drivers/target/target_core_rd.c

   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         pr_debug("CORE_HBA[%d] - Attached Ramdisk HBA: %u to Generic"
  68                 " MaxSectors: %u\n", hba->hba_id,
  69                 rd_host->rd_host_id, RD_MAX_SECTORS);
  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 void *rd_allocate_virtdevice(
 203         struct se_hba *hba,
 204         const char *name,
 205         int rd_direct)
 206 {
 207         struct rd_dev *rd_dev;
 208         struct rd_host *rd_host = hba->hba_ptr;
 209
 210         rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
 211         if (!rd_dev) {
 212                 pr_err("Unable to allocate memory for struct rd_dev\n");
 213                 return NULL;
 214         }
 215
 216         rd_dev->rd_host = rd_host;
 217         rd_dev->rd_direct = rd_direct;
 218
 219         return rd_dev;
 220 }
 221
 222 static void *rd_MEMCPY_allocate_virtdevice(struct se_hba *hba, const char *name)
 223 {
 224         return rd_allocate_virtdevice(hba, name, 0);
 225 }
 226
 227 /*      rd_create_virtdevice():
 228  *
 229  *
 230  */
 231 static struct se_device *rd_create_virtdevice(
 232         struct se_hba *hba,
 233         struct se_subsystem_dev *se_dev,
 234         void *p,
 235         int rd_direct)
 236 {
 237         struct se_device *dev;
 238         struct se_dev_limits dev_limits;
 239         struct rd_dev *rd_dev = p;
 240         struct rd_host *rd_host = hba->hba_ptr;
 241         int dev_flags = 0, ret;
 242         char prod[16], rev[4];
 243
 244         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 245
 246         ret = rd_build_device_space(rd_dev);
 247         if (ret < 0)
 248                 goto fail;
 249
 250         snprintf(prod, 16, "RAMDISK-%s", (rd_dev->rd_direct) ? "DR" : "MCP");
 251         snprintf(rev, 4, "%s", (rd_dev->rd_direct) ? RD_DR_VERSION :
 252                                                 RD_MCP_VERSION);
 253
 254         dev_limits.limits.logical_block_size = RD_BLOCKSIZE;
 255         dev_limits.limits.max_hw_sectors = RD_MAX_SECTORS;
 256         dev_limits.limits.max_sectors = RD_MAX_SECTORS;
 257         dev_limits.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 258         dev_limits.queue_depth = RD_DEVICE_QUEUE_DEPTH;
 259
 260         dev = transport_add_device_to_core_hba(hba,
 261                         &rd_mcp_template, se_dev, dev_flags, rd_dev,
 262                         &dev_limits, prod, rev);
 263         if (!dev)
 264                 goto fail;
 265
 266         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 267         rd_dev->rd_queue_depth = dev->queue_depth;
 268
 269         pr_debug("CORE_RD[%u] - Added TCM %s Ramdisk Device ID: %u of"
 270                 " %u pages in %u tables, %lu total bytes\n",
 271                 rd_host->rd_host_id, (!rd_dev->rd_direct) ? "MEMCPY" :
 272                 "DIRECT", rd_dev->rd_dev_id, rd_dev->rd_page_count,
 273                 rd_dev->sg_table_count,
 274                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 275
 276         return dev;
 277
 278 fail:
 279         rd_release_device_space(rd_dev);
 280         return ERR_PTR(ret);
 281 }
 282
 283 static struct se_device *rd_MEMCPY_create_virtdevice(
 284         struct se_hba *hba,
 285         struct se_subsystem_dev *se_dev,
 286         void *p)
 287 {
 288         return rd_create_virtdevice(hba, se_dev, p, 0);
 289 }
 290
 291 /*      rd_free_device(): (Part of se_subsystem_api_t template)
 292  *
 293  *
 294  */
 295 static void rd_free_device(void *p)
 296 {
 297         struct rd_dev *rd_dev = p;
 298
 299         rd_release_device_space(rd_dev);
 300         kfree(rd_dev);
 301 }
 302
 303 static inline struct rd_request *RD_REQ(struct se_task *task)
 304 {
 305         return container_of(task, struct rd_request, rd_task);
 306 }
 307
 308 static struct se_task *
 309 rd_alloc_task(unsigned char *cdb)
 310 {
 311         struct rd_request *rd_req;
 312
 313         rd_req = kzalloc(sizeof(struct rd_request), GFP_KERNEL);
 314         if (!rd_req) {
 315                 pr_err("Unable to allocate struct rd_request\n");
 316                 return NULL;
 317         }
 318
 319         return &rd_req->rd_task;
 320 }
 321
 322 /*      rd_get_sg_table():
 323  *
 324  *
 325  */
