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
  23 #define DM_MSG_PREFIX "table"
  24
  25 #define MAX_DEPTH 16
  26 #define NODE_SIZE L1_CACHE_BYTES
  27 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
  28 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
  29
  30 struct dm_table {
  31         struct mapped_device *md;
  32         unsigned type;
  33
  34         /* btree table */
  35         unsigned int depth;
  36         unsigned int counts[MAX_DEPTH]; /* in nodes */
  37         sector_t *index[MAX_DEPTH];
  38
  39         unsigned int num_targets;
  40         unsigned int num_allocated;
  41         sector_t *highs;
  42         struct dm_target *targets;
  43
  44         struct target_type *immutable_target_type;
  45         unsigned integrity_supported:1;
  46         unsigned singleton:1;
  47
  48         /*
  49          * Indicates the rw permissions for the new logical
  50          * device.  This should be a combination of FMODE_READ
  51          * and FMODE_WRITE.
  52          */
  53         fmode_t mode;
  54
  55         /* a list of devices used by this table */
  56         struct list_head devices;
  57
  58         /* events get handed up using this callback */
  59         void (*event_fn)(void *);
  60         void *event_context;
  61
  62         struct dm_md_mempools *mempools;
  63
  64         struct list_head target_callbacks;
  65 };
  66
  67 /*
  68  * Similar to ceiling(log_size(n))
  69  */
  70 static unsigned int int_log(unsigned int n, unsigned int base)
  71 {
  72         int result = 0;
  73
  74         while (n > 1) {
  75                 n = dm_div_up(n, base);
  76                 result++;
  77         }
  78
  79         return result;
  80 }
  81
  82 /*
  83  * Calculate the index of the child node of the n'th node k'th key.
  84  */
  85 static inline unsigned int get_child(unsigned int n, unsigned int k)
  86 {
  87         return (n * CHILDREN_PER_NODE) + k;
  88 }
  89
  90 /*
  91  * Return the n'th node of level l from table t.
  92  */
  93 static inline sector_t *get_node(struct dm_table *t,
  94                                  unsigned int l, unsigned int n)
  95 {
  96         return t->index[l] + (n * KEYS_PER_NODE);
  97 }
  98
  99 /*
 100  * Return the highest key that you could lookup from the n'th
 101  * node on level l of the btree.
 102  */
 103 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
 104 {
 105         for (; l < t->depth - 1; l++)
 106                 n = get_child(n, CHILDREN_PER_NODE - 1);
 107
 108         if (n >= t->counts[l])
 109                 return (sector_t) - 1;
 110
 111         return get_node(t, l, n)[KEYS_PER_NODE - 1];
 112 }
 113
 114 /*
 115  * Fills in a level of the btree based on the highs of the level
 116  * below it.
 117  */
 118 static int setup_btree_index(unsigned int l, struct dm_table *t)
 119 {
 120         unsigned int n, k;
 121         sector_t *node;
 122
 123         for (n = 0U; n < t->counts[l]; n++) {
 124                 node = get_node(t, l, n);
 125
 126                 for (k = 0U; k < KEYS_PER_NODE; k++)
 127                         node[k] = high(t, l + 1, get_child(n, k));
 128         }
 129
 130         return 0;
 131 }
 132
 133 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
 134 {
 135         unsigned long size;
 136         void *addr;
 137
 138         /*
 139          * Check that we're not going to overflow.
 140          */
 141         if (nmemb > (ULONG_MAX / elem_size))
 142                 return NULL;
 143
 144         size = nmemb * elem_size;
 145         addr = vzalloc(size);
 146
 147         return addr;
 148 }
 149 EXPORT_SYMBOL(dm_vcalloc);
 150
 151 /*
 152  * highs, and targets are managed as dynamic arrays during a
 153  * table load.
 154  */
 155 static int alloc_targets(struct dm_table *t, unsigned int num)
 156 {
 157         sector_t *n_highs;
 158         struct dm_target *n_targets;
 159
 160         /*
 161          * Allocate both the target array and offset array at once.
 162          * Append an empty entry to catch sectors beyond the end of
 163          * the device.
 164          */
 165         n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
 166                                           sizeof(sector_t));
 167         if (!n_highs)
 168                 return -ENOMEM;
 169
 170         n_targets = (struct dm_target *) (n_highs + num);
 171
 172         memset(n_highs, -1, sizeof(*n_highs) * num);
 173         vfree(t->highs);
 174
 175         t->num_allocated = num;
 176         t->highs = n_highs;
 177         t->targets = n_targets;
 178
 179         return 0;
 180 }
 181
 182 int dm_table_create(struct dm_table **result, fmode_t mode,
 183                     unsigned num_targets, struct mapped_device *md)
 184 {
 185         struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
 186
 187         if (!t)
 188                 return -ENOMEM;
 189
 190         INIT_LIST_HEAD(&t->devices);
 191         INIT_LIST_HEAD(&t->target_callbacks);
 192
 193         if (!num_targets)
 194                 num_targets = KEYS_PER_NODE;
 195
 196         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
 197
 198         if (!num_targets) {
 199                 kfree(t);
 200                 return -ENOMEM;
 201         }
 202
 203         if (alloc_targets(t, num_targets)) {
 204                 kfree(t);
 205                 return -ENOMEM;
 206         }
 207
 208         t->mode = mode;
 209         t->md = md;
 210         *result = t;
 211         return 0;
 212 }
 213
 214 static void free_devices(struct list_head *devices, struct mapped_device *md)
 215 {
 216         struct list_head *tmp, *next;
 217
 218         list_for_each_safe(tmp, next, devices) {
 219                 struct dm_dev_internal *dd =
 220                     list_entry(tmp, struct dm_dev_internal, list);
 221                 DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
 222                        dm_device_name(md), dd->dm_dev->name);
 223                 dm_put_table_device(md, dd->dm_dev);
 224                 kfree(dd);
 225         }
 226 }
 227
 228 void dm_table_destroy(struct dm_table *t)
 229 {
 230         unsigned int i;
 231
 232         if (!t)
 233                 return;
 234
 235         /* free the indexes */
 236         if (t->depth >= 2)
 237                 vfree(t->index[t->depth - 2]);
 238
 239         /* free the targets */
 240         for (i = 0; i < t->num_targets; i++) {
 241                 struct dm_target *tgt = t->targets + i;
 242
 243                 if (tgt->type->dtr)
 244                         tgt->type->dtr(tgt);
 245
 246                 dm_put_target_type(tgt->type);
 247         }
 248
 249         vfree(t->highs);
 250
 251         /* free the device list */
 252         free_devices(&t->devices, t->md);
 253
 254         dm_free_md_mempools(t->mempools);
 255
 256         kfree(t);
 257 }
 258
 259 /*
 260  * See if we've already got a device in the list.
