drivers/md/dm-table.c

   1 /*
   2  * Copyright (C) 2001 Sistina Software (UK) Limited.
   3  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #include "dm.h"
   9
  10 #include <linux/module.h>
  11 #include <linux/vmalloc.h>
  12 #include <linux/blkdev.h>
  13 #include <linux/namei.h>
  14 #include <linux/ctype.h>
  15 #include <linux/string.h>
  16 #include <linux/slab.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/mutex.h>
  19 #include <linux/delay.h>
  20 #include <linux/atomic.h>
  21 #include <linux/blk-mq.h>
  22 #include <linux/mount.h>
  23
  24 #define DM_MSG_PREFIX "table"
  25
  26 #define MAX_DEPTH 16
  27 #define NODE_SIZE L1_CACHE_BYTES
  28 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
  29 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
  30
  31 struct dm_table {
  32         struct mapped_device *md;
  33         unsigned type;
  34
  35         /* btree table */
  36         unsigned int depth;
  37         unsigned int counts[MAX_DEPTH]; /* in nodes */
  38         sector_t *index[MAX_DEPTH];
  39
  40         unsigned int num_targets;
  41         unsigned int num_allocated;
  42         sector_t *highs;
  43         struct dm_target *targets;
  44
  45         struct target_type *immutable_target_type;
  46         unsigned integrity_supported:1;
  47         unsigned singleton:1;
  48
  49         /*
  50          * Indicates the rw permissions for the new logical
  51          * device.  This should be a combination of FMODE_READ
  52          * and FMODE_WRITE.
  53          */
  54         fmode_t mode;
  55
  56         /* a list of devices used by this table */
  57         struct list_head devices;
  58
  59         /* events get handed up using this callback */
  60         void (*event_fn)(void *);
  61         void *event_context;
  62
  63         struct dm_md_mempools *mempools;
  64
  65         struct list_head target_callbacks;
  66 };
  67
  68 /*
  69  * Similar to ceiling(log_size(n))
  70  */
  71 static unsigned int int_log(unsigned int n, unsigned int base)
  72 {
  73         int result = 0;
  74
  75         while (n > 1) {
  76                 n = dm_div_up(n, base);
  77                 result++;
  78         }
  79
  80         return result;
  81 }
  82
  83 /*
  84  * Calculate the index of the child node of the n'th node k'th key.
  85  */
  86 static inline unsigned int get_child(unsigned int n, unsigned int k)
  87 {
  88         return (n * CHILDREN_PER_NODE) + k;
  89 }
  90
  91 /*
  92  * Return the n'th node of level l from table t.
  93  */
  94 static inline sector_t *get_node(struct dm_table *t,
  95                                  unsigned int l, unsigned int n)
  96 {
  97         return t->index[l] + (n * KEYS_PER_NODE);
  98 }
  99
 100 /*
 101  * Return the highest key that you could lookup from the n'th
 102  * node on level l of the btree.
 103  */
 104 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
 105 {
 106         for (; l < t->depth - 1; l++)
 107                 n = get_child(n, CHILDREN_PER_NODE - 1);
 108
 109         if (n >= t->counts[l])
 110                 return (sector_t) - 1;
 111
 112         return get_node(t, l, n)[KEYS_PER_NODE - 1];
 113 }
 114
 115 /*
 116  * Fills in a level of the btree based on the highs of the level
 117  * below it.
 118  */
 119 static int setup_btree_index(unsigned int l, struct dm_table *t)
 120 {
 121         unsigned int n, k;
 122         sector_t *node;
 123
 124         for (n = 0U; n < t->counts[l]; n++) {
 125                 node = get_node(t, l, n);
 126
 127                 for (k = 0U; k < KEYS_PER_NODE; k++)
 128                         node[k] = high(t, l + 1, get_child(n, k));
 129         }
 130
 131         return 0;
 132 }
 133
 134 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
 135 {
 136         unsigned long size;
 137         void *addr;
 138
 139         /*
 140          * Check that we're not going to overflow.
 141          */
 142         if (nmemb > (ULONG_MAX / elem_size))
 143                 return NULL;
 144
 145         size = nmemb * elem_size;
 146         addr = vzalloc(size);
 147
 148         return addr;
 149 }
 150 EXPORT_SYMBOL(dm_vcalloc);
 151
 152 /*
 153  * highs, and targets are managed as dynamic arrays during a
 154  * table load.
 155  */
 156 static int alloc_targets(struct dm_table *t, unsigned int num)
 157 {
 158         sector_t *n_highs;
 159         struct dm_target *n_targets;
 160
 161         /*
 162          * Allocate both the target array and offset array at once.
 163          * Append an empty entry to catch sectors beyond the end of
 164          * the device.
 165          */
 166         n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
 167                                           sizeof(sector_t));
 168         if (!n_highs)
 169                 return -ENOMEM;
 170
 171         n_targets = (struct dm_target *) (n_highs + num);
 172
 173         memset(n_highs, -1, sizeof(*n_highs) * num);
 174         vfree(t->highs);
 175
 176         t->num_allocated = num;
 177         t->highs = n_highs;
 178         t->targets = n_targets;
 179
 180         return 0;
 181 }
 182
 183 int dm_table_create(struct dm_table **result, fmode_t mode,
 184                     unsigned num_targets, struct mapped_device *md)
 185 {
 186         struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
 187
 188         if (!t)
 189                 return -ENOMEM;
 190
 191         INIT_LIST_HEAD(&t->devices);
 192         INIT_LIST_HEAD(&t->target_callbacks);
 193
 194         if (!num_targets)
 195                 num_targets = KEYS_PER_NODE;
 196
 197         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
 198
 199         if (!num_targets) {
 200                 kfree(t);
 201                 return -ENOMEM;
 202         }
 203
 204         if (alloc_targets(t, num_targets)) {
 205                 kfree(t);
 206                 return -ENOMEM;
 207         }
 208
 209         t->mode = mode;
 210         t->md = md;
 211         *result = t;
 212         return 0;
 213 }
 214
 215 static void free_devices(struct list_head *devices, struct mapped_device *md)
 216 {
 217         struct list_head *tmp, *next;
 218
 219         list_for_each_safe(tmp, next, devices) {
 220                 struct dm_dev_internal *dd =
 221                     list_entry(tmp, struct dm_dev_internal, list);
 222                 DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
 223                        dm_device_name(md), dd->dm_dev->name);
 224                 dm_put_table_device(md, dd->dm_dev);
 225                 kfree(dd);
 226         }
 227 }
 228
 229 void dm_table_destroy(struct dm_table *t)
 230 {
 231         unsigned int i;
 232
 233         if (!t)
 234                 return;
 235
 236         /* free the indexes */
 237         if (t->depth >= 2)
 238                 vfree(t->index[t->depth - 2]);
 239
 240         /* free the targets */
 241         for (i = 0; i < t->num_targets; i++) {
 242                 struct dm_target *tgt = t->targets + i;
 243
 244                 if (tgt->type->dtr)
 245                         tgt->type->dtr(tgt);
 246
 247                 dm_put_target_type(tgt->type);
 248         }
 249
 250         vfree(t->highs);
 251
 252         /* free the device list */
 253         free_devices(&t->devices, t->md);
 254
 255         dm_free_md_mempools(t->mempools);
 256
 257         kfree(t);
 258 }
 259
 260 /*
 261  * See if we've already got a device in the list.
