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