h> 33 #include <scsi/scsi.h> 34 #include <scsi/scsi_host.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 /* rd_attach_hba(): (Part of se_subsystem_api_t template) 47 * 48 * 49 */ 50 static int rd_attach_hba(struct se_hba *hba, u32 host_id) 51 { 52 struct rd_host *rd_host; 53 54 rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL); 55 if (!rd_host) { 56 pr_err("Unable to allocate memory for struct rd_host\n"); 57 return -ENOMEM; 58 } 59 60 rd_host->rd_host_id = host_id; 61 62 hba->hba_ptr = rd_host; 63 64 pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on" 65 " Generic Target Core Stack %s\n", hba->hba_id, 66 RD_HBA_VERSION, TARGET_CORE_MOD_VERSION); 67 68 return 0; 69 } 70 71 static void rd_detach_hba(struct se_hba *hba) 72 { 73 struct rd_host *rd_host = hba->hba_ptr; 74 75 pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from" 76 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id); 77 78 kfree(rd_host); 79 hba->hba_ptr = NULL; 80 } 81 82 /* rd_release_device_space(): 83 * 84 * 85 */ 86 static void rd_release_device_space(struct rd_dev *rd_dev) 87 { 88 u32 i, j, page_count = 0, sg_per_table; 89 struct rd_dev_sg_table *sg_table; 90 struct page *pg; 91 struct scatterlist *sg; 92 93 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count) 94 return; 95 96 sg_table = rd_dev->sg_table_array; 97 98 for (i = 0; i < rd_dev->sg_table_count; i++) { 99 sg = sg_table[i].sg_table; 100 sg_per_table = sg_table[i].rd_sg_count; 101 102 for (j = 0; j < sg_per_table; j++) { 103 pg = sg_page(&sg[j]); 104 if (pg) { 105 __free_page(pg); 106 page_count++; 107 } 108 } 109 110 kfree(sg); 111 } 112 113 pr_debug("CORE_RD[%u] - Released device space for Ramdisk" 114 " Device ID: %u, pages %u in %u tables total bytes %lu\n", 115 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count, 116 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE); 117 118 kfree(sg_table); 119 rd_dev->sg_table_array = NULL; 120 rd_dev->sg_table_count = 0; 121 } 122 123 124 /* rd_build_device_space(): 125 * 126 * 127 */ 128 static int rd_build_device_space(struct rd_dev *rd_dev) 129 { 130 u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed; 131 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE / 132 sizeof(struct scatterlist)); 133 struct rd_dev_sg_table *sg_table; 134 struct page *pg; 135 struct scatterlist *sg; 136 137 if (rd_dev->rd_page_count <= 0) { 138 pr_err("Illegal page count: %u for Ramdisk device\n", 139 rd_dev->rd_page_count); 140 return -EINVAL; 141 } 142 143 /* Don't need backing pages for NULLIO */ 144 if (rd_dev->rd_flags & RDF_NULLIO) 145 return 0; 146 147 total_sg_needed = rd_dev->rd_page_count; 148 149 sg_tables = (total_sg_needed / max_sg_per_table) + 1; 150 151 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL); 152 if (!sg_table) { 153 pr_err("Unable to allocate memory for Ramdisk" 154 " scatterlist tables\n"); 155 return -ENOMEM; 156 } 157 158 rd_dev->sg_table_array = sg_table; 159 rd_dev->sg_table_count = sg_tables; 160 161 while (total_sg_needed) { 162 sg_per_table = (total_sg_needed > max_sg_per_table) ? 163 max_sg_per_table : total_sg_needed; 164 165 sg = kzalloc(sg_per_table * sizeof(struct scatterlist), 166 GFP_KERNEL); 167 if (!sg) { 168 pr_err("Unable to allocate scatterlist array" 169 " for struct rd_dev\n"); 170 return -ENOMEM; 171 } 172 173 sg_init_table(sg, sg_per_table); 174 175 sg_table[i].sg_table = sg; 176 sg_table[i].rd_sg_count = sg_per_table; 177 sg_table[i].page_start_offset = page_offset; 178 sg_table[i++].page_end_offset = (page_offset + sg_per_table) 179 - 1; 180 181 for (j = 0; j < sg_per_table; j++) { 182 pg = alloc_pages(GFP_KERNEL, 0); 183 if (!pg) { 184 pr_err("Unable to allocate scatterlist" 185 " pages for struct rd_dev_sg_table\n"); 186 return -ENOMEM; 187 } 188 sg_assign_page(&sg[j], pg); 189 sg[j].length = PAGE_SIZE; 190 } 191 192 page_offset += sg_per_table; 193 total_sg_needed -= sg_per_table; 194 } 195 196 