drivers/md/dm-table.c

   1 /*
   2  * Copyright (C) 2001 Sistina Software (UK) Limited.
   3  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #include "dm.h"
   9
  10 #include <linux/module.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/blkdev.h>
  13 #include <linux/namei.h>
  14 #include <linux/ctype.h>
  15 #include <linux/string.h>
  16 #include <linux/slab.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/mutex.h>
  19 #include <linux/delay.h>
  20 #include <linux/atomic.h>
  21
  22 #define DM_MSG_PREFIX "table"
  23
  24 #define MAX_DEPTH 16
  25 #define NODE_SIZE L1_CACHE_BYTES
  26 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
  27 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
  28
  29 struct dm_table {
  30         struct mapped_device *md;
  31         unsigned type;
  32
  33         /* btree table */
  34         unsigned int depth;
  35         unsigned int counts[MAX_DEPTH]; /* in nodes */
  36         sector_t *index[MAX_DEPTH];
  37
  38         unsigned int num_targets;
  39         unsigned int num_allocated;
  40         sector_t *highs;
  41         struct dm_target *targets;
  42
  43         struct target_type *immutable_target_type;
  44         unsigned integrity_supported:1;
  45         unsigned singleton:1;
  46
  47         /*
  48          * Indicates the rw permissions for the new logical
  49          * device.  This should be a combination of FMODE_READ
  50          * and FMODE_WRITE.
  51          */
  52         fmode_t mode;
  53
  54         /* a list of devices used by this table */
  55         struct list_head devices;
  56
  57         /* events get handed up using this callback */
  58         void (*event_fn)(void *);
  59         void *event_context;
  60
  61         struct dm_md_mempools *mempools;
  62
  63         struct list_head target_callbacks;
  64 };
  65
  66 /*
  67  * Similar to ceiling(log_size(n))
  68  */
  69 static unsigned int int_log(unsigned int n, unsigned int base)
  70 {
  71         int result = 0;
  72
  73         while (n > 1) {
  74                 n = dm_div_up(n, base);
  75                 result++;
  76         }
  77
  78         return result;
  79 }
  80
  81 /*
  82  * Calculate the index of the child node of the n'th node k'th key.
  83  */
  84 static inline unsigned int get_child(unsigned int n, unsigned int k)
  85 {
  86         return (n * CHILDREN_PER_NODE) + k;
  87 }
  88
  89 /*
  90  * Return the n'th node of level l from table t.
  91  */
  92 static inline sector_t *get_node(struct dm_table *t,
  93                                  unsigned int l, unsigned int n)
  94 {
  95         return t->index[l] + (n * KEYS_PER_NODE);
  96 }
  97
  98 /*
  99  * Return the highest key that you could lookup from the n'th
 100  * node on level l of the btree.
 101  */
 102 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
 103 {
 104         for (; l < t->depth - 1; l++)
 105                 n = get_child(n, CHILDREN_PER_NODE - 1);
 106
 107         if (n >= t->counts[l])
 108                 return (sector_t) - 1;
 109
 110         return get_node(t, l, n)[KEYS_PER_NODE - 1];
 111 }
 112
 113 /*
 114  * Fills in a level of the btree based on the highs of the level
 115  * below it.
 116  */
 117 static int setup_btree_index(unsigned int l, struct dm_table *t)
 118 {
 119         unsigned int n, k;
 120         sector_t *node;
 121
 122         for (n = 0U; n < t->counts[l]; n++) {
 123                 node = get_node(t, l, n);
 124
 125                 for (k = 0U; k < KEYS_PER_NODE; k++)
 126                         node[k] = high(t, l + 1, get_child(n, k));
 127         }
 128
 129         return 0;
 130 }
 131
 132 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
 133 {
 134         unsigned long size;
 135         void *addr;
 136
 137         /*
 138          * Check that we're not going to overflow.
 139          */
 140         if (nmemb > (ULONG_MAX / elem_size))
 141                 return NULL;
 142
 143         size = nmemb * elem_size;
 144         addr = vzalloc(size);
 145
 146         return addr;
 147 }
 148 EXPORT_SYMBOL(dm_vcalloc);
 149
 150 /*
 151  * highs, and targets are managed as dynamic arrays during a
 152  * table load.
 153  */
 154 static int alloc_targets(struct dm_table *t, unsigned int num)
 155 {
 156         sector_t *n_highs;
 157         struct dm_target *n_targets;
 158
 159         /*
 160          * Allocate both the target array and offset array at once.
 161          * Append an empty entry to catch sectors beyond the end of
 162          * the device.
 163          */
 164         n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
 165                                           sizeof(sector_t));
 166         if (!n_highs)
 167                 return -ENOMEM;
 168
 169         n_targets = (struct dm_target *) (n_highs + num);
 170
 171         memset(n_highs, -1, sizeof(*n_highs) * num);
 172         vfree(t->highs);
 173
 174         t->num_allocated = num;
 175         t->highs = n_highs;
 176         t->targets = n_targets;
 177
 178         return 0;
 179 }
 180
 181 int dm_table_create(struct dm_table **result, fmode_t mode,
 182                     unsigned num_targets, struct mapped_device *md)
 183 {
 184         struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
 185
 186         if (!t)
 187                 return -ENOMEM;
 188
 189         INIT_LIST_HEAD(&t->devices);
 190         INIT_LIST_HEAD(&t->target_callbacks);
 191
 192         if (!num_targets)
 193                 num_targets = KEYS_PER_NODE;
 194
 195         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
 196
 197         if (!num_targets) {
 198                 kfree(t);
 199                 return -ENOMEM;
 200         }
 201
 202         if (alloc_targets(t, num_targets)) {
 203                 kfree(t);
 204                 return -ENOMEM;
 205         }
 206
 207         t->mode = mode;
 208         t->md = md;
 209         *result = t;
 210         return 0;
 211 }
 212
 213 static void free_devices(struct list_head *devices, struct mapped_device *md)
 214 {
 215         struct list_head *tmp, *next;
 216
 217         list_for_each_safe(tmp, next, devices) {
 218                 struct dm_dev_internal *dd =
 219                     list_entry(tmp, struct dm_dev_internal, list);
 220                 DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
 221                        dm_device_name(md), dd->dm_dev->name);
 222                 dm_put_table_device(md, dd->dm_dev);
 223                 kfree(dd);
 224         }
 225 }
 226
 227 void dm_table_destroy(struct dm_table *t)
 228 {
 229         unsigned int i;
 230
 231         if (!t)
 232                 return;
 233
 234         /* free the indexes */
 235         if (t->depth >= 2)
 236                 vfree(t->index[t->depth - 2]);
 237
 238         /* free the targets */
 239         for (i = 0; i < t->num_targets; i++) {
 240                 struct dm_target *tgt = t->targets + i;
 241
 242                 if (tgt->type->dtr)
 243                         tgt->type->dtr(tgt);
 244
 245                 dm_put_target_type(tgt->type);
 246         }
 247
 248         vfree(t->highs);
 249
 250         /* free the device list */
 251         free_devices(&t->devices, t->md);
 252
 253         dm_free_md_mempools(t->mempools);
 254
 255         kfree(t);
 256 }
 257
 258 /*
 259  * See if we've already got a device in the list.
