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  * Add a device to the list, or just increment the usage count if
 369  * it's already present.
 370  */
 371 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 372                   struct dm_dev **result)
 373 {
 374         int r;
 375         dev_t uninitialized_var(dev);
 376         struct dm_dev_internal *dd;
 377         struct dm_table *t = ti->table;
 378         struct block_device *bdev;
 379
 380         BUG_ON(!t);
 381
 382         /* convert the path to a device */
 383         bdev = lookup_bdev(path);
 384         if (IS_ERR(bdev)) {
 385                 dev = name_to_dev_t(path);
 386                 if (!dev)
 387                         return -ENODEV;
 388         } else {
 389                 dev = bdev->bd_dev;
 390                 bdput(bdev);
 391         }
 392
 393         dd = find_device(&t->devices, dev);
 394         if (!dd) {
 395                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
 396                 if (!dd)
 397                         return -ENOMEM;
 398
 399                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
 400                         kfree(dd);
 401                         return r;
 402                 }
 403
 404                 atomic_set(&dd->count, 0);
 405                 list_add(&dd->list, &t->devices);
 406
 407         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 408                 r = upgrade_mode(dd, mode, t->md);
 409                 if (r)
 410                         return r;
 411         }
 412         atomic_inc(&dd->count);
 413
 414         *result = dd->dm_dev;
 415         return 0;
 416 }
 417 EXPORT_SYMBOL(dm_get_device);
 418
 419 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 420                                 sector_t start, sector_t len, void *data)
 421 {
 422         struct queue_limits *limits = data;
 423         struct block_device *bdev = dev->bdev;
 424         struct request_queue *q = bdev_get_queue(bdev);
 425         char b[BDEVNAME_SIZE];
 426
 427         if (unlikely(!q)) {
 428                 DMWARN("%s: Cannot set limits for nonexistent device %s",
 429                        dm_device_name(ti->table->md), bdevname(bdev, b));
 430                 return 0;
 431         }
 432
 433         if (bdev_stack_limits(limits, bdev, start) < 0)
 434                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
 435                        "physical_block_size=%u, logical_block_size=%u, "
 436                        "alignment_offset=%u, start=%llu",
 437                        dm_device_name(ti->table->md), bdevname(bdev, b),
 438                        q->limits.physical_block_size,
 439                        q->limits.logical_block_size,
 440                        q->limits.alignment_offset,
 441                        (unsigned long long) start << SECTOR_SHIFT);
 442
 443         /*
 444          * Check if merge fn is supported.
 445          * If not we'll force DM to use PAGE_SIZE or
 446          * smaller I/O, just to be safe.
 447          */
 448         if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
 449                 blk_limits_max_hw_sectors(limits,
 450                                           (unsigned int) (PAGE_SIZE >> 9));
 451         return 0;
 452 }
 453
 454 /*
 455  * Decrement a device's use count and remove it if necessary.
 456  */
 457 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 458 {
 459         int found = 0;
 460         struct list_head *devices = &ti->table->devices;
 461         struct dm_dev_internal *dd;
 462
 463         list_for_each_entry(dd, devices, list) {
 464                 if (dd->dm_dev == d) {
 465                         found = 1;
 466                         break;
 467                 }
 468         }
 469         if (!found) {
 470                 DMWARN("%s: device %s not in table devices list",
 471                        dm_device_name(ti->table->md), d->name);
 472                 return;
 473         }
 474         if (atomic_dec_and_test(&dd->count)) {
 475                 dm_put_table_device(ti->table->md, d);
 476                 list_del(&dd->list);
 477                 kfree(dd);
 478         }
 479 }
 480 EXPORT_SYMBOL(dm_put_device);
 481
 482 /*
 483  * Checks to see if the target joins onto the end of the table.
 484  */
 485 static int adjoin(struct dm_table *table, struct dm_target *ti)
 486 {
 487         struct dm_target *prev;
 488
 489         if (!table->num_targets)
 490                 return !ti->begin;
 491
 492         prev = &table->targets[table->num_targets - 1];
 493         return (ti->begin == (prev->begin + prev->len));
 494 }
 495
 496 /*
 497  * Used to dynamically allocate the arg array.
 498  *
 499  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 500  * process messages even if some device is suspended. These messages have a
 501  * small fixed number of arguments.
 502  *
 503  * On the other hand, dm-switch needs to process bulk data using messages and
 504  * excessive use of GFP_NOIO could cause trouble.
 505  */
 506 static char **realloc_argv(unsigned *array_size, char **old_argv)
 507 {
 508         char **argv;
 509         unsigned new_size;
 510         gfp_t gfp;
 511
 512         if (*array_size) {
 513                 new_size = *array_size * 2;
 514                 gfp = GFP_KERNEL;
 515         } else {
 516                 new_size = 8;
 517                 gfp = GFP_NOIO;
 518         }
 519         argv = kmalloc(new_size * sizeof(*argv), gfp);
 520         if (argv) {
 521                 memcpy(argv, old_argv, *array_size * sizeof(*argv));
 522                 *array_size = new_size;
 523         }
 524
 525         kfree(old_argv);
 526         return argv;
 527 }
 528
 529 /*
 530  * Destructively splits up the argument list to pass to ctr.
