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 static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
  82                                  u32 sg_table_count)
  83 {
  84         struct page *pg;
  85         struct scatterlist *sg;
  86         u32 i, j, page_count = 0, sg_per_table;
  87
  88         for (i = 0; i < sg_table_count; i++) {
  89                 sg = sg_table[i].sg_table;
  90                 sg_per_table = sg_table[i].rd_sg_count;
  91
  92                 for (j = 0; j < sg_per_table; j++) {
  93                         pg = sg_page(&sg[j]);
  94                         if (pg) {
  95                                 __free_page(pg);
  96                                 page_count++;
  97                         }
  98                 }
  99                 kfree(sg);
 100         }
 101
 102         kfree(sg_table);
 103         return page_count;
 104 }
 105
 106 static void rd_release_device_space(struct rd_dev *rd_dev)
 107 {
 108         u32 page_count;
 109
 110         if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
 111                 return;
 112
 113         page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
 114                                           rd_dev->sg_table_count);
 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         rd_dev->sg_table_array = NULL;
 122         rd_dev->sg_table_count = 0;
 123 }
 124
 125
 126 /*      rd_build_device_space():
 127  *
 128  *
 129  */
 130 static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
 131                                  u32 total_sg_needed, unsigned char init_payload)
 132 {
 133         u32 i = 0, j, page_offset = 0, sg_per_table;
 134         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 135                                 sizeof(struct scatterlist));
 136         struct page *pg;
 137         struct scatterlist *sg;
 138         unsigned char *p;
 139
 140         while (total_sg_needed) {
 141                 sg_per_table = (total_sg_needed > max_sg_per_table) ?
 142                         max_sg_per_table : total_sg_needed;
 143
 144                 sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
 145                                 GFP_KERNEL);
 146                 if (!sg) {
 147                         pr_err("Unable to allocate scatterlist array"
 148                                 " for struct rd_dev\n");
 149                         return -ENOMEM;
 150                 }
 151
 152                 sg_init_table(sg, sg_per_table);
 153
 154                 sg_table[i].sg_table = sg;
 155                 sg_table[i].rd_sg_count = sg_per_table;
 156                 sg_table[i].page_start_offset = page_offset;
 157                 sg_table[i++].page_end_offset = (page_offset + sg_per_table)
 158                                                 - 1;
 159
 160                 for (j = 0; j < sg_per_table; j++) {
 161                         pg = alloc_pages(GFP_KERNEL, 0);
 162                         if (!pg) {
 163                                 pr_err("Unable to allocate scatterlist"
 164                                         " pages for struct rd_dev_sg_table\n");
 165                                 return -ENOMEM;
 166                         }
 167                         sg_assign_page(&sg[j], pg);
 168                         sg[j].length = PAGE_SIZE;
 169
 170                         p = kmap(pg);
 171                         memset(p, init_payload, PAGE_SIZE);
 172                         kunmap(pg);
 173                 }
 174
 175                 page_offset += sg_per_table;
 176                 total_sg_needed -= sg_per_table;
 177         }
 178
 179         return 0;
 180 }
 181
 182 static int rd_build_device_space(struct rd_dev *rd_dev)
 183 {
 184         struct rd_dev_sg_table *sg_table;
 185         u32 sg_tables, total_sg_needed;
 186         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 187                                 sizeof(struct scatterlist));
 188         int rc;
 189
 190         if (rd_dev->rd_page_count <= 0) {
 191                 pr_err("Illegal page count: %u for Ramdisk device\n",
 192                        rd_dev->rd_page_count);
 193                 return -EINVAL;
 194         }
 195
 196         /* Don't need backing pages for NULLIO */
 197         if (rd_dev->rd_flags & RDF_NULLIO)
 198                 return 0;
 199
 200         total_sg_needed = rd_dev->rd_page_count;
 201
 202         sg_tables = (total_sg_needed / max_sg_per_table) + 1;
 203
 204         sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
 205         if (!sg_table) {
 206                 pr_err("Unable to allocate memory for Ramdisk"
 207                        " scatterlist tables\n");