 260  */
 261 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
 262 {
 263         struct dm_dev_internal *dd;
 264
 265         list_for_each_entry (dd, l, list)
 266                 if (dd->dm_dev->bdev->bd_dev == dev)
 267                         return dd;
 268
 269         return NULL;
 270 }
 271
 272 /*
 273  * If possible, this checks an area of a destination device is invalid.
 274  */
 275 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 276                                   sector_t start, sector_t len, void *data)
 277 {
 278         struct request_queue *q;
 279         struct queue_limits *limits = data;
 280         struct block_device *bdev = dev->bdev;
 281         sector_t dev_size =
 282                 i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
 283         unsigned short logical_block_size_sectors =
 284                 limits->logical_block_size >> SECTOR_SHIFT;
 285         char b[BDEVNAME_SIZE];
 286
 287         /*
 288          * Some devices exist without request functions,
 289          * such as loop devices not yet bound to backing files.
 290          * Forbid the use of such devices.
 291          */
 292         q = bdev_get_queue(bdev);
 293         if (!q || !q->make_request_fn) {
 294                 DMWARN("%s: %s is not yet initialised: "
 295                        "start=%llu, len=%llu, dev_size=%llu",
 296                        dm_device_name(ti->table->md), bdevname(bdev, b),
 297                        (unsigned long long)start,
 298                        (unsigned long long)len,
 299                        (unsigned long long)dev_size);
 300                 return 1;
 301         }
 302
 303         if (!dev_size)
 304                 return 0;
 305
 306         if ((start >= dev_size) || (start + len > dev_size)) {
 307                 DMWARN("%s: %s too small for target: "
 308                        "start=%llu, len=%llu, dev_size=%llu",
 309                        dm_device_name(ti->table->md), bdevname(bdev, b),
 310                        (unsigned long long)start,
 311                        (unsigned long long)len,
 312                        (unsigned long long)dev_size);
 313                 return 1;
 314         }
 315
 316         if (logical_block_size_sectors <= 1)
 317                 return 0;
 318
 319         if (start & (logical_block_size_sectors - 1)) {
 320                 DMWARN("%s: start=%llu not aligned to h/w "
 321                        "logical block size %u of %s",
 322                        dm_device_name(ti->table->md),
 323                        (unsigned long long)start,
 324                        limits->logical_block_size, bdevname(bdev, b));
 325                 return 1;
 326         }
 327
 328         if (len & (logical_block_size_sectors - 1)) {
 329                 DMWARN("%s: len=%llu not aligned to h/w "
 330                        "logical block size %u of %s",
 331                        dm_device_name(ti->table->md),
 332                        (unsigned long long)len,
 333                        limits->logical_block_size, bdevname(bdev, b));
 334                 return 1;
 335         }
 336
 337         return 0;
 338 }
 339
 340 /*
 341  * This upgrades the mode on an already open dm_dev, being
 342  * careful to leave things as they were if we fail to reopen the
 343  * device and not to touch the existing bdev field in case
 344  * it is accessed concurrently inside dm_table_any_congested().
 345  */
 346 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 347                         struct mapped_device *md)
 348 {
 349         int r;
 350         struct dm_dev *old_dev, *new_dev;
 351
 352         old_dev = dd->dm_dev;
 353
 354         r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
 355                                 dd->dm_dev->mode | new_mode, &new_dev);
 356         if (r)
 357                 return r;
 358
 359         dd->dm_dev = new_dev;
 360         dm_put_table_device(md, old_dev);
 361
 362         return 0;
 363 }
 364
 365 /*
 366  * Add a device to the list, or just increment the usage count if
 367  * it's already present.
 368  */
 369 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 370                   struct dm_dev **result)
 371 {
 372         int r;
 373         dev_t uninitialized_var(dev);
 374         struct dm_dev_internal *dd;
 375         unsigned int major, minor;
 376         struct dm_table *t = ti->table;
 377         char dummy;
 378
 379         BUG_ON(!t);
 380
 381         if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
 382                 /* Extract the major/minor numbers */
 383                 dev = MKDEV(major, minor);
 384                 if (MAJOR(dev) != major || MINOR(dev) != minor)
 385                         return -EOVERFLOW;
 386         } else {
 387                 /* convert the path to a device */
 388                 struct block_device *bdev = lookup_bdev(path);
 389
 390                 if (IS_ERR(bdev))
 391                         return PTR_ERR(bdev);
 392                 dev = bdev->bd_dev;
 393                 bdput(bdev);
 394         }
 395
 396         dd = find_device(&t->devices, dev);
 397         if (!dd) {
 398                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
 399                 if (!dd)
 400                         return -ENOMEM;
 401
 402                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
 403                         kfree(dd);
 404                         return r;
 405                 }
 406
 407                 atomic_set(&dd->count, 0);
 408                 list_add(&dd->list, &t->devices);
 409
 410         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 411                 r = upgrade_mode(dd, mode, t->md);
 412                 if (r)
 413                         return r;
 414         }
 415         atomic_inc(&dd->count);
 416
 417         *result = dd->dm_dev;
 418         return 0;
 419 }
 420 EXPORT_SYMBOL(dm_get_device);
 421
 422 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 423                                 sector_t start, sector_t len, void *data)
 424 {
 425         struct queue_limits *limits = data;
 426         struct block_device *bdev = dev->bdev;
 427         struct request_queue *q = bdev_get_queue(bdev);
 428         char b[BDEVNAME_SIZE];
 429
 430         if (unlikely(!q)) {
 431                 DMWARN("%s: Cannot set limits for nonexistent device %s",
 432                        dm_device_name(ti->table->md), bdevname(bdev, b));
 433                 return 0;
 434         }
 435
 436         if (bdev_stack_limits(limits, bdev, start) < 0)
 437                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
 438                        "physical_block_size=%u, logical_block_size=%u, "
 439                        "alignment_offset=%u, start=%llu",
 440                        dm_device_name(ti->table->md), bdevname(bdev, b),
 441                        q->limits.physical_block_size,
 442                        q->limits.logical_block_size,
 443                        q->limits.alignment_offset,
 444                        (unsigned long long) start << SECTOR_SHIFT);
 445
 446         /*
 447          * Check if merge fn is supported.