 262  */
 263 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
 264 {
 265         struct dm_dev_internal *dd;
 266
 267         list_for_each_entry (dd, l, list)
 268                 if (dd->dm_dev->bdev->bd_dev == dev)
 269                         return dd;
 270
 271         return NULL;
 272 }
 273
 274 /*
 275  * If possible, this checks an area of a destination device is invalid.
 276  */
 277 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 278                                   sector_t start, sector_t len, void *data)
 279 {
 280         struct request_queue *q;
 281         struct queue_limits *limits = data;
 282         struct block_device *bdev = dev->bdev;
 283         sector_t dev_size =
 284                 i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
 285         unsigned short logical_block_size_sectors =
 286                 limits->logical_block_size >> SECTOR_SHIFT;
 287         char b[BDEVNAME_SIZE];
 288
 289         /*
 290          * Some devices exist without request functions,
 291          * such as loop devices not yet bound to backing files.
 292          * Forbid the use of such devices.
 293          */
 294         q = bdev_get_queue(bdev);
 295         if (!q || !q->make_request_fn) {
 296                 DMWARN("%s: %s is not yet initialised: "
 297                        "start=%llu, len=%llu, dev_size=%llu",
 298                        dm_device_name(ti->table->md), bdevname(bdev, b),
 299                        (unsigned long long)start,
 300                        (unsigned long long)len,
 301                        (unsigned long long)dev_size);
 302                 return 1;
 303         }
 304
 305         if (!dev_size)
 306                 return 0;
 307
 308         if ((start >= dev_size) || (start + len > dev_size)) {
 309                 DMWARN("%s: %s too small for target: "
 310                        "start=%llu, len=%llu, dev_size=%llu",
 311                        dm_device_name(ti->table->md), bdevname(bdev, b),
 312                        (unsigned long long)start,
 313                        (unsigned long long)len,
 314                        (unsigned long long)dev_size);
 315                 return 1;
 316         }
 317
 318         if (logical_block_size_sectors <= 1)
 319                 return 0;
 320
 321         if (start & (logical_block_size_sectors - 1)) {
 322                 DMWARN("%s: start=%llu not aligned to h/w "
 323                        "logical block size %u of %s",
 324                        dm_device_name(ti->table->md),
 325                        (unsigned long long)start,
 326                        limits->logical_block_size, bdevname(bdev, b));
 327                 return 1;
 328         }
 329
 330         if (len & (logical_block_size_sectors - 1)) {
 331                 DMWARN("%s: len=%llu not aligned to h/w "
 332                        "logical block size %u of %s",
 333                        dm_device_name(ti->table->md),
 334                        (unsigned long long)len,
 335                        limits->logical_block_size, bdevname(bdev, b));
 336                 return 1;
 337         }
 338
 339         return 0;
 340 }
 341
 342 /*
 343  * This upgrades the mode on an already open dm_dev, being
 344  * careful to leave things as they were if we fail to reopen the
 345  * device and not to touch the existing bdev field in case
 346  * it is accessed concurrently inside dm_table_any_congested().
 347  */
 348 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 349                         struct mapped_device *md)
 350 {
 351         int r;
 352         struct dm_dev *old_dev, *new_dev;
 353
 354         old_dev = dd->dm_dev;
 355
 356         r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
 357                                 dd->dm_dev->mode | new_mode, &new_dev);
 358         if (r)
 359                 return r;
 360
 361         dd->dm_dev = new_dev;
 362         dm_put_table_device(md, old_dev);
 363
 364         return 0;
 365 }
 366
 367 /*
 368  * Convert the path to a device
 369  */
 370 dev_t dm_get_dev_t(const char *path)
 371 {
 372         dev_t uninitialized_var(dev);
 373         struct block_device *bdev;
 374
 375         bdev = lookup_bdev(path);
 376         if (IS_ERR(bdev))
 377                 dev = name_to_dev_t(path);
 378         else {
 379                 dev = bdev->bd_dev;
 380                 bdput(bdev);
 381         }
 382
 383         return dev;
 384 }
 385 EXPORT_SYMBOL_GPL(dm_get_dev_t);
 386
 387 /*
 388  * Add a device to the list, or just increment the usage count if
 389  * it's already present.
 390  */
 391 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 392                   struct dm_dev **result)
 393 {
 394         int r;
 395         dev_t dev;
 396         unsigned int major, minor;
 397         char dummy;
 398         struct dm_dev_internal *dd;
 399         struct dm_table *t = ti->table;
 400
 401         BUG_ON(!t);
 402
 403         if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
 404                 /* Extract the major/minor numbers */
 405                 dev = MKDEV(major, minor);
 406                 if (MAJOR(dev) != major || MINOR(dev) != minor)
 407                         return -EOVERFLOW;
 408         } else {
 409                 dev = dm_get_dev_t(path);
 410                 if (!dev)
 411                         return -ENODEV;
 412         }
 413
 414         dd = find_device(&t->devices, dev);
 415         if (!dd) {
 416                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
 417                 if (!dd)
 418                         return -ENOMEM;
 419
 420                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
 421                         kfree(dd);
 422                         return r;
 423                 }
 424
 425                 atomic_set(&dd->count, 0);
 426                 list_add(&dd->list, &t->devices);
 427
 428         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 429                 r = upgrade_mode(dd, mode, t->md);
 430                 if (r)
 431                         return r;
 432         }
 433         atomic_inc(&dd->count);
 434
 435         *result = dd->dm_dev;
 436         return 0;
 437 }
 438 EXPORT_SYMBOL(dm_get_device);
 439
 440 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 441                                 sector_t start, sector_t len, void *data)
 442 {
 443         struct queue_limits *limits = data;
 444         struct block_device *bdev = dev->bdev;
 445         struct request_queue *q = bdev_get_queue(bdev);
 446         char b[BDEVNAME_SIZE];
 447
 448         if (unlikely(!q)) {
 449                 DMWARN("%s: Cannot set limits for nonexistent device %s",
 450                        dm_device_name(ti->table->md), bdevname(bdev, b));
 451                 return 0;
 452         }
 453
 454         if (bdev_stack_limits(limits, bdev, start) < 0)
 455                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
 456                        "physical_block_size=%u, logical_block_size=%u, "
 457                        "alignment_offset=%u, start=%llu",
 458                        dm_device_name(ti->table->md), bdevname(bdev, b),
 459                        q->limits.physical_block_size,
 460                        q->limits.logical_block_size,
 461                        q->limits.alignment_offset,
 462                        (unsigned long long) start << SECTOR_SHIFT);
 463
 464         return 0;
 465 }
 466
 467 /*
 468  * Decrement a device's use count and remove it if necessary.