 326 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 327 {
 328         u32 i;
 329         struct rd_dev_sg_table *sg_table;
 330
 331         for (i = 0; i < rd_dev->sg_table_count; i++) {
 332                 sg_table = &rd_dev->sg_table_array[i];
 333                 if ((sg_table->page_start_offset <= page) &&
 334                     (sg_table->page_end_offset >= page))
 335                         return sg_table;
 336         }
 337
 338         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 339                         page);
 340
 341         return NULL;
 342 }
 343
 344 static int rd_MEMCPY(struct rd_request *req, u32 read_rd)
 345 {
 346         struct se_task *task = &req->rd_task;
 347         struct rd_dev *dev = req->rd_task.task_se_cmd->se_dev->dev_ptr;
 348         struct rd_dev_sg_table *table;
 349         struct scatterlist *rd_sg;
 350         struct sg_mapping_iter m;
 351         u32 rd_offset = req->rd_offset;
 352         u32 src_len;
 353
 354         table = rd_get_sg_table(dev, req->rd_page);
 355         if (!table)
 356                 return -EINVAL;
 357
 358         rd_sg = &table->sg_table[req->rd_page - table->page_start_offset];
 359
 360         pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
 361                         dev->rd_dev_id, read_rd ? "Read" : "Write",
 362                         task->task_lba, req->rd_size, req->rd_page,
 363                         rd_offset);
 364
 365         src_len = PAGE_SIZE - rd_offset;
 366         sg_miter_start(&m, task->task_sg, task->task_sg_nents,
 367                         read_rd ? SG_MITER_TO_SG : SG_MITER_FROM_SG);
 368         while (req->rd_size) {
 369                 u32 len;
 370                 void *rd_addr;
 371
 372                 sg_miter_next(&m);
 373                 len = min((u32)m.length, src_len);
 374                 m.consumed = len;
 375
 376                 rd_addr = sg_virt(rd_sg) + rd_offset;
 377
 378                 if (read_rd)
 379                         memcpy(m.addr, rd_addr, len);
 380                 else
 381                         memcpy(rd_addr, m.addr, len);
 382
 383                 req->rd_size -= len;
 384                 if (!req->rd_size)
 385                         continue;
 386
 387                 src_len -= len;
 388                 if (src_len) {
 389                         rd_offset += len;
 390                         continue;
 391                 }
 392
 393                 /* rd page completed, next one please */
 394                 req->rd_page++;
 395                 rd_offset = 0;
 396                 src_len = PAGE_SIZE;
 397                 if (req->rd_page <= table->page_end_offset) {
 398                         rd_sg++;
 399                         continue;
 400                 }
 401
 402                 table = rd_get_sg_table(dev, req->rd_page);
 403                 if (!table) {
 404                         sg_miter_stop(&m);
 405                         return -EINVAL;
 406                 }
 407
 408                 /* since we increment, the first sg entry is correct */
 409                 rd_sg = table->sg_table;
 410         }
 411         sg_miter_stop(&m);
 412         return 0;
 413 }
 414
 415 /*      rd_MEMCPY_do_task(): (Part of se_subsystem_api_t template)
 416  *
 417  *
 418  */
 419 static int rd_MEMCPY_do_task(struct se_task *task)
 420 {
 421         struct se_device *dev = task->task_se_cmd->se_dev;
 422         struct rd_request *req = RD_REQ(task);
 423         u64 tmp;
 424         int ret;
 425
 426         tmp = task->task_lba * dev->se_sub_dev->se_dev_attrib.block_size;
 427         req->rd_offset = do_div(tmp, PAGE_SIZE);
 428         req->rd_page = tmp;
 429         req->rd_size = task->task_size;
 430
 431         ret = rd_MEMCPY(req, task->task_data_direction == DMA_FROM_DEVICE);
 432         if (ret != 0)
 433                 return ret;
 434
 435         task->task_scsi_status = GOOD;
 436         transport_complete_task(task, 1);
 437         return 0;
 438 }
 439
 440 /*      rd_free_task(): (Part of se_subsystem_api_t template)
 441  *
 442  *
 443  */
 444 static void rd_free_task(struct se_task *task)
 445 {
 446         kfree(RD_REQ(task));
 447 }
 448
 449 enum {
 450         Opt_rd_pages, Opt_err
 451 };
 452
 453 static match_table_t tokens = {
 454         {Opt_rd_pages, "rd_pages=%d"},
 455         {Opt_err, NULL}