 448          * If not we'll force DM to use PAGE_SIZE or
 449          * smaller I/O, just to be safe.
 450          */
 451         if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
 452                 blk_limits_max_hw_sectors(limits,
 453                                           (unsigned int) (PAGE_SIZE >> 9));
 454         return 0;
 455 }
 456
 457 /*
 458  * Decrement a device's use count and remove it if necessary.
 459  */
 460 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 461 {
 462         int found = 0;
 463         struct list_head *devices = &ti->table->devices;
 464         struct dm_dev_internal *dd;
 465
 466         list_for_each_entry(dd, devices, list) {
 467                 if (dd->dm_dev == d) {
 468                         found = 1;
 469                         break;
 470                 }
 471         }
 472         if (!found) {
 473                 DMWARN("%s: device %s not in table devices list",
 474                        dm_device_name(ti->table->md), d->name);
 475                 return;
 476         }
 477         if (atomic_dec_and_test(&dd->count)) {
 478                 dm_put_table_device(ti->table->md, d);
 479                 list_del(&dd->list);
 480                 kfree(dd);
 481         }
 482 }
 483 EXPORT_SYMBOL(dm_put_device);
 484
 485 /*
 486  * Checks to see if the target joins onto the end of the table.
 487  */
 488 static int adjoin(struct dm_table *table, struct dm_target *ti)
 489 {
 490         struct dm_target *prev;
 491
 492         if (!table->num_targets)
 493                 return !ti->begin;
 494
 495         prev = &table->targets[table->num_targets - 1];
 496         return (ti->begin == (prev->begin + prev->len));
 497 }
 498
 499 /*
 500  * Used to dynamically allocate the arg array.
 501  *
 502  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 503  * process messages even if some device is suspended. These messages have a
 504  * small fixed number of arguments.
 505  *
 506  * On the other hand, dm-switch needs to process bulk data using messages and
 507  * excessive use of GFP_NOIO could cause trouble.
 508  */
 509 static char **realloc_argv(unsigned *array_size, char **old_argv)
 510 {
 511         char **argv;
 512         unsigned new_size;
 513         gfp_t gfp;
 514
 515         if (*array_size) {
 516                 new_size = *array_size * 2;
 517                 gfp = GFP_KERNEL;
 518         } else {
 519                 new_size = 8;
 520                 gfp = GFP_NOIO;
 521         }
 522         argv = kmalloc(new_size * sizeof(*argv), gfp);
 523         if (argv) {
 524                 memcpy(argv, old_argv, *array_size * sizeof(*argv));
 525                 *array_size = new_size;
 526         }
 527
 528         kfree(old_argv);
 529         return argv;
 530 }
 531
 532 /*
 533  * Destructively splits up the argument list to pass to ctr.
 534  */
 535 int dm_split_args(int *argc, char ***argvp, char *input)
 536 {
 537         char *start, *end = input, *out, **argv = NULL;
 538         unsigned array_size = 0;
 539
 540         *argc = 0;
 541
 542         if (!input) {
 543                 *argvp = NULL;
 544                 return 0;
 545         }
 546
 547         argv = realloc_argv(&array_size, argv);
 548         if (!argv)
 549                 return -ENOMEM;
 550
 551         while (1) {
 552                 /* Skip whitespace */
 553                 start = skip_spaces(end);
 554
 555                 if (!*start)
 556                         break;  /* success, we hit the end */
 557
 558                 /* 'out' is used to remove any back-quotes */
 559                 end = out = start;
 560                 while (*end) {
 561                         /* Everything apart from '\0' can be quoted */
 562                         if (*end == '\\' && *(end + 1)) {
 563                                 *out++ = *(end + 1);
 564                                 end += 2;
 565                                 continue;
 566                         }
 567
 568                         if (isspace(*end))
 569                                 break;  /* end of token */
 570
 571                         *out++ = *end++;
 572                 }
 573
 574                 /* have we already filled the array ? */
 575                 if ((*argc + 1) > array_size) {
 576                         argv = realloc_argv(&array_size, argv);
 577                         if (!argv)
 578                                 return -ENOMEM;
 579                 }
 580
 581                 /* we know this is whitespace */
 582                 if (*end)
 583                         end++;
 584
 585                 /* terminate the string and put it in the array */
 586                 *out = '\0';
 587                 argv[*argc] = start;
 588                 (*argc)++;
 589         }
 590
 591         *argvp = argv;
 592         return 0;
 593 }
 594
 595 /*
 596  * Impose necessary and sufficient conditions on a devices's table such
 597  * that any incoming bio which respects its logical_block_size can be
 598  * processed successfully.  If it falls across the boundary between
 599  * two or more targets, the size of each piece it gets split into must
 600  * be compatible with the logical_block_size of the target processing it.
 601  */
 602 static int validate_hardware_logical_block_alignment(struct dm_table *table,
 603                                                  struct queue_limits *limits)
 604 {
 605         /*
 606          * This function uses arithmetic modulo the logical_block_size
 607          * (in units of 512-byte sectors).
 608          */
 609         unsigned short device_logical_block_size_sects =
 610                 limits->logical_block_size >> SECTOR_SHIFT;
 611
 612         /*
 613          * Offset of the start of the next table entry, mod logical_block_size.
 614          */
 615         unsigned short next_target_start = 0;
 616
 617         /*
 618          * Given an aligned bio that extends beyond the end of a
 619          * target, how many sectors must the next target handle?
 620          */
 621         unsigned short remaining = 0;
 622
 623         struct dm_target *uninitialized_var(ti);
 624         struct queue_limits ti_limits;
 625         unsigned i = 0;
 626
 627         /*
 628          * Check each entry in the table in turn.
