1 /******************************************************************************* 2 * Filename: target_core_rd.c 3 * 4 * This file contains the Storage Engine <-> Ramdisk transport 5 * specific functions. 6 * 7 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc. 8 * Copyright (c) 2005, 2006, 2007 SBE, Inc. 9 * Copyright (c) 2007-2010 Rising Tide Systems 10 * Copyright (c) 2008-2010 Linux-iSCSI.org 11 * 12 * Nicholas A. Bellinger <nab@kernel.org> 13 * 14 * This program is free software; you can redistribute it and/or modify 15 * it under the terms of the GNU General Public License as published by 16 * the Free Software Foundation; either version 2 of the License, or 17 * (at your option) any later version. 18 * 19 * This program is distributed in the hope that it will be useful, 20 * but WITHOUT ANY WARRANTY; without even the implied warranty of 21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 22 * GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with this program; if not, write to the Free Software 26 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 27 * 28 ******************************************************************************/ 29 30 #include <linux/string.h> 31 #include <linux/parser.h> 32 #include <linux/timer.h> 33 #include <linux/blkdev.h> 34 #include <linux/slab.h> 35 #include <linux/spinlock.h> 36 #include <scsi/scsi.h> 37 #include <scsi/scsi_host.h> 38 39 #include <target/target_core_base.h> 40 #include <target/target_core_backend.h> 41 42 #include "target_core_rd.h" 43 44 static inline struct rd_dev *RD_DEV(struct se_device *dev) 45 { 46 return container_of(dev, struct rd_dev, dev); 47 } 48 49 /* rd_attach_hba(): (Part of se_subsystem_api_t template) 50 * 51 * 52 */ 53 static int rd_attach_hba(struct se_hba *hba, u32 host_id) 54 { 55 struct rd_host *rd_host; 56 57 rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL); 58 if (!rd_host) { 59 pr_err("Unable to allocate memory for struct rd_host\n"); 60 return -ENOMEM; 61 } 62 63 rd_host->rd_host_id = host_id; 64 65 hba->hba_ptr = rd_host; 66 67 pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on" 68 " Generic Target Core Stack %s\n", hba->hba_id, 69 RD_HBA_VERSION, TARGET_CORE_MOD_VERSION); 70 71 return 0; 72 } 73 74 static void rd_detach_hba(struct se_hba *hba) 75 { 76 struct rd_host *rd_host = hba->hba_ptr; 77 78 pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from" 79 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id); 80 81 kfree(rd_host); 82 hba->hba_ptr = NULL; 83 } 84 85 /* rd_release_device_space(): 86 * 87 * 88 */ 89 static void rd_release_device_space(struct rd_dev *rd_dev) 90 { 91 u32 i, j, page_count = 0, sg_per_table; 92 struct rd_dev_sg_table *sg_table; 93 struct page *pg; 94 struct scatterlist *sg; 95 96 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count) 97 return; 98 99 sg_table = rd_dev->sg_table_array; 100 101 for (i = 0; i < rd_dev->sg_table_count; i++) { 102 sg = sg_table[i].sg_table; 103 sg_per_table = sg_table[i].rd_sg_count; 104 105 for (j = 0; j < sg_per_table; j++) { 106 pg = sg_page(&sg[j]); 107 if (pg) { 108 __free_page(pg); 109 page_count++; 110 } 111 } 112 113 kfree(sg); 114 } 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 kfree(sg_table); 122 rd_dev->sg_table_array = NULL; 123 rd_dev->sg_table_count = 0; 124 } 125 126 127 /* rd_build_device_space(): 128 * 129 * 130 */ 131 static int rd_build_device_space(struct rd_dev *rd_dev) 132 { 133 u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed; 134 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE / 135 sizeof(struct scatterlist)); 136 struct rd_dev_sg_table *sg_table; 137 struct page *pg; 138 struct scatterlist *sg; 139 140 if (rd_dev->rd_page_count <= 0) { 141 pr_err("Illegal page count: %u for Ramdisk device\n", 142 rd_dev->rd_page_count); 143 return -EINVAL; 144 } 145 total_sg_needed = rd_dev->rd_page_count; 146 147 sg_tables = (total_sg_needed / max_sg_per_table) + 1; 148 149 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL); 150 if (!sg_table) { 151 pr_err("Unable to allocate memory for Ramdisk" 152 " scatterlist tables\n"); 153 return -ENOMEM; 154 } 155 156 rd_dev->sg_table_array = sg_table; 157 rd_dev->sg_table_count = sg_tables; 158 159 while (total_sg_needed) { 160 sg_per_table = (total_sg_needed > max_sg_per_table) ? 