 469  */
 470 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 471 {
 472         int found = 0;
 473         struct list_head *devices = &ti->table->devices;
 474         struct dm_dev_internal *dd;
 475
 476         list_for_each_entry(dd, devices, list) {
 477                 if (dd->dm_dev == d) {
 478                         found = 1;
 479                         break;
 480                 }
 481         }
 482         if (!found) {
 483                 DMWARN("%s: device %s not in table devices list",
 484                        dm_device_name(ti->table->md), d->name);
 485                 return;
 486         }
 487         if (atomic_dec_and_test(&dd->count)) {
 488                 dm_put_table_device(ti->table->md, d);
 489                 list_del(&dd->list);
 490                 kfree(dd);
 491         }
 492 }
 493 EXPORT_SYMBOL(dm_put_device);
 494
 495 /*
 496  * Checks to see if the target joins onto the end of the table.
 497  */
 498 static int adjoin(struct dm_table *table, struct dm_target *ti)
 499 {
 500         struct dm_target *prev;
 501
 502         if (!table->num_targets)
 503                 return !ti->begin;
 504
 505         prev = &table->targets[table->num_targets - 1];
 506         return (ti->begin == (prev->begin + prev->len));
 507 }
 508
 509 /*
 510  * Used to dynamically allocate the arg array.
 511  *
 512  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 513  * process messages even if some device is suspended. These messages have a
 514  * small fixed number of arguments.
 515  *
 516  * On the other hand, dm-switch needs to process bulk data using messages and
 517  * excessive use of GFP_NOIO could cause trouble.
 518  */
 519 static char **realloc_argv(unsigned *size, char **old_argv)
 520 {
 521         char **argv;
 522         unsigned new_size;
 523         gfp_t gfp;
 524
 525         if (*size) {
 526                 new_size = *size * 2;
 527                 gfp = GFP_KERNEL;
 528         } else {
 529                 new_size = 8;
 530                 gfp = GFP_NOIO;
 531         }
 532         argv = kmalloc(new_size * sizeof(*argv), gfp);
 533         if (argv) {
 534                 memcpy(argv, old_argv, *size * sizeof(*argv));
 535                 *size = new_size;
 536         }
 537
 538         kfree(old_argv);
 539         return argv;
 540 }
 541
 542 /*
 543  * Destructively splits up the argument list to pass to ctr.
 544  */
 545 int dm_split_args(int *argc, char ***argvp, char *input)
 546 {
 547         char *start, *end = input, *out, **argv = NULL;
 548         unsigned array_size = 0;
 549
 550         *argc = 0;
 551
 552         if (!input) {
 553                 *argvp = NULL;
 554                 return 0;
 555         }
 556
 557         argv = realloc_argv(&array_size, argv);
 558         if (!argv)
 559                 return -ENOMEM;
 560
 561         while (1) {
 562                 /* Skip whitespace */
 563                 start = skip_spaces(end);
 564
 565                 if (!*start)
 566                         break;  /* success, we hit the end */
 567
 568                 /* 'out' is used to remove any back-quotes */
 569                 end = out = start;
 570                 while (*end) {
 571                         /* Everything apart from '\0' can be quoted */
 572                         if (*end == '\\' && *(end + 1)) {
 573                                 *out++ = *(end + 1);
 574                                 end += 2;
 575                                 continue;
 576                         }
 577
 578                         if (isspace(*end))
 579                                 break;  /* end of token */
 580
 581                         *out++ = *end++;
 582                 }
 583
 584                 /* have we already filled the array ? */
 585                 if ((*argc + 1) > array_size) {
 586                         argv = realloc_argv(&array_size, argv);
 587                         if (!argv)
 588                                 return -ENOMEM;
 589                 }
 590
 591                 /* we know this is whitespace */
 592                 if (*end)
 593                         end++;
 594
 595                 /* terminate the string and put it in the array */
 596                 *out = '\0';
 597                 argv[*argc] = start;
 598                 (*argc)++;
 599         }
 600
 601         *argvp = argv;
 602         return 0;
 603 }
 604
 605 /*
 606  * Impose necessary and sufficient conditions on a devices's table such
 607  * that any incoming bio which respects its logical_block_size can be
 608  * processed successfully.  If it falls across the boundary between
 609  * two or more targets, the size of each piece it gets split into must
 610  * be compatible with the logical_block_size of the target processing it.
 611  */
 612 static int validate_hardware_logical_block_alignment(struct dm_table *table,
 613                                                  struct queue_limits *limits)
 614 {
 615         /*
 616          * This function uses arithmetic modulo the logical_block_size
 617          * (in units of 512-byte sectors).
 618          */
 619         unsigned short device_logical_block_size_sects =
 620                 limits->logical_block_size >> SECTOR_SHIFT;
 621
 622         /*
 623          * Offset of the start of the next table entry, mod logical_block_size.
 624          */
 625         unsigned short next_target_start = 0;
 626
 627         /*
 628          * Given an aligned bio that extends beyond the end of a
 629          * target, how many sectors must the next target handle?
 630          */
 631         unsigned short remaining = 0;
 632
 633         struct dm_target *uninitialized_var(ti);
 634         struct queue_limits ti_limits;
 635         unsigned i = 0;
 636
 637         /*
 638          * Check each entry in the table in turn.
 639          */
 640         while (i < dm_table_get_num_targets(table)) {
 641                 ti = dm_table_get_target(table, i++);
 642
 643                 blk_set_stacking_limits(&ti_limits);
 644
 645                 /* combine all target devices' limits */
 646                 if (ti->type->iterate_devices)
 647                         ti->type->iterate_devices(ti, dm_set_device_limits,
 648                                                   &ti_limits);
 649
 650                 /*
 651                  * If the remaining sectors fall entirely within this
 652                  * table entry are they compatible with its logical_block_size?