 531  */
 532 int dm_split_args(int *argc, char ***argvp, char *input)
 533 {
 534         char *start, *end = input, *out, **argv = NULL;
 535         unsigned array_size = 0;
 536
 537         *argc = 0;
 538
 539         if (!input) {
 540                 *argvp = NULL;
 541                 return 0;
 542         }
 543
 544         argv = realloc_argv(&array_size, argv);
 545         if (!argv)
 546                 return -ENOMEM;
 547
 548         while (1) {
 549                 /* Skip whitespace */
 550                 start = skip_spaces(end);
 551
 552                 if (!*start)
 553                         break;  /* success, we hit the end */
 554
 555                 /* 'out' is used to remove any back-quotes */
 556                 end = out = start;
 557                 while (*end) {
 558                         /* Everything apart from '\0' can be quoted */
 559                         if (*end == '\\' && *(end + 1)) {
 560                                 *out++ = *(end + 1);
 561                                 end += 2;
 562                                 continue;
 563                         }
 564
 565                         if (isspace(*end))
 566                                 break;  /* end of token */
 567
 568                         *out++ = *end++;
 569                 }
 570
 571                 /* have we already filled the array ? */
 572                 if ((*argc + 1) > array_size) {
 573                         argv = realloc_argv(&array_size, argv);
 574                         if (!argv)
 575                                 return -ENOMEM;
 576                 }
 577
 578                 /* we know this is whitespace */
 579                 if (*end)
 580                         end++;
 581
 582                 /* terminate the string and put it in the array */
 583                 *out = '\0';
 584                 argv[*argc] = start;
 585                 (*argc)++;
 586         }
 587
 588         *argvp = argv;
 589         return 0;
 590 }
 591
 592 /*
 593  * Impose necessary and sufficient conditions on a devices's table such
 594  * that any incoming bio which respects its logical_block_size can be
 595  * processed successfully.  If it falls across the boundary between
 596  * two or more targets, the size of each piece it gets split into must
 597  * be compatible with the logical_block_size of the target processing it.
 598  */
 599 static int validate_hardware_logical_block_alignment(struct dm_table *table,
 600                                                  struct queue_limits *limits)
 601 {
 602         /*
 603          * This function uses arithmetic modulo the logical_block_size
 604          * (in units of 512-byte sectors).
 605          */
 606         unsigned short device_logical_block_size_sects =
 607                 limits->logical_block_size >> SECTOR_SHIFT;
 608
 609         /*
 610          * Offset of the start of the next table entry, mod logical_block_size.
 611          */
 612         unsigned short next_target_start = 0;
 613
 614         /*
 615          * Given an aligned bio that extends beyond the end of a
 616          * target, how many sectors must the next target handle?
 617          */
 618         unsigned short remaining = 0;
 619
 620         struct dm_target *uninitialized_var(ti);
 621         struct queue_limits ti_limits;
 622         unsigned i = 0;
 623
 624         /*
 625          * Check each entry in the table in turn.
 626          */
 627         while (i < dm_table_get_num_targets(table)) {
 628                 ti = dm_table_get_target(table, i++);
 629
 630                 blk_set_stacking_limits(&ti_limits);
 631
 632                 /* combine all target devices' limits */
 633                 if (ti->type->iterate_devices)
 634                         ti->type->iterate_devices(ti, dm_set_device_limits,
 635                                                   &ti_limits);
 636
 637                 /*
 638                  * If the remaining sectors fall entirely within this
 639                  * table entry are they compatible with its logical_block_size?
 640                  */
 641                 if (remaining < ti->len &&
 642                     remaining & ((ti_limits.logical_block_size >>
 643                                   SECTOR_SHIFT) - 1))
 644                         break;  /* Error */
 645
 646                 next_target_start =
 647                     (unsigned short) ((next_target_start + ti->len) &
 648                                       (device_logical_block_size_sects - 1));
 649                 remaining = next_target_start ?
