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  * (c) Copyright 2003-2012 RisingTide Systems LLC.
   8  *
   9  * Nicholas A. Bellinger <nab@kernel.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  *
  25  ******************************************************************************/
  26
  27 #include <linux/string.h>
  28 #include <linux/parser.h>
  29 #include <linux/timer.h>
  30 #include <linux/blkdev.h>
  31 #include <linux/slab.h>
  32 #include <linux/spinlock.h>
  33 #include <scsi/scsi.h>
  34 #include <scsi/scsi_host.h>
  35
  36 #include <target/target_core_base.h>
  37 #include <target/target_core_backend.h>
  38
  39 #include "target_core_rd.h"
  40
  41 static inline struct rd_dev *RD_DEV(struct se_device *dev)
  42 {
  43         return container_of(dev, struct rd_dev, dev);
  44 }
  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
 143         /* Don't need backing pages for NULLIO */
 144         if (rd_dev->rd_flags & RDF_NULLIO)
 145                 return 0;
 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 struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
 205 {
 206         struct rd_dev *rd_dev;
 207         struct rd_host *rd_host = hba->hba_ptr;
 208
 209         rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
 210         if (!rd_dev) {
 211                 pr_err("Unable to allocate memory for struct rd_dev\n");
 212                 return NULL;
 213         }
 214
 215         rd_dev->rd_host = rd_host;
 216
 217         return &rd_dev->dev;
 218 }
 219
 220 static int rd_configure_device(struct se_device *dev)
 221 {
 222         struct rd_dev *rd_dev = RD_DEV(dev);
 223         struct rd_host *rd_host = dev->se_hba->hba_ptr;
 224         int ret;
 225
 226         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 227                 pr_debug("Missing rd_pages= parameter\n");
 228                 return -EINVAL;
 229         }
 230
 231         ret = rd_build_device_space(rd_dev);
 232         if (ret < 0)
 233                 goto fail;
 234
 235         dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
 236         dev->dev_attrib.hw_max_sectors = UINT_MAX;
 237         dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 238
 239         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 240
 241         pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
 242                 " %u pages in %u tables, %lu total bytes\n",
 243                 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
 244                 rd_dev->sg_table_count,
 245                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 246
 247         return 0;
 248
 249 fail:
 250         rd_release_device_space(rd_dev);
 251         return ret;
 252 }
 253
 254 static void rd_free_device(struct se_device *dev)
 255 {
 256         struct rd_dev *rd_dev = RD_DEV(dev);
 257
 258         rd_release_device_space(rd_dev);
 259         kfree(rd_dev);
 260 }
 261
 262 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 263 {
 264         struct rd_dev_sg_table *sg_table;
 265         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 266                                 sizeof(struct scatterlist));
 267
 268         i = page / sg_per_table;
 269         if (i < rd_dev->sg_table_count) {
 270                 sg_table = &rd_dev->sg_table_array[i];
 271                 if ((sg_table->page_start_offset <= page) &&
 272                     (sg_table->page_end_offset >= page))
 273                         return sg_table;
 274         }
 275
 276         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 277                         page);
 278
 279         return NULL;
 280 }
 281
 282 static sense_reason_t
 283 rd_execute_rw(struct se_cmd *cmd)
 284 {
 285         struct scatterlist *sgl = cmd->t_data_sg;
 286         u32 sgl_nents = cmd->t_data_nents;
 287         enum dma_data_direction data_direction = cmd->data_direction;
 288         struct se_device *se_dev = cmd->se_dev;
 289         struct rd_dev *dev = RD_DEV(se_dev);
 290         struct rd_dev_sg_table *table;
 291         struct scatterlist *rd_sg;
 292         struct sg_mapping_iter m;
 293         u32 rd_offset;
 294         u32 rd_size;
 295         u32 rd_page;
 296         u32 src_len;
 297         u64 tmp;
 298
 299         if (dev->rd_flags & RDF_NULLIO) {
 300                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 301                 return 0;
 302         }
 303
 304         tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
 305         rd_offset = do_div(tmp, PAGE_SIZE);
 306         rd_page = tmp;
 307         rd_size = cmd->data_length;
 308
 309         table = rd_get_sg_table(dev, rd_page);
 310         if (!table)
 311                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 312
 313         rd_sg = &table->sg_table[rd_page - table->page_start_offset];
 314
 315         pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
 316                         dev->rd_dev_id,
 317                         data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
 318                         cmd->t_task_lba, rd_size, rd_page, rd_offset);
 319
 320         src_len = PAGE_SIZE - rd_offset;
 321         sg_miter_start(&m, sgl, sgl_nents,
 322                         data_direction == DMA_FROM_DEVICE ?
