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 struct se_subsystem_api rd_mcp_template; 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 total_sg_needed = rd_dev->rd_page_count; 143 144 sg_tables = (total_sg_needed / max_sg_per_table) + 1; 145 146 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL); 147 if (!sg_table) { 148 pr_err("Unable to allocate memory for Ramdisk" 149 " scatterlist tables\n"); 150 return -ENOMEM; 151 } 152 153 rd_dev->sg_table_array = sg_table; 154 rd_dev->sg_table_count = sg_tables; 155 156 while (total_sg_needed) { 157 sg_per_table = (total_sg_needed > max_sg_per_table) ? 158 max_sg_per_table : total_sg_needed; 159 160 sg = kzalloc(sg_per_table * sizeof(struct scatterlist), 161 GFP_KERNEL); 162 if (!sg) { 163 pr_err("Unable to allocate scatterlist array" 164 " for struct rd_dev\n"); 165 return -ENOMEM; 166 } 167 168 sg_init_table(sg, sg_per_table); 169 170 sg_table[i].sg_table = sg; 171 sg_table[i].rd_sg_count = sg_per_table; 172 sg_table[i].page_start_offset = page_offset; 173 sg_table[i++].page_end_offset = (page_offset + sg_per_table) 174 - 1; 175 176 for (j = 0; j < sg_per_table; j++) { 177 pg = alloc_pages(GFP_KERNEL, 0); 178 if (!pg) { 179 pr_err("Unable to allocate scatterlist" 180 " pages for struct rd_dev_sg_table\n"); 181 return -ENOMEM; 182 } 183 sg_assign_page(&sg[j], pg); 184 sg[j].length = PAGE_SIZE; 185 } 186 187 page_offset += sg_per_table; 188 total_sg_needed -= sg_per_table; 189 } 190 191 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of" 192 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id, 193 rd_dev->rd_dev_id, rd_dev->rd_page_count, 194 rd_dev->sg_table_count); 195 196 return 0; 197 } 198 199 static void *rd_allocate_virtdevice(struct se_hba *hba, const char *name) 200 { 201 struct rd_dev *rd_dev; 202 struct rd_host *rd_host = hba->hba_ptr; 203 204 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL); 205 if (!rd_dev) { 206 pr_err("Unable to allocate memory for struct rd_dev\n"); 207 return NULL; 208 } 209 210 rd_dev->rd_host = rd_host; 211 212 return rd_dev; 213 } 214 215 static struct se_device *rd_create_virtdevice(struct se_hba *hba, 216 struct se_subsystem_dev *se_dev, void *p) 217 { 218 struct se_device *dev; 219 struct se_dev_limits dev_limits; 220 struct rd_dev *rd_dev = p; 221 struct rd_host *rd_host = hba->hba_ptr; 222 int dev_flags = 0, ret; 223 char prod[16], rev[4]; 224 225 memset(&dev_limits, 0, sizeof(struct se_dev_limits)); 226 227 ret = rd_build_device_space(rd_dev); 228 if (ret < 0) 229 goto fail; 230 231 snprintf(prod, 16, "RAMDISK-MCP"); 232 snprintf(rev, 4, "%s", RD_MCP_VERSION); 233 234 dev_limits.limits.logical_block_size = RD_BLOCKSIZE; 235 dev_limits.limits.max_hw_sectors = UINT_MAX; 236 dev_limits.limits.max_sectors = UINT_MAX; 237 dev_limits.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH; 238 dev_limits.queue_depth = RD_DEVICE_QUEUE_DEPTH; 239 240 dev = transport_add_device_to_core_hba(hba, 241 &rd_mcp_template, se_dev, dev_flags, rd_dev, 242 &dev_limits, prod, rev); 243 if (!dev) 244 goto fail; 245 246 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++; 247 248 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of" 249 " %u pages in %u tables, %lu total bytes\n", 250 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count, 251 rd_dev->sg_table_count, 252 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE)); 253 254 return dev; 255 256 fail: 257 rd_release_device_space(rd_dev); 258 return ERR_PTR(ret); 259 } 260 261 static void rd_free_device(void *p) 262 { 263 struct rd_dev *rd_dev = p; 264 265 rd_release_device_space(rd_dev); 266 kfree(rd_dev); 267 } 268 269 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page) 270 { 271 u32 i; 272 struct rd_dev_sg_table *sg_table; 273 274 for (i = 0; i < rd_dev->sg_table_count; i++) { 275 sg_table = &rd_dev->sg_table_array[i]; 276 if ((sg_table->page_start_offset <= page) && 277 (sg_table->page_end_offset >= page)) 278 return sg_table; 279 } 280 281 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n", 282 page); 283 284 return NULL; 285 } 286 287 static int rd_execute_cmd(struct se_cmd *cmd, struct scatterlist *sgl, 288 u32 sgl_nents, enum dma_data_direction data_direction) 289 { 290 struct se_device *se_dev = cmd->se_dev; 291 struct rd_dev *dev = se_dev->dev_ptr; 292 struct rd_dev_sg_table *table; 293 struct scatterlist *rd_sg; 294 struct sg_mapping_iter m; 295 u32 rd_offset; 296 u32 rd_size; 297 u32 rd_page; 298 u32 src_len; 299 u64 tmp; 300 301 tmp = cmd->t_task_lba * se_dev->se_sub_dev->se_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 -EINVAL; 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 len = min((u32)m.length, src_len); 327 m.consumed = len; 328 329 rd_addr = sg_virt(rd_sg) + rd_offset; 330 331 if (data_direction == DMA_FROM_DEVICE) 332 memcpy(m.addr, rd_addr, len); 333 else 334 memcpy(rd_addr, m.addr, len); 335 336 rd_size -= len; 337 if (!rd_size) 338 continue; 339 340 src_len -= len; 341 if (src_len) { 342 rd_offset += len; 343 continue; 344 } 345 346 /* rd page completed, next one please */ 347 rd_page++; 348 rd_offset = 0; 349 src_len = PAGE_SIZE; 350 if (rd_page <= table->page_end_offset) { 351 rd_sg++; 352 continue; 353 } 354 355 table = rd_get_sg_table(dev, rd_page); 356 if (!table) { 357 sg_miter_stop(&m); 358 return -EINVAL; 359 } 360 361 /* since we increment, the first sg entry is correct */ 362 rd_sg = table->sg_table; 363 } 364 sg_miter_stop(&m); 365 366 target_complete_cmd(cmd, SAM_STAT_GOOD); 367 return 0; 368 } 369 370 enum { 371 Opt_rd_pages, Opt_err 372 }; 373 374 static match_table_t tokens = { 375 {Opt_rd_pages, "rd_pages=%d"}, 376 {Opt_err, NULL} 377 }; 378 379 static ssize_t rd_set_configfs_dev_params( 380 struct se_hba *hba, 381 struct se_subsystem_dev *se_dev, 382 const char *page, 383 ssize_t count) 384 { 385 struct rd_dev *rd_dev = se_dev->se_dev_su_ptr; 386 char *orig, *ptr, *opts; 387 substring_t args[MAX_OPT_ARGS]; 388 int ret = 0, arg, token; 389 390 opts = kstrdup(page, GFP_KERNEL); 391 if (!opts) 392 return -ENOMEM; 393 394 orig = opts; 395 396 while ((ptr = strsep(&opts, ",\n")) != NULL) { 397 if (!*ptr) 398 continue; 399 400 token = match_token(ptr, tokens, args); 401 switch (token) { 402 case Opt_rd_pages: 403 match_int(args, &arg); 404 rd_dev->rd_page_count = arg; 405 pr_debug("RAMDISK: Referencing Page" 406 " Count: %u\n", rd_dev->rd_page_count); 407 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT; 408 break; 409 default: 410 break; 411 } 412 } 413 414 kfree(orig); 415 return (!ret) ? count : ret; 416 } 417 418 static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev) 419 { 420 struct rd_dev *rd_dev = se_dev->se_dev_su_ptr; 421 422 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) { 423 pr_debug("Missing rd_pages= parameter\n"); 424 return -EINVAL; 425 } 426 427 return 0; 428 } 429 430 static ssize_t rd_show_configfs_dev_params( 431 struct se_hba *hba, 432 struct se_subsystem_dev *se_dev, 433 char *b) 434 { 435 struct rd_dev *rd_dev = se_dev->se_dev_su_ptr; 436 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n", 437 rd_dev->rd_dev_id); 438 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu" 439 " SG_table_count: %u\n", rd_dev->rd_page_count, 440 PAGE_SIZE, rd_dev->sg_table_count); 441 return bl; 442 } 443 444 static u32 rd_get_device_rev(struct se_device *dev) 445 { 446 return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */ 447 } 448 449 static u32 rd_get_device_type(struct se_device *dev) 450 { 451 return TYPE_DISK; 452 } 453 454 static sector_t rd_get_blocks(struct se_device *dev) 455 { 456 struct rd_dev *rd_dev = dev->dev_ptr; 457 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) / 458 dev->se_sub_dev->se_dev_attrib.block_size) - 1; 459 460 return blocks_long; 461 } 462 463 static struct se_subsystem_api rd_mcp_template = { 464 .name = "rd_mcp", 465 .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV, 466 .attach_hba = rd_attach_hba, 467 .detach_hba = rd_detach_hba, 468 .allocate_virtdevice = rd_allocate_virtdevice, 469 .create_virtdevice = rd_create_virtdevice, 470 .free_device = rd_free_device, 471 .execute_cmd = rd_execute_cmd, 472 .check_configfs_dev_params = rd_check_configfs_dev_params, 473 .set_configfs_dev_params = rd_set_configfs_dev_params, 474 .show_configfs_dev_params = rd_show_configfs_dev_params, 475 .get_device_rev = rd_get_device_rev, 476 .get_device_type = rd_get_device_type, 477 .get_blocks = rd_get_blocks, 478 }; 479 480 int __init rd_module_init(void) 481 { 482 int ret; 483 484 ret = transport_subsystem_register(&rd_mcp_template); 485 if (ret < 0) { 486 return ret; 487 } 488 489 return 0; 490 } 491 492 void rd_module_exit(void) 493 { 494 transport_subsystem_release(&rd_mcp_template); 495 } 496