 261  */
 262 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
 263 {
 264         struct dm_dev_internal *dd;
 265
 266         list_for_each_entry (dd, l, list)
 267                 if (dd->dm_dev->bdev->bd_dev == dev)
 268                         return dd;
 269
 270         return NULL;
 271 }
 272
 273 /*
 274  * If possible, this checks an area of a destination device is invalid.
 275  */
 276 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 277                                   sector_t start, sector_t len, void *data)
 278 {
 279         struct request_queue *q;
 280         struct queue_limits *limits = data;
 281         struct block_device *bdev = dev->bdev;
 282         sector_t dev_size =
 283                 i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
 284         unsigned short logical_block_size_sectors =
 285                 limits->logical_block_size >> SECTOR_SHIFT;
 286         char b[BDEVNAME_SIZE];
 287
 288         /*
 289          * Some devices exist without request functions,
 290          * such as loop devices not yet bound to backing files.
 291          * Forbid the use of such devices.
 292          */
 293         q = bdev_get_queue(bdev);
 294         if (!q || !q->make_request_fn) {
 295                 DMWARN("%s: %s is not yet initialised: "
 296                        "start=%llu, len=%llu, dev_size=%llu",
 297                        dm_device_name(ti->table->md), bdevname(bdev, b),
 298                        (unsigned long long)start,
 299                        (unsigned long long)len,
 300                        (unsigned long long)dev_size);
 301                 return 1;
 302         }
 303
 304         if (!dev_size)
 305                 return 0;
 306
 307         if ((start >= dev_size) || (start + len > dev_size)) {
 308                 DMWARN("%s: %s too small for target: "
 309                        "start=%llu, len=%llu, dev_size=%llu",
 310                        dm_device_name(ti->table->md), bdevname(bdev, b),
 311                        (unsigned long long)start,
 312                        (unsigned long long)len,
 313                        (unsigned long long)dev_size);
 314                 return 1;
 315         }
 316
 317         if (logical_block_size_sectors <= 1)
 318                 return 0;
 319
 320         if (start & (logical_block_size_sectors - 1)) {
 321                 DMWARN("%s: start=%llu not aligned to h/w "
 322                        "logical block size %u of %s",
 323                        dm_device_name(ti->table->md),
 324                        (unsigned long long)start,
 325                        limits->logical_block_size, bdevname(bdev, b));
 326                 return 1;
 327         }
 328
 329         if (len & (logical_block_size_sectors - 1)) {
 330                 DMWARN("%s: len=%llu not aligned to h/w "
 331                        "logical block size %u of %s",
 332                        dm_device_name(ti->table->md),
 333                        (unsigned long long)len,
 334                        limits->logical_block_size, bdevname(bdev, b));
 335                 return 1;
 336         }
 337
 338         return 0;
 339 }
 340
 341 /*
 342  * This upgrades the mode on an already open dm_dev, being
 343  * careful to leave things as they were if we fail to reopen the
 344  * device and not to touch the existing bdev field in case
 345  * it is accessed concurrently inside dm_table_any_congested().
 346  */
 347 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 348                         struct mapped_device *md)
 349 {
 350         int r;
 351         struct dm_dev *old_dev, *new_dev;
 352
 353         old_dev = dd->dm_dev;
 354
 355         r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
 356                                 dd->dm_dev->mode | new_mode, &new_dev);
 357         if (r)
 358                 return r;
 359
 360         dd->dm_dev = new_dev;
 361         dm_put_table_device(md, old_dev);
 362
 363         return 0;
 364 }
 365
 366 /*
 367  * Add a device to the list, or just increment the usage count if
 368  * it's already present.
 369  */
 370 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 371                   struct dm_dev **result)
 372 {
 373         int r;
 374         dev_t uninitialized_var(dev);
 375         struct dm_dev_internal *dd;
 376         unsigned int major, minor;
 377         struct dm_table *t = ti->table;
 378         char dummy;
 379
 380         BUG_ON(!t);
 381
 382         if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
 383                 /* Extract the major/minor numbers */
 384                 dev = MKDEV(major, minor);
 385                 if (MAJOR(dev) != major || MINOR(dev) != minor)
 386                         return -EOVERFLOW;
 387         } else {
 388                 /* convert the path to a device */
 389                 struct block_device *bdev = lookup_bdev(path);
 390
 391                 if (IS_ERR(bdev))
 392                         return PTR_ERR(bdev);
 393                 dev = bdev->bd_dev;
 394                 bdput(bdev);
 395         }
 396
 397         dd = find_device(&t->devices, dev);
 398         if (!dd) {
 399                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
 400                 if (!dd)
 401                         return -ENOMEM;
 402
 403                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
 404                         kfree(dd);
 405                         return r;
 406                 }
 407
 408                 atomic_set(&dd->count, 0);
 409                 list_add(&dd->list, &t->devices);
 410
 411         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 412                 r = upgrade_mode(dd, mode, t->md);
 413                 if (r)
 414                         return r;
 415         }
 416         atomic_inc(&dd->count);
 417
 418         *result = dd->dm_dev;
 419         return 0;
 420 }
 421 EXPORT_SYMBOL(dm_get_device);
 422
 423 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 424                                 sector_t start, sector_t len, void *data)
 425 {
 426         struct queue_limits *limits = data;
 427         struct block_device *bdev = dev->bdev;
 428         struct request_queue *q = bdev_get_queue(bdev);
 429         char b[BDEVNAME_SIZE];
 430
 431         if (unlikely(!q)) {
 432                 DMWARN("%s: Cannot set limits for nonexistent device %s",
 433                        dm_device_name(ti->table->md), bdevname(bdev, b));
 434                 return 0;
 435         }
 436
 437         if (bdev_stack_limits(limits, bdev, start) < 0)
 438                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
 439                        "physical_block_size=%u, logical_block_size=%u, "
 440                        "alignment_offset=%u, start=%llu",
 441                        dm_device_name(ti->table->md), bdevname(bdev, b),
 442                        q->limits.physical_block_size,
 443                        q->limits.logical_block_size,
 444                        q->limits.alignment_offset,
 445                        (unsigned long long) start << SECTOR_SHIFT);
 446
 447         /*
 448          * Check if merge fn is supported.
