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 2003-2013 Datera, Inc.
   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/slab.h>
  31 #include <linux/spinlock.h>
  32 #include <scsi/scsi.h>
  33 #include <scsi/scsi_host.h>
  34
  35 #include <target/target_core_base.h>
  36 #include <target/target_core_backend.h>
  37
  38 #include "target_core_rd.h"
  39
  40 static inline struct rd_dev *RD_DEV(struct se_device *dev)
  41 {
  42         return container_of(dev, struct rd_dev, dev);
  43 }
  44
  45 /*      rd_attach_hba(): (Part of se_subsystem_api_t template)
  46  *
  47  *
  48  */
  49 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
  50 {
  51         struct rd_host *rd_host;
  52
  53         rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
  54         if (!rd_host) {
  55                 pr_err("Unable to allocate memory for struct rd_host\n");
  56                 return -ENOMEM;
  57         }
  58
  59         rd_host->rd_host_id = host_id;
  60
  61         hba->hba_ptr = rd_host;
  62
  63         pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
  64                 " Generic Target Core Stack %s\n", hba->hba_id,
  65                 RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
  66
  67         return 0;
  68 }
  69
  70 static void rd_detach_hba(struct se_hba *hba)
  71 {
  72         struct rd_host *rd_host = hba->hba_ptr;
  73
  74         pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
  75                 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
  76
  77         kfree(rd_host);
  78         hba->hba_ptr = NULL;
  79 }
  80
  81 /*      rd_release_device_space():
  82  *
  83  *
  84  */
  85 static void rd_release_device_space(struct rd_dev *rd_dev)
  86 {
  87         u32 i, j, page_count = 0, sg_per_table;
  88         struct rd_dev_sg_table *sg_table;
  89         struct page *pg;
  90         struct scatterlist *sg;
  91
  92         if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
  93                 return;
  94
  95         sg_table = rd_dev->sg_table_array;
  96
  97         for (i = 0; i < rd_dev->sg_table_count; i++) {
  98                 sg = sg_table[i].sg_table;
  99                 sg_per_table = sg_table[i].rd_sg_count;
 100
 101                 for (j = 0; j < sg_per_table; j++) {
 102                         pg = sg_page(&sg[j]);
 103                         if (pg) {
 104                                 __free_page(pg);
 105                                 page_count++;
 106                         }
 107                 }
 108
 109                 kfree(sg);
 110         }
 111
 112         pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
 113                 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
 114                 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
 115                 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 116
 117         kfree(sg_table);
 118         rd_dev->sg_table_array = NULL;
 119         rd_dev->sg_table_count = 0;
 120 }
 121
 122
 123 /*      rd_build_device_space():
 124  *
 125  *
 126  */
 127 static int rd_build_device_space(struct rd_dev *rd_dev)
 128 {
 129         u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
 130         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 131                                 sizeof(struct scatterlist));
 132         struct rd_dev_sg_table *sg_table;
 133         struct page *pg;
 134         struct scatterlist *sg;
 135
 136         if (rd_dev->rd_page_count <= 0) {
 137                 pr_err("Illegal page count: %u for Ramdisk device\n",
 138                         rd_dev->rd_page_count);
 139                 return -EINVAL;
 140         }
 141
 142         /* Don't need backing pages for NULLIO */
 143         if (rd_dev->rd_flags & RDF_NULLIO)
 144                 return 0;
 145
 146         total_sg_needed = rd_dev->rd_page_count;
 147
 148         sg_tables = (total_sg_needed / max_sg_per_table) + 1;
 149
 150         sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
 151         if (!sg_table) {
 152                 pr_err("Unable to allocate memory for Ramdisk"
 153                         " scatterlist tables\n");
 154                 return -ENOMEM;
 155         }
 156
 157         rd_dev->sg_table_array = sg_table;
 158         rd_dev->sg_table_count = sg_tables;
 159
 160         while (total_sg_needed) {
 161                 sg_per_table = (total_sg_needed > max_sg_per_table) ?