 653                  */
 654                 if (remaining < ti->len &&
 655                     remaining & ((ti_limits.logical_block_size >>
 656                                   SECTOR_SHIFT) - 1))
 657                         break;  /* Error */
 658
 659                 next_target_start =
 660                     (unsigned short) ((next_target_start + ti->len) &
 661                                       (device_logical_block_size_sects - 1));
 662                 remaining = next_target_start ?
 663                     device_logical_block_size_sects - next_target_start : 0;
 664         }
 665
 666         if (remaining) {
 667                 DMWARN("%s: table line %u (start sect %llu len %llu) "
 668                        "not aligned to h/w logical block size %u",
 669                        dm_device_name(table->md), i,
 670                        (unsigned long long) ti->begin,
 671                        (unsigned long long) ti->len,
 672                        limits->logical_block_size);
 673                 return -EINVAL;
 674         }
 675
 676         return 0;
 677 }
 678
 679 int dm_table_add_target(struct dm_table *t, const char *type,
 680                         sector_t start, sector_t len, char *params)
 681 {
 682         int r = -EINVAL, argc;
 683         char **argv;
 684         struct dm_target *tgt;
 685
 686         if (t->singleton) {
 687                 DMERR("%s: target type %s must appear alone in table",
 688                       dm_device_name(t->md), t->targets->type->name);
 689                 return -EINVAL;
 690         }
 691
 692         BUG_ON(t->num_targets >= t->num_allocated);
 693
 694         tgt = t->targets + t->num_targets;
 695         memset(tgt, 0, sizeof(*tgt));
 696
 697         if (!len) {
 698                 DMERR("%s: zero-length target", dm_device_name(t->md));
 699                 return -EINVAL;
 700         }
 701
 702         tgt->type = dm_get_target_type(type);
 703         if (!tgt->type) {
 704                 DMERR("%s: %s: unknown target type", dm_device_name(t->md),
 705                       type);
 706                 return -EINVAL;
 707         }
 708
 709         if (dm_target_needs_singleton(tgt->type)) {
 710                 if (t->num_targets) {
 711                         DMERR("%s: target type %s must appear alone in table",
 712                               dm_device_name(t->md), type);
 713                         return -EINVAL;
 714                 }
 715                 t->singleton = 1;
 716         }
 717
 718         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
 719                 DMERR("%s: target type %s may not be included in read-only tables",
 720                       dm_device_name(t->md), type);
 721                 return -EINVAL;
 722         }
 723
 724         if (t->immutable_target_type) {
 725                 if (t->immutable_target_type != tgt->type) {
 726                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 727                               dm_device_name(t->md), t->immutable_target_type->name);
 728                         return -EINVAL;
 729                 }
 730         } else if (dm_target_is_immutable(tgt->type)) {
 731                 if (t->num_targets) {
 732                         DMERR("%s: immutable target type %s cannot be mixed with other target types",
 733                               dm_device_name(t->md), tgt->type->name);
 734                         return -EINVAL;
 735                 }
 736                 t->immutable_target_type = tgt->type;
 737         }
 738
 739         tgt->table = t;
 740         tgt->begin = start;
 741         tgt->len = len;
 742         tgt->error = "Unknown error";
 743
 744         /*
 745          * Does this target adjoin the previous one ?
 746          */
 747         if (!adjoin(t, tgt)) {
 748                 tgt->error = "Gap in table";
 749                 r = -EINVAL;
 750                 goto bad;
 751         }
 752
 753         r = dm_split_args(&argc, &argv, params);
 754         if (r) {
 755                 tgt->error = "couldn't split parameters (insufficient memory)";
 756                 goto bad;
 757         }
 758
 759         r = tgt->type->ctr(tgt, argc, argv);
 760         kfree(argv);
 761         if (r)
 762                 goto bad;
 763
 764         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 765
 766         if (!tgt->num_discard_bios && tgt->discards_supported)
 767                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 768                        dm_device_name(t->md), type);
 769
 770         return 0;
 771
 772  bad:
 773         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 774         dm_put_target_type(tgt->type);
 775         return r;
 776 }
 777
 778 /*
 779  * Target argument parsing helpers.
 780  */
 781 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 782                              unsigned *value, char **error, unsigned grouped)
 783 {
 784         const char *arg_str = dm_shift_arg(arg_set);
 785         char dummy;
 786
 787         if (!arg_str ||
 788             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
 789             (*value < arg->min) ||
 790             (*value > arg->max) ||
 791             (grouped && arg_set->argc < *value)) {
 792                 *error = arg->error;
 793                 return -EINVAL;
 794         }
 795
 796         return 0;
 797 }
 798
 799 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 800                 unsigned *value, char **error)
 801 {
 802         return validate_next_arg(arg, arg_set, value, error, 0);
 803 }
 804 EXPORT_SYMBOL(dm_read_arg);
 805
 806 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
 807                       unsigned *value, char **error)
 808 {
 809         return validate_next_arg(arg, arg_set, value, error, 1);
 810 }
 811 EXPORT_SYMBOL(dm_read_arg_group);
 812
 813 const char *dm_shift_arg(struct dm_arg_set *as)
 814 {
 815         char *r;
 816
 817         if (as->argc) {
 818                 as->argc--;
 819                 r = *as->argv;
 820                 as->argv++;
 821                 return r;
 822         }
 823
 824         return NULL;
 825 }
 826 EXPORT_SYMBOL(dm_shift_arg);
 827
 828 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 829 {
 830         BUG_ON(as->argc < num_args);
 831         as->argc -= num_args;
 832         as->argv += num_args;
 833 }
 834 EXPORT_SYMBOL(dm_consume_args);
 835
 836 static bool __table_type_request_based(unsigned table_type)
 837 {
 838         return (table_type == DM_TYPE_REQUEST_BASED ||
 839                 table_type == DM_TYPE_MQ_REQUEST_BASED);
 840 }
 841
 842 static int dm_table_set_type(struct dm_table *t)
 843 {
 844         unsigned i;
 845         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 846         bool use_blk_mq = false;
 847         struct dm_target *tgt;
 848         struct dm_dev_internal *dd;
 849         struct list_head *devices;
 850         unsigned live_md_type = dm_get_md_type(t->md);
 851
 852         for (i = 0; i < t->num_targets; i++) {
 853                 tgt = t->targets + i;
 854                 if (dm_target_hybrid(tgt))
 855                         hybrid = 1;
 856                 else if (dm_target_request_based(tgt))
 857                         request_based = 1;
 858                 else
 859                         bio_based = 1;
 860
 861                 if (bio_based && request_based) {
 862                         DMWARN("Inconsistent table: different target types"
 863                                " can't be mixed up");
 864                         return -EINVAL;
 865                 }
 866         }
 867
 868         if (hybrid && !bio_based && !request_based) {
 869                 /*
 870                  * The targets can work either way.