 449          * If not we'll force DM to use PAGE_SIZE or
 450          * smaller I/O, just to be safe.
 451          */
 452         if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
 453                 blk_limits_max_hw_sectors(limits,
 454                                           (unsigned int) (PAGE_SIZE >> 9));
 455         return 0;
 456 }
 457
 458 /*
 459  * Decrement a device's use count and remove it if necessary.
 460  */
 461 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 462 {
 463         int found = 0;
 464         struct list_head *devices = &ti->table->devices;
 465         struct dm_dev_internal *dd;
 466
 467         list_for_each_entry(dd, devices, list) {
 468                 if (dd->dm_dev == d) {
 469                         found = 1;
 470                         break;
 471                 }
 472         }
 473         if (!found) {
 474                 DMWARN("%s: device %s not in table devices list",
 475                        dm_device_name(ti->table->md), d->name);
 476                 return;
 477         }
 478         if (atomic_dec_and_test(&dd->count)) {
 479                 dm_put_table_device(ti->table->md, d);
 480                 list_del(&dd->list);
 481                 kfree(dd);
 482         }
 483 }
 484 EXPORT_SYMBOL(dm_put_device);
 485
 486 /*
 487  * Checks to see if the target joins onto the end of the table.
 488  */
 489 static int adjoin(struct dm_table *table, struct dm_target *ti)
 490 {
 491         struct dm_target *prev;
 492
 493         if (!table->num_targets)
 494                 return !ti->begin;
 495
 496         prev = &table->targets[table->num_targets - 1];
 497         return (ti->begin == (prev->begin + prev->len));
 498 }
 499
 500 /*
 501  * Used to dynamically allocate the arg array.
 502  *
 503  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 504  * process messages even if some device is suspended. These messages have a
 505  * small fixed number of arguments.
 506  *
 507  * On the other hand, dm-switch needs to process bulk data using messages and
 508  * excessive use of GFP_NOIO could cause trouble.
 509  */
 510 static char **realloc_argv(unsigned *array_size, char **old_argv)
 511 {
 512         char **argv;
 513         unsigned new_size;
 514         gfp_t gfp;
 515
 516         if (*array_size) {
 517                 new_size = *array_size * 2;
 518                 gfp = GFP_KERNEL;
 519         } else {
 520                 new_size = 8;
 521                 gfp = GFP_NOIO;
 522         }
 523         argv = kmalloc(new_size * sizeof(*argv), gfp);
 524         if (argv) {
 525                 memcpy(argv, old_argv, *array_size * sizeof(*argv));
 526                 *array_size = new_size;
 527         }
 528
 529         kfree(old_argv);
 530         return argv;
 531 }
 532
 533 /*
 534  * Destructively splits up the argument list to pass to ctr.
 535  */
 536 int dm_split_args(int *argc, char ***argvp, char *input)
 537 {
 538         char *start, *end = input, *out, **argv = NULL;
 539         unsigned array_size = 0;
 540
 541         *argc = 0;
 542
 543         if (!input) {
 544                 *argvp = NULL;
 545                 return 0;
 546         }
 547
 548         argv = realloc_argv(&array_size, argv);
 549         if (!argv)
 550                 return -ENOMEM;
 551
 552         while (1) {
 553                 /* Skip whitespace */
 554                 start = skip_spaces(end);
 555
 556                 if (!*start)
 557                         break;  /* success, we hit the end */
 558
 559                 /* 'out' is used to remove any back-quotes */
 560                 end = out = start;
 561                 while (*end) {
 562                         /* Everything apart from '\0' can be quoted */
 563                         if (*end == '\\' && *(end + 1)) {
 564                                 *out++ = *(end + 1);
 565                                 end += 2;
 566                                 continue;
 567                         }
 568
 569                         if (isspace(*end))
 570                                 break;  /* end of token */
 571
 572                         *out++ = *end++;
 573                 }
 574
 575                 /* have we already filled the array ? */
 576                 if ((*argc + 1) > array_size) {
 577                         argv = realloc_argv(&array_size, argv);
 578                         if (!argv)
 579                                 return -ENOMEM;
 580                 }
 581
 582                 /* we know this is whitespace */
 583                 if (*end)
 584                         end++;
 585
 586                 /* terminate the string and put it in the array */
 587                 *out = '\0';
 588                 argv[*argc] = start;
 589                 (*argc)++;
 590         }
 591
 592         *argvp = argv;
 593         return 0;
 594 }
 595
 596 /*
 597  * Impose necessary and sufficient conditions on a devices's table such
 598  * that any incoming bio which respects its logical_block_size can be
 599  * processed successfully.  If it falls across the boundary between
 600  * two or more targets, the size of each piece it gets split into must
 601  * be compatible with the logical_block_size of the target processing it.
 602  */
 603 static int validate_hardware_logical_block_alignment(struct dm_table *table,
 604                                                  struct queue_limits *limits)
 605 {
 606         /*
 607          * This function uses arithmetic modulo the logical_block_size
 608          * (in units of 512-byte sectors).
 609          */
 610         unsigned short device_logical_block_size_sects =
 611                 limits->logical_block_size >> SECTOR_SHIFT;
 612
 613         /*
 614          * Offset of the start of the next table entry, mod logical_block_size.
 615          */
 616         unsigned short next_target_start = 0;
 617
 618         /*
 619          * Given an aligned bio that extends beyond the end of a
 620          * target, how many sectors must the next target handle?
 621          */
 622         unsigned short remaining = 0;
 623
 624         struct dm_target *uninitialized_var(ti);
 625         struct queue_limits ti_limits;
 626         unsigned i = 0;
 627
 628         /*
 629          * Check each entry in the table in turn.
 630          */
 631         while (i < dm_table_get_num_targets(table)) {
 632                 ti = dm_table_get_target(table, i++);
 633
 634                 blk_set_stacking_limits(&ti_limits);
 635
 636                 /* combine all target devices' limits */
 637                 if (ti->type->iterate_devices)
 638                         ti->type->iterate_devices(ti, dm_set_device_limits,
 639                                                   &ti_limits);
 640
 641                 /*
 642                  * If the remaining sectors fall entirely within this
 643                  * table entry are they compatible with its logical_block_size?
 644                  */
 645                 if (remaining < ti->len &&
 646                     remaining & ((ti_limits.logical_block_size >>
 647                                   SECTOR_SHIFT) - 1))
 648                         break;  /* Error */
 649
 650                 next_target_start =
 651                     (unsigned short) ((next_target_start + ti->len) &
 652                                       (device_logical_block_size_sects - 1));
 653                 remaining = next_target_start ?