 650                     device_logical_block_size_sects - next_target_start : 0;
 651         }
 652
 653         if (remaining) {
 654                 DMWARN("%s: table line %u (start sect %llu len %llu) "
 655                        "not aligned to h/w logical block size %u",
 656                        dm_device_name(table->md), i,
 657                        (unsigned long long) ti->begin,
 658                        (unsigned long long) ti->len,
 659                        limits->logical_block_size);
 660                 return -EINVAL;
 661         }
 662
 663         return 0;
 664 }
 665
 666 int dm_table_add_target(struct dm_table *t, const char *type,
 667                         sector_t start, sector_t len, char *params)
 668 {
 669         int r = -EINVAL, argc;
 670         char **argv;
 671         struct dm_target *tgt;
 672
 673         if (t->singleton) {
 674                 DMERR("%s: target type %s must appear alone in table",
 675                       dm_device_name(t->md), t->targets->type->name);
 676                 return -EINVAL;
 677         }
 678
 679         BUG_ON(t->num_targets >= t->num_allocated);
 680
 681         tgt = t->targets + t->num_targets;
 682         memset(tgt, 0, sizeof(*tgt));
 683
 684         if (!len) {
 685                 DMERR("%s: zero-length target", dm_device_name(t->md));
 686                 return -EINVAL;
 687         }
 688
 689         tgt->type = dm_get_target_type(type);
 690         if (!tgt->type) {
 691                 DMERR("%s: %s: unknown target type", dm_device_name(t->md),
 692                       type);
 693                 return -EINVAL;
 694         }
 695
 696         if (dm_target_needs_singleton(tgt->type)) {
 697                 if (t->num_targets) {
 698                         DMERR("%s: target type %s must appear alone in table",
 699                               dm_device_name(t->md), type);
 700                         return -EINVAL;
 701                 }
 702                 t->singleton = 1;
 703         }
 704
 705         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
 706                 DMERR("%s: target type %s may not be included in read-only tables",
 707                       dm_device_name(t->md), type);
 708                 return -EINVAL;
 709         }
 710
 711         if (t->immutable_target_type) {
 712                 if (t->immutable_target_type != tgt->type) {
 713                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 714                               dm_device_name(t->md), t->immutable_target_type->name);
 715                         return -EINVAL;
 716                 }
 717         } else if (dm_target_is_immutable(tgt->type)) {
 718                 if (t->num_targets) {
 719                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 720                               dm_device_name(t->md), tgt->type->name);
 721                         return -EINVAL;
 722                 }
 723                 t->immutable_target_type = tgt->type;
 724         }
 725
 726         tgt->table = t;
 727         tgt->begin = start;
 728         tgt->len = len;
 729         tgt->error = "Unknown error";
 730
 731         /*
 732          * Does this target adjoin the previous one ?
 733          */
 734         if (!adjoin(t, tgt)) {
 735                 tgt->error = "Gap in table";
 736                 r = -EINVAL;
 737                 goto bad;
 738         }
 739
 740         r = dm_split_args(&argc, &argv, params);
 741         if (r) {
 742                 tgt->error = "couldn't split parameters (insufficient memory)";
 743                 goto bad;
 744         }
 745
 746         r = tgt->type->ctr(tgt, argc, argv);
 747         kfree(argv);
 748         if (r)
 749                 goto bad;
 750
 751         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 752
 753         if (!tgt->num_discard_bios && tgt->discards_supported)
 754                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 755                        dm_device_name(t->md), type);
 756
 757         return 0;
 758
 759  bad:
 760         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 761         dm_put_target_type(tgt->type);
 762         return r;
 763 }
 764
 765 /*
 766  * Target argument parsing helpers.
 767  */
 768 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 769                              unsigned *value, char **error, unsigned grouped)
 770 {
 771         const char *arg_str = dm_shift_arg(arg_set);
 772         char dummy;
 773
 774         if (!arg_str ||
 775             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
 776             (*value < arg->min) ||
 777             (*value > arg->max) ||
 778             (grouped && arg_set->argc < *value)) {
 779                 *error = arg->error;
 780                 return -EINVAL;
 781         }
 782
 783         return 0;
 784 }
 785
 786 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 787                 unsigned *value, char **error)
 788 {
 789         return validate_next_arg(arg, arg_set, value, error, 0);
 790 }
 791 EXPORT_SYMBOL(dm_read_arg);
 792
 793 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
 794                       unsigned *value, char **error)
 795 {
 796         return validate_next_arg(arg, arg_set, value, error, 1);
 797 }
 798 EXPORT_SYMBOL(dm_read_arg_group);
 799
 800 const char *dm_shift_arg(struct dm_arg_set *as)
 801 {
 802         char *r;
 803
 804         if (as->argc) {
 805                 as->argc--;
 806                 r = *as->argv;
 807                 as->argv++;
 808                 return r;
 809         }
 810
 811         return NULL;
 812 }
 813 EXPORT_SYMBOL(dm_shift_arg);
 814
 815 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 816 {
 817         BUG_ON(as->argc < num_args);
 818         as->argc -= num_args;
 819         as->argv += num_args;
 820 }
 821 EXPORT_SYMBOL(dm_consume_args);
 822
 823 static int dm_table_set_type(struct dm_table *t)
 824 {
 825         unsigned i;
 826         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 827         bool use_blk_mq = false;
 828         struct dm_target *tgt;
 829         struct dm_dev_internal *dd;
 830         struct list_head *devices;
 831         unsigned live_md_type = dm_get_md_type(t->md);
 832
 833         for (i = 0; i < t->num_targets; i++) {
 834                 tgt = t->targets + i;
 835                 if (dm_target_hybrid(tgt))
 836                         hybrid = 1;
 837                 else if (dm_target_request_based(tgt))
 838                         request_based = 1;
 839                 else
 840                         bio_based = 1;
 841
 842                 if (bio_based && request_based) {
 843                         DMWARN("Inconsistent table: different target types"
 844                                " can't be mixed up");
 845                         return -EINVAL;
 846                 }
 847         }
 848
 849         if (hybrid && !bio_based && !request_based) {
 850                 /*
 851                  * The targets can work either way.
 852                  * Determine the type from the live device.
 853                  * Default to bio-based if device is new.