 629          */
 630         while (i < dm_table_get_num_targets(table)) {
 631                 ti = dm_table_get_target(table, i++);
 632
 633                 blk_set_stacking_limits(&ti_limits);
 634
 635                 /* combine all target devices' limits */
 636                 if (ti->type->iterate_devices)
 637                         ti->type->iterate_devices(ti, dm_set_device_limits,
 638                                                   &ti_limits);
 639
 640                 /*
 641                  * If the remaining sectors fall entirely within this
 642                  * table entry are they compatible with its logical_block_size?
 643                  */
 644                 if (remaining < ti->len &&
 645                     remaining & ((ti_limits.logical_block_size >>
 646                                   SECTOR_SHIFT) - 1))
 647                         break;  /* Error */
 648
 649                 next_target_start =
 650                     (unsigned short) ((next_target_start + ti->len) &
 651                                       (device_logical_block_size_sects - 1));
 652                 remaining = next_target_start ?
 653                     device_logical_block_size_sects - next_target_start : 0;
 654         }
 655
 656         if (remaining) {
 657                 DMWARN("%s: table line %u (start sect %llu len %llu) "
 658                        "not aligned to h/w logical block size %u",
 659                        dm_device_name(table->md), i,
 660                        (unsigned long long) ti->begin,
 661                        (unsigned long long) ti->len,
 662                        limits->logical_block_size);
 663                 return -EINVAL;
 664         }
 665
 666         return 0;
 667 }
 668
 669 int dm_table_add_target(struct dm_table *t, const char *type,
 670                         sector_t start, sector_t len, char *params)
 671 {
 672         int r = -EINVAL, argc;
 673         char **argv;
 674         struct dm_target *tgt;
 675
 676         if (t->singleton) {
 677                 DMERR("%s: target type %s must appear alone in table",
 678                       dm_device_name(t->md), t->targets->type->name);
 679                 return -EINVAL;
 680         }
 681
 682         BUG_ON(t->num_targets >= t->num_allocated);
 683
 684         tgt = t->targets + t->num_targets;
 685         memset(tgt, 0, sizeof(*tgt));
 686
 687         if (!len) {
 688                 DMERR("%s: zero-length target", dm_device_name(t->md));
 689                 return -EINVAL;
 690         }
 691
 692         tgt->type = dm_get_target_type(type);
 693         if (!tgt->type) {
 694                 DMERR("%s: %s: unknown target type", dm_device_name(t->md),
 695                       type);
 696                 return -EINVAL;
 697         }
 698
 699         if (dm_target_needs_singleton(tgt->type)) {
 700                 if (t->num_targets) {
 701                         DMERR("%s: target type %s must appear alone in table",
 702                               dm_device_name(t->md), type);
 703                         return -EINVAL;
 704                 }
 705                 t->singleton = 1;
 706         }
 707
 708         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
 709                 DMERR("%s: target type %s may not be included in read-only tables",
 710                       dm_device_name(t->md), type);
 711                 return -EINVAL;
 712         }
 713
 714         if (t->immutable_target_type) {
 715                 if (t->immutable_target_type != tgt->type) {
 716                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 717                               dm_device_name(t->md), t->immutable_target_type->name);
 718                         return -EINVAL;
 719                 }
 720         } else if (dm_target_is_immutable(tgt->type)) {
 721                 if (t->num_targets) {
 722                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 723                               dm_device_name(t->md), tgt->type->name);
 724                         return -EINVAL;
 725                 }
 726                 t->immutable_target_type = tgt->type;
 727         }
 728
 729         tgt->table = t;
 730         tgt->begin = start;
 731         tgt->len = len;
 732         tgt->error = "Unknown error";
 733
 734         /*
 735          * Does this target adjoin the previous one ?
 736          */
 737         if (!adjoin(t, tgt)) {
 738                 tgt->error = "Gap in table";
 739                 r = -EINVAL;
 740                 goto bad;
 741         }
 742
 743         r = dm_split_args(&argc, &argv, params);
 744         if (r) {
 745                 tgt->error = "couldn't split parameters (insufficient memory)";
 746                 goto bad;
 747         }
 748
 749         r = tgt->type->ctr(tgt, argc, argv);
 750         kfree(argv);
 751         if (r)
 752                 goto bad;
 753
 754         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 755
 756         if (!tgt->num_discard_bios && tgt->discards_supported)
 757                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 758                        dm_device_name(t->md), type);
 759
 760         return 0;
 761
 762  bad:
 763         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 764         dm_put_target_type(tgt->type);
 765         return r;
 766 }
 767
 768 /*
 769  * Target argument parsing helpers.
 770  */
 771 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 772                              unsigned *value, char **error, unsigned grouped)
 773 {
 774         const char *arg_str = dm_shift_arg(arg_set);
 775         char dummy;
 776
 777         if (!arg_str ||
 778             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
 779             (*value < arg->min) ||
 780             (*value > arg->max) ||
 781             (grouped && arg_set->argc < *value)) {
 782                 *error = arg->error;
 783                 return -EINVAL;
 784         }
 785
 786         return 0;
 787 }
 788
 789 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 790                 unsigned *value, char **error)
 791 {
 792         return validate_next_arg(arg, arg_set, value, error, 0);
 793 }
 794 EXPORT_SYMBOL(dm_read_arg);
 795
 796 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
 797                       unsigned *value, char **error)
 798 {
 799         return validate_next_arg(arg, arg_set, value, error, 1);
 800 }
 801 EXPORT_SYMBOL(dm_read_arg_group);
 802
 803 const char *dm_shift_arg(struct dm_arg_set *as)
 804 {
 805         char *r;
 806
 807         if (as->argc) {
 808                 as->argc--;
 809                 r = *as->argv;
 810                 as->argv++;
 811                 return r;
 812         }
 813
 814         return NULL;
 815 }
 816 EXPORT_SYMBOL(dm_shift_arg);
 817
 818 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 819 {
 820         BUG_ON(as->argc < num_args);
 821         as->argc -= num_args;
 822         as->argv += num_args;
 823 }
 824 EXPORT_SYMBOL(dm_consume_args);
 825
 826 static int dm_table_set_type(struct dm_table *t)
 827 {
 828         unsigned i;
 829         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 830         struct dm_target *tgt;
 831         struct dm_dev_internal *dd;
 832         struct list_head *devices;
 833         unsigned live_md_type;
 834
 835         for (i = 0; i < t->num_targets; i++) {
 836                 tgt = t->targets + i;
 837                 if (dm_target_hybrid(tgt))
 838                         hybrid = 1;
 839                 else if (dm_target_request_based(tgt))
 840                         request_based = 1;
 841                 else
 842                         bio_based = 1;
 843
 844                 if (bio_based && request_based) {
 845                         DMWARN("Inconsistent table: different target types"
 846                                " can't be mixed up");
 847                         return -EINVAL;
 848                 }
 849         }
 850
 851         if (hybrid && !bio_based && !request_based) {
 852                 /*
 853                  * The targets can work either way.