 654                     device_logical_block_size_sects - next_target_start : 0;
 655         }
 656
 657         if (remaining) {
 658                 DMWARN("%s: table line %u (start sect %llu len %llu) "
 659                        "not aligned to h/w logical block size %u",
 660                        dm_device_name(table->md), i,
 661                        (unsigned long long) ti->begin,
 662                        (unsigned long long) ti->len,
 663                        limits->logical_block_size);
 664                 return -EINVAL;
 665         }
 666
 667         return 0;
 668 }
 669
 670 int dm_table_add_target(struct dm_table *t, const char *type,
 671                         sector_t start, sector_t len, char *params)
 672 {
 673         int r = -EINVAL, argc;
 674         char **argv;
 675         struct dm_target *tgt;
 676
 677         if (t->singleton) {
 678                 DMERR("%s: target type %s must appear alone in table",
 679                       dm_device_name(t->md), t->targets->type->name);
 680                 return -EINVAL;
 681         }
 682
 683         BUG_ON(t->num_targets >= t->num_allocated);
 684
 685         tgt = t->targets + t->num_targets;
 686         memset(tgt, 0, sizeof(*tgt));
 687
 688         if (!len) {
 689                 DMERR("%s: zero-length target", dm_device_name(t->md));
 690                 return -EINVAL;
 691         }
 692
 693         tgt->type = dm_get_target_type(type);
 694         if (!tgt->type) {
 695                 DMERR("%s: %s: unknown target type", dm_device_name(t->md),
 696                       type);
 697                 return -EINVAL;
 698         }
 699
 700         if (dm_target_needs_singleton(tgt->type)) {
 701                 if (t->num_targets) {
 702                         DMERR("%s: target type %s must appear alone in table",
 703                               dm_device_name(t->md), type);
 704                         return -EINVAL;
 705                 }
 706                 t->singleton = 1;
 707         }
 708
 709         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
 710                 DMERR("%s: target type %s may not be included in read-only tables",
 711                       dm_device_name(t->md), type);
 712                 return -EINVAL;
 713         }
 714
 715         if (t->immutable_target_type) {
 716                 if (t->immutable_target_type != tgt->type) {
 717                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 718                               dm_device_name(t->md), t->immutable_target_type->name);
 719                         return -EINVAL;
 720                 }
 721         } else if (dm_target_is_immutable(tgt->type)) {
 722                 if (t->num_targets) {
 723                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 724                               dm_device_name(t->md), tgt->type->name);
 725                         return -EINVAL;
 726                 }
 727                 t->immutable_target_type = tgt->type;
 728         }
 729
 730         tgt->table = t;
 731         tgt->begin = start;
 732         tgt->len = len;
 733         tgt->error = "Unknown error";
 734
 735         /*
 736          * Does this target adjoin the previous one ?
 737          */
 738         if (!adjoin(t, tgt)) {
 739                 tgt->error = "Gap in table";
 740                 r = -EINVAL;
 741                 goto bad;
 742         }
 743
 744         r = dm_split_args(&argc, &argv, params);
 745         if (r) {
 746                 tgt->error = "couldn't split parameters (insufficient memory)";
 747                 goto bad;
 748         }
 749
 750         r = tgt->type->ctr(tgt, argc, argv);
 751         kfree(argv);
 752         if (r)
 753                 goto bad;
 754
 755         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 756
 757         if (!tgt->num_discard_bios && tgt->discards_supported)
 758                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 759                        dm_device_name(t->md), type);
 760
 761         return 0;
 762
 763  bad:
 764         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 765         dm_put_target_type(tgt->type);
 766         return r;
 767 }
 768
 769 /*
 770  * Target argument parsing helpers.
 771  */
 772 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 773                              unsigned *value, char **error, unsigned grouped)
 774 {
 775         const char *arg_str = dm_shift_arg(arg_set);
 776         char dummy;
 777
 778         if (!arg_str ||
 779             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
 780             (*value < arg->min) ||
 781             (*value > arg->max) ||
 782             (grouped && arg_set->argc < *value)) {
 783                 *error = arg->error;
 784                 return -EINVAL;
 785         }
 786
 787         return 0;
 788 }
 789
 790 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 791                 unsigned *value, char **error)
 792 {
 793         return validate_next_arg(arg, arg_set, value, error, 0);
 794 }
 795 EXPORT_SYMBOL(dm_read_arg);
 796
 797 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
 798                       unsigned *value, char **error)
 799 {
 800         return validate_next_arg(arg, arg_set, value, error, 1);
 801 }
 802 EXPORT_SYMBOL(dm_read_arg_group);
 803
 804 const char *dm_shift_arg(struct dm_arg_set *as)
 805 {
 806         char *r;
 807
 808         if (as->argc) {
 809                 as->argc--;
 810                 r = *as->argv;
 811                 as->argv++;
 812                 return r;
 813         }
 814
 815         return NULL;
 816 }
 817 EXPORT_SYMBOL(dm_shift_arg);
 818
 819 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 820 {
 821         BUG_ON(as->argc < num_args);
 822         as->argc -= num_args;
 823         as->argv += num_args;
 824 }
 825 EXPORT_SYMBOL(dm_consume_args);
 826
 827 static int dm_table_set_type(struct dm_table *t)
 828 {
 829         unsigned i;
 830         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 831         bool use_blk_mq = false;
 832         struct dm_target *tgt;
 833         struct dm_dev_internal *dd;
 834         struct list_head *devices;
 835         unsigned live_md_type = dm_get_md_type(t->md);
 836
 837         for (i = 0; i < t->num_targets; i++) {
 838                 tgt = t->targets + i;
 839                 if (dm_target_hybrid(tgt))
 840                         hybrid = 1;
 841                 else if (dm_target_request_based(tgt))
 842                         request_based = 1;
 843                 else
 844                         bio_based = 1;
 845
 846                 if (bio_based && request_based) {
 847                         DMWARN("Inconsistent table: different target types"
 848                                " can't be mixed up");
 849                         return -EINVAL;
 850                 }
 851         }
 852
 853         if (hybrid && !bio_based && !request_based) {
 854                 /*
 855                  * The targets can work either way.
 856                  * Determine the type from the live device.
 857                  * Default to bio-based if device is new.