 854                  */
 855                 if (live_md_type == DM_TYPE_REQUEST_BASED ||
 856                     live_md_type == DM_TYPE_MQ_REQUEST_BASED)
 857                         request_based = 1;
 858                 else
 859                         bio_based = 1;
 860         }
 861
 862         if (bio_based) {
 863                 /* We must use this table as bio-based */
 864                 t->type = DM_TYPE_BIO_BASED;
 865                 return 0;
 866         }
 867
 868         BUG_ON(!request_based); /* No targets in this table */
 869
 870         /*
 871          * Request-based dm supports only tables that have a single target now.
 872          * To support multiple targets, request splitting support is needed,
 873          * and that needs lots of changes in the block-layer.
 874          * (e.g. request completion process for partial completion.)
 875          */
 876         if (t->num_targets > 1) {
 877                 DMWARN("Request-based dm doesn't support multiple targets yet");
 878                 return -EINVAL;
 879         }
 880
 881         /* Non-request-stackable devices can't be used for request-based dm */
 882         devices = dm_table_get_devices(t);
 883         list_for_each_entry(dd, devices, list) {
 884                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
 885
 886                 if (!blk_queue_stackable(q)) {
 887                         DMERR("table load rejected: including"
 888                               " non-request-stackable devices");
 889                         return -EINVAL;
 890                 }
 891
 892                 if (q->mq_ops)
 893                         use_blk_mq = true;
 894         }
 895
 896         if (use_blk_mq) {
 897                 /* verify _all_ devices in the table are blk-mq devices */
 898                 list_for_each_entry(dd, devices, list)
 899                         if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
 900                                 DMERR("table load rejected: not all devices"
 901                                       " are blk-mq request-stackable");
 902                                 return -EINVAL;
 903                         }
 904                 t->type = DM_TYPE_MQ_REQUEST_BASED;
 905
 906         } else if (hybrid && list_empty(devices) && live_md_type != DM_TYPE_NONE) {
 907                 /* inherit live MD type */
 908                 t->type = live_md_type;
 909
 910         } else
 911                 t->type = DM_TYPE_REQUEST_BASED;
 912
 913         return 0;
 914 }
 915
 916 unsigned dm_table_get_type(struct dm_table *t)
 917 {
 918         return t->type;
 919 }
 920
 921 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 922 {
 923         return t->immutable_target_type;
 924 }
 925
 926 bool dm_table_request_based(struct dm_table *t)
 927 {
 928         unsigned table_type = dm_table_get_type(t);
 929
 930         return (table_type == DM_TYPE_REQUEST_BASED ||
 931                 table_type == DM_TYPE_MQ_REQUEST_BASED);
 932 }
 933
 934 bool dm_table_mq_request_based(struct dm_table *t)
 935 {
 936         return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
 937 }
 938
 939 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
 940 {
 941         unsigned type = dm_table_get_type(t);
 942         unsigned per_bio_data_size = 0;
 943         struct dm_target *tgt;
 944         unsigned i;
 945
 946         if (unlikely(type == DM_TYPE_NONE)) {
 947                 DMWARN("no table type is set, can't allocate mempools");
 948                 return -EINVAL;
 949         }
 950
 951         if (type == DM_TYPE_BIO_BASED)
 952                 for (i = 0; i < t->num_targets; i++) {
 953                         tgt = t->targets + i;
 954                         per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
 955                 }
 956
 957         t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_bio_data_size);
 958         if (!t->mempools)
 959                 return -ENOMEM;
 960
 961         return 0;
 962 }
 963
 964 void dm_table_free_md_mempools(struct dm_table *t)
 965 {
 966         dm_free_md_mempools(t->mempools);
 967         t->mempools = NULL;
 968 }
 969
 970 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
 971 {
 972         return t->mempools;
 973 }
 974
 975 static int setup_indexes(struct dm_table *t)
 976 {
 977         int i;
 978         unsigned int total = 0;
 979         sector_t *indexes;
 980
 981         /* allocate the space for *all* the indexes */
 982         for (i = t->depth - 2; i >= 0; i--) {
 983                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
 984                 total += t->counts[i];
 985         }
 986
 987         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
 988         if (!indexes)
 989                 return -ENOMEM;
 990
 991         /* set up internal nodes, bottom-up */
 992         for (i = t->depth - 2; i >= 0; i--) {
 993                 t->index[i] = indexes;
 994                 indexes += (KEYS_PER_NODE * t->counts[i]);
 995                 setup_btree_index(i, t);
 996         }
 997
 998         return 0;
 999 }
1000
1001 /*
1002  * Builds the btree to index the map.
1003  */
1004 static int dm_table_build_index(struct dm_table *t)
1005 {
1006         int r = 0;
1007         unsigned int leaf_nodes;
1008
1009         /* how many indexes will the btree have ? */
1010         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1011         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1012
1013         /* leaf layer has already been set up */
1014         t->counts[t->depth - 1] = leaf_nodes;
1015         t->index[t->depth - 1] = t->highs;
1016
1017         if (t->depth >= 2)
1018                 r = setup_indexes(t);
1019
1020         return r;
1021 }
1022
1023 /*
1024  * Get a disk whose integrity profile reflects the table's profile.
1025  * If %match_all is true, all devices' profiles must match.