 854                  * Determine the type from the live device.
 855                  * Default to bio-based if device is new.
 856                  */
 857                 live_md_type = dm_get_md_type(t->md);
 858                 if (live_md_type == DM_TYPE_REQUEST_BASED)
 859                         request_based = 1;
 860                 else
 861                         bio_based = 1;
 862         }
 863
 864         if (bio_based) {
 865                 /* We must use this table as bio-based */
 866                 t->type = DM_TYPE_BIO_BASED;
 867                 return 0;
 868         }
 869
 870         BUG_ON(!request_based); /* No targets in this table */
 871
 872         /* Non-request-stackable devices can't be used for request-based dm */
 873         devices = dm_table_get_devices(t);
 874         list_for_each_entry(dd, devices, list) {
 875                 if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev->bdev))) {
 876                         DMWARN("table load rejected: including"
 877                                " non-request-stackable devices");
 878                         return -EINVAL;
 879                 }
 880         }
 881
 882         /*
 883          * Request-based dm supports only tables that have a single target now.
 884          * To support multiple targets, request splitting support is needed,
 885          * and that needs lots of changes in the block-layer.
 886          * (e.g. request completion process for partial completion.)
 887          */
 888         if (t->num_targets > 1) {
 889                 DMWARN("Request-based dm doesn't support multiple targets yet");
 890                 return -EINVAL;
 891         }
 892
 893         t->type = DM_TYPE_REQUEST_BASED;
 894
 895         return 0;
 896 }
 897
 898 unsigned dm_table_get_type(struct dm_table *t)
 899 {
 900         return t->type;
 901 }
 902
 903 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 904 {
 905         return t->immutable_target_type;
 906 }
 907
 908 bool dm_table_request_based(struct dm_table *t)
 909 {
 910         return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
 911 }
 912
 913 static int dm_table_alloc_md_mempools(struct dm_table *t)
 914 {
 915         unsigned type = dm_table_get_type(t);
 916         unsigned per_bio_data_size = 0;
 917         struct dm_target *tgt;
 918         unsigned i;
 919
 920         if (unlikely(type == DM_TYPE_NONE)) {
 921                 DMWARN("no table type is set, can't allocate mempools");
 922                 return -EINVAL;
 923         }
 924
 925         if (type == DM_TYPE_BIO_BASED)
 926                 for (i = 0; i < t->num_targets; i++) {
 927                         tgt = t->targets + i;
 928                         per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
 929                 }
 930
 931         t->mempools = dm_alloc_md_mempools(type, t->integrity_supported, per_bio_data_size);
 932         if (!t->mempools)
 933                 return -ENOMEM;
 934
 935         return 0;
 936 }
 937
 938 void dm_table_free_md_mempools(struct dm_table *t)
 939 {
 940         dm_free_md_mempools(t->mempools);
 941         t->mempools = NULL;
 942 }
 943
 944 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
 945 {
 946         return t->mempools;
 947 }
 948
 949 static int setup_indexes(struct dm_table *t)
 950 {
 951         int i;
 952         unsigned int total = 0;
 953         sector_t *indexes;
 954
 955         /* allocate the space for *all* the indexes */
 956         for (i = t->depth - 2; i >= 0; i--) {
 957                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
 958                 total += t->counts[i];
 959         }
 960
 961         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
 962         if (!indexes)
 963                 return -ENOMEM;
 964
 965         /* set up internal nodes, bottom-up */
 966         for (i = t->depth - 2; i >= 0; i--) {
 967                 t->index[i] = indexes;
 968                 indexes += (KEYS_PER_NODE * t->counts[i]);
 969                 setup_btree_index(i, t);
 970         }
 971
 972         return 0;
 973 }
 974
 975 /*
 976  * Builds the btree to index the map.
 977  */
 978 static int dm_table_build_index(struct dm_table *t)
 979 {
 980         int r = 0;
 981         unsigned int leaf_nodes;
 982
 983         /* how many indexes will the btree have ? */
 984         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
 985         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
 986
 987         /* leaf layer has already been set up */
 988         t->counts[t->depth - 1] = leaf_nodes;
 989         t->index[t->depth - 1] = t->highs;
 990
 991         if (t->depth >= 2)
 992                 r = setup_indexes(t);
 993
 994         return r;
 995 }
 996
 997 /*
 998  * Get a disk whose integrity profile reflects the table's profile.
 999  * If %match_all is true, all devices' profiles must match.
1000  * If %match_all is false, all devices must at least have an
1001  * allocated integrity profile; but uninitialized is ok.
1002  * Returns NULL if integrity support was inconsistent or unavailable.
1003  */
1004 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
1005                                                     bool match_all)
1006 {
1007         struct list_head *devices = dm_table_get_devices(t);
1008         struct dm_dev_internal *dd = NULL;
1009         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1010
1011         list_for_each_entry(dd, devices, list) {
1012                 template_disk = dd->dm_dev->bdev->bd_disk;
1013                 if (!blk_get_integrity(template_disk))
1014                         goto no_integrity;
1015                 if (!match_all && !blk_integrity_is_initialized(template_disk))
1016                         continue; /* skip uninitialized profiles */
1017                 else if (prev_disk &&
1018                          blk_integrity_compare(prev_disk, template_disk) < 0)
1019                         goto no_integrity;
1020                 prev_disk = template_disk;
1021         }
1022
1023         return template_disk;
1024
1025 no_integrity:
1026         if (prev_disk)
1027                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1028                        dm_device_name(t->md),
1029                        prev_disk->disk_name,
1030                        template_disk->disk_name);
1031         return NULL;
1032 }
1033
1034 /*
1035  * Register the mapped device for blk_integrity support if
1036  * the underlying devices have an integrity profile.  But all devices
1037  * may not have matching profiles (checking all devices isn't reliable
1038  * during table load because this table may use other DM device(s) which
1039  * must be resumed before they will have an initialized integity profile).
