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 #include <linux/blk-mq.h>
  22 #include <linux/mount.h>
  23
  24 #define DM_MSG_PREFIX "table"
  25
  26 #define MAX_DEPTH 16
  27 #define NODE_SIZE L1_CACHE_BYTES
  28 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
  29 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
  30
  31 struct dm_table {
  32         struct mapped_device *md;
  33         unsigned type;
  34
  35         /* btree table */
  36         unsigned int depth;
  37         unsigned int counts[MAX_DEPTH]; /* in nodes */
  38         sector_t *index[MAX_DEPTH];
  39
  40         unsigned int num_targets;
  41         unsigned int num_allocated;
  42         sector_t *highs;
  43         struct dm_target *targets;
  44
  45         struct target_type *immutable_target_type;
  46         unsigned integrity_supported:1;
  47         unsigned singleton:1;
  48
  49         /*
  50          * Indicates the rw permissions for the new logical
  51          * device.  This should be a combination of FMODE_READ
  52          * and FMODE_WRITE.
  53          */
  54         fmode_t mode;
  55
  56         /* a list of devices used by this table */
  57         struct list_head devices;
  58
  59         /* events get handed up using this callback */
  60         void (*event_fn)(void *);
  61         void *event_context;
  62
  63         struct dm_md_mempools *mempools;
  64
  65         struct list_head target_callbacks;
  66 };
  67
  68 /*
  69  * Similar to ceiling(log_size(n))
  70  */
  71 static unsigned int int_log(unsigned int n, unsigned int base)
  72 {
  73         int result = 0;
  74
  75         while (n > 1) {
  76                 n = dm_div_up(n, base);
  77                 result++;
  78         }
  79
  80         return result;
  81 }
  82
  83 /*
  84  * Calculate the index of the child node of the n'th node k'th key.
  85  */
  86 static inline unsigned int get_child(unsigned int n, unsigned int k)
  87 {
  88         return (n * CHILDREN_PER_NODE) + k;
  89 }
  90
  91 /*
  92  * Return the n'th node of level l from table t.
  93  */
  94 static inline sector_t *get_node(struct dm_table *t,
  95                                  unsigned int l, unsigned int n)
  96 {
  97         return t->index[l] + (n * KEYS_PER_NODE);
  98 }
  99
 100 /*
 101  * Return the highest key that you could lookup from the n'th
 102  * node on level l of the btree.
 103  */
 104 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
 105 {
 106         for (; l < t->depth - 1; l++)
 107                 n = get_child(n, CHILDREN_PER_NODE - 1);
 108
 109         if (n >= t->counts[l])
 110                 return (sector_t) - 1;
 111
 112         return get_node(t, l, n)[KEYS_PER_NODE - 1];
 113 }
 114
 115 /*
 116  * Fills in a level of the btree based on the highs of the level
 117  * below it.
 118  */
 119 static int setup_btree_index(unsigned int l, struct dm_table *t)
 120 {
 121         unsigned int n, k;
 122         sector_t *node;
 123
 124         for (n = 0U; n < t->counts[l]; n++) {
 125                 node = get_node(t, l, n);
 126
 127                 for (k = 0U; k < KEYS_PER_NODE; k++)
 128                         node[k] = high(t, l + 1, get_child(n, k));
 129         }
 130
 131         return 0;
 132 }
 133
 134 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
 135 {
 136         unsigned long size;
 137         void *addr;
 138
 139         /*
 140          * Check that we're not going to overflow.
 141          */
 142         if (nmemb > (ULONG_MAX / elem_size))
 143                 return NULL;
 144
 145         size = nmemb * elem_size;
 146         addr = vzalloc(size);
 147
 148         return addr;
 149 }
 150 EXPORT_SYMBOL(dm_vcalloc);
 151
 152 /*
 153  * highs, and targets are managed as dynamic arrays during a
 154  * table load.
 155  */
 156 static int alloc_targets(struct dm_table *t, unsigned int num)
 157 {
 158         sector_t *n_highs;
 159         struct dm_target *n_targets;
 160
 161         /*
 162          * Allocate both the target array and offset array at once.
 163          * Append an empty entry to catch sectors beyond the end of
 164          * the device.
 165          */
 166         n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
 167                                           sizeof(sector_t));
 168         if (!n_highs)
 169                 return -ENOMEM;
 170
 171         n_targets = (struct dm_target *) (n_highs + num);
 172
 173         memset(n_highs, -1, sizeof(*n_highs) * num);
 174         vfree(t->highs);
 175
 176         t->num_allocated = num;
 177         t->highs = n_highs;
 178         t->targets = n_targets;
 179
 180         return 0;
 181 }
 182
 183 int dm_table_create(struct dm_table **result, fmode_t mode,
 184                     unsigned num_targets, struct mapped_device *md)
 185 {
 186         struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
 187
 188         if (!t)
 189                 return -ENOMEM;
 190
 191         INIT_LIST_HEAD(&t->devices);
 192         INIT_LIST_HEAD(&t->target_callbacks);
 193
 194         if (!num_targets)
 195                 num_targets = KEYS_PER_NODE;
 196
 197         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
 198
 199         if (!num_targets) {
 200                 kfree(t);
 201                 return -ENOMEM;
 202         }
 203
 204         if (alloc_targets(t, num_targets)) {
 205                 kfree(t);
 206                 return -ENOMEM;
 207         }
 208
 209         t->mode = mode;
 210         t->md = md;
 211         *result = t;
 212         return 0;
 213 }
 214
 215 static void free_devices(struct list_head *devices, struct mapped_device *md)
 216 {
 217         struct list_head *tmp, *next;
 218
 219         list_for_each_safe(tmp, next, devices) {
 220                 struct dm_dev_internal *dd =
 221                     list_entry(tmp, struct dm_dev_internal, list);
 222                 DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
 223                        dm_device_name(md), dd->dm_dev->name);
 224                 dm_put_table_device(md, dd->dm_dev);
 225                 kfree(dd);
 226         }
 227 }
 228
 229 void dm_table_destroy(struct dm_table *t)
 230 {
 231         unsigned int i;
 232
 233         if (!t)
 234                 return;
 235
 236         /* free the indexes */
 237         if (t->depth >= 2)
 238                 vfree(t->index[t->depth - 2]);
 239
 240         /* free the targets */
 241         for (i = 0; i < t->num_targets; i++) {
 242                 struct dm_target *tgt = t->targets + i;
 243
 244                 if (tgt->type->dtr)
 245                         tgt->type->dtr(tgt);
 246
 247                 dm_put_target_type(tgt->type);
 248         }
 249
 250         vfree(t->highs);
 251
 252         /* free the device list */
 253         free_devices(&t->devices, t->md);
 254
 255         dm_free_md_mempools(t->mempools);
 256
 257         kfree(t);
 258 }
 259
 260 /*
 261  * See if we've already got a device in the list.