 456 };
 457
 458 static ssize_t rd_set_configfs_dev_params(
 459         struct se_hba *hba,
 460         struct se_subsystem_dev *se_dev,
 461         const char *page,
 462         ssize_t count)
 463 {
 464         struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
 465         char *orig, *ptr, *opts;
 466         substring_t args[MAX_OPT_ARGS];
 467         int ret = 0, arg, token;
 468
 469         opts = kstrdup(page, GFP_KERNEL);
 470         if (!opts)
 471                 return -ENOMEM;
 472
 473         orig = opts;
 474
 475         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 476                 if (!*ptr)
 477                         continue;
 478
 479                 token = match_token(ptr, tokens, args);
 480                 switch (token) {
 481                 case Opt_rd_pages:
 482                         match_int(args, &arg);
 483                         rd_dev->rd_page_count = arg;
 484                         pr_debug("RAMDISK: Referencing Page"
 485                                 " Count: %u\n", rd_dev->rd_page_count);
 486                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 487                         break;
 488                 default:
 489                         break;
 490                 }
 491         }
 492
 493         kfree(orig);
 494         return (!ret) ? count : ret;
 495 }
 496
 497 static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
 498 {
 499         struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
 500
 501         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 502                 pr_debug("Missing rd_pages= parameter\n");
 503                 return -EINVAL;
 504         }
 505
 506         return 0;
 507 }
 508
 509 static ssize_t rd_show_configfs_dev_params(
 510         struct se_hba *hba,
 511         struct se_subsystem_dev *se_dev,
 512         char *b)
 513 {
 514         struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
 515         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: %s\n",
 516                         rd_dev->rd_dev_id, (rd_dev->rd_direct) ?
 517                         "rd_direct" : "rd_mcp");
 518         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 519                         "  SG_table_count: %u\n", rd_dev->rd_page_count,
 520                         PAGE_SIZE, rd_dev->sg_table_count);
 521         return bl;
 522 }
 523
 524 static u32 rd_get_device_rev(struct se_device *dev)
 525 {
 526         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 527 }
 528
 529 static u32 rd_get_device_type(struct se_device *dev)
 530 {
 531         return TYPE_DISK;
 532 }
 533
 534 static sector_t rd_get_blocks(struct se_device *dev)
 535 {
 536         struct rd_dev *rd_dev = dev->dev_ptr;
 537         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 538                         dev->se_sub_dev->se_dev_attrib.block_size) - 1;
 539
 540         return blocks_long;
 541 }
 542
 543 static struct se_subsystem_api rd_mcp_template = {
 544         .name                   = "rd_mcp",
 545         .transport_type         = TRANSPORT_PLUGIN_VHBA_VDEV,
 546         .attach_hba             = rd_attach_hba,
 547         .detach_hba             = rd_detach_hba,
 548         .allocate_virtdevice    = rd_MEMCPY_allocate_virtdevice,
 549         .create_virtdevice      = rd_MEMCPY_create_virtdevice,
 550         .free_device            = rd_free_device,
 551         .alloc_task             = rd_alloc_task,
 552         .do_task                = rd_MEMCPY_do_task,
 553         .free_task              = rd_free_task,
 554         .check_configfs_dev_params = rd_check_configfs_dev_params,
 555         .set_configfs_dev_params = rd_set_configfs_dev_params,
 556         .show_configfs_dev_params = rd_show_configfs_dev_params,
 557         .get_device_rev         = rd_get_device_rev,
 558         .get_device_type        = rd_get_device_type,
 559         .get_blocks             = rd_get_blocks,
 560 };
 561
 562 int __init rd_module_init(void)
 563 {
 564         int ret;
 565
 566         ret = transport_subsystem_register(&rd_mcp_template);
 567         if (ret < 0) {
 568                 return ret;
 569         }
 570
 571         return 0;
 572 }
 573
 574 void rd_module_exit(void)
 575 {
 576         transport_subsystem_release(&rd_mcp_template);
 577 }