 858                  */
 859                 if (live_md_type == DM_TYPE_REQUEST_BASED ||
 860                     live_md_type == DM_TYPE_MQ_REQUEST_BASED)
 861                         request_based = 1;
 862                 else
 863                         bio_based = 1;
 864         }
 865
 866         if (bio_based) {
 867                 /* We must use this table as bio-based */
 868                 t->type = DM_TYPE_BIO_BASED;
 869                 return 0;
 870         }
 871
 872         BUG_ON(!request_based); /* No targets in this table */
 873
 874         /*
 875          * Request-based dm supports only tables that have a single target now.
 876          * To support multiple targets, request splitting support is needed,
 877          * and that needs lots of changes in the block-layer.
 878          * (e.g. request completion process for partial completion.)
 879          */
 880         if (t->num_targets > 1) {
 881                 DMWARN("Request-based dm doesn't support multiple targets yet");
 882                 return -EINVAL;
 883         }
 884
 885         /* Non-request-stackable devices can't be used for request-based dm */
 886         devices = dm_table_get_devices(t);
 887         list_for_each_entry(dd, devices, list) {
 888                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
 889
 890                 if (!blk_queue_stackable(q)) {
 891                         DMERR("table load rejected: including"
 892                               " non-request-stackable devices");
 893                         return -EINVAL;
 894                 }
 895
 896                 if (q->mq_ops)
 897                         use_blk_mq = true;
 898         }
 899
 900         if (use_blk_mq) {
 901                 /* verify _all_ devices in the table are blk-mq devices */
 902                 list_for_each_entry(dd, devices, list)
 903                         if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
 904                                 DMERR("table load rejected: not all devices"
 905                                       " are blk-mq request-stackable");
 906                                 return -EINVAL;
 907                         }
 908                 t->type = DM_TYPE_MQ_REQUEST_BASED;
 909
 910         } else if (hybrid && list_empty(devices) && live_md_type != DM_TYPE_NONE) {
 911                 /* inherit live MD type */
 912                 t->type = live_md_type;
 913
 914         } else
 915                 t->type = DM_TYPE_REQUEST_BASED;
 916
 917         return 0;
 918 }
 919
 920 unsigned dm_table_get_type(struct dm_table *t)
 921 {
 922         return t->type;
 923 }
 924
 925 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 926 {
 927         return t->immutable_target_type;
 928 }
 929
 930 bool dm_table_request_based(struct dm_table *t)
 931 {
 932         unsigned table_type = dm_table_get_type(t);
 933
 934         return (table_type == DM_TYPE_REQUEST_BASED ||
 935                 table_type == DM_TYPE_MQ_REQUEST_BASED);
 936 }
 937
 938 bool dm_table_mq_request_based(struct dm_table *t)
 939 {
 940         return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
 941 }
 942
 943 static int dm_table_alloc_md_mempools(struct dm_table *t)
 944 {
 945         unsigned type = dm_table_get_type(t);
 946         unsigned per_bio_data_size = 0;
 947         struct dm_target *tgt;
 948         unsigned i;
 949
 950         if (unlikely(type == DM_TYPE_NONE)) {
 951                 DMWARN("no table type is set, can't allocate mempools");
 952                 return -EINVAL;
 953         }
 954
 955         if (type == DM_TYPE_BIO_BASED)
 956                 for (i = 0; i < t->num_targets; i++) {
 957                         tgt = t->targets + i;
 958                         per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
 959                 }
 960
 961         t->mempools = dm_alloc_md_mempools(type, t->integrity_supported, per_bio_data_size);
 962         if (!t->mempools)
 963                 return -ENOMEM;
 964
 965         return 0;
 966 }
 967
 968 void dm_table_free_md_mempools(struct dm_table *t)
 969 {
 970         dm_free_md_mempools(t->mempools);
 971         t->mempools = NULL;
 972 }
 973
 974 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
 975 {
 976         return t->mempools;
 977 }
 978
 979 static int setup_indexes(struct dm_table *t)
 980 {
 981         int i;
 982         unsigned int total = 0;
 983         sector_t *indexes;
 984
 985         /* allocate the space for *all* the indexes */
 986         for (i = t->depth - 2; i >= 0; i--) {
 987                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
 988                 total += t->counts[i];
 989         }
 990
 991         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
 992         if (!indexes)
 993                 return -ENOMEM;
 994
 995         /* set up internal nodes, bottom-up */
 996         for (i = t->depth - 2; i >= 0; i--) {
 997                 t->index[i] = indexes;
 998                 indexes += (KEYS_PER_NODE * t->counts[i]);
 999                 setup_btree_index(i, t);
1000         }
1001
1002         return 0;
1003 }
1004
1005 /*
1006  * Builds the btree to index the map.
1007  */
1008 static int dm_table_build_index(struct dm_table *t)
1009 {
1010         int r = 0;
1011         unsigned int leaf_nodes;
1012
1013         /* how many indexes will the btree have ? */
1014         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1015         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1016
1017         /* leaf layer has already been set up */
1018         t->counts[t->depth - 1] = leaf_nodes;
1019         t->index[t->depth - 1] = t->highs;
1020
1021         if (t->depth >= 2)
1022                 r = setup_indexes(t);
1023
1024         return r;
1025 }
1026
1027 /*
1028  * Get a disk whose integrity profile reflects the table's profile.
1029  * If %match_all is true, all devices' profiles must match.
1030  * If %match_all is false, all devices must at least have an
1031  * allocated integrity profile; but uninitialized is ok.
1032  * Returns NULL if integrity support was inconsistent or unavailable.
1033  */
1034 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
1035                                                     bool match_all)
1036 {
1037         struct list_head *devices = dm_table_get_devices(t);
1038         struct dm_dev_internal *dd = NULL;
1039         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1040
1041         list_for_each_entry(dd, devices, list) {
1042                 template_disk = dd->dm_dev->bdev->bd_disk;
1043                 if (!blk_get_integrity(template_disk))
1044                         goto no_integrity;
1045                 if (!match_all && !blk_integrity_is_initialized(template_disk))
1046                         continue; /* skip uninitialized profiles */
1047                 else if (prev_disk &&
1048                          blk_integrity_compare(prev_disk, template_disk) < 0)
1049                         goto no_integrity;
1050                 prev_disk = template_disk;
1051         }
1052
1053         return template_disk;
1054
1055 no_integrity:
1056         if (prev_disk)
1057                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1058                        dm_device_name(t->md),
1059                        prev_disk->disk_name,
1060                        template_disk->disk_name);
1061         return NULL;
1062 }
1063
1064 /*
1065  * Register the mapped device for blk_integrity support if
1066  * the underlying devices have an integrity profile.  But all devices
1067  * may not have matching profiles (checking all devices isn't reliable
1068  * during table load because this table may use other DM device(s) which
1069  * must be resumed before they will have an initialized integity profile).
