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 bool __table_type_request_based(unsigned table_type)
 824 {
 825         return (table_type == DM_TYPE_REQUEST_BASED ||
 826                 table_type == DM_TYPE_MQ_REQUEST_BASED);
 827 }
 828
 829 static int dm_table_set_type(struct dm_table *t)
 830 {
 831         unsigned i;
 832         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 833         bool use_blk_mq = false;
 834         struct dm_target *tgt;
 835         struct dm_dev_internal *dd;
 836         struct list_head *devices;
 837         unsigned live_md_type = dm_get_md_type(t->md);
 838
 839         for (i = 0; i < t->num_targets; i++) {
 840                 tgt = t->targets + i;
 841                 if (dm_target_hybrid(tgt))
 842                         hybrid = 1;
 843                 else if (dm_target_request_based(tgt))
 844                         request_based = 1;
 845                 else
 846                         bio_based = 1;
 847
 848                 if (bio_based && request_based) {
 849                         DMWARN("Inconsistent table: different target types"
 850                                " can't be mixed up");
 851                         return -EINVAL;
 852                 }
 853         }
 854
 855         if (hybrid && !bio_based && !request_based) {
 856                 /*
 857                  * The targets can work either way.
 858                  * Determine the type from the live device.
 859                  * Default to bio-based if device is new.
 860                  */
 861                 if (__table_type_request_based(live_md_type))
 862                         request_based = 1;
 863                 else
 864                         bio_based = 1;
 865         }
 866
 867         if (bio_based) {
 868                 /* We must use this table as bio-based */
 869                 t->type = DM_TYPE_BIO_BASED;
 870                 return 0;
 871         }
 872
 873         BUG_ON(!request_based); /* No targets in this table */
 874
 875         /*
 876          * Request-based dm supports only tables that have a single target now.
 877          * To support multiple targets, request splitting support is needed,
 878          * and that needs lots of changes in the block-layer.
 879          * (e.g. request completion process for partial completion.)
 880          */
 881         if (t->num_targets > 1) {
 882                 DMWARN("Request-based dm doesn't support multiple targets yet");
 883                 return -EINVAL;
 884         }
 885
 886         /* Non-request-stackable devices can't be used for request-based dm */
 887         devices = dm_table_get_devices(t);
 888         list_for_each_entry(dd, devices, list) {
 889                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
 890
 891                 if (!blk_queue_stackable(q)) {
 892                         DMERR("table load rejected: including"
 893                               " non-request-stackable devices");
 894                         return -EINVAL;
 895                 }
 896
 897                 if (q->mq_ops)
 898                         use_blk_mq = true;
 899         }
 900
 901         if (use_blk_mq) {
 902                 /* verify _all_ devices in the table are blk-mq devices */
 903                 list_for_each_entry(dd, devices, list)
 904                         if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
 905                                 DMERR("table load rejected: not all devices"
 906                                       " are blk-mq request-stackable");
 907                                 return -EINVAL;
 908                         }
 909                 t->type = DM_TYPE_MQ_REQUEST_BASED;
 910
 911         } else if (list_empty(devices) && __table_type_request_based(live_md_type)) {
 912                 /* inherit live MD type */
 913                 t->type = live_md_type;
 914
 915         } else
 916                 t->type = DM_TYPE_REQUEST_BASED;
 917
 918         return 0;
 919 }
 920
 921 unsigned dm_table_get_type(struct dm_table *t)
 922 {
 923         return t->type;
 924 }
 925
 926 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 927 {
 928         return t->immutable_target_type;
 929 }
 930
 931 bool dm_table_request_based(struct dm_table *t)
 932 {
 933         return __table_type_request_based(dm_table_get_type(t));
 934 }
 935
 936 bool dm_table_mq_request_based(struct dm_table *t)
 937 {
 938         return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
 939 }
 940
 941 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
 942 {
 943         unsigned type = dm_table_get_type(t);
 944         unsigned per_bio_data_size = 0;
 945         struct dm_target *tgt;
 946         unsigned i;
 947
 948         if (unlikely(type == DM_TYPE_NONE)) {
 949                 DMWARN("no table type is set, can't allocate mempools");
 950                 return -EINVAL;
 951         }
 952
 953         if (type == DM_TYPE_BIO_BASED)
 954                 for (i = 0; i < t->num_targets; i++) {
 955                         tgt = t->targets + i;
 956                         per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
 957                 }
 958
 959         t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_bio_data_size);
 960         if (!t->mempools)
 961                 return -ENOMEM;
 962
 963         return 0;
 964 }
 965
 966 void dm_table_free_md_mempools(struct dm_table *t)
 967 {
 968         dm_free_md_mempools(t->mempools);
 969         t->mempools = NULL;
 970 }
 971
 972 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
 973 {
 974         return t->mempools;
 975 }
 976
 977 static int setup_indexes(struct dm_table *t)
 978 {
 979         int i;
 980         unsigned int total = 0;
 981         sector_t *indexes;
 982
 983         /* allocate the space for *all* the indexes */
 984         for (i = t->depth - 2; i >= 0; i--) {
 985                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
 986                 total += t->counts[i];
 987         }
 988
 989         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
 990         if (!indexes)
 991                 return -ENOMEM;
 992
 993         /* set up internal nodes, bottom-up */
 994         for (i = t->depth - 2; i >= 0; i--) {
 995                 t->index[i] = indexes;
 996                 indexes += (KEYS_PER_NODE * t->counts[i]);
 997                 setup_btree_index(i, t);
 998         }
 999
1000         return 0;
1001 }
1002
1003 /*
1004  * Builds the btree to index the map.