 262  */
 263 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
 264 {
 265         struct dm_dev_internal *dd;
 266
 267         list_for_each_entry (dd, l, list)
 268                 if (dd->dm_dev->bdev->bd_dev == dev)
 269                         return dd;
 270
 271         return NULL;
 272 }
 273
 274 /*
 275  * If possible, this checks an area of a destination device is invalid.
 276  */
 277 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 278                                   sector_t start, sector_t len, void *data)
 279 {
 280         struct request_queue *q;
 281         struct queue_limits *limits = data;
 282         struct block_device *bdev = dev->bdev;
 283         sector_t dev_size =
 284                 i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
 285         unsigned short logical_block_size_sectors =
 286                 limits->logical_block_size >> SECTOR_SHIFT;
 287         char b[BDEVNAME_SIZE];
 288
 289         /*
 290          * Some devices exist without request functions,
 291          * such as loop devices not yet bound to backing files.
 292          * Forbid the use of such devices.
 293          */
 294         q = bdev_get_queue(bdev);
 295         if (!q || !q->make_request_fn) {
 296                 DMWARN("%s: %s is not yet initialised: "
 297                        "start=%llu, len=%llu, dev_size=%llu",
 298                        dm_device_name(ti->table->md), bdevname(bdev, b),
 299                        (unsigned long long)start,
 300                        (unsigned long long)len,
 301                        (unsigned long long)dev_size);
 302                 return 1;
 303         }
 304
 305         if (!dev_size)
 306                 return 0;
 307
 308         if ((start >= dev_size) || (start + len > dev_size)) {
 309                 DMWARN("%s: %s too small for target: "
 310                        "start=%llu, len=%llu, dev_size=%llu",
 311                        dm_device_name(ti->table->md), bdevname(bdev, b),
 312                        (unsigned long long)start,
 313                        (unsigned long long)len,
 314                        (unsigned long long)dev_size);
 315                 return 1;
 316         }
 317
 318         if (logical_block_size_sectors <= 1)
 319                 return 0;
 320
 321         if (start & (logical_block_size_sectors - 1)) {
 322                 DMWARN("%s: start=%llu not aligned to h/w "
 323                        "logical block size %u of %s",
 324                        dm_device_name(ti->table->md),
 325                        (unsigned long long)start,
 326                        limits->logical_block_size, bdevname(bdev, b));
 327                 return 1;
 328         }
 329
 330         if (len & (logical_block_size_sectors - 1)) {
 331                 DMWARN("%s: len=%llu not aligned to h/w "
 332                        "logical block size %u of %s",
 333                        dm_device_name(ti->table->md),
 334                        (unsigned long long)len,
 335                        limits->logical_block_size, bdevname(bdev, b));
 336                 return 1;
 337         }
 338
 339         return 0;
 340 }
 341
 342 /*
 343  * This upgrades the mode on an already open dm_dev, being
 344  * careful to leave things as they were if we fail to reopen the
 345  * device and not to touch the existing bdev field in case
 346  * it is accessed concurrently inside dm_table_any_congested().
 347  */
 348 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 349                         struct mapped_device *md)
 350 {
 351         int r;
 352         struct dm_dev *old_dev, *new_dev;
 353
 354         old_dev = dd->dm_dev;
 355
 356         r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
 357                                 dd->dm_dev->mode | new_mode, &new_dev);
 358         if (r)
 359                 return r;
 360
 361         dd->dm_dev = new_dev;
 362         dm_put_table_device(md, old_dev);
 363
 364         return 0;
 365 }
 366
 367 /*
 368  * Convert the path to a device
 369  */
 370 dev_t dm_get_dev_t(const char *path)
 371 {
 372         dev_t uninitialized_var(dev);
 373         struct block_device *bdev;
 374
 375         bdev = lookup_bdev(path);
 376         if (IS_ERR(bdev))
 377                 dev = name_to_dev_t(path);
 378         else {
 379                 dev = bdev->bd_dev;
 380                 bdput(bdev);
 381         }
 382
 383         return dev;
 384 }
 385 EXPORT_SYMBOL_GPL(dm_get_dev_t);
 386
 387 /*
 388  * Add a device to the list, or just increment the usage count if
 389  * it's already present.
 390  */
 391 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 392                   struct dm_dev **result)
 393 {
 394         int r;
 395         dev_t dev;
 396         struct dm_dev_internal *dd;
 397         struct dm_table *t = ti->table;
 398
 399         BUG_ON(!t);
 400
 401         dev = dm_get_dev_t(path);
 402         if (!dev)
 403                 return -ENODEV;
 404
 405         dd = find_device(&t->devices, dev);
 406         if (!dd) {
 407                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
 408                 if (!dd)
 409                         return -ENOMEM;
 410
 411                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
 412                         kfree(dd);
 413                         return r;
 414                 }
 415
 416                 atomic_set(&dd->count, 0);
 417                 list_add(&dd->list, &t->devices);
 418
 419         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 420                 r = upgrade_mode(dd, mode, t->md);
 421                 if (r)
 422                         return r;
 423         }
 424         atomic_inc(&dd->count);
 425
 426         *result = dd->dm_dev;
 427         return 0;
 428 }
 429 EXPORT_SYMBOL(dm_get_device);
 430
 431 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 432                                 sector_t start, sector_t len, void *data)
 433 {
 434         struct queue_limits *limits = data;
 435         struct block_device *bdev = dev->bdev;
 436         struct request_queue *q = bdev_get_queue(bdev);
 437         char b[BDEVNAME_SIZE];
 438
 439         if (unlikely(!q)) {
 440                 DMWARN("%s: Cannot set limits for nonexistent device %s",
 441                        dm_device_name(ti->table->md), bdevname(bdev, b));
 442                 return 0;
 443         }
 444
 445         if (bdev_stack_limits(limits, bdev, start) < 0)
 446                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
 447                        "physical_block_size=%u, logical_block_size=%u, "
 448                        "alignment_offset=%u, start=%llu",
 449                        dm_device_name(ti->table->md), bdevname(bdev, b),
 450                        q->limits.physical_block_size,
 451                        q->limits.logical_block_size,
 452                        q->limits.alignment_offset,
 453                        (unsigned long long) start << SECTOR_SHIFT);
 454
 455         return 0;
 456 }
 457
 458 /*
 459  * Decrement a device's use count and remove it if necessary.