 162                         max_sg_per_table : total_sg_needed;
 163
 164                 sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
 165                                 GFP_KERNEL);
 166                 if (!sg) {
 167                         pr_err("Unable to allocate scatterlist array"
 168                                 " for struct rd_dev\n");
 169                         return -ENOMEM;
 170                 }
 171
 172                 sg_init_table(sg, sg_per_table);
 173
 174                 sg_table[i].sg_table = sg;
 175                 sg_table[i].rd_sg_count = sg_per_table;
 176                 sg_table[i].page_start_offset = page_offset;
 177                 sg_table[i++].page_end_offset = (page_offset + sg_per_table)
 178                                                 - 1;
 179
 180                 for (j = 0; j < sg_per_table; j++) {
 181                         pg = alloc_pages(GFP_KERNEL, 0);
 182                         if (!pg) {
 183                                 pr_err("Unable to allocate scatterlist"
 184                                         " pages for struct rd_dev_sg_table\n");
 185                                 return -ENOMEM;
 186                         }
 187                         sg_assign_page(&sg[j], pg);
 188                         sg[j].length = PAGE_SIZE;
 189                 }
 190
 191                 page_offset += sg_per_table;
 192                 total_sg_needed -= sg_per_table;
 193         }
 194
 195         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
 196                 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
 197                 rd_dev->rd_dev_id, rd_dev->rd_page_count,
 198                 rd_dev->sg_table_count);
 199
 200         return 0;
 201 }
 202
 203 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
 204 {
 205         struct rd_dev *rd_dev;
 206         struct rd_host *rd_host = hba->hba_ptr;
 207
 208         rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
 209         if (!rd_dev) {
 210                 pr_err("Unable to allocate memory for struct rd_dev\n");
 211                 return NULL;
 212         }
 213
 214         rd_dev->rd_host = rd_host;
 215
 216         return &rd_dev->dev;
 217 }
 218
 219 static int rd_configure_device(struct se_device *dev)
 220 {
 221         struct rd_dev *rd_dev = RD_DEV(dev);
 222         struct rd_host *rd_host = dev->se_hba->hba_ptr;
 223         int ret;
 224
 225         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 226                 pr_debug("Missing rd_pages= parameter\n");
 227                 return -EINVAL;
 228         }
 229
 230         ret = rd_build_device_space(rd_dev);
 231         if (ret < 0)
 232                 goto fail;
 233
 234         dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
 235         dev->dev_attrib.hw_max_sectors = UINT_MAX;
 236         dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 237
 238         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 239
 240         pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
 241                 " %u pages in %u tables, %lu total bytes\n",
 242                 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
 243                 rd_dev->sg_table_count,
 244                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 245
 246         return 0;
 247
 248 fail:
 249         rd_release_device_space(rd_dev);
 250         return ret;
 251 }
 252
 253 static void rd_free_device(struct se_device *dev)
 254 {
 255         struct rd_dev *rd_dev = RD_DEV(dev);
 256
 257         rd_release_device_space(rd_dev);
 258         kfree(rd_dev);
 259 }
 260
 261 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 262 {
 263         struct rd_dev_sg_table *sg_table;
 264         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 265                                 sizeof(struct scatterlist));
 266
 267         i = page / sg_per_table;
 268         if (i < rd_dev->sg_table_count) {
 269                 sg_table = &rd_dev->sg_table_array[i];
 270                 if ((sg_table->page_start_offset <= page) &&
 271                     (sg_table->page_end_offset >= page))
 272                         return sg_table;
 273         }
 274
 275         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 276                         page);
 277
 278         return NULL;
 279 }
 280
 281 static sense_reason_t
 282 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 283               enum dma_data_direction data_direction)
 284 {
 285         struct se_device *se_dev = cmd->se_dev;
 286         struct rd_dev *dev = RD_DEV(se_dev);
 287         struct rd_dev_sg_table *table;
 288         struct scatterlist *rd_sg;
 289         struct sg_mapping_iter m;
 290         u32 rd_offset;
 291         u32 rd_size;
 292         u32 rd_page;
 293         u32 src_len;
 294         u64 tmp;
 295
 296         if (dev->rd_flags & RDF_NULLIO) {
 297                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 298                 return 0;
 299         }
 300
 301         tmp = cmd->t_task_lba * se_dev->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 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 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                 if (!(u32)m.length) {
 327                         pr_debug("RD[%u]: invalid sgl %p len %zu\n",
 328                                  dev->rd_dev_id, m.addr, m.length);
 329                         sg_miter_stop(&m);
 330                         return TCM_INCORRECT_AMOUNT_OF_DATA;
 331                 }
 332                 len = min((u32)m.length, src_len);
 333                 if (len > rd_size) {
 334                         pr_debug("RD[%u]: size underrun page %d offset %d "
 335                                  "size %d\n", dev->rd_dev_id,