 323                                 SG_MITER_TO_SG : SG_MITER_FROM_SG);
 324         while (rd_size) {
 325                 u32 len;
 326                 void *rd_addr;
 327
 328                 sg_miter_next(&m);
 329                 if (!(u32)m.length) {
 330                         pr_debug("RD[%u]: invalid sgl %p len %zu\n",
 331                                  dev->rd_dev_id, m.addr, m.length);
 332                         sg_miter_stop(&m);
 333                         return TCM_INCORRECT_AMOUNT_OF_DATA;
 334                 }
 335                 len = min((u32)m.length, src_len);
 336                 if (len > rd_size) {
 337                         pr_debug("RD[%u]: size underrun page %d offset %d "
 338                                  "size %d\n", dev->rd_dev_id,
 339                                  rd_page, rd_offset, rd_size);
 340                         len = rd_size;
 341                 }
 342                 m.consumed = len;
 343
 344                 rd_addr = sg_virt(rd_sg) + rd_offset;
 345
 346                 if (data_direction == DMA_FROM_DEVICE)
 347                         memcpy(m.addr, rd_addr, len);
 348                 else
 349                         memcpy(rd_addr, m.addr, len);
 350
 351                 rd_size -= len;
 352                 if (!rd_size)
 353                         continue;
 354
 355                 src_len -= len;
 356                 if (src_len) {
 357                         rd_offset += len;
 358                         continue;
 359                 }
 360
 361                 /* rd page completed, next one please */
 362                 rd_page++;
 363                 rd_offset = 0;
 364                 src_len = PAGE_SIZE;
 365                 if (rd_page <= table->page_end_offset) {
 366                         rd_sg++;
 367                         continue;
 368                 }
 369
 370                 table = rd_get_sg_table(dev, rd_page);
 371                 if (!table) {
 372                         sg_miter_stop(&m);
 373                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 374                 }
 375
 376                 /* since we increment, the first sg entry is correct */
 377                 rd_sg = table->sg_table;
 378         }
 379         sg_miter_stop(&m);
 380
 381         target_complete_cmd(cmd, SAM_STAT_GOOD);
 382         return 0;
 383 }
 384
 385 enum {
 386         Opt_rd_pages, Opt_rd_nullio, Opt_err
 387 };
 388
 389 static match_table_t tokens = {
 390         {Opt_rd_pages, "rd_pages=%d"},
 391         {Opt_rd_nullio, "rd_nullio=%d"},
 392         {Opt_err, NULL}
 393 };
 394
 395 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
 396                 const char *page, ssize_t count)
 397 {
 398         struct rd_dev *rd_dev = RD_DEV(dev);
 399         char *orig, *ptr, *opts;
 400         substring_t args[MAX_OPT_ARGS];
 401         int ret = 0, arg, token;
 402
 403         opts = kstrdup(page, GFP_KERNEL);
 404         if (!opts)
 405                 return -ENOMEM;
 406
 407         orig = opts;
 408
 409         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 410                 if (!*ptr)
 411                         continue;
 412
 413                 token = match_token(ptr, tokens, args);
 414                 switch (token) {
 415                 case Opt_rd_pages:
 416                         match_int(args, &arg);
 417                         rd_dev->rd_page_count = arg;
 418                         pr_debug("RAMDISK: Referencing Page"
 419                                 " Count: %u\n", rd_dev->rd_page_count);
 420                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 421                         break;
 422                 case Opt_rd_nullio:
 423                         match_int(args, &arg);
 424                         if (arg != 1)
 425                                 break;
 426
 427                         pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
 428                         rd_dev->rd_flags |= RDF_NULLIO;
 429                         break;
 430                 default:
 431                         break;
 432                 }
 433         }
 434
 435         kfree(orig);
 436         return (!ret) ? count : ret;
 437 }
 438
 439 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
 440 {
 441         struct rd_dev *rd_dev = RD_DEV(dev);
 442
 443         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
 444                         rd_dev->rd_dev_id);
 445         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 446                         "  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
 447                         PAGE_SIZE, rd_dev->sg_table_count,
 448                         !!(rd_dev->rd_flags & RDF_NULLIO));
 449         return bl;
 450 }
 451
 452 static sector_t rd_get_blocks(struct se_device *dev)
 453 {
 454         struct rd_dev *rd_dev = RD_DEV(dev);
 455
 456         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 457                         dev->dev_attrib.block_size) - 1;
 458
 459         return blocks_long;
 460 }
 461
 462 static struct sbc_ops rd_sbc_ops = {
 463         .execute_rw             = rd_execute_rw,
 464 };
 465
 466 static sense_reason_t
 467 rd_parse_cdb(struct se_cmd *cmd)
 468 {
 469         return sbc_parse_cdb(cmd, &rd_sbc_ops);
 470 }
 471
 472 static struct se_subsystem_api rd_mcp_template = {
 473         .name                   = "rd_mcp",
 474         .inquiry_prod           = "RAMDISK-MCP",
 475         .inquiry_rev            = RD_MCP_VERSION,
 476         .transport_type         = TRANSPORT_PLUGIN_VHBA_VDEV,
 477         .attach_hba             = rd_attach_hba,
 478         .detach_hba             = rd_detach_hba,
 479         .alloc_device           = rd_alloc_device,
 480         .configure_device       = rd_configure_device,
 481         .free_device            = rd_free_device,
 482         .parse_cdb              = rd_parse_cdb,
 483         .set_configfs_dev_params = rd_set_configfs_dev_params,
 484         .show_configfs_dev_params = rd_show_configfs_dev_params,
 485         .get_device_type        = sbc_get_device_type,
 486         .get_blocks             = rd_get_blocks,
 487 };
 488
 489 int __init rd_module_init(void)
 490 {
 491         int ret;
 492
 493         ret = transport_subsystem_register(&rd_mcp_template);
 494         if (ret < 0) {
 495                 return ret;
 496         }
 497
 498         return 0;
 499 }
 500
 501 void rd_module_exit(void)
 502 {
 503         transport_subsystem_release(&rd_mcp_template);
 504 }