 460  */
 461 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 462 {
 463         int found = 0;
 464         struct list_head *devices = &ti->table->devices;
 465         struct dm_dev_internal *dd;
 466
 467         list_for_each_entry(dd, devices, list) {
 468                 if (dd->dm_dev == d) {
 469                         found = 1;
 470                         break;
 471                 }
 472         }
 473         if (!found) {
 474                 DMWARN("%s: device %s not in table devices list",
 475                        dm_device_name(ti->table->md), d->name);
 476                 return;
 477         }
 478         if (atomic_dec_and_test(&dd->count)) {
 479                 dm_put_table_device(ti->table->md, d);
 480                 list_del(&dd->list);
 481                 kfree(dd);
 482         }
 483 }
 484 EXPORT_SYMBOL(dm_put_device);
 485
 486 /*
 487  * Checks to see if the target joins onto the end of the table.
 488  */
 489 static int adjoin(struct dm_table *table, struct dm_target *ti)
 490 {
 491         struct dm_target *prev;
 492
 493         if (!table->num_targets)
 494                 return !ti->begin;
 495
 496         prev = &table->targets[table->num_targets - 1];
 497         return (ti->begin == (prev->begin + prev->len));
 498 }
 499
 500 /*
 501  * Used to dynamically allocate the arg array.
 502  *
 503  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 504  * process messages even if some device is suspended. These messages have a
 505  * small fixed number of arguments.
 506  *
 507  * On the other hand, dm-switch needs to process bulk data using messages and
 508  * excessive use of GFP_NOIO could cause trouble.
 509  */
 510 static char **realloc_argv(unsigned *array_size, char **old_argv)
 511 {
 512         char **argv;
 513         unsigned new_size;
 514         gfp_t gfp;
 515
 516         if (*array_size) {
 517                 new_size = *array_size * 2;
 518                 gfp = GFP_KERNEL;
 519         } else {
 520                 new_size = 8;
 521                 gfp = GFP_NOIO;
 522         }
 523         argv = kmalloc(new_size * sizeof(*argv), gfp);
 524         if (argv) {
 525                 memcpy(argv, old_argv, *array_size * sizeof(*argv));
 526                 *array_size = new_size;
 527         }
 528
 529         kfree(old_argv);
 530         return argv;
 531 }
 532
 533 /*
 534  * Destructively splits up the argument list to pass to ctr.
 535  */
 536 int dm_split_args(int *argc, char ***argvp, char *input)
 537 {
 538         char *start, *end = input, *out, **argv = NULL;
 539         unsigned array_size = 0;
 540
 541         *argc = 0;
 542
 543         if (!input) {
 544                 *argvp = NULL;
 545                 return 0;
 546         }
 547
 548         argv = realloc_argv(&array_size, argv);
 549         if (!argv)
 550                 return -ENOMEM;
 551
 552         while (1) {
 553                 /* Skip whitespace */
 554                 start = skip_spaces(end);
 555
 556                 if (!*start)
 557                         break;  /* success, we hit the end */
 558
 559                 /* 'out' is used to remove any back-quotes */
 560                 end = out = start;
 561                 while (*end) {
 562                         /* Everything apart from '\0' can be quoted */
 563                         if (*end == '\\' && *(end + 1)) {
 564                                 *out++ = *(end + 1);
 565                                 end += 2;
 566                                 continue;
 567                         }
 568
 569                         if (isspace(*end))
 570                                 break;  /* end of token */
 571
 572                         *out++ = *end++;
 573                 }
 574
 575                 /* have we already filled the array ? */
 576                 if ((*argc + 1) > array_size) {
 577                         argv = realloc_argv(&array_size, argv);
 578                         if (!argv)
 579                                 return -ENOMEM;
 580                 }
 581
 582                 /* we know this is whitespace */
 583                 if (*end)
 584                         end++;
 585
 586                 /* terminate the string and put it in the array */
 587                 *out = '\0';
 588                 argv[*argc] = start;
 589                 (*argc)++;
 590         }
 591
 592         *argvp = argv;
 593         return 0;
 594 }
 595
 596 /*
 597  * Impose necessary and sufficient conditions on a devices's table such
 598  * that any incoming bio which respects its logical_block_size can be
 599  * processed successfully.  If it falls across the boundary between
 600  * two or more targets, the size of each piece it gets split into must
 601  * be compatible with the logical_block_size of the target processing it.
 602  */
 603 static int validate_hardware_logical_block_alignment(struct dm_table *table,
 604                                                  struct queue_limits *limits)
 605 {
 606         /*
 607          * This function uses arithmetic modulo the logical_block_size
 608          * (in units of 512-byte sectors).
 609          */
 610         unsigned short device_logical_block_size_sects =
 611                 limits->logical_block_size >> SECTOR_SHIFT;
 612
 613         /*
 614          * Offset of the start of the next table entry, mod logical_block_size.
 615          */
 616         unsigned short next_target_start = 0;
 617
 618         /*
 619          * Given an aligned bio that extends beyond the end of a
 620          * target, how many sectors must the next target handle?
 621          */
 622         unsigned short remaining = 0;
 623
 624         struct dm_target *uninitialized_var(ti);
 625         struct queue_limits ti_limits;
 626         unsigned i = 0;
 627
 628         /*
 629          * Check each entry in the table in turn.
 630          */
 631         while (i < dm_table_get_num_targets(table)) {
 632                 ti = dm_table_get_target(table, i++);
 633
 634                 blk_set_stacking_limits(&ti_limits);
 635
 636                 /* combine all target devices' limits */
 637                 if (ti->type->iterate_devices)
 638                         ti->type->iterate_devices(ti, dm_set_device_limits,
 639                                                   &ti_limits);
 640
 641                 /*
 642                  * If the remaining sectors fall entirely within this
 643                  * table entry are they compatible with its logical_block_size?
 644                  */
 645                 if (remaining < ti->len &&
 646                     remaining & ((ti_limits.logical_block_size >>
 647                                   SECTOR_SHIFT) - 1))
 648                         break;  /* Error */
 649
 650                 next_target_start =
 651                     (unsigned short) ((next_target_start + ti->len) &
 652                                       (device_logical_block_size_sects - 1));
 653                 remaining = next_target_start ?