1005  */
1006 static int dm_table_build_index(struct dm_table *t)
1007 {
1008         int r = 0;
1009         unsigned int leaf_nodes;
1010
1011         /* how many indexes will the btree have ? */
1012         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1013         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1014
1015         /* leaf layer has already been set up */
1016         t->counts[t->depth - 1] = leaf_nodes;
1017         t->index[t->depth - 1] = t->highs;
1018
1019         if (t->depth >= 2)
1020                 r = setup_indexes(t);
1021
1022         return r;
1023 }
1024
1025 /*
1026  * Get a disk whose integrity profile reflects the table's profile.
1027  * If %match_all is true, all devices' profiles must match.
1028  * If %match_all is false, all devices must at least have an
1029  * allocated integrity profile; but uninitialized is ok.
1030  * Returns NULL if integrity support was inconsistent or unavailable.
1031  */
1032 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
1033                                                     bool match_all)
1034 {
1035         struct list_head *devices = dm_table_get_devices(t);
1036         struct dm_dev_internal *dd = NULL;
1037         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1038
1039         list_for_each_entry(dd, devices, list) {
1040                 template_disk = dd->dm_dev->bdev->bd_disk;
1041                 if (!blk_get_integrity(template_disk))
1042                         goto no_integrity;
1043                 if (!match_all && !blk_integrity_is_initialized(template_disk))
1044                         continue; /* skip uninitialized profiles */
1045                 else if (prev_disk &&
1046                          blk_integrity_compare(prev_disk, template_disk) < 0)
1047                         goto no_integrity;
1048                 prev_disk = template_disk;
1049         }
1050
1051         return template_disk;
1052
1053 no_integrity:
1054         if (prev_disk)
1055                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1056                        dm_device_name(t->md),
1057                        prev_disk->disk_name,
1058                        template_disk->disk_name);
1059         return NULL;
1060 }
1061
1062 /*
1063  * Register the mapped device for blk_integrity support if
1064  * the underlying devices have an integrity profile.  But all devices
1065  * may not have matching profiles (checking all devices isn't reliable
1066  * during table load because this table may use other DM device(s) which
1067  * must be resumed before they will have an initialized integity profile).
1068  * Stacked DM devices force a 2 stage integrity profile validation:
1069  * 1 - during load, validate all initialized integrity profiles match
1070  * 2 - during resume, validate all integrity profiles match
1071  */
1072 static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
1073 {
1074         struct gendisk *template_disk = NULL;
1075
1076         template_disk = dm_table_get_integrity_disk(t, false);
1077         if (!template_disk)
1078                 return 0;
1079
1080         if (!blk_integrity_is_initialized(dm_disk(md))) {
1081                 t->integrity_supported = 1;
1082                 return blk_integrity_register(dm_disk(md), NULL);
1083         }
1084
1085         /*
1086          * If DM device already has an initalized integrity
1087          * profile the new profile should not conflict.
1088          */
1089         if (blk_integrity_is_initialized(template_disk) &&
1090             blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1091                 DMWARN("%s: conflict with existing integrity profile: "
1092                        "%s profile mismatch",
1093                        dm_device_name(t->md),
1094                        template_disk->disk_name);
1095                 return 1;
1096         }
1097
1098         /* Preserve existing initialized integrity profile */
1099         t->integrity_supported = 1;
1100         return 0;
1101 }
1102
1103 /*
1104  * Prepares the table for use by building the indices,
1105  * setting the type, and allocating mempools.