1040  * Stacked DM devices force a 2 stage integrity profile validation:
1041  * 1 - during load, validate all initialized integrity profiles match
1042  * 2 - during resume, validate all integrity profiles match
1043  */
1044 static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
1045 {
1046         struct gendisk *template_disk = NULL;
1047
1048         template_disk = dm_table_get_integrity_disk(t, false);
1049         if (!template_disk)
1050                 return 0;
1051
1052         if (!blk_integrity_is_initialized(dm_disk(md))) {
1053                 t->integrity_supported = 1;
1054                 return blk_integrity_register(dm_disk(md), NULL);
1055         }
1056
1057         /*
1058          * If DM device already has an initalized integrity
1059          * profile the new profile should not conflict.
1060          */
1061         if (blk_integrity_is_initialized(template_disk) &&
1062             blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1063                 DMWARN("%s: conflict with existing integrity profile: "
1064                        "%s profile mismatch",
1065                        dm_device_name(t->md),
1066                        template_disk->disk_name);
1067                 return 1;
1068         }
1069
1070         /* Preserve existing initialized integrity profile */
1071         t->integrity_supported = 1;
1072         return 0;
1073 }
1074
1075 /*
1076  * Prepares the table for use by building the indices,
1077  * setting the type, and allocating mempools.
1078  */
1079 int dm_table_complete(struct dm_table *t)
1080 {
1081         int r;
1082
1083         r = dm_table_set_type(t);
1084         if (r) {
1085                 DMERR("unable to set table type");
1086                 return r;
1087         }
1088
1089         r = dm_table_build_index(t);
1090         if (r) {
1091                 DMERR("unable to build btrees");
1092                 return r;
1093         }
1094
1095         r = dm_table_prealloc_integrity(t, t->md);
1096         if (r) {
1097                 DMERR("could not register integrity profile.");
1098                 return r;
1099         }
1100
1101         r = dm_table_alloc_md_mempools(t);
1102         if (r)
1103                 DMERR("unable to allocate mempools");
1104
1105         return r;
1106 }
1107
1108 static DEFINE_MUTEX(_event_lock);
1109 void dm_table_event_callback(struct dm_table *t,
1110                              void (*fn)(void *), void *context)
1111 {
1112         mutex_lock(&_event_lock);
1113         t->event_fn = fn;
1114         t->event_context = context;
1115         mutex_unlock(&_event_lock);
1116 }
1117
1118 void dm_table_event(struct dm_table *t)
1119 {
1120         /*
1121          * You can no longer call dm_table_event() from interrupt
1122          * context, use a bottom half instead.
1123          */
1124         BUG_ON(in_interrupt());
1125
1126         mutex_lock(&_event_lock);
1127         if (t->event_fn)
1128                 t->event_fn(t->event_context);
1129         mutex_unlock(&_event_lock);
1130 }
1131 EXPORT_SYMBOL(dm_table_event);
1132
1133 sector_t dm_table_get_size(struct dm_table *t)
1134 {
1135         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1136 }
1137 EXPORT_SYMBOL(dm_table_get_size);
1138
1139 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1140 {
1141         if (index >= t->num_targets)
1142                 return NULL;
1143
1144         return t->targets + index;
1145 }
1146
1147 /*
1148  * Search the btree for the correct target.
1149  *
1150  * Caller should check returned pointer with dm_target_is_valid()
1151  * to trap I/O beyond end of device.
1152  */
1153 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1154 {
1155         unsigned int l, n = 0, k = 0;
1156         sector_t *node;
1157
1158         for (l = 0; l < t->depth; l++) {
1159                 n = get_child(n, k);
1160                 node = get_node(t, l, n);
1161
1162                 for (k = 0; k < KEYS_PER_NODE; k++)
1163                         if (node[k] >= sector)
1164                                 break;
1165         }
1166
1167         return &t->targets[(KEYS_PER_NODE * n) + k];
1168 }
1169
1170 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1171                         sector_t start, sector_t len, void *data)
1172 {
1173         unsigned *num_devices = data;
1174
1175         (*num_devices)++;
1176
1177         return 0;
1178 }
1179
1180 /*
1181  * Check whether a table has no data devices attached using each
1182  * target's iterate_devices method.
1183  * Returns false if the result is unknown because a target doesn't
1184  * support iterate_devices.
1185  */
1186 bool dm_table_has_no_data_devices(struct dm_table *table)
1187 {
1188         struct dm_target *uninitialized_var(ti);
1189         unsigned i = 0, num_devices = 0;
1190
1191         while (i < dm_table_get_num_targets(table)) {
1192                 ti = dm_table_get_target(table, i++);
1193
1194                 if (!ti->type->iterate_devices)
1195                         return false;
1196
1197                 ti->type->iterate_devices(ti, count_device, &num_devices);
1198                 if (num_devices)
1199                         return false;
1200         }
1201
1202         return true;
1203 }
1204
1205 /*
1206  * Establish the new table's queue_limits and validate them.
1207  */
1208 int dm_calculate_queue_limits(struct dm_table *table,
1209                               struct queue_limits *limits)
1210 {
1211         struct dm_target *uninitialized_var(ti);
1212         struct queue_limits ti_limits;
1213         unsigned i = 0;
1214
1215         blk_set_stacking_limits(limits);
1216
1217         while (i < dm_table_get_num_targets(table)) {
1218                 blk_set_stacking_limits(&ti_limits);
1219
1220                 ti = dm_table_get_target(table, i++);
1221
1222                 if (!ti->type->iterate_devices)
1223                         goto combine_limits;
1224
1225                 /*
1226                  * Combine queue limits of all the devices this target uses.
1227                  */
1228                 ti->type->iterate_devices(ti, dm_set_device_limits,
1229                                           &ti_limits);
1230
1231                 /* Set I/O hints portion of queue limits */
1232                 if (ti->type->io_hints)
1233                         ti->type->io_hints(ti, &ti_limits);
1234
1235                 /*
1236                  * Check each device area is consistent with the target's
1237                  * overall queue limits.
1238                  */
1239                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1240                                               &ti_limits))
1241                         return -EINVAL;
1242
1243 combine_limits:
1244                 /*
1245                  * Merge this target's queue limits into the overall limits
1246                  * for the table.