 871                  * Determine the type from the live device.
 872                  * Default to bio-based if device is new.
 873                  */
 874                 if (__table_type_request_based(live_md_type))
 875                         request_based = 1;
 876                 else
 877                         bio_based = 1;
 878         }
 879
 880         if (bio_based) {
 881                 /* We must use this table as bio-based */
 882                 t->type = DM_TYPE_BIO_BASED;
 883                 return 0;
 884         }
 885
 886         BUG_ON(!request_based); /* No targets in this table */
 887
 888         /*
 889          * Request-based dm supports only tables that have a single target now.
 890          * To support multiple targets, request splitting support is needed,
 891          * and that needs lots of changes in the block-layer.
 892          * (e.g. request completion process for partial completion.)
 893          */
 894         if (t->num_targets > 1) {
 895                 DMWARN("Request-based dm doesn't support multiple targets yet");
 896                 return -EINVAL;
 897         }
 898
 899         /* Non-request-stackable devices can't be used for request-based dm */
 900         devices = dm_table_get_devices(t);
 901         list_for_each_entry(dd, devices, list) {
 902                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
 903
 904                 if (!blk_queue_stackable(q)) {
 905                         DMERR("table load rejected: including"
 906                               " non-request-stackable devices");
 907                         return -EINVAL;
 908                 }
 909
 910                 if (q->mq_ops)
 911                         use_blk_mq = true;
 912         }
 913
 914         if (use_blk_mq) {
 915                 /* verify _all_ devices in the table are blk-mq devices */
 916                 list_for_each_entry(dd, devices, list)
 917                         if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
 918                                 DMERR("table load rejected: not all devices"
 919                                       " are blk-mq request-stackable");
 920                                 return -EINVAL;
 921                         }
 922                 t->type = DM_TYPE_MQ_REQUEST_BASED;
 923
 924         } else if (list_empty(devices) && __table_type_request_based(live_md_type)) {
 925                 /* inherit live MD type */
 926                 t->type = live_md_type;
 927
 928         } else
 929                 t->type = DM_TYPE_REQUEST_BASED;
 930
 931         return 0;
 932 }
 933
 934 unsigned dm_table_get_type(struct dm_table *t)
 935 {
 936         return t->type;
 937 }
 938
 939 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 940 {
 941         return t->immutable_target_type;
 942 }
 943
 944 bool dm_table_request_based(struct dm_table *t)
 945 {
 946         return __table_type_request_based(dm_table_get_type(t));
 947 }
 948
 949 bool dm_table_mq_request_based(struct dm_table *t)
 950 {
 951         return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
 952 }
 953
 954 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
 955 {
 956         unsigned type = dm_table_get_type(t);
 957         unsigned per_bio_data_size = 0;
 958         struct dm_target *tgt;
 959         unsigned i;
 960
 961         if (unlikely(type == DM_TYPE_NONE)) {
 962                 DMWARN("no table type is set, can't allocate mempools");
 963                 return -EINVAL;
 964         }
 965
 966         if (type == DM_TYPE_BIO_BASED)
 967                 for (i = 0; i < t->num_targets; i++) {
 968                         tgt = t->targets + i;
 969                         per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
 970                 }
 971
 972         t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_bio_data_size);
 973         if (!t->mempools)
 974                 return -ENOMEM;
 975
 976         return 0;
 977 }
 978
 979 void dm_table_free_md_mempools(struct dm_table *t)
 980 {
 981         dm_free_md_mempools(t->mempools);
 982         t->mempools = NULL;
 983 }
 984
 985 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
 986 {
 987         return t->mempools;
 988 }
 989
 990 static int setup_indexes(struct dm_table *t)
 991 {
 992         int i;
 993         unsigned int total = 0;
 994         sector_t *indexes;
 995
 996         /* allocate the space for *all* the indexes */
 997         for (i = t->depth - 2; i >= 0; i--) {
 998                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
 999                 total += t->counts[i];
1000         }
1001
1002         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
1003         if (!indexes)
1004                 return -ENOMEM;
1005
1006         /* set up internal nodes, bottom-up */
1007         for (i = t->depth - 2; i >= 0; i--) {
1008                 t->index[i] = indexes;
1009                 indexes += (KEYS_PER_NODE * t->counts[i]);
1010                 setup_btree_index(i, t);
1011         }
1012
1013         return 0;
1014 }
1015
1016 /*
1017  * Builds the btree to index the map.
1018  */
1019 static int dm_table_build_index(struct dm_table *t)
1020 {
1021         int r = 0;
1022         unsigned int leaf_nodes;
1023
1024         /* how many indexes will the btree have ? */
1025         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1026         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1027
1028         /* leaf layer has already been set up */
1029         t->counts[t->depth - 1] = leaf_nodes;
1030         t->index[t->depth - 1] = t->highs;
1031
1032         if (t->depth >= 2)
1033                 r = setup_indexes(t);
1034
1035         return r;
1036 }
1037
1038 static bool integrity_profile_exists(struct gendisk *disk)
1039 {
1040         return !!blk_get_integrity(disk);
1041 }
1042
1043 /*
1044  * Get a disk whose integrity profile reflects the table's profile.
1045  * Returns NULL if integrity support was inconsistent or unavailable.
1046  */
1047 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
1048 {
1049         struct list_head *devices = dm_table_get_devices(t);
1050         struct dm_dev_internal *dd = NULL;
1051         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1052
1053         list_for_each_entry(dd, devices, list) {
1054                 template_disk = dd->dm_dev->bdev->bd_disk;
1055                 if (!integrity_profile_exists(template_disk))
1056                         goto no_integrity;
1057                 else if (prev_disk &&
1058                          blk_integrity_compare(prev_disk, template_disk) < 0)
1059                         goto no_integrity;
1060                 prev_disk = template_disk;
1061         }
1062
1063         return template_disk;
1064
1065 no_integrity:
1066         if (prev_disk)
1067                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1068                        dm_device_name(t->md),
1069                        prev_disk->disk_name,
1070                        template_disk->disk_name);
1071         return NULL;
1072 }
1073
1074 /*
1075  * Register the mapped device for blk_integrity support if the
1076  * underlying devices have an integrity profile.  But all devices may
1077  * not have matching profiles (checking all devices isn't reliable
1078  * during table load because this table may use other DM device(s) which
1079  * must be resumed before they will have an initialized integity
1080  * profile).  Consequently, stacked DM devices force a 2 stage integrity
1081  * profile validation: First pass during table load, final pass during
1082  * resume.