1070  * Stacked DM devices force a 2 stage integrity profile validation:
1071  * 1 - during load, validate all initialized integrity profiles match
1072  * 2 - during resume, validate all integrity profiles match
1073  */
1074 static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
1075 {
1076         struct gendisk *template_disk = NULL;
1077
1078         template_disk = dm_table_get_integrity_disk(t, false);
1079         if (!template_disk)
1080                 return 0;
1081
1082         if (!blk_integrity_is_initialized(dm_disk(md))) {
1083                 t->integrity_supported = 1;
1084                 return blk_integrity_register(dm_disk(md), NULL);
1085         }
1086
1087         /*
1088          * If DM device already has an initalized integrity
1089          * profile the new profile should not conflict.
1090          */
1091         if (blk_integrity_is_initialized(template_disk) &&
1092             blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1093                 DMWARN("%s: conflict with existing integrity profile: "
1094                        "%s profile mismatch",
1095                        dm_device_name(t->md),
1096                        template_disk->disk_name);
1097                 return 1;
1098         }
1099
1100         /* Preserve existing initialized integrity profile */
1101         t->integrity_supported = 1;
1102         return 0;
1103 }
1104
1105 /*
1106  * Prepares the table for use by building the indices,
1107  * setting the type, and allocating mempools.
1108  */
1109 int dm_table_complete(struct dm_table *t)
1110 {
1111         int r;
1112
1113         r = dm_table_set_type(t);
1114         if (r) {
1115                 DMERR("unable to set table type");
1116                 return r;
1117         }
1118
1119         r = dm_table_build_index(t);
1120         if (r) {
1121                 DMERR("unable to build btrees");
1122                 return r;
1123         }
1124
1125         r = dm_table_prealloc_integrity(t, t->md);
1126         if (r) {
1127                 DMERR("could not register integrity profile.");
1128                 return r;
1129         }
1130
1131         r = dm_table_alloc_md_mempools(t);
1132         if (r)
1133                 DMERR("unable to allocate mempools");
1134
1135         return r;
1136 }
1137
1138 static DEFINE_MUTEX(_event_lock);
1139 void dm_table_event_callback(struct dm_table *t,
1140                              void (*fn)(void *), void *context)
1141 {
1142         mutex_lock(&_event_lock);
1143         t->event_fn = fn;
1144         t->event_context = context;
1145         mutex_unlock(&_event_lock);
1146 }
1147
1148 void dm_table_event(struct dm_table *t)
1149 {
1150         /*
1151          * You can no longer call dm_table_event() from interrupt
1152          * context, use a bottom half instead.
1153          */
1154         BUG_ON(in_interrupt());
1155
1156         mutex_lock(&_event_lock);
1157         if (t->event_fn)
1158                 t->event_fn(t->event_context);
1159         mutex_unlock(&_event_lock);
1160 }
1161 EXPORT_SYMBOL(dm_table_event);
1162
1163 sector_t dm_table_get_size(struct dm_table *t)
1164 {
1165         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1166 }
1167 EXPORT_SYMBOL(dm_table_get_size);
1168
1169 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1170 {
1171         if (index >= t->num_targets)
1172                 return NULL;
1173
1174         return t->targets + index;
1175 }
1176
1177 /*
1178  * Search the btree for the correct target.
1179  *
1180  * Caller should check returned pointer with dm_target_is_valid()
1181  * to trap I/O beyond end of device.
1182  */
1183 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1184 {
1185         unsigned int l, n = 0, k = 0;
1186         sector_t *node;
1187
1188         for (l = 0; l < t->depth; l++) {
1189                 n = get_child(n, k);
1190                 node = get_node(t, l, n);
1191
1192                 for (k = 0; k < KEYS_PER_NODE; k++)
1193                         if (node[k] >= sector)
1194                                 break;
1195         }
1196
1197         return &t->targets[(KEYS_PER_NODE * n) + k];
1198 }
1199
1200 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1201                         sector_t start, sector_t len, void *data)
1202 {
1203         unsigned *num_devices = data;
1204
1205         (*num_devices)++;
1206
1207         return 0;
1208 }
1209
1210 /*
1211  * Check whether a table has no data devices attached using each
1212  * target's iterate_devices method.
1213  * Returns false if the result is unknown because a target doesn't
1214  * support iterate_devices.
1215  */
1216 bool dm_table_has_no_data_devices(struct dm_table *table)
1217 {
1218         struct dm_target *uninitialized_var(ti);
1219         unsigned i = 0, num_devices = 0;
1220
1221         while (i < dm_table_get_num_targets(table)) {
1222                 ti = dm_table_get_target(table, i++);
1223
1224                 if (!ti->type->iterate_devices)
1225                         return false;
1226
1227                 ti->type->iterate_devices(ti, count_device, &num_devices);
1228                 if (num_devices)
1229                         return false;
1230         }
1231
1232         return true;
1233 }
1234
1235 /*
1236  * Establish the new table's queue_limits and validate them.
1237  */
1238 int dm_calculate_queue_limits(struct dm_table *table,
1239                               struct queue_limits *limits)
1240 {
1241         struct dm_target *uninitialized_var(ti);
1242         struct queue_limits ti_limits;
1243         unsigned i = 0;
1244
1245         blk_set_stacking_limits(limits);
1246
1247         while (i < dm_table_get_num_targets(table)) {
1248                 blk_set_stacking_limits(&ti_limits);
1249
1250                 ti = dm_table_get_target(table, i++);
1251
1252                 if (!ti->type->iterate_devices)
1253                         goto combine_limits;
1254
1255                 /*
1256                  * Combine queue limits of all the devices this target uses.
1257                  */
1258                 ti->type->iterate_devices(ti, dm_set_device_limits,
1259                                           &ti_limits);
1260
1261                 /* Set I/O hints portion of queue limits */
1262                 if (ti->type->io_hints)
1263                         ti->type->io_hints(ti, &ti_limits);
1264
1265                 /*
1266                  * Check each device area is consistent with the target's
1267                  * overall queue limits.
1268                  */
1269                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1270                                               &ti_limits))
1271                         return -EINVAL;
1272
1273 combine_limits:
1274                 /*
1275                  * Merge this target's queue limits into the overall limits
1276                  * for the table.