 208                 return -ENOMEM;
 209         }
 210
 211         rd_dev->sg_table_array = sg_table;
 212         rd_dev->sg_table_count = sg_tables;
 213
 214         rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
 215         if (rc)
 216                 return rc;
 217
 218         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
 219                  " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
 220                  rd_dev->rd_dev_id, rd_dev->rd_page_count,
 221                  rd_dev->sg_table_count);
 222
 223         return 0;
 224 }
 225
 226 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
 227 {
 228         struct rd_dev *rd_dev;
 229         struct rd_host *rd_host = hba->hba_ptr;
 230
 231         rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
 232         if (!rd_dev) {
 233                 pr_err("Unable to allocate memory for struct rd_dev\n");
 234                 return NULL;
 235         }
 236
 237         rd_dev->rd_host = rd_host;
 238
 239         return &rd_dev->dev;
 240 }
 241
 242 static int rd_configure_device(struct se_device *dev)
 243 {
 244         struct rd_dev *rd_dev = RD_DEV(dev);
 245         struct rd_host *rd_host = dev->se_hba->hba_ptr;
 246         int ret;
 247
 248         if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
 249                 pr_debug("Missing rd_pages= parameter\n");
 250                 return -EINVAL;
 251         }
 252
 253         ret = rd_build_device_space(rd_dev);
 254         if (ret < 0)
 255                 goto fail;
 256
 257         dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
 258         dev->dev_attrib.hw_max_sectors = UINT_MAX;
 259         dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
 260
 261         rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
 262
 263         pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
 264                 " %u pages in %u tables, %lu total bytes\n",
 265                 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
 266                 rd_dev->sg_table_count,
 267                 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
 268
 269         return 0;
 270
 271 fail:
 272         rd_release_device_space(rd_dev);
 273         return ret;
 274 }
 275
 276 static void rd_free_device(struct se_device *dev)
 277 {
 278         struct rd_dev *rd_dev = RD_DEV(dev);
 279
 280         rd_release_device_space(rd_dev);
 281         kfree(rd_dev);
 282 }
 283
 284 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
 285 {
 286         struct rd_dev_sg_table *sg_table;
 287         u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
 288                                 sizeof(struct scatterlist));
 289
 290         i = page / sg_per_table;
 291         if (i < rd_dev->sg_table_count) {
 292                 sg_table = &rd_dev->sg_table_array[i];
 293                 if ((sg_table->page_start_offset <= page) &&
 294                     (sg_table->page_end_offset >= page))
 295                         return sg_table;
 296         }
 297
 298         pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
 299                         page);
 300
 301         return NULL;
 302 }
 303
 304 static sense_reason_t
 305 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 306               enum dma_data_direction data_direction)
 307 {
 308         struct se_device *se_dev = cmd->se_dev;
 309         struct rd_dev *dev = RD_DEV(se_dev);
 310         struct rd_dev_sg_table *table;
 311         struct scatterlist *rd_sg;
 312         struct sg_mapping_iter m;
 313         u32 rd_offset;
 314         u32 rd_size;
 315         u32 rd_page;
 316         u32 src_len;
 317         u64 tmp;
 318
 319         if (dev->rd_flags & RDF_NULLIO) {
 320                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 321                 return 0;
 322         }
 323
 324         tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
 325         rd_offset = do_div(tmp, PAGE_SIZE);
 326         rd_page = tmp;
 327         rd_size = cmd->data_length;
 328
 329         table = rd_get_sg_table(dev, rd_page);
 330         if (!table)
 331                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 332
 333         rd_sg = &table->sg_table[rd_page - table->page_start_offset];
 334
 335         pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
 336                         dev->rd_dev_id,
 337                         data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
 338                         cmd->t_task_lba, rd_size, rd_page, rd_offset);
 339
 340         src_len = PAGE_SIZE - rd_offset;
 341         sg_miter_start(&m, sgl, sgl_nents,
 342                         data_direction == DMA_FROM_DEVICE ?