1247                  */
1248                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1249                         DMWARN("%s: adding target device "
1250                                "(start sect %llu len %llu) "
1251                                "caused an alignment inconsistency",
1252                                dm_device_name(table->md),
1253                                (unsigned long long) ti->begin,
1254                                (unsigned long long) ti->len);
1255         }
1256
1257         return validate_hardware_logical_block_alignment(table, limits);
1258 }
1259
1260 /*
1261  * Set the integrity profile for this device if all devices used have
1262  * matching profiles.  We're quite deep in the resume path but still
1263  * don't know if all devices (particularly DM devices this device
1264  * may be stacked on) have matching profiles.  Even if the profiles
1265  * don't match we have no way to fail (to resume) at this point.
1266  */
1267 static void dm_table_set_integrity(struct dm_table *t)
1268 {
1269         struct gendisk *template_disk = NULL;
1270
1271         if (!blk_get_integrity(dm_disk(t->md)))
1272                 return;
1273
1274         template_disk = dm_table_get_integrity_disk(t, true);
1275         if (template_disk)
1276                 blk_integrity_register(dm_disk(t->md),
1277                                        blk_get_integrity(template_disk));
1278         else if (blk_integrity_is_initialized(dm_disk(t->md)))
1279                 DMWARN("%s: device no longer has a valid integrity profile",
1280                        dm_device_name(t->md));
1281         else
1282                 DMWARN("%s: unable to establish an integrity profile",
1283                        dm_device_name(t->md));
1284 }
1285
1286 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1287                                 sector_t start, sector_t len, void *data)
1288 {
1289         unsigned flush = (*(unsigned *)data);
1290         struct request_queue *q = bdev_get_queue(dev->bdev);
1291
1292         return q && (q->flush_flags & flush);
1293 }
1294
1295 static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
1296 {
1297         struct dm_target *ti;
1298         unsigned i = 0;
1299
1300         /*
1301          * Require at least one underlying device to support flushes.
1302          * t->devices includes internal dm devices such as mirror logs
1303          * so we need to use iterate_devices here, which targets
1304          * supporting flushes must provide.
1305          */
1306         while (i < dm_table_get_num_targets(t)) {
1307                 ti = dm_table_get_target(t, i++);
1308
1309                 if (!ti->num_flush_bios)
1310                         continue;
1311
1312                 if (ti->flush_supported)
1313                         return 1;
1314
1315                 if (ti->type->iterate_devices &&
1316                     ti->type->iterate_devices(ti, device_flush_capable, &flush))
1317                         return 1;
1318         }
1319
1320         return 0;
1321 }
1322
1323 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1324 {
1325         struct dm_target *ti;
1326         unsigned i = 0;
1327
1328         /* Ensure that all targets supports discard_zeroes_data. */
1329         while (i < dm_table_get_num_targets(t)) {
1330                 ti = dm_table_get_target(t, i++);
1331
1332                 if (ti->discard_zeroes_data_unsupported)
1333                         return 0;
1334         }
1335
1336         return 1;
1337 }
1338
1339 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1340                             sector_t start, sector_t len, void *data)
1341 {
1342         struct request_queue *q = bdev_get_queue(dev->bdev);
1343
1344         return q && blk_queue_nonrot(q);
1345 }
1346
1347 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1348                              sector_t start, sector_t len, void *data)
1349 {
1350         struct request_queue *q = bdev_get_queue(dev->bdev);
1351
1352         return q && !blk_queue_add_random(q);
1353 }
1354
1355 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1356                                    sector_t start, sector_t len, void *data)
1357 {
1358         struct request_queue *q = bdev_get_queue(dev->bdev);
1359
1360         return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1361 }
1362
1363 static bool dm_table_all_devices_attribute(struct dm_table *t,
1364                                            iterate_devices_callout_fn func)
1365 {
1366         struct dm_target *ti;
1367         unsigned i = 0;
1368
1369         while (i < dm_table_get_num_targets(t)) {
1370                 ti = dm_table_get_target(t, i++);
1371
1372                 if (!ti->type->iterate_devices ||
1373                     !ti->type->iterate_devices(ti, func, NULL))
1374                         return 0;
1375         }
1376
1377         return 1;
1378 }
1379
1380 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1381                                          sector_t start, sector_t len, void *data)
1382 {
1383         struct request_queue *q = bdev_get_queue(dev->bdev);
1384
1385         return q && !q->limits.max_write_same_sectors;
1386 }
1387
1388 static bool dm_table_supports_write_same(struct dm_table *t)
1389 {
1390         struct dm_target *ti;
1391         unsigned i = 0;
1392
1393         while (i < dm_table_get_num_targets(t)) {
1394                 ti = dm_table_get_target(t, i++);
1395
1396                 if (!ti->num_write_same_bios)
1397                         return false;
1398
1399                 if (!ti->type->iterate_devices ||
1400                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1401                         return false;
1402         }
1403
1404         return true;
1405 }
1406
1407 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1408                                   sector_t start, sector_t len, void *data)
1409 {
1410         struct request_queue *q = bdev_get_queue(dev->bdev);
1411
1412         return q && blk_queue_discard(q);
1413 }
1414
1415 static bool dm_table_supports_discards(struct dm_table *t)
1416 {
1417         struct dm_target *ti;
1418         unsigned i = 0;
1419
1420         /*
1421          * Unless any target used by the table set discards_supported,
1422          * require at least one underlying device to support discards.
1423          * t->devices includes internal dm devices such as mirror logs
1424          * so we need to use iterate_devices here, which targets
1425          * supporting discard selectively must provide.
