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-core.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         enum dm_queue_mode 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
  47         bool integrity_supported:1;
  48         bool singleton:1;
  49         bool all_blk_mq:1;
  50         unsigned integrity_added:1;
  51
  52         /*
  53          * Indicates the rw permissions for the new logical
  54          * device.  This should be a combination of FMODE_READ
  55          * and FMODE_WRITE.
  56          */
  57         fmode_t mode;
  58
  59         /* a list of devices used by this table */
  60         struct list_head devices;
  61
  62         /* events get handed up using this callback */
  63         void (*event_fn)(void *);
  64         void *event_context;
  65
  66         struct dm_md_mempools *mempools;
  67
  68         struct list_head target_callbacks;
  69 };
  70
  71 /*
  72  * Similar to ceiling(log_size(n))
  73  */
  74 static unsigned int int_log(unsigned int n, unsigned int base)
  75 {
  76         int result = 0;
  77
  78         while (n > 1) {
  79                 n = dm_div_up(n, base);
  80                 result++;
  81         }
  82
  83         return result;
  84 }
  85
  86 /*
  87  * Calculate the index of the child node of the n'th node k'th key.
  88  */
  89 static inline unsigned int get_child(unsigned int n, unsigned int k)
  90 {
  91         return (n * CHILDREN_PER_NODE) + k;
  92 }
  93
  94 /*
  95  * Return the n'th node of level l from table t.
  96  */
  97 static inline sector_t *get_node(struct dm_table *t,
  98                                  unsigned int l, unsigned int n)
  99 {
 100         return t->index[l] + (n * KEYS_PER_NODE);
 101 }
 102
 103 /*
 104  * Return the highest key that you could lookup from the n'th
 105  * node on level l of the btree.
 106  */
 107 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
 108 {
 109         for (; l < t->depth - 1; l++)
 110                 n = get_child(n, CHILDREN_PER_NODE - 1);
 111
 112         if (n >= t->counts[l])
 113                 return (sector_t) - 1;
 114
 115         return get_node(t, l, n)[KEYS_PER_NODE - 1];
 116 }
 117
 118 /*
 119  * Fills in a level of the btree based on the highs of the level
 120  * below it.
 121  */
 122 static int setup_btree_index(unsigned int l, struct dm_table *t)
 123 {
 124         unsigned int n, k;
 125         sector_t *node;
 126
 127         for (n = 0U; n < t->counts[l]; n++) {
 128                 node = get_node(t, l, n);
 129
 130                 for (k = 0U; k < KEYS_PER_NODE; k++)
 131                         node[k] = high(t, l + 1, get_child(n, k));
 132         }
 133
 134         return 0;
 135 }
 136
 137 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
 138 {
 139         unsigned long size;
 140         void *addr;
 141
 142         /*
 143          * Check that we're not going to overflow.
 144          */
 145         if (nmemb > (ULONG_MAX / elem_size))
 146                 return NULL;
 147
 148         size = nmemb * elem_size;
 149         addr = vzalloc(size);
 150
 151         return addr;
 152 }
 153 EXPORT_SYMBOL(dm_vcalloc);
 154
 155 /*
 156  * highs, and targets are managed as dynamic arrays during a
 157  * table load.
 158  */
 159 static int alloc_targets(struct dm_table *t, unsigned int num)
 160 {
 161         sector_t *n_highs;
 162         struct dm_target *n_targets;
 163
 164         /*
 165          * Allocate both the target array and offset array at once.
 166          * Append an empty entry to catch sectors beyond the end of
 167          * the device.
 168          */
 169         n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
 170                                           sizeof(sector_t));
 171         if (!n_highs)
 172                 return -ENOMEM;
 173
 174         n_targets = (struct dm_target *) (n_highs + num);
 175
 176         memset(n_highs, -1, sizeof(*n_highs) * num);
 177         vfree(t->highs);
 178
 179         t->num_allocated = num;
 180         t->highs = n_highs;
 181         t->targets = n_targets;
 182
 183         return 0;
 184 }
 185
 186 int dm_table_create(struct dm_table **result, fmode_t mode,
 187                     unsigned num_targets, struct mapped_device *md)
 188 {
 189         struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
 190
 191         if (!t)
 192                 return -ENOMEM;
 193
 194         INIT_LIST_HEAD(&t->devices);
 195         INIT_LIST_HEAD(&t->target_callbacks);
 196
 197         if (!num_targets)
 198                 num_targets = KEYS_PER_NODE;
 199
 200         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
 201
 202         if (!num_targets) {
 203                 kfree(t);
 204                 return -ENOMEM;
 205         }
 206
 207         if (alloc_targets(t, num_targets)) {
 208                 kfree(t);
 209                 return -ENOMEM;
 210         }
 211
 212         t->type = DM_TYPE_NONE;
 213         t->mode = mode;
 214         t->md = md;
 215         *result = t;
 216         return 0;
 217 }
 218
 219 static void free_devices(struct list_head *devices, struct mapped_device *md)
 220 {
 221         struct list_head *tmp, *next;
 222
 223         list_for_each_safe(tmp, next, devices) {
 224                 struct dm_dev_internal *dd =
 225                     list_entry(tmp, struct dm_dev_internal, list);
 226                 DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
 227                        dm_device_name(md), dd->dm_dev->name);
 228                 dm_put_table_device(md, dd->dm_dev);
 229                 kfree(dd);
 230         }
 231 }
 232
 233 void dm_table_destroy(struct dm_table *t)
 234 {
 235         unsigned int i;
 236
 237         if (!t)
 238                 return;
 239
 240         /* free the indexes */
 241         if (t->depth >= 2)
 242                 vfree(t->index[t->depth - 2]);
 243
 244         /* free the targets */
 245         for (i = 0; i < t->num_targets; i++) {
 246                 struct dm_target *tgt = t->targets + i;
 247
 248                 if (tgt->type->dtr)
 249                         tgt->type->dtr(tgt);
 250
 251                 dm_put_target_type(tgt->type);
 252         }
 253
 254         vfree(t->highs);
 255
 256         /* free the device list */
 257         free_devices(&t->devices, t->md);
 258
 259         dm_free_md_mempools(t->mempools);
 260
 261         kfree(t);
 262 }
 263
 264 /*
 265  * See if we've already got a device in the list.