1277                  */
1278                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1279                         DMWARN("%s: adding target device "
1280                                "(start sect %llu len %llu) "
1281                                "caused an alignment inconsistency",
1282                                dm_device_name(table->md),
1283                                (unsigned long long) ti->begin,
1284                                (unsigned long long) ti->len);
1285         }
1286
1287         return validate_hardware_logical_block_alignment(table, limits);
1288 }
1289
1290 /*
1291  * Set the integrity profile for this device if all devices used have
1292  * matching profiles.  We're quite deep in the resume path but still
1293  * don't know if all devices (particularly DM devices this device
1294  * may be stacked on) have matching profiles.  Even if the profiles
1295  * don't match we have no way to fail (to resume) at this point.
1296  */
1297 static void dm_table_set_integrity(struct dm_table *t)
1298 {
1299         struct gendisk *template_disk = NULL;
1300
1301         if (!blk_get_integrity(dm_disk(t->md)))
1302                 return;
1303
1304         template_disk = dm_table_get_integrity_disk(t, true);
1305         if (template_disk)
1306                 blk_integrity_register(dm_disk(t->md),
1307                                        blk_get_integrity(template_disk));
1308         else if (blk_integrity_is_initialized(dm_disk(t->md)))
1309                 DMWARN("%s: device no longer has a valid integrity profile",
1310                        dm_device_name(t->md));
1311         else
1312                 DMWARN("%s: unable to establish an integrity profile",
1313                        dm_device_name(t->md));
1314 }
1315
1316 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1317                                 sector_t start, sector_t len, void *data)
1318 {
1319         unsigned flush = (*(unsigned *)data);
1320         struct request_queue *q = bdev_get_queue(dev->bdev);
1321
1322         return q && (q->flush_flags & flush);
1323 }
1324
1325 static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
1326 {
1327         struct dm_target *ti;
1328         unsigned i = 0;
1329
1330         /*
1331          * Require at least one underlying device to support flushes.
1332          * t->devices includes internal dm devices such as mirror logs
1333          * so we need to use iterate_devices here, which targets
1334          * supporting flushes must provide.
1335          */
1336         while (i < dm_table_get_num_targets(t)) {
1337                 ti = dm_table_get_target(t, i++);
1338
1339                 if (!ti->num_flush_bios)
1340                         continue;
1341
1342                 if (ti->flush_supported)
1343                         return 1;
1344
1345                 if (ti->type->iterate_devices &&
1346                     ti->type->iterate_devices(ti, device_flush_capable, &flush))
1347                         return 1;
1348         }
1349
1350         return 0;
1351 }
1352
1353 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1354 {
1355         struct dm_target *ti;
1356         unsigned i = 0;
1357
1358         /* Ensure that all targets supports discard_zeroes_data. */
1359         while (i < dm_table_get_num_targets(t)) {
1360                 ti = dm_table_get_target(t, i++);
1361
1362                 if (ti->discard_zeroes_data_unsupported)
1363                         return 0;
1364         }
1365
1366         return 1;
1367 }
1368
1369 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1370                             sector_t start, sector_t len, void *data)
1371 {
1372         struct request_queue *q = bdev_get_queue(dev->bdev);
1373
1374         return q && blk_queue_nonrot(q);
1375 }
1376
1377 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1378                              sector_t start, sector_t len, void *data)
1379 {
1380         struct request_queue *q = bdev_get_queue(dev->bdev);
1381
1382         return q && !blk_queue_add_random(q);
1383 }
1384
1385 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1386                                    sector_t start, sector_t len, void *data)
1387 {
1388         struct request_queue *q = bdev_get_queue(dev->bdev);
1389
1390         return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1391 }
1392
1393 static int queue_supports_sg_gaps(struct dm_target *ti, struct dm_dev *dev,
1394                                   sector_t start, sector_t len, void *data)
1395 {
1396         struct request_queue *q = bdev_get_queue(dev->bdev);
1397
1398         return q && !test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags);
1399 }
1400
1401 static bool dm_table_all_devices_attribute(struct dm_table *t,
1402                                            iterate_devices_callout_fn func)
1403 {
1404         struct dm_target *ti;
1405         unsigned i = 0;
1406
1407         while (i < dm_table_get_num_targets(t)) {
1408                 ti = dm_table_get_target(t, i++);
1409
1410                 if (!ti->type->iterate_devices ||
1411                     !ti->type->iterate_devices(ti, func, NULL))
1412                         return 0;
1413         }
1414
1415         return 1;
1416 }
1417
1418 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1419                                          sector_t start, sector_t len, void *data)
1420 {
1421         struct request_queue *q = bdev_get_queue(dev->bdev);
1422
1423         return q && !q->limits.max_write_same_sectors;
1424 }
1425
1426 static bool dm_table_supports_write_same(struct dm_table *t)
1427 {
1428         struct dm_target *ti;
1429         unsigned i = 0;
1430
1431         while (i < dm_table_get_num_targets(t)) {
1432                 ti = dm_table_get_target(t, i++);
1433
1434                 if (!ti->num_write_same_bios)
1435                         return false;
1436
1437                 if (!ti->type->iterate_devices ||
1438                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1439                         return false;
1440         }
1441
1442         return true;
1443 }
1444
1445 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1446                                   sector_t start, sector_t len, void *data)
1447 {
1448         struct request_queue *q = bdev_get_queue(dev->bdev);
1449
1450         return q && blk_queue_discard(q);
1451 }
1452
1453 static bool dm_table_supports_discards(struct dm_table *t)
1454 {
1455         struct dm_target *ti;
1456         unsigned i = 0;
1457
1458         /*
1459          * Unless any target used by the table set discards_supported,
1460          * require at least one underlying device to support discards.
1461          * t->devices includes internal dm devices such as mirror logs
1462          * so we need to use iterate_devices here, which targets
1463          * supporting discard selectively must provide.