1026  * If %match_all is false, all devices must at least have an
1027  * allocated integrity profile; but uninitialized is ok.
1028  * Returns NULL if integrity support was inconsistent or unavailable.
1029  */
1030 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
1031                                                     bool match_all)
1032 {
1033         struct list_head *devices = dm_table_get_devices(t);
1034         struct dm_dev_internal *dd = NULL;
1035         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1036
1037         list_for_each_entry(dd, devices, list) {
1038                 template_disk = dd->dm_dev->bdev->bd_disk;
1039                 if (!blk_get_integrity(template_disk))
1040                         goto no_integrity;
1041                 if (!match_all && !blk_integrity_is_initialized(template_disk))
1042                         continue; /* skip uninitialized profiles */
1043                 else if (prev_disk &&
1044                          blk_integrity_compare(prev_disk, template_disk) < 0)
1045                         goto no_integrity;
1046                 prev_disk = template_disk;
1047         }
1048
1049         return template_disk;
1050
1051 no_integrity:
1052         if (prev_disk)
1053                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1054                        dm_device_name(t->md),
1055                        prev_disk->disk_name,
1056                        template_disk->disk_name);
1057         return NULL;
1058 }
1059
1060 /*
1061  * Register the mapped device for blk_integrity support if
1062  * the underlying devices have an integrity profile.  But all devices
1063  * may not have matching profiles (checking all devices isn't reliable
1064  * during table load because this table may use other DM device(s) which
1065  * must be resumed before they will have an initialized integity profile).
1066  * Stacked DM devices force a 2 stage integrity profile validation:
1067  * 1 - during load, validate all initialized integrity profiles match
1068  * 2 - during resume, validate all integrity profiles match
1069  */
1070 static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
1071 {
1072         struct gendisk *template_disk = NULL;
1073
1074         template_disk = dm_table_get_integrity_disk(t, false);
1075         if (!template_disk)
1076                 return 0;
1077
1078         if (!blk_integrity_is_initialized(dm_disk(md))) {
1079                 t->integrity_supported = 1;
1080                 return blk_integrity_register(dm_disk(md), NULL);
1081         }
1082
1083         /*
1084          * If DM device already has an initalized integrity
1085          * profile the new profile should not conflict.
1086          */
1087         if (blk_integrity_is_initialized(template_disk) &&
1088             blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1089                 DMWARN("%s: conflict with existing integrity profile: "
1090                        "%s profile mismatch",
1091                        dm_device_name(t->md),
1092                        template_disk->disk_name);
1093                 return 1;
1094         }
1095
1096         /* Preserve existing initialized integrity profile */
1097         t->integrity_supported = 1;
1098         return 0;
1099 }
1100
1101 /*
1102  * Prepares the table for use by building the indices,
1103  * setting the type, and allocating mempools.
1104  */
1105 int dm_table_complete(struct dm_table *t)
1106 {
1107         int r;
1108
1109         r = dm_table_set_type(t);
1110         if (r) {
1111                 DMERR("unable to set table type");
1112                 return r;
1113         }
1114
1115         r = dm_table_build_index(t);
1116         if (r) {
1117                 DMERR("unable to build btrees");
1118                 return r;
1119         }
1120
1121         r = dm_table_prealloc_integrity(t, t->md);
1122         if (r) {
1123                 DMERR("could not register integrity profile.");
1124                 return r;
1125         }
1126
1127         r = dm_table_alloc_md_mempools(t, t->md);
1128         if (r)
1129                 DMERR("unable to allocate mempools");
1130
1131         return r;
1132 }
1133
1134 static DEFINE_MUTEX(_event_lock);
1135 void dm_table_event_callback(struct dm_table *t,
1136                              void (*fn)(void *), void *context)
1137 {
1138         mutex_lock(&_event_lock);
1139         t->event_fn = fn;
1140         t->event_context = context;
1141         mutex_unlock(&_event_lock);
1142 }
1143
1144 void dm_table_event(struct dm_table *t)
1145 {
1146         /*
1147          * You can no longer call dm_table_event() from interrupt
1148          * context, use a bottom half instead.
1149          */
1150         BUG_ON(in_interrupt());
1151
1152         mutex_lock(&_event_lock);
1153         if (t->event_fn)
1154                 t->event_fn(t->event_context);
1155         mutex_unlock(&_event_lock);
1156 }
1157 EXPORT_SYMBOL(dm_table_event);
1158
1159 sector_t dm_table_get_size(struct dm_table *t)
1160 {
1161         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1162 }
1163 EXPORT_SYMBOL(dm_table_get_size);
1164
1165 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1166 {
1167         if (index >= t->num_targets)
1168                 return NULL;
1169
1170         return t->targets + index;
1171 }
1172
1173 /*
1174  * Search the btree for the correct target.
1175  *
1176  * Caller should check returned pointer with dm_target_is_valid()
1177  * to trap I/O beyond end of device.