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of" 197 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id, 198 rd_dev->rd_dev_id, rd_dev->rd_page_count, 199 rd_dev->sg_table_count); 200 201 return 0; 202 } 203 204 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name) 205 { 206 struct rd_dev *rd_dev; 207 struct rd_host *rd_host = hba->hba_ptr; 208 209 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL); 210 if (!rd_dev) { 211 pr_err("Unable to allocate memory for struct rd_dev\n"); 212 return NULL; 213 } 214 215 rd_dev->rd_host = rd_host; 216 217 return &rd_dev->dev; 218 } 219 220 static int rd_configure_device(struct se_device *dev) 221 { 222 struct rd_dev *rd_dev = RD_DEV(dev); 223 struct rd_host *rd_host = dev->se_hba->hba_ptr; 224 int ret; 225 226 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) { 227 pr_debug("Missing rd_pages= parameter\n"); 228 return -EINVAL; 229 } 230 231 ret = rd_build_device_space(rd_dev); 232 if (ret < 0) 233 goto fail; 234 235 dev->dev_attrib.hw_block_size = RD_BLOCKSIZE; 236 dev->dev_attrib.hw_max_sectors = UINT_MAX; 237 dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH; 238 239 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++; 240 241 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of" 242 " %u pages in %u tables, %lu total bytes\n", 243 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count, 244 rd_dev->sg_table_count, 245 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE)); 246 247 return 0; 248 249 fail: 250 rd_release_device_space(rd_dev); 251 return ret; 252 } 253 254 static void rd_free_device(struct se_device *dev) 255 { 256 struct rd_dev *rd_dev = RD_DEV(dev); 257 258 rd_release_device_space(rd_dev); 259 kfree(rd_dev); 260 } 261 262 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page) 263 { 264 struct rd_dev_sg_table *sg_table; 265 u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE / 266 sizeof(struct scatterlist)); 267 268 i = page / sg_per_table; 269 if (i < rd_dev->sg_table_count) { 270 sg_table = &rd_dev->sg_table_array[i]; 271 if ((sg_table->page_start_offset <= page) && 272 (sg_table->page_end_offset >= page)) 273 return sg_table; 274 } 275 276 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n", 277 page); 278 279 return NULL; 280 } 281 282 static sense_reason_t 283 rd_execute_rw(struct se_cmd *cmd) 284 { 285 struct scatterlist *sgl = cmd->t_data_sg; 286 u32 sgl_nents = cmd->t_data_nents; 287 enum dma_data_direction data_direction = cmd->data_direction; 288 struct se_device *se_dev = cmd->se_dev; 289 struct rd_dev *dev = RD_DEV(se_dev); 290 struct rd_dev_sg_table *table; 291 struct scatterlist *rd_sg; 292 struct sg_mapping_iter m; 293 u32 rd_offset; 294 u32 rd_size; 295 u32 rd_page; 296 u32 src_len; 297 u64 tmp; 298 299 if (dev->rd_flags & RDF_NULLIO) { 300 target_complete_cmd(cmd, SAM_STAT_GOOD); 301 return 0; 302 } 303 304 tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size; 305 rd_offset = do_div(tmp, PAGE_SIZE); 306 rd_page = tmp; 307 rd_size = cmd->data_length; 308 309 table = rd_get_sg_table(dev, rd_page); 310 if (!table) 311 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 312 313 rd_sg = &table->sg_table[rd_page - table->page_start_offset]; 314 315 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n", 316 dev->rd_dev_id, 317 data_direction == DMA_FROM_DEVICE ? "Read" : "Write", 318 cmd->t_task_lba, rd_size, rd_page, rd_offset); 319 320 src_len = PAGE_SIZE - rd_offset; 321 sg_miter_start(&m, sgl, sgl_nents, 322 data_direction == DMA_FROM_DEVICE ? 323 SG_MITER_TO_SG : SG_MITER_FROM_SG); 324 while (rd_size) { 325 u32 len; 326 void *rd_addr; 327 328 sg_miter_next(&m); 329 if (!