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_device.h>
  41 #include <target/target_core_transport.h>
  42 #include <target/target_core_fabric_ops.h>
  43
  44 #include "target_core_rd.h"
  45
  46 static struct se_subsystem_api rd_mcp_template;
  47
  48 /*      rd_attach_hba(): (Part of se_subsystem_api_t template)
  49  *
  50  *
  51  */
  52 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
  53 {
  54         struct rd_host *rd_host;
  55
  56         rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
  57         if (!rd_host) {
  58                 pr_err("Unable to allocate memory for struct rd_host\n");
  59                 return -ENOMEM;
  60         }
  61
  62         rd_host->rd_host_id = host_id;
  63
  64         hba->hba_ptr = rd_host;
  65
  66         pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
  67                 " Generic Target Core Stack %s\n", hba->hba_id,
  68                 RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
  69         pr_debug("CORE_HBA[%d] - Attached Ramdisk HBA: %u to Generic"
  70                 " MaxSectors: %u\n", hba->hba_id,
  71                 rd_host->rd_host_id, RD_MAX_SECTORS);
  72
  73         return 0;
  74 }
  75
  76 static void rd_detach_hba(struct se_hba *hba)
  77 {
  78         struct rd_host *rd_host = hba->hba_ptr;
  79
  80         pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
  81                 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
  82
  83         kfree(rd_host);
  84         hba->hba_ptr = NULL;
  85 }
  86
  87 /*      rd_release_device_space():
  88  *
  89  *
  90  */
  91 static void rd_release_device_space(struct rd_dev *rd_dev)
  92 {
  93         u32 i, j, page_count = 0, sg_per_table;
  94         struct rd_dev_sg_table *sg_table;
  95         struct page *pg;
  96         struct scatterlist *sg;
  97
  98         if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
  99                 return;
 100
 101         sg_table = rd_dev->sg_table_array;
 102
 103         for (i = 0; i < rd_dev->sg_table_count; i++) {
 104                 sg = sg_table[i].sg_table;
 105                 sg_per_table = sg_table[i].rd_sg_count;
 106
 107                 for (j = 0; j < sg_per_table; j++) {
 108                         pg = sg_page(&sg[j]);
 109                         if (pg) {
 110                                 __free_page(pg);
 111                                 page_count++;
 112                         }
 113                 }
 114
 115                 kfree(sg);
 116         }
 117
 118         pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
 119                 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
 120                 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
 121                 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 122
 123         kfree(sg_table);
 124         rd_dev->sg_table_array = NULL;
 125         rd_dev->sg_table_count = 0;
 126 }
 127
 128
 129 /*      rd_build_device_space():
 130  *
 131  *
 132  */
 133 static int rd_build_device_space(struct rd_dev *rd_dev)
 134 {
 135         u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
 136         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 137                                 sizeof(struct scatterlist));
 138         struct rd_dev_sg_table *sg_table;
 139         struct page *pg;
 140         struct scatterlist *sg;
 141
 142         if (rd_dev->rd_page_count <= 0) {
 143                 pr_err("Illegal page count: %u for Ramdisk device\n",
 144                         rd_dev->rd_page_count);
 145                 return -EINVAL;
 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 void *rd_allocate_virtdevice(
 205         struct se_hba *hba,
 206         const char *name,
 207         int rd_direct)
 208 {
 209         struct rd_dev *rd_dev;
 210         struct rd_host *rd_host = hba->hba_ptr;
 211
 212         rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
 213         if (!rd_dev) {
 214                 pr_err("Unable to allocate memory for struct rd_dev\n");
 215                 return NULL;