1178  */
1179 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1180 {
1181         unsigned int l, n = 0, k = 0;
1182         sector_t *node;
1183
1184         for (l = 0; l < t->depth; l++) {
1185                 n = get_child(n, k);
1186                 node = get_node(t, l, n);
1187
1188                 for (k = 0; k < KEYS_PER_NODE; k++)
1189                         if (node[k] >= sector)
1190                                 break;
1191         }
1192
1193         return &t->targets[(KEYS_PER_NODE * n) + k];
1194 }
1195
1196 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1197                         sector_t start, sector_t len, void *data)
1198 {
1199         unsigned *num_devices = data;
1200
1201         (*num_devices)++;
1202
1203         return 0;
1204 }
1205
1206 /*
1207  * Check whether a table has no data devices attached using each
1208  * target's iterate_devices method.
1209  * Returns false if the result is unknown because a target doesn't
1210  * support iterate_devices.
1211  */
1212 bool dm_table_has_no_data_devices(struct dm_table *table)
1213 {
1214         struct dm_target *uninitialized_var(ti);
1215         unsigned i = 0, num_devices = 0;
1216
1217         while (i < dm_table_get_num_targets(table)) {
1218                 ti = dm_table_get_target(table, i++);
1219
1220                 if (!ti->type->iterate_devices)
1221                         return false;
1222
1223                 ti->type->iterate_devices(ti, count_device, &num_devices);
1224                 if (num_devices)
1225                         return false;
1226         }
1227
1228         return true;
1229 }
1230
1231 /*
1232  * Establish the new table's queue_limits and validate them.
1233  */
1234 int dm_calculate_queue_limits(struct dm_table *table,
1235                               struct queue_limits *limits)
1236 {
1237         struct dm_target *uninitialized_var(ti);
1238         struct queue_limits ti_limits;
1239         unsigned i = 0;
1240
1241         blk_set_stacking_limits(limits);
1242
1243         while (i < dm_table_get_num_targets(table)) {
1244                 blk_set_stacking_limits(&ti_limits);
1245
1246                 ti = dm_table_get_target(table, i++);
1247
1248                 if (!ti->type->iterate_devices)
1249                         goto combine_limits;
1250
1251                 /*
1252                  * Combine queue limits of all the devices this target uses.
1253                  */
1254                 ti->type->iterate_devices(ti, dm_set_device_limits,
1255                                           &ti_limits);
1256
1257                 /* Set I/O hints portion of queue limits */
1258                 if (ti->type->io_hints)
1259                         ti->type->io_hints(ti, &ti_limits);
1260
1261                 /*
1262                  * Check each device area is consistent with the target's
1263                  * overall queue limits.
1264                  */
1265                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1266                                               &ti_limits))
1267                         return -EINVAL;
1268
1269 combine_limits:
1270                 /*
1271                  * Merge this target's queue limits into the overall limits
1272                  * for the table.
1273                  */
1274                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1275                         DMWARN("%s: adding target device "
1276                                "(start sect %llu len %llu) "
1277                                "caused an alignment inconsistency",
1278                                dm_device_name(table->md),
1279                                (unsigned long long) ti->begin,
1280                                (unsigned long long) ti->len);
1281         }
1282
1283         return validate_hardware_logical_block_alignment(table, limits);
1284 }
1285
1286 /*
1287  * Set the integrity profile for this device if all devices used have
1288  * matching profiles.  We're quite deep in the resume path but still
1289  * don't know if all devices (particularly DM devices this device
1290  * may be stacked on) have matching profiles.  Even if the profiles
1291  * don't match we have no way to fail (to resume) at this point.
1292  */
1293 static void dm_table_set_integrity(struct dm_table *t)
1294 {
1295         struct gendisk *template_disk = NULL;
1296
1297         if (!blk_get_integrity(dm_disk(t->md)))
1298                 return;
1299
1300         template_disk = dm_table_get_integrity_disk(t, true);
1301         if (template_disk)
1302                 blk_integrity_register(dm_disk(t->md),
1303                                        blk_get_integrity(template_disk));
1304         else if (blk_integrity_is_initialized(dm_disk(t->md)))
1305                 DMWARN("%s: device no longer has a valid integrity profile",
1306                        dm_device_name(t->md));
1307         else
1308                 DMWARN("%s: unable to establish an integrity profile",
1309                        dm_device_name(t->md));
1310 }
1311
1312 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1313                                 sector_t start, sector_t len, void *data)
1314 {
1315         unsigned flush = (*(unsigned *)data);
1316         struct request_queue *q = bdev_get_queue(dev->bdev);
1317
1318         return q && (q->flush_flags & flush);
1319 }
1320
1321 static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
1322 {
1323         struct dm_target *ti;
1324         unsigned i = 0;
1325
1326         /*
1327          * Require at least one underlying device to support flushes.
1328          * t->devices includes internal dm devices such as mirror logs
1329          * so we need to use iterate_devices here, which targets
1330          * supporting flushes must provide.
