drivers/target/target_core_file.c

   1 /*******************************************************************************
   2  * Filename:  target_core_file.c
   3  *
   4  * This file contains the Storage Engine <-> FILEIO transport specific functions
   5  *
   6  * Copyright (c) 2005 PyX Technologies, Inc.
   7  * Copyright (c) 2005-2006 SBE, Inc.  All Rights Reserved.
   8  * Copyright (c) 2007-2010 Rising Tide Systems
   9  * Copyright (c) 2008-2010 Linux-iSCSI.org
  10  *
  11  * Nicholas A. Bellinger <nab@kernel.org>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26  *
  27  ******************************************************************************/
  28
  29 #include <linux/string.h>
  30 #include <linux/parser.h>
  31 #include <linux/timer.h>
  32 #include <linux/blkdev.h>
  33 #include <linux/slab.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/module.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_file.h"
  43
  44 static struct se_subsystem_api fileio_template;
  45
  46 /*      fd_attach_hba(): (Part of se_subsystem_api_t template)
  47  *
  48  *
  49  */
  50 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
  51 {
  52         struct fd_host *fd_host;
  53
  54         fd_host = kzalloc(sizeof(struct fd_host), GFP_KERNEL);
  55         if (!fd_host) {
  56                 pr_err("Unable to allocate memory for struct fd_host\n");
  57                 return -ENOMEM;
  58         }
  59
  60         fd_host->fd_host_id = host_id;
  61
  62         hba->hba_ptr = fd_host;
  63
  64         pr_debug("CORE_HBA[%d] - TCM FILEIO HBA Driver %s on Generic"
  65                 " Target Core Stack %s\n", hba->hba_id, FD_VERSION,
  66                 TARGET_CORE_MOD_VERSION);
  67         pr_debug("CORE_HBA[%d] - Attached FILEIO HBA: %u to Generic"
  68                 " MaxSectors: %u\n",
  69                 hba->hba_id, fd_host->fd_host_id, FD_MAX_SECTORS);
  70
  71         return 0;
  72 }
  73
  74 static void fd_detach_hba(struct se_hba *hba)
  75 {
  76         struct fd_host *fd_host = hba->hba_ptr;
  77
  78         pr_debug("CORE_HBA[%d] - Detached FILEIO HBA: %u from Generic"
  79                 " Target Core\n", hba->hba_id, fd_host->fd_host_id);
  80
  81         kfree(fd_host);
  82         hba->hba_ptr = NULL;
  83 }
  84
  85 static void *fd_allocate_virtdevice(struct se_hba *hba, const char *name)
  86 {
  87         struct fd_dev *fd_dev;
  88         struct fd_host *fd_host = hba->hba_ptr;
  89
  90         fd_dev = kzalloc(sizeof(struct fd_dev), GFP_KERNEL);
  91         if (!fd_dev) {
  92                 pr_err("Unable to allocate memory for struct fd_dev\n");
  93                 return NULL;
  94         }
  95
  96         fd_dev->fd_host = fd_host;
  97
  98         pr_debug("FILEIO: Allocated fd_dev for %p\n", name);
  99
 100         return fd_dev;
 101 }
 102
 103 /*      fd_create_virtdevice(): (Part of se_subsystem_api_t template)
 104  *
 105  *
 106  */
 107 static struct se_device *fd_create_virtdevice(
 108         struct se_hba *hba,
 109         struct se_subsystem_dev *se_dev,
 110         void *p)
 111 {
 112         char *dev_p = NULL;
 113         struct se_device *dev;
 114         struct se_dev_limits dev_limits;
 115         struct queue_limits *limits;
 116         struct fd_dev *fd_dev = p;
 117         struct fd_host *fd_host = hba->hba_ptr;
 118         mm_segment_t old_fs;
 119         struct file *file;
 120         struct inode *inode = NULL;
 121         int dev_flags = 0, flags, ret = -EINVAL;
 122
 123         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 124
 125         old_fs = get_fs();
 126         set_fs(get_ds());
 127         dev_p = getname(fd_dev->fd_dev_name);
 128         set_fs(old_fs);
 129
 130         if (IS_ERR(dev_p)) {
 131                 pr_err("getname(%s) failed: %lu\n",
 132                         fd_dev->fd_dev_name, IS_ERR(dev_p));
 133                 ret = PTR_ERR(dev_p);
 134                 goto fail;
 135         }
 136
 137         /* O_DIRECT too? */
 138         flags = O_RDWR | O_CREAT | O_LARGEFILE;
 139
 140         /*
 141          * If fd_buffered_io=1 has not been set explicitly (the default),
 142          * use O_SYNC to force FILEIO writes to disk.