1106  */
1107 int dm_table_complete(struct dm_table *t)
1108 {
1109         int r;
1110
1111         r = dm_table_set_type(t);
1112         if (r) {
1113                 DMERR("unable to set table type");
1114                 return r;
1115         }
1116
1117         r = dm_table_build_index(t);
1118         if (r) {
1119                 DMERR("unable to build btrees");
1120                 return r;
1121         }
1122
1123         r = dm_table_prealloc_integrity(t, t->md);
1124         if (r) {
1125                 DMERR("could not register integrity profile.");
1126                 return r;
1127         }
1128
1129         r = dm_table_alloc_md_mempools(t, t->md);
1130         if (r)
1131                 DMERR("unable to allocate mempools");
1132
1133         return r;
1134 }
1135
1136 static DEFINE_MUTEX(_event_lock);
1137 void dm_table_event_callback(struct dm_table *t,
1138                              void (*fn)(void *), void *context)
1139 {
1140         mutex_lock(&_event_lock);
1141         t->event_fn = fn;
1142         t->event_context = context;
1143         mutex_unlock(&_event_lock);
1144 }
1145
1146 void dm_table_event(struct dm_table *t)
1147 {
1148         /*
1149          * You can no longer call dm_table_event() from interrupt
1150          * context, use a bottom half instead.
1151          */
1152         BUG_ON(in_interrupt());
1153
1154         mutex_lock(&_event_lock);
1155         if (t->event_fn)
1156                 t->event_fn(t->event_context);
1157         mutex_unlock(&_event_lock);
1158 }
1159 EXPORT_SYMBOL(dm_table_event);
1160
1161 sector_t dm_table_get_size(struct dm_table *t)
1162 {
1163         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1164 }
1165 EXPORT_SYMBOL(dm_table_get_size);
1166
1167 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1168 {
1169         if (index >= t->num_targets)
1170                 return NULL;
1171
1172         return t->targets + index;
1173 }
1174
1175 /*
1176  * Search the btree for the correct target.
1177  *
1178  * Caller should check returned pointer with dm_target_is_valid()
1179  * to trap I/O beyond end of device.
1180  */
1181 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1182 {
1183         unsigned int l, n = 0, k = 0;
1184         sector_t *node;
1185
1186         for (l = 0; l < t->depth; l++) {
1187                 n = get_child(n, k);
1188                 node = get_node(t, l, n);
1189
1190                 for (k = 0; k < KEYS_PER_NODE; k++)
1191                         if (node[k] >= sector)
1192                                 break;
1193         }
1194
1195         return &t->targets[(KEYS_PER_NODE * n) + k];
1196 }
1197
1198 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1199                         sector_t start, sector_t len, void *data)
1200 {
1201         unsigned *num_devices = data;
1202
1203         (*num_devices)++;
1204
1205         return 0;
1206 }
1207
1208 /*
1209  * Check whether a table has no data devices attached using each
1210  * target's iterate_devices method.
1211  * Returns false if the result is unknown because a target doesn't
1212  * support iterate_devices.
1213  */
1214 bool dm_table_has_no_data_devices(struct dm_table *table)
1215 {
1216         struct dm_target *uninitialized_var(ti);
1217         unsigned i = 0, num_devices = 0;
1218
1219         while (i < dm_table_get_num_targets(table)) {
1220                 ti = dm_table_get_target(table, i++);
1221
1222                 if (!ti->type->iterate_devices)
1223                         return false;
1224
1225                 ti->type->iterate_devices(ti, count_device, &num_devices);
1226                 if (num_devices)
1227                         return false;
1228         }
1229
1230         return true;
1231 }
1232
1233 /*
1234  * Establish the new table's queue_limits and validate them.
1235  */
1236 int dm_calculate_queue_limits(struct dm_table *table,
1237                               struct queue_limits *limits)
1238 {
1239         struct dm_target *uninitialized_var(ti);
1240         struct queue_limits ti_limits;
1241         unsigned i = 0;
1242
1243         blk_set_stacking_limits(limits);
1244
1245         while (i < dm_table_get_num_targets(table)) {
1246                 blk_set_stacking_limits(&ti_limits);
1247
1248                 ti = dm_table_get_target(table, i++);
1249
1250                 if (!ti->type->iterate_devices)
1251                         goto combine_limits;
1252
1253                 /*
1254                  * Combine queue limits of all the devices this target uses.