1331          */
1332         while (i < dm_table_get_num_targets(t)) {
1333                 ti = dm_table_get_target(t, i++);
1334
1335                 if (!ti->num_flush_bios)
1336                         continue;
1337
1338                 if (ti->flush_supported)
1339                         return true;
1340
1341                 if (ti->type->iterate_devices &&
1342                     ti->type->iterate_devices(ti, device_flush_capable, &flush))
1343                         return true;
1344         }
1345
1346         return false;
1347 }
1348
1349 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1350 {
1351         struct dm_target *ti;
1352         unsigned i = 0;
1353
1354         /* Ensure that all targets supports discard_zeroes_data. */
1355         while (i < dm_table_get_num_targets(t)) {
1356                 ti = dm_table_get_target(t, i++);
1357
1358                 if (ti->discard_zeroes_data_unsupported)
1359                         return false;
1360         }
1361
1362         return true;
1363 }
1364
1365 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1366                             sector_t start, sector_t len, void *data)
1367 {
1368         struct request_queue *q = bdev_get_queue(dev->bdev);
1369
1370         return q && blk_queue_nonrot(q);
1371 }
1372
1373 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1374                              sector_t start, sector_t len, void *data)
1375 {
1376         struct request_queue *q = bdev_get_queue(dev->bdev);
1377
1378         return q && !blk_queue_add_random(q);
1379 }
1380
1381 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1382                                    sector_t start, sector_t len, void *data)
1383 {
1384         struct request_queue *q = bdev_get_queue(dev->bdev);
1385
1386         return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1387 }
1388
1389 static int queue_supports_sg_gaps(struct dm_target *ti, struct dm_dev *dev,
1390                                   sector_t start, sector_t len, void *data)
1391 {
1392         struct request_queue *q = bdev_get_queue(dev->bdev);
1393
1394         return q && !test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags);
1395 }
1396
1397 static bool dm_table_all_devices_attribute(struct dm_table *t,
1398                                            iterate_devices_callout_fn func)
1399 {
1400         struct dm_target *ti;
1401         unsigned i = 0;
1402
1403         while (i < dm_table_get_num_targets(t)) {
1404                 ti = dm_table_get_target(t, i++);
1405
1406                 if (!ti->type->iterate_devices ||
1407                     !ti->type->iterate_devices(ti, func, NULL))
1408                         return false;
1409         }
1410
1411         return true;
1412 }
1413
1414 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1415                                          sector_t start, sector_t len, void *data)
1416 {
1417         struct request_queue *q = bdev_get_queue(dev->bdev);
1418
1419         return q && !q->limits.max_write_same_sectors;
1420 }
1421
1422 static bool dm_table_supports_write_same(struct dm_table *t)
1423 {
1424         struct dm_target *ti;
1425         unsigned i = 0;
1426
1427         while (i < dm_table_get_num_targets(t)) {
1428                 ti = dm_table_get_target(t, i++);
1429
1430                 if (!ti->num_write_same_bios)
1431                         return false;
1432
1433                 if (!ti->type->iterate_devices ||
1434                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1435                         return false;
1436         }
1437
1438         return true;
1439 }
1440
1441 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1442                                   sector_t start, sector_t len, void *data)
1443 {
1444         struct request_queue *q = bdev_get_queue(dev->bdev);
1445
1446         return q && blk_queue_discard(q);
1447 }
1448
1449 static bool dm_table_supports_discards(struct dm_table *t)
1450 {
1451         struct dm_target *ti;
1452         unsigned i = 0;
1453
1454         /*
1455          * Unless any target used by the table set discards_supported,
1456          * require at least one underlying device to support discards.
1457          * t->devices includes internal dm devices such as mirror logs
1458          * so we need to use iterate_devices here, which targets
1459          * supporting discard selectively must provide.
1460          */
1461         while (i < dm_table_get_num_targets(t)) {
1462                 ti = dm_table_get_target(t, i++);
1463
1464                 if (!ti->num_discard_bios)
1465                         continue;
1466
1467                 if (ti->discards_supported)
1468                         return true;
1469
1470                 if (ti->type->iterate_devices &&
1471                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1472                         return true;
1473         }
1474
1475         return false;
1476 }
1477
1478 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1479                                struct queue_limits *limits)
1480 {
1481         unsigned flush = 0;
1482
1483         /*
1484          * Copy table's limits to the DM device's request_queue
1485          */
1486         q->limits = *limits;
1487
1488         if (!dm_table_supports_discards(t))
1489                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1490         else
1491                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1492
1493         if (dm_table_supports_flush(t, REQ_FLUSH)) {
1494                 flush |= REQ_FLUSH;
1495                 if (dm_table_supports_flush(t, REQ_FUA))
1496                         flush |= REQ_FUA;
1497         }
1498         blk_queue_flush(q, flush);
1499
1500         if (!dm_table_discard_zeroes_data(t))
1501                 q->limits.discard_zeroes_data = 0;
1502
1503         /* Ensure that all underlying devices are non-rotational. */
1504         if (dm_table_all_devices_attribute(t, device_is_nonrot))
1505                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1506         else
1507                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1508
1509         if (!dm_table_supports_write_same(t))
1510                 q->limits.max_write_same_sectors = 0;
1511
1512         if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1513                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1514         else
1515                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1516
1517         if (dm_table_all_devices_attribute(t, queue_supports_sg_gaps))
1518                 queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, q);
1519         else
1520                 queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, q);
1521
1522         dm_table_set_integrity(t);
1523
1524         /*
1525          * Determine whether or not this queue's I/O timings contribute
1526          * to the entropy pool, Only request-based targets use this.