 654                     device_logical_block_size_sects - next_target_start : 0;
 655         }
 656
 657         if (remaining) {
 658                 DMWARN("%s: table line %u (start sect %llu len %llu) "
 659                        "not aligned to h/w logical block size %u",
 660                        dm_device_name(table->md), i,
 661                        (unsigned long long) ti->begin,
 662                        (unsigned long long) ti->len,
 663                        limits->logical_block_size);
 664                 return -EINVAL;
 665         }
 666
 667         return 0;
 668 }
 669
 670 int dm_table_add_target(struct dm_table *t, const char *type,
 671                         sector_t start, sector_t len, char *params)
 672 {
 673         int r = -EINVAL, argc;
 674         char **argv;
 675         struct dm_target *tgt;
 676
 677         if (t->singleton) {
 678                 DMERR("%s: target type %s must appear alone in table",
 679                       dm_device_name(t->md), t->targets->type->name);
 680                 return -EINVAL;
 681         }
 682
 683         BUG_ON(t->num_targets >= t->num_allocated);
 684
 685         tgt = t->targets + t->num_targets;
 686         memset(tgt, 0, sizeof(*tgt));
 687
 688         if (!len) {
 689                 DMERR("%s: zero-length target", dm_device_name(t->md));
 690                 return -EINVAL;
 691         }
 692
 693         tgt->type = dm_get_target_type(type);
 694         if (!tgt->type) {
 695                 DMERR("%s: %s: unknown target type", dm_device_name(t->md),
 696                       type);
 697                 return -EINVAL;
 698         }
 699
 700         if (dm_target_needs_singleton(tgt->type)) {
 701                 if (t->num_targets) {
 702                         DMERR("%s: target type %s must appear alone in table",
 703                               dm_device_name(t->md), type);
 704                         return -EINVAL;
 705                 }
 706                 t->singleton = 1;
 707         }
 708
 709         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
 710                 DMERR("%s: target type %s may not be included in read-only tables",
 711                       dm_device_name(t->md), type);
 712                 return -EINVAL;
 713         }
 714
 715         if (t->immutable_target_type) {
 716                 if (t->immutable_target_type != tgt->type) {
 717                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 718                               dm_device_name(t->md), t->immutable_target_type->name);
 719                         return -EINVAL;
 720                 }
 721         } else if (dm_target_is_immutable(tgt->type)) {
 722                 if (t->num_targets) {
 723                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 724                               dm_device_name(t->md), tgt->type->name);
 725                         return -EINVAL;
 726                 }
 727                 t->immutable_target_type = tgt->type;
 728         }
 729
 730         tgt->table = t;
 731         tgt->begin = start;
 732         tgt->len = len;
 733         tgt->error = "Unknown error";
 734
 735         /*
 736          * Does this target adjoin the previous one ?
 737          */
 738         if (!adjoin(t, tgt)) {
 739                 tgt->error = "Gap in table";
 740                 r = -EINVAL;
 741                 goto bad;
 742         }
 743
 744         r = dm_split_args(&argc, &argv, params);
 745         if (r) {
 746                 tgt->error = "couldn't split parameters (insufficient memory)";
 747                 goto bad;
 748         }
 749
 750         r = tgt->type->ctr(tgt, argc, argv);
 751         kfree(argv);
 752         if (r)
 753                 goto bad;
 754
 755         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 756
 757         if (!tgt->num_discard_bios && tgt->discards_supported)
 758                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 759                        dm_device_name(t->md), type);
 760
 761         return 0;
 762
 763  bad:
 764         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 765         dm_put_target_type(tgt->type);
 766         return r;
 767 }
 768
 769 /*
 770  * Target argument parsing helpers.
 771  */
 772 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 773                              unsigned *value, char **error, unsigned grouped)
 774 {
 775         const char *arg_str = dm_shift_arg(arg_set);
 776         char dummy;
 777
 778         if (!arg_str ||
 779             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
 780             (*value < arg->min) ||
 781             (*value > arg->max) ||
 782             (grouped && arg_set->argc < *value)) {
 783                 *error = arg->error;
 784                 return -EINVAL;
 785         }
 786
 787         return 0;
 788 }
 789
 790 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 791                 unsigned *value, char **error)
 792 {
 793         return validate_next_arg(arg, arg_set, value, error, 0);
 794 }
 795 EXPORT_SYMBOL(dm_read_arg);
 796
 797 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
 798                       unsigned *value, char **error)
 799 {
 800         return validate_next_arg(arg, arg_set, value, error, 1);
 801 }
 802 EXPORT_SYMBOL(dm_read_arg_group);
 803
 804 const char *dm_shift_arg(struct dm_arg_set *as)
 805 {
 806         char *r;
 807
 808         if (as->argc) {
 809                 as->argc--;
 810                 r = *as->argv;
 811                 as->argv++;
 812                 return r;
 813         }
 814
 815         return NULL;
 816 }
 817 EXPORT_SYMBOL(dm_shift_arg);
 818
 819 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 820 {
 821         BUG_ON(as->argc < num_args);
 822         as->argc -= num_args;
 823         as->argv += num_args;
 824 }
 825 EXPORT_SYMBOL(dm_consume_args);
 826
 827 static bool __table_type_request_based(unsigned table_type)
 828 {
 829         return (table_type == DM_TYPE_REQUEST_BASED ||
 830                 table_type == DM_TYPE_MQ_REQUEST_BASED);
 831 }
 832
 833 static int dm_table_set_type(struct dm_table *t)
 834 {
 835         unsigned i;
 836         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 837         bool use_blk_mq = false;
 838         struct dm_target *tgt;
 839         struct dm_dev_internal *dd;
 840         struct list_head *devices;
 841         unsigned live_md_type = dm_get_md_type(t->md);
 842
 843         for (i = 0; i < t->num_targets; i++) {
 844                 tgt = t->targets + i;
 845                 if (dm_target_hybrid(tgt))
 846                         hybrid = 1;
 847                 else if (dm_target_request_based(tgt))
 848                         request_based = 1;
 849                 else
 850                         bio_based = 1;
 851
 852                 if (bio_based && request_based) {
 853                         DMWARN("Inconsistent table: different target types"
 854                                " can't be mixed up");
 855                         return -EINVAL;
 856                 }
 857         }
 858
 859         if (hybrid && !bio_based && !request_based) {
 860                 /*
 861                  * The targets can work either way.