1255                  */
1256                 ti->type->iterate_devices(ti, dm_set_device_limits,
1257                                           &ti_limits);
1258
1259                 /* Set I/O hints portion of queue limits */
1260                 if (ti->type->io_hints)
1261                         ti->type->io_hints(ti, &ti_limits);
1262
1263                 /*
1264                  * Check each device area is consistent with the target's
1265                  * overall queue limits.
1266                  */
1267                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1268                                               &ti_limits))
1269                         return -EINVAL;
1270
1271 combine_limits:
1272                 /*
1273                  * Merge this target's queue limits into the overall limits
1274                  * for the table.
1275                  */
1276                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1277                         DMWARN("%s: adding target device "
1278                                "(start sect %llu len %llu) "
1279                                "caused an alignment inconsistency",
1280                                dm_device_name(table->md),
1281                                (unsigned long long) ti->begin,
1282                                (unsigned long long) ti->len);
1283         }
1284
1285         return validate_hardware_logical_block_alignment(table, limits);
1286 }
1287
1288 /*
1289  * Set the integrity profile for this device if all devices used have
1290  * matching profiles.  We're quite deep in the resume path but still
1291  * don't know if all devices (particularly DM devices this device
1292  * may be stacked on) have matching profiles.  Even if the profiles
1293  * don't match we have no way to fail (to resume) at this point.
1294  */
1295 static void dm_table_set_integrity(struct dm_table *t)
1296 {
1297         struct gendisk *template_disk = NULL;
1298
1299         if (!blk_get_integrity(dm_disk(t->md)))
1300                 return;
1301
1302         template_disk = dm_table_get_integrity_disk(t, true);
1303         if (template_disk)
1304                 blk_integrity_register(dm_disk(t->md),
1305                                        blk_get_integrity(template_disk));
1306         else if (blk_integrity_is_initialized(dm_disk(t->md)))
1307                 DMWARN("%s: device no longer has a valid integrity profile",
1308                        dm_device_name(t->md));
1309         else
1310                 DMWARN("%s: unable to establish an integrity profile",
1311                        dm_device_name(t->md));
1312 }
1313
1314 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1315                                 sector_t start, sector_t len, void *data)
1316 {
1317         unsigned flush = (*(unsigned *)data);
1318         struct request_queue *q = bdev_get_queue(dev->bdev);
1319
1320         return q && (q->flush_flags & flush);
1321 }
1322
1323 static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
1324 {
1325         struct dm_target *ti;
1326         unsigned i = 0;
1327
1328         /*
1329          * Require at least one underlying device to support flushes.
1330          * t->devices includes internal dm devices such as mirror logs
1331          * so we need to use iterate_devices here, which targets
1332          * supporting flushes must provide.
1333          */
1334         while (i < dm_table_get_num_targets(t)) {
1335                 ti = dm_table_get_target(t, i++);
1336
1337                 if (!ti->num_flush_bios)
1338                         continue;
1339
1340                 if (ti->flush_supported)
1341                         return true;
1342
1343                 if (ti->type->iterate_devices &&
1344                     ti->type->iterate_devices(ti, device_flush_capable, &flush))
1345                         return true;
1346         }
1347
1348         return false;
1349 }
1350
1351 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1352 {
1353         struct dm_target *ti;
1354         unsigned i = 0;
1355
1356         /* Ensure that all targets supports discard_zeroes_data. */
1357         while (i < dm_table_get_num_targets(t)) {
1358                 ti = dm_table_get_target(t, i++);
1359
1360                 if (ti->discard_zeroes_data_unsupported)
1361                         return false;
1362         }
1363
1364         return true;
1365 }
1366
1367 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1368                             sector_t start, sector_t len, void *data)
1369 {
1370         struct request_queue *q = bdev_get_queue(dev->bdev);
1371
1372         return q && blk_queue_nonrot(q);
1373 }
1374
1375 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1376                              sector_t start, sector_t len, void *data)
1377 {
1378         struct request_queue *q = bdev_get_queue(dev->bdev);
1379
1380         return q && !blk_queue_add_random(q);
1381 }
1382
1383 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1384                                    sector_t start, sector_t len, void *data)
1385 {
1386         struct request_queue *q = bdev_get_queue(dev->bdev);
1387
1388         return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1389 }
1390
1391 static int queue_supports_sg_gaps(struct dm_target *ti, struct dm_dev *dev,
1392                                   sector_t start, sector_t len, void *data)
1393 {
1394         struct request_queue *q = bdev_get_queue(dev->bdev);
1395
1396         return q && !test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags);