 343                                 SG_MITER_TO_SG : SG_MITER_FROM_SG);
 344         while (rd_size) {
 345                 u32 len;
 346                 void *rd_addr;
 347
 348                 sg_miter_next(&m);
 349                 if (!(u32)m.length) {
 350                         pr_debug("RD[%u]: invalid sgl %p len %zu\n",
 351                                  dev->rd_dev_id, m.addr, m.length);
 352                         sg_miter_stop(&m);
 353                         return TCM_INCORRECT_AMOUNT_OF_DATA;
 354                 }
 355                 len = min((u32)m.length, src_len);
 356                 if (len > rd_size) {
 357                         pr_debug("RD[%u]: size underrun page %d offset %d "
 358                                  "size %d\n", dev->rd_dev_id,
 359                                  rd_page, rd_offset, rd_size);
 360                         len = rd_size;
 361                 }
 362                 m.consumed = len;
 363
 364                 rd_addr = sg_virt(rd_sg) + rd_offset;
 365
 366                 if (data_direction == DMA_FROM_DEVICE)
 367                         memcpy(m.addr, rd_addr, len);
 368                 else
 369                         memcpy(rd_addr, m.addr, len);
 370
 371                 rd_size -= len;
 372                 if (!rd_size)
 373                         continue;
 374
 375                 src_len -= len;
 376                 if (src_len) {
 377                         rd_offset += len;
 378                         continue;
 379                 }
 380
 381                 /* rd page completed, next one please */
 382                 rd_page++;
 383                 rd_offset = 0;
 384                 src_len = PAGE_SIZE;
 385                 if (rd_page <= table->page_end_offset) {
 386                         rd_sg++;
 387                         continue;
 388                 }
 389
 390                 table = rd_get_sg_table(dev, rd_page);
 391                 if (!table) {
 392                         sg_miter_stop(&m);
 393                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 394                 }
 395
 396                 /* since we increment, the first sg entry is correct */
 397                 rd_sg = table->sg_table;
 398         }
 399         sg_miter_stop(&m);
 400
 401         target_complete_cmd(cmd, SAM_STAT_GOOD);
 402         return 0;
 403 }
 404
 405 enum {
 406         Opt_rd_pages, Opt_rd_nullio, Opt_err
 407 };
 408
 409 static match_table_t tokens = {
 410         {Opt_rd_pages, "rd_pages=%d"},
 411         {Opt_rd_nullio, "rd_nullio=%d"},
 412         {Opt_err, NULL}
 413 };
 414
 415 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
 416                 const char *page, ssize_t count)
 417 {
 418         struct rd_dev *rd_dev = RD_DEV(dev);
 419         char *orig, *ptr, *opts;
 420         substring_t args[MAX_OPT_ARGS];
 421         int ret = 0, arg, token;
 422
 423         opts = kstrdup(page, GFP_KERNEL);
 424         if (!opts)
 425                 return -ENOMEM;
 426
 427         orig = opts;
 428
 429         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 430                 if (!*ptr)
 431                         continue;
 432
 433                 token = match_token(ptr, tokens, args);
 434                 switch (token) {
 435                 case Opt_rd_pages:
 436                         match_int(args, &arg);
 437                         rd_dev->rd_page_count = arg;
 438                         pr_debug("RAMDISK: Referencing Page"
 439                                 " Count: %u\n", rd_dev->rd_page_count);
 440                         rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
 441                         break;
 442                 case Opt_rd_nullio:
 443                         match_int(args, &arg);
 444                         if (arg != 1)
 445                                 break;
 446
 447                         pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
 448                         rd_dev->rd_flags |= RDF_NULLIO;
 449                         break;
 450                 default:
 451                         break;
 452                 }
 453         }
 454
 455         kfree(orig);
 456         return (!ret) ? count : ret;
 457 }
 458
 459 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
 460 {
 461         struct rd_dev *rd_dev = RD_DEV(dev);
 462
 463         ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
 464                         rd_dev->rd_dev_id);
 465         bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
 466                         "  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
 467                         PAGE_SIZE, rd_dev->sg_table_count,
 468                         !!(rd_dev->rd_flags & RDF_NULLIO));
 469         return bl;
 470 }
 471
 472 static sector_t rd_get_blocks(struct se_device *dev)
 473 {
 474         struct rd_dev *rd_dev = RD_DEV(dev);
 475
 476         unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
 477                         dev->dev_attrib.block_size) - 1;
 478
 479         return blocks_long;
 480 }
 481
 482 static struct sbc_ops rd_sbc_ops = {
 483         .execute_rw             = rd_execute_rw,
 484 };
 485
 486 static sense_reason_t
 487 rd_parse_cdb(struct se_cmd *cmd)
 488 {
 489         return sbc_parse_cdb(cmd, &rd_sbc_ops);
 490 }
 491
 492 static struct se_subsystem_api rd_mcp_template = {
 493         .name                   = "rd_mcp",
 494         .inquiry_prod           = "RAMDISK-MCP",
 495         .inquiry_rev            = RD_MCP_VERSION,
 496         .transport_type         = TRANSPORT_PLUGIN_VHBA_VDEV,
 497         .attach_hba             = rd_attach_hba,
 498         .detach_hba             = rd_detach_hba,
 499         .alloc_device           = rd_alloc_device,
 500         .configure_device       = rd_configure_device,
 501         .free_device            = rd_free_device,
 502         .parse_cdb              = rd_parse_cdb,
 503         .set_configfs_dev_params = rd_set_configfs_dev_params,
 504         .show_configfs_dev_params = rd_show_configfs_dev_params,
 505         .get_device_type        = sbc_get_device_type,
 506         .get_blocks             = rd_get_blocks,
 507 };
 508
 509 int __init rd_module_init(void)
 510 {
 511         int ret;
 512
 513         ret = transport_subsystem_register(&rd_mcp_template);
 514         if (ret < 0) {
 515                 return ret;
 516         }
 517
 518         return 0;
 519 }
 520
 521 void rd_module_exit(void)
 522 {
 523         transport_subsystem_release(&rd_mcp_template);
 524 }