1527          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1528          * have it set.
1529          */
1530         if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1531                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1532
1533         /*
1534          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1535          * visible to other CPUs because, once the flag is set, incoming bios
1536          * are processed by request-based dm, which refers to the queue
1537          * settings.
1538          * Until the flag set, bios are passed to bio-based dm and queued to
1539          * md->deferred where queue settings are not needed yet.
1540          * Those bios are passed to request-based dm at the resume time.
1541          */
1542         smp_mb();
1543         if (dm_table_request_based(t))
1544                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1545 }
1546
1547 unsigned int dm_table_get_num_targets(struct dm_table *t)
1548 {
1549         return t->num_targets;
1550 }
1551
1552 struct list_head *dm_table_get_devices(struct dm_table *t)
1553 {
1554         return &t->devices;
1555 }
1556
1557 fmode_t dm_table_get_mode(struct dm_table *t)
1558 {
1559         return t->mode;
1560 }
1561 EXPORT_SYMBOL(dm_table_get_mode);
1562
1563 enum suspend_mode {
1564         PRESUSPEND,
1565         PRESUSPEND_UNDO,
1566         POSTSUSPEND,
1567 };
1568
1569 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1570 {
1571         int i = t->num_targets;
1572         struct dm_target *ti = t->targets;
1573
1574         while (i--) {
1575                 switch (mode) {
1576                 case PRESUSPEND:
1577                         if (ti->type->presuspend)
1578                                 ti->type->presuspend(ti);
1579                         break;
1580                 case PRESUSPEND_UNDO:
1581                         if (ti->type->presuspend_undo)
1582                                 ti->type->presuspend_undo(ti);
1583                         break;
1584                 case POSTSUSPEND:
1585                         if (ti->type->postsuspend)
1586                                 ti->type->postsuspend(ti);
1587                         break;
1588                 }
1589                 ti++;
1590         }
1591 }
1592
1593 void dm_table_presuspend_targets(struct dm_table *t)
1594 {
1595         if (!t)
1596                 return;
1597
1598         suspend_targets(t, PRESUSPEND);
1599 }
1600
1601 void dm_table_presuspend_undo_targets(struct dm_table *t)
1602 {
1603         if (!t)
1604                 return;
1605
1606         suspend_targets(t, PRESUSPEND_UNDO);
1607 }
1608
1609 void dm_table_postsuspend_targets(struct dm_table *t)
1610 {
1611         if (!t)
1612                 return;
1613
1614         suspend_targets(t, POSTSUSPEND);
1615 }
1616
1617 int dm_table_resume_targets(struct dm_table *t)
1618 {
1619         int i, r = 0;
1620
1621         for (i = 0; i < t->num_targets; i++) {
1622                 struct dm_target *ti = t->targets + i;
1623
1624                 if (!ti->type->preresume)
1625                         continue;
1626
1627                 r = ti->type->preresume(ti);
1628                 if (r) {
1629                         DMERR("%s: %s: preresume failed, error = %d",
1630                               dm_device_name(t->md), ti->type->name, r);
1631                         return r;
1632                 }
1633         }
1634
1635         for (i = 0; i < t->num_targets; i++) {
1636                 struct dm_target *ti = t->targets + i;
1637
1638                 if (ti->type->resume)
1639                         ti->type->resume(ti);
1640         }
1641
1642         return 0;
1643 }
1644
1645 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1646 {
1647         list_add(&cb->list, &t->target_callbacks);
1648 }
1649 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1650
1651 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1652 {
1653         struct dm_dev_internal *dd;
1654         struct list_head *devices = dm_table_get_devices(t);
1655         struct dm_target_callbacks *cb;
1656         int r = 0;
1657
1658         list_for_each_entry(dd, devices, list) {
1659                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1660                 char b[BDEVNAME_SIZE];
1661
1662                 if (likely(q))
1663                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1664                 else
1665                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1666                                      dm_device_name(t->md),
1667                                      bdevname(dd->dm_dev->bdev, b));
1668         }
1669
1670         list_for_each_entry(cb, &t->target_callbacks, list)
1671                 if (cb->congested_fn)
1672                         r |= cb->congested_fn(cb, bdi_bits);
1673
1674         return r;
1675 }
1676
1677 struct mapped_device *dm_table_get_md(struct dm_table *t)
1678 {
1679         return t->md;
1680 }
1681 EXPORT_SYMBOL(dm_table_get_md);
1682
1683 void dm_table_run_md_queue_async(struct dm_table *t)
1684 {
1685         struct mapped_device *md;
1686         struct request_queue *queue;
1687         unsigned long flags;
1688
1689         if (!dm_table_request_based(t))
1690                 return;
1691
1692         md = dm_table_get_md(t);
1693         queue = dm_get_md_queue(md);
1694         if (queue) {
1695                 if (queue->mq_ops)
1696                         blk_mq_run_hw_queues(queue, true);
1697                 else {
1698                         spin_lock_irqsave(queue->queue_lock, flags);
1699                         blk_run_queue_async(queue);
1700                         spin_unlock_irqrestore(queue->queue_lock, flags);
1701                 }
1702         }
1703 }
1704 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1705