 143          */
 144         if (!(fd_dev->fbd_flags & FDBD_USE_BUFFERED_IO))
 145                 flags |= O_SYNC;
 146
 147         file = filp_open(dev_p, flags, 0600);
 148         if (IS_ERR(file)) {
 149                 pr_err("filp_open(%s) failed\n", dev_p);
 150                 ret = PTR_ERR(file);
 151                 goto fail;
 152         }
 153         if (!file || !file->f_dentry) {
 154                 pr_err("filp_open(%s) failed\n", dev_p);
 155                 goto fail;
 156         }
 157         fd_dev->fd_file = file;
 158         /*
 159          * If using a block backend with this struct file, we extract
 160          * fd_dev->fd_[block,dev]_size from struct block_device.
 161          *
 162          * Otherwise, we use the passed fd_size= from configfs
 163          */
 164         inode = file->f_mapping->host;
 165         if (S_ISBLK(inode->i_mode)) {
 166                 struct request_queue *q;
 167                 unsigned long long dev_size;
 168                 /*
 169                  * Setup the local scope queue_limits from struct request_queue->limits
 170                  * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 171                  */
 172                 q = bdev_get_queue(inode->i_bdev);
 173                 limits = &dev_limits.limits;
 174                 limits->logical_block_size = bdev_logical_block_size(inode->i_bdev);
 175                 limits->max_hw_sectors = queue_max_hw_sectors(q);
 176                 limits->max_sectors = queue_max_sectors(q);
 177                 /*
 178                  * Determine the number of bytes from i_size_read() minus
 179                  * one (1) logical sector from underlying struct block_device
 180                  */
 181                 fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
 182                 dev_size = (i_size_read(file->f_mapping->host) -
 183                                        fd_dev->fd_block_size);
 184
 185                 pr_debug("FILEIO: Using size: %llu bytes from struct"
 186                         " block_device blocks: %llu logical_block_size: %d\n",
 187                         dev_size, div_u64(dev_size, fd_dev->fd_block_size),
 188                         fd_dev->fd_block_size);
 189         } else {
 190                 if (!(fd_dev->fbd_flags & FBDF_HAS_SIZE)) {
 191                         pr_err("FILEIO: Missing fd_dev_size="
 192                                 " parameter, and no backing struct"
 193                                 " block_device\n");
 194                         goto fail;
 195                 }
 196
 197                 limits = &dev_limits.limits;
 198                 limits->logical_block_size = FD_BLOCKSIZE;
 199                 limits->max_hw_sectors = FD_MAX_SECTORS;
 200                 limits->max_sectors = FD_MAX_SECTORS;
 201                 fd_dev->fd_block_size = FD_BLOCKSIZE;
 202         }
 203
 204         dev_limits.hw_queue_depth = FD_MAX_DEVICE_QUEUE_DEPTH;
 205         dev_limits.queue_depth = FD_DEVICE_QUEUE_DEPTH;
 206
 207         dev = transport_add_device_to_core_hba(hba, &fileio_template,
 208                                 se_dev, dev_flags, fd_dev,
 209                                 &dev_limits, "FILEIO", FD_VERSION);
 210         if (!dev)
 211                 goto fail;
 212
 213         fd_dev->fd_dev_id = fd_host->fd_host_dev_id_count++;
 214         fd_dev->fd_queue_depth = dev->queue_depth;
 215
 216         pr_debug("CORE_FILE[%u] - Added TCM FILEIO Device ID: %u at %s,"
 217                 " %llu total bytes\n", fd_host->fd_host_id, fd_dev->fd_dev_id,
 218                         fd_dev->fd_dev_name, fd_dev->fd_dev_size);
 219
 220         putname(dev_p);
 221         return dev;
 222 fail:
 223         if (fd_dev->fd_file) {
 224                 filp_close(fd_dev->fd_file, NULL);
 225                 fd_dev->fd_file = NULL;
 226         }
 227         putname(dev_p);
 228         return ERR_PTR(ret);
 229 }
 230
 231 /*      fd_free_device(): (Part of se_subsystem_api_t template)
 232  *
 233  *
 234  */
 235 static void fd_free_device(void *p)
 236 {
 237         struct fd_dev *fd_dev = p;
 238
 239         if (fd_dev->fd_file) {
 240                 filp_close(fd_dev->fd_file, NULL);
 241                 fd_dev->fd_file = NULL;
 242         }
 243
 244         kfree(fd_dev);
 245 }
 246
 247 static int fd_do_readv(struct se_cmd *cmd, struct scatterlist *sgl,
 248                 u32 sgl_nents)
 249 {
 250         struct se_device *se_dev = cmd->se_dev;
 251         struct fd_dev *dev = se_dev->dev_ptr;
 252         struct file *fd = dev->fd_file;
 253         struct scatterlist *sg;
 254         struct iovec *iov;
 255         mm_segment_t old_fs;
 256         loff_t pos = (cmd->t_task_lba *
 257                       se_dev->se_sub_dev->se_dev_attrib.block_size);
 258         int ret = 0, i;
 259
 260         iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 261         if (!iov) {
 262                 pr_err("Unable to allocate fd_do_readv iov[]\n");
 263                 return -ENOMEM;
 264         }
 265
 266         for_each_sg(sgl, sg, sgl_nents, i) {
 267                 iov[i].iov_len = sg->length;
 268                 iov[i].iov_base = sg_virt(sg);
 269         }
 270
 271         old_fs = get_fs();
 272         set_fs(get_ds());
 273         ret = vfs_readv(fd, &iov[0], sgl_nents, &pos);
 274         set_fs(old_fs);
 275
 276         kfree(iov);
 277         /*
 278          * Return zeros and GOOD status even if the READ did not return
 279          * the expected virt_size for struct file w/o a backing struct
 280          * block_device.