1464          */
1465         while (i < dm_table_get_num_targets(t)) {
1466                 ti = dm_table_get_target(t, i++);
1467
1468                 if (!ti->num_discard_bios)
1469                         continue;
1470
1471                 if (ti->discards_supported)
1472                         return 1;
1473
1474                 if (ti->type->iterate_devices &&
1475                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1476                         return 1;
1477         }
1478
1479         return 0;
1480 }
1481
1482 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1483                                struct queue_limits *limits)
1484 {
1485         unsigned flush = 0;
1486
1487         /*
1488          * Copy table's limits to the DM device's request_queue
1489          */
1490         q->limits = *limits;
1491
1492         if (!dm_table_supports_discards(t))
1493                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1494         else
1495                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1496
1497         if (dm_table_supports_flush(t, REQ_FLUSH)) {
1498                 flush |= REQ_FLUSH;
1499                 if (dm_table_supports_flush(t, REQ_FUA))
1500                         flush |= REQ_FUA;
1501         }
1502         blk_queue_flush(q, flush);
1503
1504         if (!dm_table_discard_zeroes_data(t))
1505                 q->limits.discard_zeroes_data = 0;
1506
1507         /* Ensure that all underlying devices are non-rotational. */
1508         if (dm_table_all_devices_attribute(t, device_is_nonrot))
1509                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1510         else
1511                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1512
1513         if (!dm_table_supports_write_same(t))
1514                 q->limits.max_write_same_sectors = 0;
1515
1516         if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1517                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1518         else
1519                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1520
1521         if (dm_table_all_devices_attribute(t, queue_supports_sg_gaps))
1522                 queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, q);
1523         else
1524                 queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, q);
1525
1526         dm_table_set_integrity(t);
1527
1528         /*
1529          * Determine whether or not this queue's I/O timings contribute
1530          * to the entropy pool, Only request-based targets use this.
1531          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1532          * have it set.
1533          */
1534         if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1535                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1536
1537         /*
1538          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1539          * visible to other CPUs because, once the flag is set, incoming bios
1540          * are processed by request-based dm, which refers to the queue
1541          * settings.
1542          * Until the flag set, bios are passed to bio-based dm and queued to
1543          * md->deferred where queue settings are not needed yet.
1544          * Those bios are passed to request-based dm at the resume time.
1545          */
1546         smp_mb();
1547         if (dm_table_request_based(t))
1548                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1549 }
1550
1551 unsigned int dm_table_get_num_targets(struct dm_table *t)
1552 {
1553         return t->num_targets;
1554 }
1555
1556 struct list_head *dm_table_get_devices(struct dm_table *t)
1557 {
1558         return &t->devices;
1559 }
1560
1561 fmode_t dm_table_get_mode(struct dm_table *t)
1562 {
1563         return t->mode;
1564 }
1565 EXPORT_SYMBOL(dm_table_get_mode);
1566
1567 enum suspend_mode {
1568         PRESUSPEND,
1569         PRESUSPEND_UNDO,
1570         POSTSUSPEND,
1571 };
1572
1573 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1574 {
1575         int i = t->num_targets;
1576         struct dm_target *ti = t->targets;
1577
1578         while (i--) {
1579                 switch (mode) {
1580                 case PRESUSPEND:
1581                         if (ti->type->presuspend)
1582                                 ti->type->presuspend(ti);
1583                         break;
1584                 case PRESUSPEND_UNDO:
1585                         if (ti->type->presuspend_undo)
1586                                 ti->type->presuspend_undo(ti);
1587                         break;
1588                 case POSTSUSPEND:
1589                         if (ti->type->postsuspend)
1590                                 ti->type->postsuspend(ti);
1591                         break;
1592                 }
1593                 ti++;
1594         }
1595 }
1596
1597 void dm_table_presuspend_targets(struct dm_table *t)
1598 {
1599         if (!t)
1600                 return;
1601
1602         suspend_targets(t, PRESUSPEND);
1603 }
1604
1605 void dm_table_presuspend_undo_targets(struct dm_table *t)
1606 {
1607         if (!t)
1608                 return;
1609
1610         suspend_targets(t, PRESUSPEND_UNDO);
1611 }
1612
1613 void dm_table_postsuspend_targets(struct dm_table *t)
1614 {
1615         if (!t)
1616                 return;
1617
1618         suspend_targets(t, POSTSUSPEND);
1619 }
1620
1621 int dm_table_resume_targets(struct dm_table *t)
1622 {
1623         int i, r = 0;
1624
1625         for (i = 0; i < t->num_targets; i++) {
1626                 struct dm_target *ti = t->targets + i;
1627
1628                 if (!ti->type->preresume)
1629                         continue;
1630
1631                 r = ti->type->preresume(ti);
1632                 if (r) {
1633                         DMERR("%s: %s: preresume failed, error = %d",
1634                               dm_device_name(t->md), ti->type->name, r);
1635                         return r;
1636                 }
1637         }
1638
1639         for (i = 0; i < t->num_targets; i++) {
1640                 struct dm_target *ti = t->targets + i;
1641
1642                 if (ti->type->resume)
1643                         ti->type->resume(ti);
1644         }
1645
1646         return 0;
1647 }
1648
1649 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1650 {
1651         list_add(&cb->list, &t->target_callbacks);
1652 }
1653 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1654
1655 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1656 {
1657         struct dm_dev_internal *dd;
1658         struct list_head *devices = dm_table_get_devices(t);
1659         struct dm_target_callbacks *cb;
1660         int r = 0;
1661
1662         list_for_each_entry(dd, devices, list) {
1663                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1664                 char b[BDEVNAME_SIZE];
1665
1666                 if (likely(q))
1667                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1668                 else
1669                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1670                                      dm_device_name(t->md),
1671                                      bdevname(dd->dm_dev->bdev, b));
1672         }
1673
1674         list_for_each_entry(cb, &t->target_callbacks, list)
1675                 if (cb->congested_fn)
1676                         r |= cb->congested_fn(cb, bdi_bits);
1677
1678         return r;
1679 }
1680
1681 struct mapped_device *dm_table_get_md(struct dm_table *t)
1682 {
1683         return t->md;
1684 }
1685 EXPORT_SYMBOL(dm_table_get_md);
1686
1687 void dm_table_run_md_queue_async(struct dm_table *t)
1688 {
1689         struct mapped_device *md;
1690         struct request_queue *queue;
1691         unsigned long flags;
1692
1693         if (!dm_table_request_based(t))
1694                 return;
1695
1696         md = dm_table_get_md(t);
1697         queue = dm_get_md_queue(md);
1698         if (queue) {
1699                 if (queue->mq_ops)
1700                         blk_mq_run_hw_queues(queue, true);
1701                 else {
1702                         spin_lock_irqsave(queue->queue_lock, flags);
1703                         blk_run_queue_async(queue);
1704                         spin_unlock_irqrestore(queue->queue_lock, flags);
1705                 }
1706         }
1707 }
1708 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1709