1397 }
1398
1399 static bool dm_table_all_devices_attribute(struct dm_table *t,
1400                                            iterate_devices_callout_fn func)
1401 {
1402         struct dm_target *ti;
1403         unsigned i = 0;
1404
1405         while (i < dm_table_get_num_targets(t)) {
1406                 ti = dm_table_get_target(t, i++);
1407
1408                 if (!ti->type->iterate_devices ||
1409                     !ti->type->iterate_devices(ti, func, NULL))
1410                         return false;
1411         }
1412
1413         return true;
1414 }
1415
1416 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1417                                          sector_t start, sector_t len, void *data)
1418 {
1419         struct request_queue *q = bdev_get_queue(dev->bdev);
1420
1421         return q && !q->limits.max_write_same_sectors;
1422 }
1423
1424 static bool dm_table_supports_write_same(struct dm_table *t)
1425 {
1426         struct dm_target *ti;
1427         unsigned i = 0;
1428
1429         while (i < dm_table_get_num_targets(t)) {
1430                 ti = dm_table_get_target(t, i++);
1431
1432                 if (!ti->num_write_same_bios)
1433                         return false;
1434
1435                 if (!ti->type->iterate_devices ||
1436                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1437                         return false;
1438         }
1439
1440         return true;
1441 }
1442
1443 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1444                                   sector_t start, sector_t len, void *data)
1445 {
1446         struct request_queue *q = bdev_get_queue(dev->bdev);
1447
1448         return q && blk_queue_discard(q);
1449 }
1450
1451 static bool dm_table_supports_discards(struct dm_table *t)
1452 {
1453         struct dm_target *ti;
1454         unsigned i = 0;
1455
1456         /*
1457          * Unless any target used by the table set discards_supported,
1458          * require at least one underlying device to support discards.
1459          * t->devices includes internal dm devices such as mirror logs
1460          * so we need to use iterate_devices here, which targets
1461          * supporting discard selectively must provide.
1462          */
1463         while (i < dm_table_get_num_targets(t)) {
1464                 ti = dm_table_get_target(t, i++);
1465
1466                 if (!ti->num_discard_bios)
1467                         continue;
1468
1469                 if (ti->discards_supported)
1470                         return true;
1471
1472                 if (ti->type->iterate_devices &&
1473                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1474                         return true;
1475         }
1476
1477         return false;
1478 }
1479
1480 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1481                                struct queue_limits *limits)
1482 {
1483         unsigned flush = 0;
1484
1485         /*
1486          * Copy table's limits to the DM device's request_queue
1487          */
1488         q->limits = *limits;
1489
1490         if (!dm_table_supports_discards(t))
1491                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1492         else
1493                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1494
1495         if (dm_table_supports_flush(t, REQ_FLUSH)) {
1496                 flush |= REQ_FLUSH;
1497                 if (dm_table_supports_flush(t, REQ_FUA))
1498                         flush |= REQ_FUA;
1499         }
1500         blk_queue_flush(q, flush);
1501
1502         if (!dm_table_discard_zeroes_data(t))
1503                 q->limits.discard_zeroes_data = 0;
1504
1505         /* Ensure that all underlying devices are non-rotational. */
1506         if (dm_table_all_devices_attribute(t, device_is_nonrot))
1507                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1508         else
1509                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1510
1511         if (!dm_table_supports_write_same(t))
1512                 q->limits.max_write_same_sectors = 0;
1513
1514         if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1515                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1516         else
1517                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1518
1519         if (dm_table_all_devices_attribute(t, queue_supports_sg_gaps))
1520                 queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, q);
1521         else
1522                 queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, q);
1523
1524         dm_table_set_integrity(t);
1525
1526         /*
1527          * Determine whether or not this queue's I/O timings contribute
1528          * to the entropy pool, Only request-based targets use this.
1529          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1530          * have it set.
1531          */
1532         if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1533                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1534
1535         /*
1536          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1537          * visible to other CPUs because, once the flag is set, incoming bios
1538          * are processed by request-based dm, which refers to the queue
1539          * settings.
1540          * Until the flag set, bios are passed to bio-based dm and queued to
1541          * md->deferred where queue settings are not needed yet.
1542          * Those bios are passed to request-based dm at the resume time.