1083  */
1084 static int dm_table_register_integrity(struct dm_table *t)
1085 {
1086         struct mapped_device *md = t->md;
1087         struct gendisk *template_disk = NULL;
1088
1089         template_disk = dm_table_get_integrity_disk(t);
1090         if (!template_disk)
1091                 return 0;
1092
1093         if (!integrity_profile_exists(dm_disk(md))) {
1094                 t->integrity_supported = 1;
1095                 /*
1096                  * Register integrity profile during table load; we can do
1097                  * this because the final profile must match during resume.
1098                  */
1099                 blk_integrity_register(dm_disk(md),
1100                                        blk_get_integrity(template_disk));
1101                 return 0;
1102         }
1103
1104         /*
1105          * If DM device already has an initialized integrity
1106          * profile the new profile should not conflict.
1107          */
1108         if (blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1109                 DMWARN("%s: conflict with existing integrity profile: "
1110                        "%s profile mismatch",
1111                        dm_device_name(t->md),
1112                        template_disk->disk_name);
1113                 return 1;
1114         }
1115
1116         /* Preserve existing integrity profile */
1117         t->integrity_supported = 1;
1118         return 0;
1119 }
1120
1121 /*
1122  * Prepares the table for use by building the indices,
1123  * setting the type, and allocating mempools.
1124  */
1125 int dm_table_complete(struct dm_table *t)
1126 {
1127         int r;
1128
1129         r = dm_table_set_type(t);
1130         if (r) {
1131                 DMERR("unable to set table type");
1132                 return r;
1133         }
1134
1135         r = dm_table_build_index(t);
1136         if (r) {
1137                 DMERR("unable to build btrees");
1138                 return r;
1139         }
1140
1141         r = dm_table_register_integrity(t);
1142         if (r) {
1143                 DMERR("could not register integrity profile.");
1144                 return r;
1145         }
1146
1147         r = dm_table_alloc_md_mempools(t, t->md);
1148         if (r)
1149                 DMERR("unable to allocate mempools");
1150
1151         return r;
1152 }
1153
1154 static DEFINE_MUTEX(_event_lock);
1155 void dm_table_event_callback(struct dm_table *t,
1156                              void (*fn)(void *), void *context)
1157 {
1158         mutex_lock(&_event_lock);
1159         t->event_fn = fn;
1160         t->event_context = context;
1161         mutex_unlock(&_event_lock);
1162 }
1163
1164 void dm_table_event(struct dm_table *t)
1165 {
1166         mutex_lock(&_event_lock);
1167         if (t->event_fn)
1168                 t->event_fn(t->event_context);
1169         mutex_unlock(&_event_lock);
1170 }
1171 EXPORT_SYMBOL(dm_table_event);
1172
1173 inline sector_t dm_table_get_size(struct dm_table *t)
1174 {
1175         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1176 }
1177 EXPORT_SYMBOL(dm_table_get_size);
1178
1179 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1180 {
1181         if (index >= t->num_targets)
1182                 return NULL;
1183
1184         return t->targets + index;
1185 }
1186
1187 /*
1188  * Search the btree for the correct target.
1189  *
1190  * Caller should check returned pointer with dm_target_is_valid()
1191  * to trap I/O beyond end of device.
1192  */
1193 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1194 {
1195         unsigned int l, n = 0, k = 0;
1196         sector_t *node;
1197
1198         if (unlikely(sector >= dm_table_get_size(t)))
1199                 return &t->targets[t->num_targets];
1200
1201         for (l = 0; l < t->depth; l++) {
1202                 n = get_child(n, k);
1203                 node = get_node(t, l, n);
1204
1205                 for (k = 0; k < KEYS_PER_NODE; k++)
1206                         if (node[k] >= sector)
1207                                 break;
1208         }
1209
1210         return &t->targets[(KEYS_PER_NODE * n) + k];
1211 }
1212
1213 /*
1214  * type->iterate_devices() should be called when the sanity check needs to
1215  * iterate and check all underlying data devices. iterate_devices() will
1216  * iterate all underlying data devices until it encounters a non-zero return
1217  * code, returned by whether the input iterate_devices_callout_fn, or
1218  * iterate_devices() itself internally.
1219  *
1220  * For some target type (e.g. dm-stripe), one call of iterate_devices() may
1221  * iterate multiple underlying devices internally, in which case a non-zero
1222  * return code returned by iterate_devices_callout_fn will stop the iteration
1223  * in advance.
1224  *
1225  * Cases requiring _any_ underlying device supporting some kind of attribute,
1226  * should use the iteration structure like dm_table_any_dev_attr(), or call
1227  * it directly. @func should handle semantics of positive examples, e.g.
1228  * capable of something.
1229  *
1230  * Cases requiring _all_ underlying devices supporting some kind of attribute,
1231  * should use the iteration structure like dm_table_supports_nowait() or
1232  * dm_table_supports_discards(). Or introduce dm_table_all_devs_attr() that
1233  * uses an @anti_func that handle semantics of counter examples, e.g. not
1234  * capable of something. So: return !dm_table_any_dev_attr(t, anti_func);
1235  */
1236 static bool dm_table_any_dev_attr(struct dm_table *t,
1237                                   iterate_devices_callout_fn func)
1238 {
1239         struct dm_target *ti;
1240         unsigned int i;
1241
1242         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1243                 ti = dm_table_get_target(t, i);
1244
1245                 if (ti->type->iterate_devices &&
1246                     ti->type->iterate_devices(ti, func, NULL))
1247                         return true;
1248         }
1249
1250         return false;
1251 }
1252
1253 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1254                         sector_t start, sector_t len, void *data)
1255 {
1256         unsigned *num_devices = data;
1257
1258         (*num_devices)++;
1259
1260         return 0;
1261 }
1262
1263 /*
1264  * Check whether a table has no data devices attached using each
1265  * target's iterate_devices method.
1266  * Returns false if the result is unknown because a target doesn't
1267  * support iterate_devices.
1268  */
1269 bool dm_table_has_no_data_devices(struct dm_table *table)
1270 {
1271         struct dm_target *uninitialized_var(ti);
1272         unsigned i = 0, num_devices = 0;
1273
1274         while (i < dm_table_get_num_targets(table)) {
1275                 ti = dm_table_get_target(table, i++);
1276
1277                 if (!ti->type->iterate_devices)
1278                         return false;
1279
1280                 ti->type->iterate_devices(ti, count_device, &num_devices);
1281                 if (num_devices)
1282                         return false;
1283         }
1284
1285         return true;
1286 }
1287
1288 /*
1289  * Establish the new table's queue_limits and validate them.