 281          */
 282         if (S_ISBLK(fd->f_dentry->d_inode->i_mode)) {
 283                 if (ret < 0 || ret != cmd->data_length) {
 284                         pr_err("vfs_readv() returned %d,"
 285                                 " expecting %d for S_ISBLK\n", ret,
 286                                 (int)cmd->data_length);
 287                         return (ret < 0 ? ret : -EINVAL);
 288                 }
 289         } else {
 290                 if (ret < 0) {
 291                         pr_err("vfs_readv() returned %d for non"
 292                                 " S_ISBLK\n", ret);
 293                         return ret;
 294                 }
 295         }
 296
 297         return 1;
 298 }
 299
 300 static int fd_do_writev(struct se_cmd *cmd, struct scatterlist *sgl,
 301                 u32 sgl_nents)
 302 {
 303         struct se_device *se_dev = cmd->se_dev;
 304         struct fd_dev *dev = se_dev->dev_ptr;
 305         struct file *fd = dev->fd_file;
 306         struct scatterlist *sg;
 307         struct iovec *iov;
 308         mm_segment_t old_fs;
 309         loff_t pos = (cmd->t_task_lba *
 310                       se_dev->se_sub_dev->se_dev_attrib.block_size);
 311         int ret, i = 0;
 312
 313         iov = kzalloc(sizeof(struct iovec) * sgl_nents, GFP_KERNEL);
 314         if (!iov) {
 315                 pr_err("Unable to allocate fd_do_writev iov[]\n");
 316                 return -ENOMEM;
 317         }
 318
 319         for_each_sg(sgl, sg, sgl_nents, i) {
 320                 iov[i].iov_len = sg->length;
 321                 iov[i].iov_base = sg_virt(sg);
 322         }
 323
 324         old_fs = get_fs();
 325         set_fs(get_ds());
 326         ret = vfs_writev(fd, &iov[0], sgl_nents, &pos);
 327         set_fs(old_fs);
 328
 329         kfree(iov);
 330
 331         if (ret < 0 || ret != cmd->data_length) {
 332                 pr_err("vfs_writev() returned %d\n", ret);
 333                 return (ret < 0 ? ret : -EINVAL);
 334         }
 335
 336         return 1;
 337 }
 338
 339 static void fd_emulate_sync_cache(struct se_cmd *cmd)
 340 {
 341         struct se_device *dev = cmd->se_dev;
 342         struct fd_dev *fd_dev = dev->dev_ptr;
 343         int immed = (cmd->t_task_cdb[1] & 0x2);
 344         loff_t start, end;
 345         int ret;
 346
 347         /*
 348          * If the Immediate bit is set, queue up the GOOD response
 349          * for this SYNCHRONIZE_CACHE op
 350          */
 351         if (immed)
 352                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 353
 354         /*
 355          * Determine if we will be flushing the entire device.