 862                  * Determine the type from the live device.
 863                  * Default to bio-based if device is new.
 864                  */
 865                 if (__table_type_request_based(live_md_type))
 866                         request_based = 1;
 867                 else
 868                         bio_based = 1;
 869         }
 870
 871         if (bio_based) {
 872                 /* We must use this table as bio-based */
 873                 t->type = DM_TYPE_BIO_BASED;
 874                 return 0;
 875         }
 876
 877         BUG_ON(!request_based); /* No targets in this table */
 878
 879         /*
 880          * Request-based dm supports only tables that have a single target now.
 881          * To support multiple targets, request splitting support is needed,
 882          * and that needs lots of changes in the block-layer.
 883          * (e.g. request completion process for partial completion.)
 884          */
 885         if (t->num_targets > 1) {
 886                 DMWARN("Request-based dm doesn't support multiple targets yet");
 887                 return -EINVAL;
 888         }
 889
 890         /* Non-request-stackable devices can't be used for request-based dm */
 891         devices = dm_table_get_devices(t);
 892         list_for_each_entry(dd, devices, list) {
 893                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
 894
 895                 if (!blk_queue_stackable(q)) {
 896                         DMERR("table load rejected: including"
 897                               " non-request-stackable devices");
 898                         return -EINVAL;
 899                 }
 900
 901                 if (q->mq_ops)
 902                         use_blk_mq = true;
 903         }
 904
 905         if (use_blk_mq) {
 906                 /* verify _all_ devices in the table are blk-mq devices */
 907                 list_for_each_entry(dd, devices, list)
 908                         if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
 909                                 DMERR("table load rejected: not all devices"
 910                                       " are blk-mq request-stackable");
 911                                 return -EINVAL;
 912                         }
 913                 t->type = DM_TYPE_MQ_REQUEST_BASED;
 914
 915         } else if (list_empty(devices) && __table_type_request_based(live_md_type)) {
 916                 /* inherit live MD type */
 917                 t->type = live_md_type;
 918
 919         } else
 920                 t->type = DM_TYPE_REQUEST_BASED;
 921
 922         return 0;
 923 }
 924
 925 unsigned dm_table_get_type(struct dm_table *t)
 926 {
 927         return t->type;
 928 }
 929
 930 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 931 {
 932         return t->immutable_target_type;
 933 }
 934
 935 struct dm_target *dm_table_get_immutable_target(struct dm_table *t)
 936 {
 937         /* Immutable target is implicitly a singleton */
 938         if (t->num_targets > 1 ||
 939             !dm_target_is_immutable(t->targets[0].type))
 940                 return NULL;
 941
 942         return t->targets;
 943 }
 944
 945 struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
 946 {
 947         struct dm_target *uninitialized_var(ti);
 948         unsigned i = 0;
 949
 950         while (i < dm_table_get_num_targets(t)) {
 951                 ti = dm_table_get_target(t, i++);
 952                 if (dm_target_is_wildcard(ti->type))
 953                         return ti;
 954         }
 955
 956         return NULL;
 957 }
 958
 959 bool dm_table_request_based(struct dm_table *t)
 960 {
 961         return __table_type_request_based(dm_table_get_type(t));
 962 }
 963
 964 bool dm_table_mq_request_based(struct dm_table *t)
 965 {
 966         return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
 967 }
 968
 969 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
 970 {
 971         unsigned type = dm_table_get_type(t);
 972         unsigned per_io_data_size = 0;
 973         struct dm_target *tgt;
 974         unsigned i;
 975
 976         if (unlikely(type == DM_TYPE_NONE)) {
 977                 DMWARN("no table type is set, can't allocate mempools");
 978                 return -EINVAL;
 979         }
 980
 981         if (type == DM_TYPE_BIO_BASED)
 982                 for (i = 0; i < t->num_targets; i++) {
 983                         tgt = t->targets + i;
 984                         per_io_data_size = max(per_io_data_size, tgt->per_io_data_size);
 985                 }
 986
 987         t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_io_data_size);
 988         if (!t->mempools)
 989                 return -ENOMEM;
 990
 991         return 0;
 992 }
 993
 994 void dm_table_free_md_mempools(struct dm_table *t)
 995 {
 996         dm_free_md_mempools(t->mempools);
 997         t->mempools = NULL;
 998 }
 999
1000 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
1001 {
1002         return t->mempools;
1003 }
1004
1005 static int setup_indexes(struct dm_table *t)
1006 {
1007         int i;
1008         unsigned int total = 0;
1009         sector_t *indexes;
1010
1011         /* allocate the space for *all* the indexes */
1012         for (i = t->depth - 2; i >= 0; i--) {
1013                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
1014                 total += t->counts[i];
1015         }
1016
1017         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
1018         if (!indexes)
1019                 return -ENOMEM;
1020
1021         /* set up internal nodes, bottom-up */
1022         for (i = t->depth - 2; i >= 0; i--) {
1023                 t->index[i] = indexes;
1024                 indexes += (KEYS_PER_NODE * t->counts[i]);
1025                 setup_btree_index(i, t);
1026         }
1027
1028         return 0;
1029 }
1030
1031 /*
1032  * Builds the btree to index the map.
1033  */
1034 static int dm_table_build_index(struct dm_table *t)
1035 {
1036         int r = 0;
1037         unsigned int leaf_nodes;
1038
1039         /* how many indexes will the btree have ? */
1040         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1041         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1042
1043         /* leaf layer has already been set up */
1044         t->counts[t->depth - 1] = leaf_nodes;
1045         t->index[t->depth - 1] = t->highs;
1046
1047         if (t->depth >= 2)
1048                 r = setup_indexes(t);
1049
1050         return r;
1051 }
1052
1053 static bool integrity_profile_exists(struct gendisk *disk)
1054 {
1055         return !!blk_get_integrity(disk);
1056 }
1057
1058 /*
1059  * Get a disk whose integrity profile reflects the table's profile.
1060  * Returns NULL if integrity support was inconsistent or unavailable.