(u32)m.length) { 330 pr_debug("RD[%u]: invalid sgl %p len %zu\n", 331 dev->rd_dev_id, m.addr, m.length); 332 sg_miter_stop(&m); 333 return TCM_INCORRECT_AMOUNT_OF_DATA; 334 } 335 len = min((u32)m.length, src_len); 336 if (len > rd_size) { 337 pr_debug("RD[%u]: size underrun page %d offset %d " 338 "size %d\n", dev->rd_dev_id, 339 rd_page, rd_offset, rd_size); 340 len = rd_size; 341 } 342 m.consumed = len; 343 344 rd_addr = sg_virt(rd_sg) + rd_offset; 345 346 if (data_direction == DMA_FROM_DEVICE) 347 memcpy(m.addr, rd_addr, len); 348 else 349 memcpy(rd_addr, m.addr, len); 350 351 rd_size -= len; 352 if (!rd_size) 353 continue; 354 355 src_len -= len; 356 if (src_len) { 357 rd_offset += len; 358 continue; 359 } 360 361 /* rd page completed, next one please */ 362 rd_page++; 363 rd_offset = 0; 364 src_len = PAGE_SIZE; 365 if (rd_page <= table->page_end_offset) { 366 rd_sg++; 367 continue; 368 } 369 370 table = rd_get_sg_table(dev, rd_page); 371 if (!table) { 372 sg_miter_stop(&m); 373 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; 374 } 375 376 /* since we increment, the first sg entry is correct */ 377 rd_sg = table->sg_table; 378 } 379 sg_miter_stop(&m); 380 381 target_complete_cmd(cmd, SAM_STAT_GOOD); 382 return 0; 383 } 384 385 enum { 386 Opt_rd_pages, Opt_rd_nullio, Opt_err 387 }; 388 389 static match_table_t tokens = { 390 {Opt_rd_pages, "rd_pages=%d"}, 391 {Opt_rd_nullio, "rd_nullio=%d"}, 392 {Opt_err, NULL} 393 }; 394 395 static ssize_t rd_set_configfs_dev_params(struct se_device *dev, 396 const char *page, ssize_t count) 397 { 398 struct rd_dev *rd_dev = RD_DEV(dev); 399 char *orig, *ptr, *opts; 400 substring_t args[MAX_OPT_ARGS]; 401 int ret = 0, arg, token; 402 403 opts = kstrdup(page, GFP_KERNEL); 404 if (!opts) 405 return -ENOMEM; 406 407 orig = opts; 408 409 while ((ptr = strsep(&opts, ",\n")) != NULL) { 410 if (!*ptr) 411 continue; 412 413 token = match_token(ptr, tokens, args); 414 switch (token) { 415 case Opt_rd_pages: 416 match_int(args, &arg); 417 rd_dev->rd_page_count = arg; 418 pr_debug("RAMDISK: Referencing Page" 419 " Count: %u\n", rd_dev->rd_page_count); 420 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT; 421 break; 422 case Opt_rd_nullio: 423 match_int(args, &arg); 424 if (arg != 1) 425 break; 426 427 pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg); 428 rd_dev->rd_flags |= RDF_NULLIO; 429 break; 430 default: 431 break; 432 } 433 } 434 435 kfree(orig); 436 return (!ret) ? count : ret; 437 } 438 439 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b) 440 { 441 struct rd_dev *rd_dev = RD_DEV(dev); 442 443 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n", 444 rd_dev->rd_dev_id); 445 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu" 446 " SG_table_count: %u nullio: %d\n", rd_dev->rd_page_count, 447 PAGE_SIZE, rd_dev->sg_table_count, 448 !!(rd_dev->rd_flags & RDF_NULLIO)); 449 return bl; 450 } 451 452 static sector_t rd_get_blocks(struct se_device *dev) 453 { 454 struct rd_dev *rd_dev = RD_DEV(dev); 455 456 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) / 457 dev->dev_attrib.block_size) - 1; 458 459 return blocks_long; 460 } 461 462 static struct sbc_ops rd_sbc_ops = { 463 .execute_rw = rd_execute_rw, 464 }; 465 466 static sense_reason_t 467 rd_parse_cdb(struct se_cmd *cmd) 468 { 469 return sbc_parse_cdb(cmd, &rd_sbc_ops); 470 } 471 472 static struct se_subsystem_api rd_mcp_template = { 473 .name = "rd_mcp", 474 .inquiry_prod = "RAMDISK-MCP", 475 .inquiry_rev = RD_MCP_VERSION, 476 .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV, 477 .attach_hba = rd_attach_hba, 478 .detach_hba = rd_detach_hba, 479 .alloc_device = rd_alloc_device, 480 .configure_device = rd_configure_device, 481 .free_device = rd_free_device, 482 .parse_cdb = rd_parse_cdb, 483 .set_configfs_dev_params = rd_set_configfs_dev_params, 484 .show_configfs_dev_params = rd_show_configfs_dev_params, 485 .get_device_type = sbc_get_device_type, 486 .get_blocks = rd_get_blocks, 487 }; 488 489 int __init rd_module_init(void) 490 { 491 int ret; 492 493 ret = transport_subsystem_register(&rd_mcp_template); 494 if (ret < 0) { 495 return ret; 496 } 497 498 return 0; 499 } 500 501 void rd_module_exit(void) 502 { 503 transport_subsystem_release(&rd_mcp_template); 504 } 505