 336                                  rd_page, rd_offset, rd_size);
 337                         len = rd_size;
 338                 }
 339                 m.consumed = len;
 340
 341                 rd_addr = sg_virt(rd_sg) + rd_offset;
 342
 343                 if (data_direction == DMA_FROM_DEVICE)
 344                         memcpy(m.addr, rd_addr, len);
 345                 else
 346                         memcpy(rd_addr, m.addr, len);
 347
 348                 rd_size -= len;
 349                 if (!rd_size)
 350                         continue;
 351
 352                 src_len -= len;
 353                 if (src_len) {
 354                         rd_offset += len;
 355                         continue;
 356                 }
 357
 358                 /* rd page completed, next one please */
 359                 rd_page++;
 360                 rd_offset = 0;
 361                 src_len = PAGE_SIZE;
 362                 if (rd_page <= table->page_end_offset) {
 363                         rd_sg++;
 364                         continue;
 365                 }
 366
 367                 table = rd_get_sg_table(dev, rd_page);
 368                 if (!table) {
 369                         sg_miter_stop(&m);
 370                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 371                 }
 372
 373                 /* since we increment, the first sg entry is correct */
 374                 rd_sg = table->sg_table;
 375         }
 376         sg_miter_stop(&m);
 377
 378         target_complete_cmd(cmd, SAM_STAT_GOOD);
 379         return 0;
 380 }
 381
 382 enum {
 383         Opt_rd_pages, Opt_rd_nullio, Opt_err
 384 };
 385
 386 static match_table_t tokens = {
 387         {Opt_rd_pages, "rd_pages=%d"},
 388         {Opt_rd_nullio, "rd_nullio=%d"},
 389         {Opt_err, NULL}
 390 };
 391
 392 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
 393                 const char *page, ssize_t count)
 394 {
 395         struct rd_dev *rd_dev = RD_DEV(dev);
 396         char *orig, *ptr, *opts;
 397         substring_t args[MAX_OPT_ARGS];
 398         int ret = 0, arg, token;
 399
 400         opts = kstrdup(page, GFP_KERNEL);
 401         if (!opts)
 402                 return -ENOMEM;
 403
 404         orig = opts;
 405
 406         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 407                 if (!*ptr)
 408                         continue;
 409
 410                 token = match_token(ptr, tokens, args);
 411                 switch (token) {
 412                 case Opt_rd_pages:
 413                         match_int(args, &arg);
 414                         rd_dev->rd_page_count = arg;
 415                         pr_debug("RAMDISK: Referencing Page"
 416                                 " Count: %u\n", rd_dev->rd_page_count);
 417                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 418                         break;
 419                 case Opt_rd_nullio:
 420                         match_int(args, &arg);
 421                         if (arg != 1)
 422                                 break;
 423
 424                         pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
 425                         rd_dev->rd_flags |= RDF_NULLIO;
 426                         break;
 427                 default:
 428                         break;
 429                 }
 430         }
 431
 432         kfree(orig);
 433         return (!ret) ? count : ret;
 434 }
 435
 436 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
 437 {
 438         struct rd_dev *rd_dev = RD_DEV(dev);
 439
 440         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
 441                         rd_dev->rd_dev_id);
 442         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 443                         "  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
 444                         PAGE_SIZE, rd_dev->sg_table_count,
 445                         !!(rd_dev->rd_flags & RDF_NULLIO));
 446         return bl;
 447 }
 448
 449 static sector_t rd_get_blocks(struct se_device *dev)
 450 {
 451         struct rd_dev *rd_dev = RD_DEV(dev);
 452
 453         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 454                         dev->dev_attrib.block_size) - 1;
 455
 456         return blocks_long;
 457 }
 458
 459 static struct sbc_ops rd_sbc_ops = {
 460         .execute_rw             = rd_execute_rw,
 461 };
 462
 463 static sense_reason_t
 464 rd_parse_cdb(struct se_cmd *cmd)
 465 {
 466         return sbc_parse_cdb(cmd, &rd_sbc_ops);
 467 }
 468
 469 static struct se_subsystem_api rd_mcp_template = {
 470         .name                   = "rd_mcp",
 471         .inquiry_prod           = "RAMDISK-MCP",
 472         .inquiry_rev            = RD_MCP_VERSION,
 473         .transport_type         = TRANSPORT_PLUGIN_VHBA_VDEV,
 474         .attach_hba             = rd_attach_hba,
 475         .detach_hba             = rd_detach_hba,
 476         .alloc_device           = rd_alloc_device,
 477         .configure_device       = rd_configure_device,
 478         .free_device            = rd_free_device,
 479         .parse_cdb              = rd_parse_cdb,
 480         .set_configfs_dev_params = rd_set_configfs_dev_params,
 481         .show_configfs_dev_params = rd_show_configfs_dev_params,
 482         .get_device_type        = sbc_get_device_type,
 483         .get_blocks             = rd_get_blocks,
 484 };
 485
 486 int __init rd_module_init(void)
 487 {
 488         int ret;
 489
 490         ret = transport_subsystem_register(&rd_mcp_template);
 491         if (ret < 0) {
 492                 return ret;
 493         }
 494
 495         return 0;
 496 }
 497
 498 void rd_module_exit(void)
 499 {
 500         transport_subsystem_release(&rd_mcp_template);
 501 }