1061  */
1062 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
1063 {
1064         struct list_head *devices = dm_table_get_devices(t);
1065         struct dm_dev_internal *dd = NULL;
1066         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1067
1068         list_for_each_entry(dd, devices, list) {
1069                 template_disk = dd->dm_dev->bdev->bd_disk;
1070                 if (!integrity_profile_exists(template_disk))
1071                         goto no_integrity;
1072                 else if (prev_disk &&
1073                          blk_integrity_compare(prev_disk, template_disk) < 0)
1074                         goto no_integrity;
1075                 prev_disk = template_disk;
1076         }
1077
1078         return template_disk;
1079
1080 no_integrity:
1081         if (prev_disk)
1082                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1083                        dm_device_name(t->md),
1084                        prev_disk->disk_name,
1085                        template_disk->disk_name);
1086         return NULL;
1087 }
1088
1089 /*
1090  * Register the mapped device for blk_integrity support if the
1091  * underlying devices have an integrity profile.  But all devices may
1092  * not have matching profiles (checking all devices isn't reliable
1093  * during table load because this table may use other DM device(s) which
1094  * must be resumed before they will have an initialized integity
1095  * profile).  Consequently, stacked DM devices force a 2 stage integrity
1096  * profile validation: First pass during table load, final pass during
1097  * resume.
1098  */
1099 static int dm_table_register_integrity(struct dm_table *t)
1100 {
1101         struct mapped_device *md = t->md;
1102         struct gendisk *template_disk = NULL;
1103
1104         template_disk = dm_table_get_integrity_disk(t);
1105         if (!template_disk)
1106                 return 0;
1107
1108         if (!integrity_profile_exists(dm_disk(md))) {
1109                 t->integrity_supported = 1;
1110                 /*
1111                  * Register integrity profile during table load; we can do
1112                  * this because the final profile must match during resume.
1113                  */
1114                 blk_integrity_register(dm_disk(md),
1115                                        blk_get_integrity(template_disk));
1116                 return 0;
1117         }
1118
1119         /*
1120          * If DM device already has an initialized integrity
1121          * profile the new profile should not conflict.
1122          */
1123         if (blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1124                 DMWARN("%s: conflict with existing integrity profile: "
1125                        "%s profile mismatch",
1126                        dm_device_name(t->md),
1127                        template_disk->disk_name);
1128                 return 1;
1129         }
1130
1131         /* Preserve existing integrity profile */
1132         t->integrity_supported = 1;
1133         return 0;
1134 }
1135
1136 /*
1137  * Prepares the table for use by building the indices,
1138  * setting the type, and allocating mempools.
1139  */
1140 int dm_table_complete(struct dm_table *t)
1141 {
1142         int r;
1143
1144         r = dm_table_set_type(t);
1145         if (r) {
1146                 DMERR("unable to set table type");
1147                 return r;
1148         }
1149
1150         r = dm_table_build_index(t);
1151         if (r) {
1152                 DMERR("unable to build btrees");
1153                 return r;
1154         }
1155
1156         r = dm_table_register_integrity(t);
1157         if (r) {
1158                 DMERR("could not register integrity profile.");
1159                 return r;
1160         }
1161
1162         r = dm_table_alloc_md_mempools(t, t->md);
1163         if (r)
1164                 DMERR("unable to allocate mempools");
1165
1166         return r;
1167 }
1168
1169 static DEFINE_MUTEX(_event_lock);
1170 void dm_table_event_callback(struct dm_table *t,
1171                              void (*fn)(void *), void *context)
1172 {
1173         mutex_lock(&_event_lock);
1174         t->event_fn = fn;
1175         t->event_context = context;
1176         mutex_unlock(&_event_lock);
1177 }
1178
1179 void dm_table_event(struct dm_table *t)
1180 {
1181         /*
1182          * You can no longer call dm_table_event() from interrupt
1183          * context, use a bottom half instead.
1184          */
1185         BUG_ON(in_interrupt());
1186
1187         mutex_lock(&_event_lock);
1188         if (t->event_fn)
1189                 t->event_fn(t->event_context);
1190         mutex_unlock(&_event_lock);
1191 }
1192 EXPORT_SYMBOL(dm_table_event);
1193
1194 sector_t dm_table_get_size(struct dm_table *t)
1195 {
1196         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1197 }
1198 EXPORT_SYMBOL(dm_table_get_size);
1199
1200 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1201 {
1202         if (index >= t->num_targets)
1203                 return NULL;
1204
1205         return t->targets + index;
1206 }
1207
1208 /*
1209  * Search the btree for the correct target.
1210  *
1211  * Caller should check returned pointer with dm_target_is_valid()
1212  * to trap I/O beyond end of device.
1213  */
1214 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1215 {
1216         unsigned int l, n = 0, k = 0;
1217         sector_t *node;
1218
1219         for (l = 0; l < t->depth; l++) {
1220                 n = get_child(n, k);
1221                 node = get_node(t, l, n);
1222
1223                 for (k = 0; k < KEYS_PER_NODE; k++)
1224                         if (node[k] >= sector)
1225                                 break;
1226         }
1227
1228         return &t->targets[(KEYS_PER_NODE * n) + k];
1229 }
1230
1231 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1232                         sector_t start, sector_t len, void *data)
1233 {
1234         unsigned *num_devices = data;
1235
1236         (*num_devices)++;
1237
1238         return 0;
1239 }
1240
1241 /*
1242  * Check whether a table has no data devices attached using each
1243  * target's iterate_devices method.
1244  * Returns false if the result is unknown because a target doesn't
1245  * support iterate_devices.
1246  */
1247 bool dm_table_has_no_data_devices(struct dm_table *table)
1248 {
1249         struct dm_target *uninitialized_var(ti);
1250         unsigned i = 0, num_devices = 0;
1251
1252         while (i < dm_table_get_num_targets(table)) {
1253                 ti = dm_table_get_target(table, i++);
1254
1255                 if (!ti->type->iterate_devices)
1256                         return false;
1257
1258                 ti->type->iterate_devices(ti, count_device, &num_devices);
1259                 if (num_devices)
1260                         return false;
1261         }
1262
1263         return true;
1264 }
1265
1266 /*
1267  * Establish the new table's queue_limits and validate them.
1268  */
1269 int dm_calculate_queue_limits(struct dm_table *table,
1270                               struct queue_limits *limits)
1271 {
1272         struct dm_target *uninitialized_var(ti);
1273         struct queue_limits ti_limits;
1274         unsigned i = 0;
1275
1276         blk_set_stacking_limits(limits);
1277
1278         while (i < dm_table_get_num_targets(table)) {
1279                 blk_set_stacking_limits(&ti_limits);
1280
1281                 ti = dm_table_get_target(table, i++);
1282
1283                 if (!ti->type->iterate_devices)
1284                         goto combine_limits;
1285
1286                 /*
1287                  * Combine queue limits of all the devices this target uses.