161 max_sg_per_table : total_sg_needed; 162 163 sg = kzalloc(sg_per_table * sizeof(struct scatterlist), 164 GFP_KERNEL); 165 if (!sg) { 166 pr_err("Unable to allocate scatterlist array" 167 " for struct rd_dev\n"); 168 return -ENOMEM; 169 } 170 171 sg_init_table(sg, sg_per_table); 172 173 sg_table[i].sg_table = sg; 174 sg_table[i].rd_sg_count = sg_per_table; 175 sg_table[i].page_start_offset = page_offset; 176 sg_table[i++].page_end_offset = (page_offset + sg_per_table) 177 - 1; 178 179 for (j = 0; j < sg_per_table; j++) { 180 pg = alloc_pages(GFP_KERNEL, 0); 181 if (!pg) { 182 pr_err("Unable to allocate scatterlist" 183 " pages for struct rd_dev_sg_table\n"); 184 return -ENOMEM; 185 } 186 sg_assign_page(&sg[j], pg); 187 sg[j].length = PAGE_SIZE; 188 } 189 190 page_offset += sg_per_table; 191 total_sg_needed -= sg_per_table; 192 } 193 194 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of" 195 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id, 196 rd_dev->rd_dev_id, rd_dev->rd_page_count, 197 rd_dev->sg_table_count); 198 199 return 0; 200 } 201 202 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name) 203 { 204 struct rd_dev *rd_dev; 205 struct rd_host *rd_host = hba->hba_ptr; 206 207 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL); 208 if (!rd_dev) { 209 pr_err("Unable to allocate memory for struct rd_dev\n"); 210 return NULL; 211 } 212 213 rd_dev->rd_host = rd_host; 214 215 return &rd_dev->dev; 216 } 217 218 static int rd_configure_device(struct se_device *dev) 219 { 220 struct rd_dev *rd_dev = RD_DEV(dev); 221 struct rd_host *rd_host = dev->se_hba->hba_ptr; 222 int ret; 223 224 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) { 225 pr_debug("Missing rd_pages= parameter\n"); 226 return -EINVAL; 227 } 228 229 ret = rd_build_device_space(rd_dev); 230 if (ret < 0) 231 goto fail; 232 233 dev->dev_attrib.hw_block_size = RD_BLOCKSIZE; 234 dev->dev_attrib.hw_max_sectors = UINT_MAX; 235 dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH; 236 237 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++; 238 239 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of" 240 " %u pages in %u tables, %lu total bytes\n", 241 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count, 242 rd_dev->sg_table_count, 243 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE)); 244 245 return 0; 246 247 fail: 248 rd_release_device_space(rd_dev); 249 return ret; 250 } 251 252 static void rd_free_device(struct se_device *dev) 253 { 254 struct rd_dev *rd_dev = RD_DEV(dev); 255 256 rd_release_device_space(rd_dev); 257 kfree(rd_dev); 258 } 259 260 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page) 261 { 262 u32 i; 263 struct rd_dev_sg_table *sg_table; 264 265 for (i = 0; i < rd_dev->sg_table_count; i++) { 266 sg_table = &rd_dev->sg_table_array[i]; 267 if ((sg_table->page_start_offset <= page) && 268 (sg_table->page_end_offset >= page)) 269 return sg_table; 270 } 271 272 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n", 273 page); 274 275 return NULL; 276 } 277 278 static int rd_execute_rw(struct se_cmd *cmd) 279 { 280 struct scatterlist *sgl = cmd->t_data_sg; 281 u32 sgl_nents = cmd->t_data_nents; 282 enum dma_data_direction data_direction = cmd->data_direction; 283 struct se_device *se_dev = cmd->se_dev; 284 struct rd_dev *dev = RD_DEV(se_dev); 285 struct rd_dev_sg_table *table; 286 struct scatterlist *rd_sg; 287 struct sg_mapping_iter m; 288 u32 rd_offset; 289 u32 rd_size; 290 u32 rd_page; 291 u32 src_len; 292 u64 tmp; 293 294 tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size; 295 rd_offset = do_div(tmp, PAGE_SIZE); 296 rd_page = tmp; 297 rd_size = cmd->data_length; 298 299 table = rd_get_sg_table(dev, rd_page); 300 if (!table) 301 return -EINVAL; 302 303 rd_sg = &table->sg_table[rd_page - table->page_start_offset]; 304 305 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n", 306 dev->rd_dev_id, 307 data_direction == DMA_FROM_DEVICE ? "Read" : "Write", 308 cmd->t_task_lba, rd_size, rd_page, rd_offset); 309 310 src_len = PAGE_SIZE - rd_offset; 311 sg_miter_start(&m, sgl, sgl_nents, 312 data_direction == DMA_FROM_DEVICE ? 