1543          */
1544         smp_mb();
1545         if (dm_table_request_based(t))
1546                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1547 }
1548
1549 unsigned int dm_table_get_num_targets(struct dm_table *t)
1550 {
1551         return t->num_targets;
1552 }
1553
1554 struct list_head *dm_table_get_devices(struct dm_table *t)
1555 {
1556         return &t->devices;
1557 }
1558
1559 fmode_t dm_table_get_mode(struct dm_table *t)
1560 {
1561         return t->mode;
1562 }
1563 EXPORT_SYMBOL(dm_table_get_mode);
1564
1565 enum suspend_mode {
1566         PRESUSPEND,
1567         PRESUSPEND_UNDO,
1568         POSTSUSPEND,
1569 };
1570
1571 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1572 {
1573         int i = t->num_targets;
1574         struct dm_target *ti = t->targets;
1575
1576         while (i--) {
1577                 switch (mode) {
1578                 case PRESUSPEND:
1579                         if (ti->type->presuspend)
1580                                 ti->type->presuspend(ti);
1581                         break;
1582                 case PRESUSPEND_UNDO:
1583                         if (ti->type->presuspend_undo)
1584                                 ti->type->presuspend_undo(ti);
1585                         break;
1586                 case POSTSUSPEND:
1587                         if (ti->type->postsuspend)
1588                                 ti->type->postsuspend(ti);
1589                         break;
1590                 }
1591                 ti++;
1592         }
1593 }
1594
1595 void dm_table_presuspend_targets(struct dm_table *t)
1596 {
1597         if (!t)
1598                 return;
1599
1600         suspend_targets(t, PRESUSPEND);
1601 }
1602
1603 void dm_table_presuspend_undo_targets(struct dm_table *t)
1604 {
1605         if (!t)
1606                 return;
1607
1608         suspend_targets(t, PRESUSPEND_UNDO);
1609 }
1610
1611 void dm_table_postsuspend_targets(struct dm_table *t)
1612 {
1613         if (!t)
1614                 return;
1615
1616         suspend_targets(t, POSTSUSPEND);
1617 }
1618
1619 int dm_table_resume_targets(struct dm_table *t)
1620 {
1621         int i, r = 0;
1622
1623         for (i = 0; i < t->num_targets; i++) {
1624                 struct dm_target *ti = t->targets + i;
1625
1626                 if (!ti->type->preresume)
1627                         continue;
1628
1629                 r = ti->type->preresume(ti);
1630                 if (r) {
1631                         DMERR("%s: %s: preresume failed, error = %d",
1632                               dm_device_name(t->md), ti->type->name, r);
1633                         return r;
1634                 }
1635         }
1636
1637         for (i = 0; i < t->num_targets; i++) {
1638                 struct dm_target *ti = t->targets + i;
1639
1640                 if (ti->type->resume)
1641                         ti->type->resume(ti);
1642         }
1643
1644         return 0;
1645 }
1646
1647 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1648 {
1649         list_add(&cb->list, &t->target_callbacks);
1650 }
1651 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1652
1653 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1654 {
1655         struct dm_dev_internal *dd;
1656         struct list_head *devices = dm_table_get_devices(t);
1657         struct dm_target_callbacks *cb;
1658         int r = 0;
1659
1660         list_for_each_entry(dd, devices, list) {
1661                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1662                 char b[BDEVNAME_SIZE];
1663
1664                 if (likely(q))
1665                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1666                 else
1667                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1668                                      dm_device_name(t->md),
1669                                      bdevname(dd->dm_dev->bdev, b));
1670         }
1671
1672         list_for_each_entry(cb, &t->target_callbacks, list)
1673                 if (cb->congested_fn)
1674                         r |= cb->congested_fn(cb, bdi_bits);
1675
1676         return r;
1677 }
1678
1679 struct mapped_device *dm_table_get_md(struct dm_table *t)
1680 {
1681         return t->md;
1682 }
1683 EXPORT_SYMBOL(dm_table_get_md);
1684
1685 void dm_table_run_md_queue_async(struct dm_table *t)
1686 {
1687         struct mapped_device *md;
1688         struct request_queue *queue;
1689         unsigned long flags;
1690
1691         if (!dm_table_request_based(t))
1692                 return;
1693
1694         md = dm_table_get_md(t);
1695         queue = dm_get_md_queue(md);
1696         if (queue) {
1697                 if (queue->mq_ops)
1698                         blk_mq_run_hw_queues(queue, true);
1699                 else {
1700                         spin_lock_irqsave(queue->queue_lock, flags);
1701                         blk_run_queue_async(queue);
1702                         spin_unlock_irqrestore(queue->queue_lock, flags);
1703                 }
1704         }
1705 }
1706 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1707