1426          */
1427         while (i < dm_table_get_num_targets(t)) {
1428                 ti = dm_table_get_target(t, i++);
1429
1430                 if (!ti->num_discard_bios)
1431                         continue;
1432
1433                 if (ti->discards_supported)
1434                         return 1;
1435
1436                 if (ti->type->iterate_devices &&
1437                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1438                         return 1;
1439         }
1440
1441         return 0;
1442 }
1443
1444 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1445                                struct queue_limits *limits)
1446 {
1447         unsigned flush = 0;
1448
1449         /*
1450          * Copy table's limits to the DM device's request_queue
1451          */
1452         q->limits = *limits;
1453
1454         if (!dm_table_supports_discards(t))
1455                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1456         else
1457                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1458
1459         if (dm_table_supports_flush(t, REQ_FLUSH)) {
1460                 flush |= REQ_FLUSH;
1461                 if (dm_table_supports_flush(t, REQ_FUA))
1462                         flush |= REQ_FUA;
1463         }
1464         blk_queue_flush(q, flush);
1465
1466         if (!dm_table_discard_zeroes_data(t))
1467                 q->limits.discard_zeroes_data = 0;
1468
1469         /* Ensure that all underlying devices are non-rotational. */
1470         if (dm_table_all_devices_attribute(t, device_is_nonrot))
1471                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1472         else
1473                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1474
1475         if (!dm_table_supports_write_same(t))
1476                 q->limits.max_write_same_sectors = 0;
1477
1478         if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1479                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1480         else
1481                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1482
1483         dm_table_set_integrity(t);
1484
1485         /*
1486          * Determine whether or not this queue's I/O timings contribute
1487          * to the entropy pool, Only request-based targets use this.
1488          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1489          * have it set.
1490          */
1491         if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1492                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1493
1494         /*
1495          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1496          * visible to other CPUs because, once the flag is set, incoming bios
1497          * are processed by request-based dm, which refers to the queue
1498          * settings.
1499          * Until the flag set, bios are passed to bio-based dm and queued to
1500          * md->deferred where queue settings are not needed yet.
1501          * Those bios are passed to request-based dm at the resume time.
1502          */
1503         smp_mb();
1504         if (dm_table_request_based(t))
1505                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1506 }
1507
1508 unsigned int dm_table_get_num_targets(struct dm_table *t)
1509 {
1510         return t->num_targets;
1511 }
1512
1513 struct list_head *dm_table_get_devices(struct dm_table *t)
1514 {
1515         return &t->devices;
1516 }
1517
1518 fmode_t dm_table_get_mode(struct dm_table *t)
1519 {
1520         return t->mode;
1521 }
1522 EXPORT_SYMBOL(dm_table_get_mode);
1523
1524 enum suspend_mode {
1525         PRESUSPEND,
1526         PRESUSPEND_UNDO,
1527         POSTSUSPEND,
1528 };
1529
1530 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1531 {
1532         int i = t->num_targets;
1533         struct dm_target *ti = t->targets;
1534
1535         while (i--) {
1536                 switch (mode) {
1537                 case PRESUSPEND:
1538                         if (ti->type->presuspend)
1539                                 ti->type->presuspend(ti);
1540                         break;
1541                 case PRESUSPEND_UNDO:
1542                         if (ti->type->presuspend_undo)
1543                                 ti->type->presuspend_undo(ti);
1544                         break;
1545                 case POSTSUSPEND:
1546                         if (ti->type->postsuspend)
1547                                 ti->type->postsuspend(ti);
1548                         break;
1549                 }
1550                 ti++;
1551         }
1552 }
1553
1554 void dm_table_presuspend_targets(struct dm_table *t)
1555 {
1556         if (!t)
1557                 return;
1558
1559         suspend_targets(t, PRESUSPEND);
1560 }
1561
1562 void dm_table_presuspend_undo_targets(struct dm_table *t)
1563 {
1564         if (!t)
1565                 return;
1566
1567         suspend_targets(t, PRESUSPEND_UNDO);
1568 }
1569
1570 void dm_table_postsuspend_targets(struct dm_table *t)
1571 {
1572         if (!t)
1573                 return;
1574
1575         suspend_targets(t, POSTSUSPEND);
1576 }
1577
1578 int dm_table_resume_targets(struct dm_table *t)
1579 {
1580         int i, r = 0;
1581
1582         for (i = 0; i < t->num_targets; i++) {
1583                 struct dm_target *ti = t->targets + i;
1584
1585                 if (!ti->type->preresume)
1586                         continue;
1587
1588                 r = ti->type->preresume(ti);
1589                 if (r) {
1590                         DMERR("%s: %s: preresume failed, error = %d",
1591                               dm_device_name(t->md), ti->type->name, r);
1592                         return r;
1593                 }
1594         }
1595
1596         for (i = 0; i < t->num_targets; i++) {
1597                 struct dm_target *ti = t->targets + i;
1598
1599                 if (ti->type->resume)
1600                         ti->type->resume(ti);
1601         }
1602
1603         return 0;
1604 }
1605
1606 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1607 {
1608         list_add(&cb->list, &t->target_callbacks);
1609 }
1610 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1611
1612 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1613 {
1614         struct dm_dev_internal *dd;
1615         struct list_head *devices = dm_table_get_devices(t);
1616         struct dm_target_callbacks *cb;
1617         int r = 0;
1618
1619         list_for_each_entry(dd, devices, list) {
1620                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1621                 char b[BDEVNAME_SIZE];
1622
1623                 if (likely(q))
1624                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1625                 else
1626                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1627                                      dm_device_name(t->md),
1628                                      bdevname(dd->dm_dev->bdev, b));
1629         }
1630
1631         list_for_each_entry(cb, &t->target_callbacks, list)
1632                 if (cb->congested_fn)
1633                         r |= cb->congested_fn(cb, bdi_bits);
1634
1635         return r;
1636 }
1637
1638 int dm_table_any_busy_target(struct dm_table *t)
1639 {
1640         unsigned i;
1641         struct dm_target *ti;
1642
1643         for (i = 0; i < t->num_targets; i++) {
1644                 ti = t->targets + i;
1645                 if (ti->type->busy && ti->type->busy(ti))
1646                         return 1;
1647         }
1648
1649         return 0;
1650 }
1651
1652 struct mapped_device *dm_table_get_md(struct dm_table *t)
1653 {
1654         return t->md;
1655 }
1656 EXPORT_SYMBOL(dm_table_get_md);
1657
1658 void dm_table_run_md_queue_async(struct dm_table *t)
1659 {
1660         struct mapped_device *md;
1661         struct request_queue *queue;
1662         unsigned long flags;
1663
1664         if (!dm_table_request_based(t))
1665                 return;
1666
1667         md = dm_table_get_md(t);
1668         queue = dm_get_md_queue(md);
1669         if (queue) {
1670                 spin_lock_irqsave(queue->queue_lock, flags);
1671                 blk_run_queue_async(queue);
1672                 spin_unlock_irqrestore(queue->queue_lock, flags);
1673         }
1674 }
1675 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1676