313 SG_MITER_TO_SG : SG_MITER_FROM_SG); 314 while (rd_size) { 315 u32 len; 316 void *rd_addr; 317 318 sg_miter_next(&m); 319 len = min((u32)m.length, src_len); 320 m.consumed = len; 321 322 rd_addr = sg_virt(rd_sg) + rd_offset; 323 324 if (data_direction == DMA_FROM_DEVICE) 325 memcpy(m.addr, rd_addr, len); 326 else 327 memcpy(rd_addr, m.addr, len); 328 329 rd_size -= len; 330 if (!rd_size) 331 continue; 332 333 src_len -= len; 334 if (src_len) { 335 rd_offset += len; 336 continue; 337 } 338 339 /* rd page completed, next one please */ 340 rd_page++; 341 rd_offset = 0; 342 src_len = PAGE_SIZE; 343 if (rd_page <= table->page_end_offset) { 344 rd_sg++; 345 continue; 346 } 347 348 table = rd_get_sg_table(dev, rd_page); 349 if (!table) { 350 sg_miter_stop(&m); 351 return -EINVAL; 352 } 353 354 /* since we increment, the first sg entry is correct */ 355 rd_sg = table->sg_table; 356 } 357 sg_miter_stop(&m); 358 359 target_complete_cmd(cmd, SAM_STAT_GOOD); 360 return 0; 361 } 362 363 enum { 364 Opt_rd_pages, Opt_err 365 }; 366 367 static match_table_t tokens = { 368 {Opt_rd_pages, "rd_pages=%d"}, 369 {Opt_err, NULL} 370 }; 371 372 static ssize_t rd_set_configfs_dev_params(struct se_device *dev, 373 const char *page, ssize_t count) 374 { 375 struct rd_dev *rd_dev = RD_DEV(dev); 376 char *orig, *ptr, *opts; 377 substring_t args[MAX_OPT_ARGS]; 378 int ret = 0, arg, token; 379 380 opts = kstrdup(page, GFP_KERNEL); 381 if (!opts) 382 return -ENOMEM; 383 384 orig = opts; 385 386 while ((ptr = strsep(&opts, ",\n")) != NULL) { 387 if (!*ptr) 388 continue; 389 390 token = match_token(ptr, tokens, args); 391 switch (token) { 392 case Opt_rd_pages: 393 match_int(args, &arg); 394 rd_dev->rd_page_count = arg; 395 pr_debug("RAMDISK: Referencing Page" 396 " Count: %u\n", rd_dev->rd_page_count); 397 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT; 398 break; 399 default: 400 break; 401 } 402 } 403 404 kfree(orig); 405 return (!ret) ? count : ret; 406 } 407 408 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b) 409 { 410 struct rd_dev *rd_dev = RD_DEV(dev); 411 412 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n", 413 rd_dev->rd_dev_id); 414 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu" 415 " SG_table_count: %u\n", rd_dev->rd_page_count, 416 PAGE_SIZE, rd_dev->sg_table_count); 417 return bl; 418 } 419 420 static u32 rd_get_device_rev(struct se_device *dev) 421 { 422 return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */ 423 } 424 425 static u32 rd_get_device_type(struct se_device *dev) 426 { 427 return TYPE_DISK; 428 } 429 430 static sector_t rd_get_blocks(struct se_device *dev) 431 { 432 struct rd_dev *rd_dev = RD_DEV(dev); 433 434 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) / 435 dev->dev_attrib.block_size) - 1; 436 437 return blocks_long; 438 } 439 440 static struct spc_ops rd_spc_ops = { 441 .execute_rw = rd_execute_rw, 442 }; 443 444 static int rd_parse_cdb(struct se_cmd *cmd) 445 { 446 return sbc_parse_cdb(cmd, &rd_spc_ops); 447 } 448 449 static struct se_subsystem_api rd_mcp_template = { 450 .name = "rd_mcp", 451 .inquiry_prod = "RAMDISK-MCP", 452 .inquiry_rev = RD_MCP_VERSION, 453 .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV, 454 .attach_hba = rd_attach_hba, 455 .detach_hba = rd_detach_hba, 456 .alloc_device = rd_alloc_device, 457 .configure_device = rd_configure_device, 458 .free_device = rd_free_device, 459 .parse_cdb = rd_parse_cdb, 460 .set_configfs_dev_params = rd_set_configfs_dev_params, 461 .show_configfs_dev_params = rd_show_configfs_dev_params, 462 .get_device_rev = rd_get_device_rev, 463 .get_device_type = rd_get_device_type, 464 .get_blocks = rd_get_blocks, 465 }; 466 467 int __init rd_module_init(void) 468 { 469 int ret; 470 471 ret = transport_subsystem_register(&rd_mcp_template); 472 if (ret < 0) { 473 return ret; 474 } 475 476 return 0; 477 } 478 479 void rd_module_exit(void) 480 { 481 transport_subsystem_release(&rd_mcp_template); 482 } 483