1288                  */
1289                 ti->type->iterate_devices(ti, dm_set_device_limits,
1290                                           &ti_limits);
1291
1292                 /* Set I/O hints portion of queue limits */
1293                 if (ti->type->io_hints)
1294                         ti->type->io_hints(ti, &ti_limits);
1295
1296                 /*
1297                  * Check each device area is consistent with the target's
1298                  * overall queue limits.
1299                  */
1300                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1301                                               &ti_limits))
1302                         return -EINVAL;
1303
1304 combine_limits:
1305                 /*
1306                  * Merge this target's queue limits into the overall limits
1307                  * for the table.
1308                  */
1309                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1310                         DMWARN("%s: adding target device "
1311                                "(start sect %llu len %llu) "
1312                                "caused an alignment inconsistency",
1313                                dm_device_name(table->md),
1314                                (unsigned long long) ti->begin,
1315                                (unsigned long long) ti->len);
1316         }
1317
1318         return validate_hardware_logical_block_alignment(table, limits);
1319 }
1320
1321 /*
1322  * Verify that all devices have an integrity profile that matches the
1323  * DM device's registered integrity profile.  If the profiles don't
1324  * match then unregister the DM device's integrity profile.
1325  */
1326 static void dm_table_verify_integrity(struct dm_table *t)
1327 {
1328         struct gendisk *template_disk = NULL;
1329
1330         if (t->integrity_supported) {
1331                 /*
1332                  * Verify that the original integrity profile
1333                  * matches all the devices in this table.
1334                  */
1335                 template_disk = dm_table_get_integrity_disk(t);
1336                 if (template_disk &&
1337                     blk_integrity_compare(dm_disk(t->md), template_disk) >= 0)
1338                         return;
1339         }
1340
1341         if (integrity_profile_exists(dm_disk(t->md))) {
1342                 DMWARN("%s: unable to establish an integrity profile",
1343                        dm_device_name(t->md));
1344                 blk_integrity_unregister(dm_disk(t->md));
1345         }
1346 }
1347
1348 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1349                                 sector_t start, sector_t len, void *data)
1350 {
1351         unsigned long flush = (unsigned long) data;
1352         struct request_queue *q = bdev_get_queue(dev->bdev);
1353
1354         return q && (q->queue_flags & flush);
1355 }
1356
1357 static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
1358 {
1359         struct dm_target *ti;
1360         unsigned i = 0;
1361
1362         /*
1363          * Require at least one underlying device to support flushes.
1364          * t->devices includes internal dm devices such as mirror logs
1365          * so we need to use iterate_devices here, which targets
1366          * supporting flushes must provide.
1367          */
1368         while (i < dm_table_get_num_targets(t)) {
1369                 ti = dm_table_get_target(t, i++);
1370
1371                 if (!ti->num_flush_bios)
1372                         continue;
1373
1374                 if (ti->flush_supported)
1375                         return true;
1376
1377                 if (ti->type->iterate_devices &&
1378                     ti->type->iterate_devices(ti, device_flush_capable, (void *) flush))
1379                         return true;
1380         }
1381
1382         return false;
1383 }
1384
1385 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1386 {
1387         struct dm_target *ti;
1388         unsigned i = 0;
1389
1390         /* Ensure that all targets supports discard_zeroes_data. */
1391         while (i < dm_table_get_num_targets(t)) {
1392                 ti = dm_table_get_target(t, i++);
1393
1394                 if (ti->discard_zeroes_data_unsupported)
1395                         return false;
1396         }
1397
1398         return true;
1399 }
1400
1401 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1402                             sector_t start, sector_t len, void *data)
1403 {
1404         struct request_queue *q = bdev_get_queue(dev->bdev);
1405
1406         return q && blk_queue_nonrot(q);
1407 }
1408
1409 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1410                              sector_t start, sector_t len, void *data)
1411 {
1412         struct request_queue *q = bdev_get_queue(dev->bdev);
1413
1414         return q && !blk_queue_add_random(q);
1415 }
1416
1417 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1418                                    sector_t start, sector_t len, void *data)
1419 {
1420         struct request_queue *q = bdev_get_queue(dev->bdev);
1421
1422         return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1423 }
1424
1425 static bool dm_table_all_devices_attribute(struct dm_table *t,
1426                                            iterate_devices_callout_fn func)
1427 {
1428         struct dm_target *ti;
1429         unsigned i = 0;
1430
1431         while (i < dm_table_get_num_targets(t)) {
1432                 ti = dm_table_get_target(t, i++);
1433
1434                 if (!ti->type->iterate_devices ||
1435                     !ti->type->iterate_devices(ti, func, NULL))
1436                         return false;
1437         }
1438
1439         return true;
1440 }
1441
1442 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1443                                          sector_t start, sector_t len, void *data)
1444 {
1445         struct request_queue *q = bdev_get_queue(dev->bdev);
1446
1447         return q && !q->limits.max_write_same_sectors;
1448 }
1449
1450 static bool dm_table_supports_write_same(struct dm_table *t)
1451 {
1452         struct dm_target *ti;
1453         unsigned i = 0;
1454
1455         while (i < dm_table_get_num_targets(t)) {
1456                 ti = dm_table_get_target(t, i++);
1457
1458                 if (!ti->num_write_same_bios)
1459                         return false;
1460
1461                 if (!ti->type->iterate_devices ||
1462                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1463                         return false;
1464         }
1465
1466         return true;
1467 }
1468
1469 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1470                                   sector_t start, sector_t len, void *data)
1471 {
1472         struct request_queue *q = bdev_get_queue(dev->bdev);
1473
1474         return q && blk_queue_discard(q);
1475 }
1476
1477 static bool dm_table_supports_discards(struct dm_table *t)
1478 {
1479         struct dm_target *ti;
1480         unsigned i = 0;
1481
1482         /*
1483          * Unless any target used by the table set discards_supported,
1484          * require at least one underlying device to support discards.
1485          * t->devices includes internal dm devices such as mirror logs
1486          * so we need to use iterate_devices here, which targets
1487          * supporting discard selectively must provide.