1290  */
1291 int dm_calculate_queue_limits(struct dm_table *table,
1292                               struct queue_limits *limits)
1293 {
1294         struct dm_target *uninitialized_var(ti);
1295         struct queue_limits ti_limits;
1296         unsigned i = 0;
1297
1298         blk_set_stacking_limits(limits);
1299
1300         while (i < dm_table_get_num_targets(table)) {
1301                 blk_set_stacking_limits(&ti_limits);
1302
1303                 ti = dm_table_get_target(table, i++);
1304
1305                 if (!ti->type->iterate_devices)
1306                         goto combine_limits;
1307
1308                 /*
1309                  * Combine queue limits of all the devices this target uses.
1310                  */
1311                 ti->type->iterate_devices(ti, dm_set_device_limits,
1312                                           &ti_limits);
1313
1314                 /* Set I/O hints portion of queue limits */
1315                 if (ti->type->io_hints)
1316                         ti->type->io_hints(ti, &ti_limits);
1317
1318                 /*
1319                  * Check each device area is consistent with the target's
1320                  * overall queue limits.
1321                  */
1322                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1323                                               &ti_limits))
1324                         return -EINVAL;
1325
1326 combine_limits:
1327                 /*
1328                  * Merge this target's queue limits into the overall limits
1329                  * for the table.
1330                  */
1331                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1332                         DMWARN("%s: adding target device "
1333                                "(start sect %llu len %llu) "
1334                                "caused an alignment inconsistency",
1335                                dm_device_name(table->md),
1336                                (unsigned long long) ti->begin,
1337                                (unsigned long long) ti->len);
1338         }
1339
1340         return validate_hardware_logical_block_alignment(table, limits);
1341 }
1342
1343 /*
1344  * Verify that all devices have an integrity profile that matches the
1345  * DM device's registered integrity profile.  If the profiles don't
1346  * match then unregister the DM device's integrity profile.
1347  */
1348 static void dm_table_verify_integrity(struct dm_table *t)
1349 {
1350         struct gendisk *template_disk = NULL;
1351
1352         if (t->integrity_supported) {
1353                 /*
1354                  * Verify that the original integrity profile
1355                  * matches all the devices in this table.
1356                  */
1357                 template_disk = dm_table_get_integrity_disk(t);
1358                 if (template_disk &&
1359                     blk_integrity_compare(dm_disk(t->md), template_disk) >= 0)
1360                         return;
1361         }
1362
1363         if (integrity_profile_exists(dm_disk(t->md))) {
1364                 DMWARN("%s: unable to establish an integrity profile",
1365                        dm_device_name(t->md));
1366                 blk_integrity_unregister(dm_disk(t->md));
1367         }
1368 }
1369
1370 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1371                                 sector_t start, sector_t len, void *data)
1372 {
1373         unsigned flush = (*(unsigned *)data);
1374         struct request_queue *q = bdev_get_queue(dev->bdev);
1375
1376         return q && (q->flush_flags & flush);
1377 }
1378
1379 static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
1380 {
1381         struct dm_target *ti;
1382         unsigned i = 0;
1383
1384         /*
1385          * Require at least one underlying device to support flushes.
1386          * t->devices includes internal dm devices such as mirror logs
1387          * so we need to use iterate_devices here, which targets
1388          * supporting flushes must provide.
1389          */
1390         while (i < dm_table_get_num_targets(t)) {
1391                 ti = dm_table_get_target(t, i++);
1392
1393                 if (!ti->num_flush_bios)
1394                         continue;
1395
1396                 if (ti->flush_supported)
1397                         return true;
1398
1399                 if (ti->type->iterate_devices &&
1400                     ti->type->iterate_devices(ti, device_flush_capable, &flush))
1401                         return true;
1402         }
1403
1404         return false;
1405 }
1406
1407 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1408 {
1409         struct dm_target *ti;
1410         unsigned i = 0;
1411
1412         /* Ensure that all targets supports discard_zeroes_data. */
1413         while (i < dm_table_get_num_targets(t)) {
1414                 ti = dm_table_get_target(t, i++);
1415
1416                 if (ti->discard_zeroes_data_unsupported)
1417                         return false;
1418         }
1419
1420         return true;
1421 }
1422
1423 static int device_is_rotational(struct dm_target *ti, struct dm_dev *dev,
1424                                 sector_t start, sector_t len, void *data)
1425 {
1426         struct request_queue *q = bdev_get_queue(dev->bdev);
1427
1428         return q && !blk_queue_nonrot(q);
1429 }
1430
1431 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1432                              sector_t start, sector_t len, void *data)
1433 {
1434         struct request_queue *q = bdev_get_queue(dev->bdev);
1435
1436         return q && !blk_queue_add_random(q);
1437 }
1438
1439 static int queue_no_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1440                              sector_t start, sector_t len, void *data)
1441 {
1442         struct request_queue *q = bdev_get_queue(dev->bdev);
1443
1444         return q && test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1445 }
1446
1447 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1448                                          sector_t start, sector_t len, void *data)
1449 {
1450         struct request_queue *q = bdev_get_queue(dev->bdev);
1451
1452         return q && !q->limits.max_write_same_sectors;
1453 }
1454
1455 static bool dm_table_supports_write_same(struct dm_table *t)
1456 {
1457         struct dm_target *ti;
1458         unsigned i = 0;
1459
1460         while (i < dm_table_get_num_targets(t)) {
1461                 ti = dm_table_get_target(t, i++);
1462
1463                 if (!ti->num_write_same_bios)
1464                         return false;
1465
1466                 if (!ti->type->iterate_devices ||
1467                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1468                         return false;
1469         }
1470
1471         return true;
1472 }
1473
1474 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1475                                   sector_t start, sector_t len, void *data)
1476 {
1477         struct request_queue *q = bdev_get_queue(dev->bdev);
1478
1479         return q && blk_queue_discard(q);
1480 }
1481
1482 static bool dm_table_supports_discards(struct dm_table *t)
1483 {
1484         struct dm_target *ti;
1485         unsigned i = 0;
1486
1487         /*
1488          * Unless any target used by the table set discards_supported,
1489          * require at least one underlying device to support discards.
1490          * t->devices includes internal dm devices such as mirror logs
1491          * so we need to use iterate_devices here, which targets
1492          * supporting discard selectively must provide.