 216         }
 217
 218         rd_dev->rd_host = rd_host;
 219         rd_dev->rd_direct = rd_direct;
 220
 221         return rd_dev;
 222 }
 223
 224 static void *rd_MEMCPY_allocate_virtdevice(struct se_hba *hba, const char *name)
 225 {
 226         return rd_allocate_virtdevice(hba, name, 0);
 227 }
 228
 229 /*      rd_create_virtdevice():
 230  *
 231  *
 232  */
 233 static struct se_device *rd_create_virtdevice(
 234         struct se_hba *hba,
 235         struct se_subsystem_dev *se_dev,
 236         void *p,
 237         int rd_direct)
 238 {
 239         struct se_device *dev;
 240         struct se_dev_limits dev_limits;
 241         struct rd_dev *rd_dev = p;
 242         struct rd_host *rd_host = hba->hba_ptr;
 243         int dev_flags = 0, ret;
 244         char prod[16], rev[4];
 245
 246         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 247
 248         ret = rd_build_device_space(rd_dev);
 249         if (ret < 0)
 250                 goto fail;
 251
 252         snprintf(prod, 16, "RAMDISK-%s", (rd_dev->rd_direct) ? "DR" : "MCP");
 253         snprintf(rev, 4, "%s", (rd_dev->rd_direct) ? RD_DR_VERSION :
 254                                                 RD_MCP_VERSION);
 255
 256         dev_limits.limits.logical_block_size = RD_BLOCKSIZE;
 257         dev_limits.limits.max_hw_sectors = RD_MAX_SECTORS;
 258         dev_limits.limits.max_sectors = RD_MAX_SECTORS;
 259         dev_limits.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 260         dev_limits.queue_depth = RD_DEVICE_QUEUE_DEPTH;
 261
 262         dev = transport_add_device_to_core_hba(hba,
 263                         &rd_mcp_template, se_dev, dev_flags, rd_dev,
 264                         &dev_limits, prod, rev);
 265         if (!dev)
 266                 goto fail;
 267
 268         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 269         rd_dev->rd_queue_depth = dev->queue_depth;
 270
 271         pr_debug("CORE_RD[%u] - Added TCM %s Ramdisk Device ID: %u of"
 272                 " %u pages in %u tables, %lu total bytes\n",
 273                 rd_host->rd_host_id, (!rd_dev->rd_direct) ? "MEMCPY" :
 274                 "DIRECT", rd_dev->rd_dev_id, rd_dev->rd_page_count,
 275                 rd_dev->sg_table_count,
 276                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 277
 278         return dev;
 279
 280 fail:
 281         rd_release_device_space(rd_dev);
 282         return ERR_PTR(ret);
 283 }
 284
 285 static struct se_device *rd_MEMCPY_create_virtdevice(
 286         struct se_hba *hba,
 287         struct se_subsystem_dev *se_dev,
 288         void *p)
 289 {
 290         return rd_create_virtdevice(hba, se_dev, p, 0);
 291 }
 292
 293 /*      rd_free_device(): (Part of se_subsystem_api_t template)
 294  *
 295  *
 296  */
 297 static void rd_free_device(void *p)
 298 {
 299         struct rd_dev *rd_dev = p;
 300
 301         rd_release_device_space(rd_dev);
 302         kfree(rd_dev);
 303 }
 304
 305 static inline struct rd_request *RD_REQ(struct se_task *task)
 306 {
 307         return container_of(task, struct rd_request, rd_task);
 308 }
 309
 310 static struct se_task *
 311 rd_alloc_task(unsigned char *cdb)
 312 {
 313         struct rd_request *rd_req;
 314
 315         rd_req = kzalloc(sizeof(struct rd_request), GFP_KERNEL);
 316         if (!rd_req) {
 317                 pr_err("Unable to allocate struct rd_request\n");
 318                 return NULL;
 319         }
 320
 321         return &rd_req->rd_task;
 322 }
 323
 324 /*      rd_get_sg_table():
 325  *
 326  *
 327  */
 328 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 329 {
 330         u32 i;
 331         struct rd_dev_sg_table *sg_table;
 332
 333         for (i = 0; i < rd_dev->sg_table_count; i++) {
 334                 sg_table = &rd_dev->sg_table_array[i];
 335                 if ((sg_table->page_start_offset <= page) &&
 336                     (sg_table->page_end_offset >= page))
 337                         return sg_table;
 338         }
 339
 340         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 341                         page);