 356          */
 357         if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
 358                 start = 0;
 359                 end = LLONG_MAX;
 360         } else {
 361                 start = cmd->t_task_lba * dev->se_sub_dev->se_dev_attrib.block_size;
 362                 if (cmd->data_length)
 363                         end = start + cmd->data_length;
 364                 else
 365                         end = LLONG_MAX;
 366         }
 367
 368         ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 369         if (ret != 0)
 370                 pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
 371
 372         if (immed)
 373                 return;
 374
 375         if (ret) {
 376                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 377                 target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 378         } else {
 379                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 380         }
 381 }
 382
 383 static void fd_emulate_write_fua(struct se_cmd *cmd)
 384 {
 385         struct se_device *dev = cmd->se_dev;
 386         struct fd_dev *fd_dev = dev->dev_ptr;
 387         loff_t start = cmd->t_task_lba *
 388                 dev->se_sub_dev->se_dev_attrib.block_size;
 389         loff_t end = start + cmd->data_length;
 390         int ret;
 391
 392         pr_debug("FILEIO: FUA WRITE LBA: %llu, bytes: %u\n",
 393                 cmd->t_task_lba, cmd->data_length);
 394
 395         ret = vfs_fsync_range(fd_dev->fd_file, start, end, 1);
 396         if (ret != 0)
 397                 pr_err("FILEIO: vfs_fsync_range() failed: %d\n", ret);
 398 }
 399
 400 static int fd_execute_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
 401                 u32 sgl_nents, enum dma_data_direction data_direction)
 402 {
 403         struct se_device *dev = cmd->se_dev;
 404         int ret = 0;
 405
 406         /*
 407          * Call vectorized fileio functions to map struct scatterlist
 408          * physical memory addresses to struct iovec virtual memory.
 409          */
 410         if (data_direction == DMA_FROM_DEVICE) {
 411                 ret = fd_do_readv(cmd, sgl, sgl_nents);
 412         } else {
 413                 ret = fd_do_writev(cmd, sgl, sgl_nents);
 414
 415                 if (ret > 0 &&
 416                     dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0 &&
 417                     dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 418                     (cmd->se_cmd_flags & SCF_FUA)) {
 419                         /*
 420                          * We might need to be a bit smarter here
 421                          * and return some sense data to let the initiator
 422                          * know the FUA WRITE cache sync failed..?
 423                          */
 424                         fd_emulate_write_fua(cmd);
 425                 }
 426
 427         }
 428
 429         if (ret < 0) {
 430                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 431                 return ret;
 432         }
 433         if (ret)
 434                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 435         return 0;
 436 }
 437
 438 enum {
 439         Opt_fd_dev_name, Opt_fd_dev_size, Opt_fd_buffered_io, Opt_err
 440 };
 441
 442 static match_table_t tokens = {
 443         {Opt_fd_dev_name, "fd_dev_name=%s"},
 444         {Opt_fd_dev_size, "fd_dev_size=%s"},
 445         {Opt_fd_buffered_io, "fd_buffered_io=%d"},
 446         {Opt_err, NULL}
 447 };
 448
 449 static ssize_t fd_set_configfs_dev_params(
 450         struct se_hba *hba,
 451         struct se_subsystem_dev *se_dev,
 452         const char *page, ssize_t count)
 453 {
 454         struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 455         char *orig, *ptr, *arg_p, *opts;
 456         substring_t args[MAX_OPT_ARGS];
 457         int ret = 0, arg, token;
 458
 459         opts = kstrdup(page, GFP_KERNEL);
 460         if (!opts)
 461                 return -ENOMEM;
 462
 463         orig = opts;
 464
 465         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 466                 if (!*ptr)
 467                         continue;
 468
 469                 token = match_token(ptr, tokens, args);
 470                 switch (token) {
 471                 case Opt_fd_dev_name:
 472                         arg_p = match_strdup(&args[0]);
 473                         if (!arg_p) {
 474                                 ret = -ENOMEM;
 475                                 break;
 476                         }
 477                         snprintf(fd_dev->fd_dev_name, FD_MAX_DEV_NAME,
 478                                         "%s", arg_p);
 479                         kfree(arg_p);
 480                         pr_debug("FILEIO: Referencing Path: %s\n",
 481                                         fd_dev->fd_dev_name);
 482                         fd_dev->fbd_flags |= FBDF_HAS_PATH;
 483                         break;
 484                 case Opt_fd_dev_size:
 485                         arg_p = match_strdup(&args[0]);
 486                         if (!arg_p) {
 487                                 ret = -ENOMEM;
 488                                 break;
 489                         }