1493          */
1494         while (i < dm_table_get_num_targets(t)) {
1495                 ti = dm_table_get_target(t, i++);
1496
1497                 if (!ti->num_discard_bios)
1498                         continue;
1499
1500                 if (ti->discards_supported)
1501                         return true;
1502
1503                 if (ti->type->iterate_devices &&
1504                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1505                         return true;
1506         }
1507
1508         return false;
1509 }
1510
1511 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1512                                struct queue_limits *limits)
1513 {
1514         unsigned flush = 0;
1515
1516         /*
1517          * Copy table's limits to the DM device's request_queue
1518          */
1519         q->limits = *limits;
1520
1521         if (!dm_table_supports_discards(t))
1522                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1523         else
1524                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1525
1526         if (dm_table_supports_flush(t, REQ_FLUSH)) {
1527                 flush |= REQ_FLUSH;
1528                 if (dm_table_supports_flush(t, REQ_FUA))
1529                         flush |= REQ_FUA;
1530         }
1531         blk_queue_flush(q, flush);
1532
1533         if (!dm_table_discard_zeroes_data(t))
1534                 q->limits.discard_zeroes_data = 0;
1535
1536         /* Ensure that all underlying devices are non-rotational. */
1537         if (dm_table_any_dev_attr(t, device_is_rotational))
1538                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1539         else
1540                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1541
1542         if (!dm_table_supports_write_same(t))
1543                 q->limits.max_write_same_sectors = 0;
1544
1545         if (dm_table_any_dev_attr(t, queue_no_sg_merge))
1546                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1547         else
1548                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1549
1550         dm_table_verify_integrity(t);
1551
1552         /*
1553          * Determine whether or not this queue's I/O timings contribute
1554          * to the entropy pool, Only request-based targets use this.
1555          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1556          * have it set.
1557          */
1558         if (blk_queue_add_random(q) && dm_table_any_dev_attr(t, device_is_not_random))
1559                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1560
1561         /*
1562          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1563          * visible to other CPUs because, once the flag is set, incoming bios
1564          * are processed by request-based dm, which refers to the queue
1565          * settings.
1566          * Until the flag set, bios are passed to bio-based dm and queued to
1567          * md->deferred where queue settings are not needed yet.
1568          * Those bios are passed to request-based dm at the resume time.
1569          */
1570         smp_mb();
1571         if (dm_table_request_based(t))
1572                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1573 }
1574
1575 unsigned int dm_table_get_num_targets(struct dm_table *t)
1576 {
1577         return t->num_targets;
1578 }
1579
1580 struct list_head *dm_table_get_devices(struct dm_table *t)
1581 {
1582         return &t->devices;
1583 }
1584
1585 fmode_t dm_table_get_mode(struct dm_table *t)
1586 {
1587         return t->mode;
1588 }
1589 EXPORT_SYMBOL(dm_table_get_mode);
1590
1591 enum suspend_mode {
1592         PRESUSPEND,
1593         PRESUSPEND_UNDO,
1594         POSTSUSPEND,
1595 };
1596
1597 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1598 {
1599         int i = t->num_targets;
1600         struct dm_target *ti = t->targets;
1601
1602         while (i--) {
1603                 switch (mode) {
1604                 case PRESUSPEND:
1605                         if (ti->type->presuspend)
1606                                 ti->type->presuspend(ti);
1607                         break;
1608                 case PRESUSPEND_UNDO:
1609                         if (ti->type->presuspend_undo)
1610                                 ti->type->presuspend_undo(ti);
1611                         break;
1612                 case POSTSUSPEND:
1613                         if (ti->type->postsuspend)
1614                                 ti->type->postsuspend(ti);
1615                         break;
1616                 }
1617                 ti++;
1618         }
1619 }
1620
1621 void dm_table_presuspend_targets(struct dm_table *t)
1622 {
1623         if (!t)
1624                 return;
1625
1626         suspend_targets(t, PRESUSPEND);
1627 }
1628
1629 void dm_table_presuspend_undo_targets(struct dm_table *t)
1630 {
1631         if (!t)
1632                 return;
1633
1634         suspend_targets(t, PRESUSPEND_UNDO);
1635 }
1636
1637 void dm_table_postsuspend_targets(struct dm_table *t)
1638 {
1639         if (!t)
1640                 return;
1641
1642         suspend_targets(t, POSTSUSPEND);
1643 }
1644
1645 int dm_table_resume_targets(struct dm_table *t)
1646 {
1647         int i, r = 0;
1648
1649         for (i = 0; i < t->num_targets; i++) {
1650                 struct dm_target *ti = t->targets + i;
1651
1652                 if (!ti->type->preresume)
1653                         continue;
1654
1655                 r = ti->type->preresume(ti);
1656                 if (r) {
1657                         DMERR("%s: %s: preresume failed, error = %d",
1658                               dm_device_name(t->md), ti->type->name, r);
1659                         return r;
1660                 }
1661         }
1662
1663         for (i = 0; i < t->num_targets; i++) {
1664                 struct dm_target *ti = t->targets + i;
1665
1666                 if (ti->type->resume)
1667                         ti->type->resume(ti);
1668         }
1669
1670         return 0;
1671 }
1672
1673 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1674 {
1675         list_add(&cb->list, &t->target_callbacks);
1676 }
1677 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1678
1679 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1680 {
1681         struct dm_dev_internal *dd;
1682         struct list_head *devices = dm_table_get_devices(t);
1683         struct dm_target_callbacks *cb;
1684         int r = 0;
1685
1686         list_for_each_entry(dd, devices, list) {
1687                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1688                 char b[BDEVNAME_SIZE];
1689
1690                 if (likely(q))
1691                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1692                 else
1693                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1694                                      dm_device_name(t->md),
1695                                      bdevname(dd->dm_dev->bdev, b));
1696         }
1697
1698         list_for_each_entry(cb, &t->target_callbacks, list)
1699                 if (cb->congested_fn)
1700                         r |= cb->congested_fn(cb, bdi_bits);
1701
1702         return r;
1703 }
1704
1705 struct mapped_device *dm_table_get_md(struct dm_table *t)
1706 {
1707         return t->md;
1708 }
1709 EXPORT_SYMBOL(dm_table_get_md);
1710
1711 void dm_table_run_md_queue_async(struct dm_table *t)
1712 {
1713         struct mapped_device *md;
1714         struct request_queue *queue;
1715         unsigned long flags;
1716
1717         if (!dm_table_request_based(t))
1718                 return;
1719
1720         md = dm_table_get_md(t);
1721         queue = dm_get_md_queue(md);
1722         if (queue) {
1723                 if (queue->mq_ops)
1724                         blk_mq_run_hw_queues(queue, true);
1725                 else {
1726                         spin_lock_irqsave(queue->queue_lock, flags);
1727                         blk_run_queue_async(queue);
1728                         spin_unlock_irqrestore(queue->queue_lock, flags);
1729                 }
1730         }
1731 }
1732 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1733