 342
 343         return NULL;
 344 }
 345
 346 static int rd_MEMCPY(struct rd_request *req, u32 read_rd)
 347 {
 348         struct se_task *task = &req->rd_task;
 349         struct rd_dev *dev = req->rd_task.task_se_cmd->se_dev->dev_ptr;
 350         struct rd_dev_sg_table *table;
 351         struct scatterlist *rd_sg;
 352         struct sg_mapping_iter m;
 353         u32 rd_offset = req->rd_offset;
 354         u32 src_len;
 355
 356         table = rd_get_sg_table(dev, req->rd_page);
 357         if (!table)
 358                 return -EINVAL;
 359
 360         rd_sg = &table->sg_table[req->rd_page - table->page_start_offset];
 361
 362         pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
 363                         dev->rd_dev_id, read_rd ? "Read" : "Write",
 364                         task->task_lba, req->rd_size, req->rd_page,
 365                         rd_offset);
 366
 367         src_len = PAGE_SIZE - rd_offset;
 368         sg_miter_start(&m, task->task_sg, task->task_sg_nents,
 369                         read_rd ? SG_MITER_TO_SG : SG_MITER_FROM_SG);
 370         while (req->rd_size) {
 371                 u32 len;
 372                 void *rd_addr;
 373
 374                 sg_miter_next(&m);
 375                 len = min((u32)m.length, src_len);
 376                 m.consumed = len;
 377
 378                 rd_addr = sg_virt(rd_sg) + rd_offset;
 379
 380                 if (read_rd)
 381                         memcpy(m.addr, rd_addr, len);
 382                 else
 383                         memcpy(rd_addr, m.addr, len);
 384
 385                 req->rd_size -= len;
 386                 if (!req->rd_size)
 387                         continue;
 388
 389                 src_len -= len;
 390                 if (src_len) {
 391                         rd_offset += len;
 392                         continue;
 393                 }
 394
 395                 /* rd page completed, next one please */
 396                 req->rd_page++;
 397                 rd_offset = 0;
 398                 src_len = PAGE_SIZE;
 399                 if (req->rd_page <= table->page_end_offset) {
 400                         rd_sg++;
 401                         continue;
 402                 }
 403
 404                 table = rd_get_sg_table(dev, req->rd_page);
 405                 if (!table) {
 406                         sg_miter_stop(&m);
 407                         return -EINVAL;
 408                 }
 409
 410                 /* since we increment, the first sg entry is correct */
 411                 rd_sg = table->sg_table;
 412         }
 413         sg_miter_stop(&m);
 414         return 0;
 415 }
 416
 417 /*      rd_MEMCPY_do_task(): (Part of se_subsystem_api_t template)
 418  *
 419  *
 420  */
 421 static int rd_MEMCPY_do_task(struct se_task *task)
 422 {
 423         struct se_device *dev = task->task_se_cmd->se_dev;
 424         struct rd_request *req = RD_REQ(task);
 425         u64 tmp;
 426         int ret;
 427
 428         tmp = task->task_lba * dev->se_sub_dev->se_dev_attrib.block_size;
 429         req->rd_offset = do_div(tmp, PAGE_SIZE);
 430         req->rd_page = tmp;
 431         req->rd_size = task->task_size;
 432
 433         ret = rd_MEMCPY(req, task->task_data_direction == DMA_FROM_DEVICE);
 434         if (ret != 0)
 435                 return ret;
 436
 437         task->task_scsi_status = GOOD;
 438         transport_complete_task(task, 1);
 439         return 0;
 440 }
 441
 442 /*      rd_free_task(): (Part of se_subsystem_api_t template)
 443  *
 444  *
 445  */
 446 static void rd_free_task(struct se_task *task)
 447 {
 448         kfree(RD_REQ(task));
 449 }
 450
 451 enum {
 452         Opt_rd_pages, Opt_err
 453 };
 454
 455 static match_table_t tokens = {
 456         {Opt_rd_pages, "rd_pages=%d"},
 457         {Opt_err, NULL}
 458 };
 459
 460 static ssize_t rd_set_configfs_dev_params(
 461         struct se_hba *hba,
 462         struct se_subsystem_dev *se_dev,
 463         const char *page,
 464         ssize_t count)
 465 {
