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 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 sbc_ops rd_sbc_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_sbc_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 }