 490                         ret = strict_strtoull(arg_p, 0, &fd_dev->fd_dev_size);
 491                         kfree(arg_p);
 492                         if (ret < 0) {
 493                                 pr_err("strict_strtoull() failed for"
 494                                                 " fd_dev_size=\n");
 495                                 goto out;
 496                         }
 497                         pr_debug("FILEIO: Referencing Size: %llu"
 498                                         " bytes\n", fd_dev->fd_dev_size);
 499                         fd_dev->fbd_flags |= FBDF_HAS_SIZE;
 500                         break;
 501                 case Opt_fd_buffered_io:
 502                         match_int(args, &arg);
 503                         if (arg != 1) {
 504                                 pr_err("bogus fd_buffered_io=%d value\n", arg);
 505                                 ret = -EINVAL;
 506                                 goto out;
 507                         }
 508
 509                         pr_debug("FILEIO: Using buffered I/O"
 510                                 " operations for struct fd_dev\n");
 511
 512                         fd_dev->fbd_flags |= FDBD_USE_BUFFERED_IO;
 513                         break;
 514                 default:
 515                         break;
 516                 }
 517         }
 518
 519 out:
 520         kfree(orig);
 521         return (!ret) ? count : ret;
 522 }
 523
 524 static ssize_t fd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
 525 {
 526         struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 527
 528         if (!(fd_dev->fbd_flags & FBDF_HAS_PATH)) {
 529                 pr_err("Missing fd_dev_name=\n");
 530                 return -EINVAL;
 531         }
 532
 533         return 0;
 534 }
 535
 536 static ssize_t fd_show_configfs_dev_params(
 537         struct se_hba *hba,
 538         struct se_subsystem_dev *se_dev,
 539         char *b)
 540 {
 541         struct fd_dev *fd_dev = se_dev->se_dev_su_ptr;
 542         ssize_t bl = 0;
 543
 544         bl = sprintf(b + bl, "TCM FILEIO ID: %u", fd_dev->fd_dev_id);
 545         bl += sprintf(b + bl, "        File: %s  Size: %llu  Mode: %s\n",
 546                 fd_dev->fd_dev_name, fd_dev->fd_dev_size,
 547                 (fd_dev->fbd_flags & FDBD_USE_BUFFERED_IO) ?
 548                 "Buffered" : "Synchronous");
 549         return bl;
 550 }
 551
 552 /*      fd_get_device_rev(): (Part of se_subsystem_api_t template)
 553  *
 554  *
 555  */
 556 static u32 fd_get_device_rev(struct se_device *dev)
 557 {
 558         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 559 }
 560
 561 /*      fd_get_device_type(): (Part of se_subsystem_api_t template)
 562  *
 563  *
 564  */
 565 static u32 fd_get_device_type(struct se_device *dev)
 566 {
 567         return TYPE_DISK;
 568 }
 569
 570 static sector_t fd_get_blocks(struct se_device *dev)
 571 {
 572         struct fd_dev *fd_dev = dev->dev_ptr;
 573         struct file *f = fd_dev->fd_file;
 574         struct inode *i = f->f_mapping->host;
 575         unsigned long long dev_size;
 576         /*
 577          * When using a file that references an underlying struct block_device,
 578          * ensure dev_size is always based on the current inode size in order
 579          * to handle underlying block_device resize operations.
 580          */
 581         if (S_ISBLK(i->i_mode))
 582                 dev_size = (i_size_read(i) - fd_dev->fd_block_size);
 583         else
 584                 dev_size = fd_dev->fd_dev_size;
 585
 586         return div_u64(dev_size, dev->se_sub_dev->se_dev_attrib.block_size);
 587 }
 588
 589 static struct se_subsystem_api fileio_template = {
 590         .name                   = "fileio",
 591         .owner                  = THIS_MODULE,
 592         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 593         .write_cache_emulated   = 1,
 594         .fua_write_emulated     = 1,
 595         .attach_hba             = fd_attach_hba,
 596         .detach_hba             = fd_detach_hba,
 597         .allocate_virtdevice    = fd_allocate_virtdevice,
 598         .create_virtdevice      = fd_create_virtdevice,
 599         .free_device            = fd_free_device,
 600         .execute_cmd            = fd_execute_cmd,
 601         .do_sync_cache          = fd_emulate_sync_cache,
 602         .check_configfs_dev_params = fd_check_configfs_dev_params,
 603         .set_configfs_dev_params = fd_set_configfs_dev_params,
 604         .show_configfs_dev_params = fd_show_configfs_dev_params,
 605         .get_device_rev         = fd_get_device_rev,
 606         .get_device_type        = fd_get_device_type,
 607         .get_blocks             = fd_get_blocks,
 608 };
 609
 610 static int __init fileio_module_init(void)
 611 {
 612         return transport_subsystem_register(&fileio_template);
 613 }
 614
 615 static void fileio_module_exit(void)
 616 {
 617         transport_subsystem_release(&fileio_template);
 618 }
 619
 620 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");
 621 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 622 MODULE_LICENSE("GPL");
 623
 624 module_init(fileio_module_init);
 625 module_exit(fileio_module_exit);