1488          */
1489         while (i < dm_table_get_num_targets(t)) {
1490                 ti = dm_table_get_target(t, i++);
1491
1492                 if (!ti->num_discard_bios)
1493                         continue;
1494
1495                 if (ti->discards_supported)
1496                         return true;
1497
1498                 if (ti->type->iterate_devices &&
1499                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1500                         return true;
1501         }
1502
1503         return false;
1504 }
1505
1506 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1507                                struct queue_limits *limits)
1508 {
1509         bool wc = false, fua = false;
1510
1511         /*
1512          * Copy table's limits to the DM device's request_queue
1513          */
1514         q->limits = *limits;
1515
1516         if (!dm_table_supports_discards(t))
1517                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1518         else
1519                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1520
1521         if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
1522                 wc = true;
1523                 if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))
1524                         fua = true;
1525         }
1526         blk_queue_write_cache(q, wc, fua);
1527
1528         if (!dm_table_discard_zeroes_data(t))
1529                 q->limits.discard_zeroes_data = 0;
1530
1531         /* Ensure that all underlying devices are non-rotational. */
1532         if (dm_table_all_devices_attribute(t, device_is_nonrot))
1533                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1534         else
1535                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1536
1537         if (!dm_table_supports_write_same(t))
1538                 q->limits.max_write_same_sectors = 0;
1539
1540         if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1541                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1542         else
1543                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1544
1545         dm_table_verify_integrity(t);
1546
1547         /*
1548          * Determine whether or not this queue's I/O timings contribute
1549          * to the entropy pool, Only request-based targets use this.
1550          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1551          * have it set.
1552          */
1553         if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1554                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1555
1556         /*
1557          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1558          * visible to other CPUs because, once the flag is set, incoming bios
1559          * are processed by request-based dm, which refers to the queue
1560          * settings.
1561          * Until the flag set, bios are passed to bio-based dm and queued to
1562          * md->deferred where queue settings are not needed yet.
1563          * Those bios are passed to request-based dm at the resume time.
1564          */
1565         smp_mb();
1566         if (dm_table_request_based(t))
1567                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1568 }
1569
1570 unsigned int dm_table_get_num_targets(struct dm_table *t)
1571 {
1572         return t->num_targets;
1573 }
1574
1575 struct list_head *dm_table_get_devices(struct dm_table *t)
1576 {
1577         return &t->devices;
1578 }
1579
1580 fmode_t dm_table_get_mode(struct dm_table *t)
1581 {
1582         return t->mode;
1583 }
1584 EXPORT_SYMBOL(dm_table_get_mode);
1585
1586 enum suspend_mode {
1587         PRESUSPEND,
1588         PRESUSPEND_UNDO,
1589         POSTSUSPEND,
1590 };
1591
1592 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1593 {
1594         int i = t->num_targets;
1595         struct dm_target *ti = t->targets;
1596
1597         while (i--) {
1598                 switch (mode) {
1599                 case PRESUSPEND:
1600                         if (ti->type->presuspend)
1601                                 ti->type->presuspend(ti);
1602                         break;
1603                 case PRESUSPEND_UNDO:
1604                         if (ti->type->presuspend_undo)
1605                                 ti->type->presuspend_undo(ti);
1606                         break;
1607                 case POSTSUSPEND:
1608                         if (ti->type->postsuspend)
1609                                 ti->type->postsuspend(ti);
1610                         break;
1611                 }
1612                 ti++;
1613         }
1614 }
1615
1616 void dm_table_presuspend_targets(struct dm_table *t)
1617 {
1618         if (!t)
1619                 return;
1620
1621         suspend_targets(t, PRESUSPEND);
1622 }
1623
1624 void dm_table_presuspend_undo_targets(struct dm_table *t)
1625 {
1626         if (!t)
1627                 return;
1628
1629         suspend_targets(t, PRESUSPEND_UNDO);
1630 }
1631
1632 void dm_table_postsuspend_targets(struct dm_table *t)
1633 {
1634         if (!t)
1635                 return;
1636
1637         suspend_targets(t, POSTSUSPEND);
1638 }
1639
1640 int dm_table_resume_targets(struct dm_table *t)
1641 {
1642         int i, r = 0;
1643
1644         for (i = 0; i < t->num_targets; i++) {
1645                 struct dm_target *ti = t->targets + i;
1646
1647                 if (!ti->type->preresume)
1648                         continue;
1649
1650                 r = ti->type->preresume(ti);
1651                 if (r) {
1652                         DMERR("%s: %s: preresume failed, error = %d",
1653                               dm_device_name(t->md), ti->type->name, r);
1654                         return r;
1655                 }
1656         }
1657
1658         for (i = 0; i < t->num_targets; i++) {
1659                 struct dm_target *ti = t->targets + i;
1660
1661                 if (ti->type->resume)
1662                         ti->type->resume(ti);
1663         }
1664
1665         return 0;
1666 }
1667
1668 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1669 {
1670         list_add(&cb->list, &t->target_callbacks);
1671 }
1672 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1673
1674 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1675 {
1676         struct dm_dev_internal *dd;
1677         struct list_head *devices = dm_table_get_devices(t);
1678         struct dm_target_callbacks *cb;
1679         int r = 0;
1680
1681         list_for_each_entry(dd, devices, list) {
1682                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1683                 char b[BDEVNAME_SIZE];
1684
1685                 if (likely(q))
1686                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1687                 else
1688                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1689                                      dm_device_name(t->md),
1690                                      bdevname(dd->dm_dev->bdev, b));
1691         }
1692
1693         list_for_each_entry(cb, &t->target_callbacks, list)
1694                 if (cb->congested_fn)
1695                         r |= cb->congested_fn(cb, bdi_bits);
1696
1697         return r;
1698 }
1699
1700 struct mapped_device *dm_table_get_md(struct dm_table *t)
1701 {
1702         return t->md;
1703 }
1704 EXPORT_SYMBOL(dm_table_get_md);
1705
1706 void dm_table_run_md_queue_async(struct dm_table *t)
1707 {
1708         struct mapped_device *md;
1709         struct request_queue *queue;
1710         unsigned long flags;
1711
1712         if (!dm_table_request_based(t))
1713                 return;
1714
1715         md = dm_table_get_md(t);
1716         queue = dm_get_md_queue(md);
1717         if (queue) {
1718                 if (queue->mq_ops)
1719                         blk_mq_run_hw_queues(queue, true);
1720                 else {
1721                         spin_lock_irqsave(queue->queue_lock, flags);
1722                         blk_run_queue_async(queue);
1723                         spin_unlock_irqrestore(queue->queue_lock, flags);
1724                 }
1725         }
1726 }
1727 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1728