 466         struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
 467         char *orig, *ptr, *opts;
 468         substring_t args[MAX_OPT_ARGS];
 469         int ret = 0, arg, token;
 470
 471         opts = kstrdup(page, GFP_KERNEL);
 472         if (!opts)
 473                 return -ENOMEM;
 474
 475         orig = opts;
 476
 477         while ((ptr = strsep(&opts, ",")) != NULL) {
 478                 if (!*ptr)
 479                         continue;
 480
 481                 token = match_token(ptr, tokens, args);
 482                 switch (token) {
 483                 case Opt_rd_pages:
 484                         match_int(args, &arg);
 485                         rd_dev->rd_page_count = arg;
 486                         pr_debug("RAMDISK: Referencing Page"
 487                                 " Count: %u\n", rd_dev->rd_page_count);
 488                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 489                         break;
 490                 default:
 491                         break;
 492                 }
 493         }
 494
 495         kfree(orig);
 496         return (!ret) ? count : ret;
 497 }
 498
 499 static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
 500 {
 501         struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
 502
 503         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 504                 pr_debug("Missing rd_pages= parameter\n");
 505                 return -EINVAL;
 506         }
 507
 508         return 0;
 509 }
 510
 511 static ssize_t rd_show_configfs_dev_params(
 512         struct se_hba *hba,
 513         struct se_subsystem_dev *se_dev,
 514         char *b)
 515 {
 516         struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
 517         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: %s\n",
 518                         rd_dev->rd_dev_id, (rd_dev->rd_direct) ?
 519                         "rd_direct" : "rd_mcp");
 520         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 521                         "  SG_table_count: %u\n", rd_dev->rd_page_count,
 522                         PAGE_SIZE, rd_dev->sg_table_count);
 523         return bl;
 524 }
 525
 526 static u32 rd_get_device_rev(struct se_device *dev)
 527 {
 528         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 529 }
 530
 531 static u32 rd_get_device_type(struct se_device *dev)
 532 {
 533         return TYPE_DISK;
 534 }
 535
 536 static sector_t rd_get_blocks(struct se_device *dev)
 537 {
 538         struct rd_dev *rd_dev = dev->dev_ptr;
 539         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 540                         dev->se_sub_dev->se_dev_attrib.block_size) - 1;
 541
 542         return blocks_long;
 543 }
 544
 545 static struct se_subsystem_api rd_mcp_template = {
 546         .name                   = "rd_mcp",
 547         .transport_type         = TRANSPORT_PLUGIN_VHBA_VDEV,
 548         .attach_hba             = rd_attach_hba,
 549         .detach_hba             = rd_detach_hba,
 550         .allocate_virtdevice    = rd_MEMCPY_allocate_virtdevice,
 551         .create_virtdevice      = rd_MEMCPY_create_virtdevice,
 552         .free_device            = rd_free_device,
 553         .alloc_task             = rd_alloc_task,
 554         .do_task                = rd_MEMCPY_do_task,
 555         .free_task              = rd_free_task,
 556         .check_configfs_dev_params = rd_check_configfs_dev_params,
 557         .set_configfs_dev_params = rd_set_configfs_dev_params,
 558         .show_configfs_dev_params = rd_show_configfs_dev_params,
 559         .get_device_rev         = rd_get_device_rev,
 560         .get_device_type        = rd_get_device_type,
 561         .get_blocks             = rd_get_blocks,
 562 };
 563
 564 int __init rd_module_init(void)
 565 {
 566         int ret;
 567
 568         ret = transport_subsystem_register(&rd_mcp_template);
 569         if (ret < 0) {
 570                 return ret;
 571         }
 572
 573         return 0;
 574 }
 575
 576 void rd_module_exit(void)
 577 {
 578         transport_subsystem_release(&rd_mcp_template);
 579 }