 266  */
 267 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
 268 {
 269         struct dm_dev_internal *dd;
 270
 271         list_for_each_entry (dd, l, list)
 272                 if (dd->dm_dev->bdev->bd_dev == dev)
 273                         return dd;
 274
 275         return NULL;
 276 }
 277
 278 /*
 279  * If possible, this checks an area of a destination device is invalid.
 280  */
 281 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
 282                                   sector_t start, sector_t len, void *data)
 283 {
 284         struct request_queue *q;
 285         struct queue_limits *limits = data;
 286         struct block_device *bdev = dev->bdev;
 287         sector_t dev_size =
 288                 i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
 289         unsigned short logical_block_size_sectors =
 290                 limits->logical_block_size >> SECTOR_SHIFT;
 291         char b[BDEVNAME_SIZE];
 292
 293         /*
 294          * Some devices exist without request functions,
 295          * such as loop devices not yet bound to backing files.
 296          * Forbid the use of such devices.
 297          */
 298         q = bdev_get_queue(bdev);
 299         if (!q || !q->make_request_fn) {
 300                 DMWARN("%s: %s is not yet initialised: "
 301                        "start=%llu, len=%llu, dev_size=%llu",
 302                        dm_device_name(ti->table->md), bdevname(bdev, b),
 303                        (unsigned long long)start,
 304                        (unsigned long long)len,
 305                        (unsigned long long)dev_size);
 306                 return 1;
 307         }
 308
 309         if (!dev_size)
 310                 return 0;
 311
 312         if ((start >= dev_size) || (start + len > dev_size)) {
 313                 DMWARN("%s: %s too small for target: "
 314                        "start=%llu, len=%llu, dev_size=%llu",
 315                        dm_device_name(ti->table->md), bdevname(bdev, b),
 316                        (unsigned long long)start,
 317                        (unsigned long long)len,
 318                        (unsigned long long)dev_size);
 319                 return 1;
 320         }
 321
 322         if (logical_block_size_sectors <= 1)
 323                 return 0;
 324
 325         if (start & (logical_block_size_sectors - 1)) {
 326                 DMWARN("%s: start=%llu not aligned to h/w "
 327                        "logical block size %u of %s",
 328                        dm_device_name(ti->table->md),
 329                        (unsigned long long)start,
 330                        limits->logical_block_size, bdevname(bdev, b));
 331                 return 1;
 332         }
 333
 334         if (len & (logical_block_size_sectors - 1)) {
 335                 DMWARN("%s: len=%llu not aligned to h/w "
 336                        "logical block size %u of %s",
 337                        dm_device_name(ti->table->md),
 338                        (unsigned long long)len,
 339                        limits->logical_block_size, bdevname(bdev, b));
 340                 return 1;
 341         }
 342
 343         return 0;
 344 }
 345
 346 /*
 347  * This upgrades the mode on an already open dm_dev, being
 348  * careful to leave things as they were if we fail to reopen the
 349  * device and not to touch the existing bdev field in case
 350  * it is accessed concurrently inside dm_table_any_congested().
 351  */
 352 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
 353                         struct mapped_device *md)
 354 {
 355         int r;
 356         struct dm_dev *old_dev, *new_dev;
 357
 358         old_dev = dd->dm_dev;
 359
 360         r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
 361                                 dd->dm_dev->mode | new_mode, &new_dev);
 362         if (r)
 363                 return r;
 364
 365         dd->dm_dev = new_dev;
 366         dm_put_table_device(md, old_dev);
 367
 368         return 0;
 369 }
 370
 371 /*
 372  * Convert the path to a device
 373  */
 374 dev_t dm_get_dev_t(const char *path)
 375 {
 376         dev_t dev;
 377         struct block_device *bdev;
 378
 379         bdev = lookup_bdev(path);
 380         if (IS_ERR(bdev))
 381                 dev = name_to_dev_t(path);
 382         else {
 383                 dev = bdev->bd_dev;
 384                 bdput(bdev);
 385         }
 386
 387         return dev;
 388 }
 389 EXPORT_SYMBOL_GPL(dm_get_dev_t);
 390
 391 /*
 392  * Add a device to the list, or just increment the usage count if
 393  * it's already present.
 394  */
 395 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 396                   struct dm_dev **result)
 397 {
 398         int r;
 399         dev_t dev;
 400         struct dm_dev_internal *dd;
 401         struct dm_table *t = ti->table;
 402
 403         BUG_ON(!t);
 404
 405         dev = dm_get_dev_t(path);
 406         if (!dev)
 407                 return -ENODEV;
 408
 409         dd = find_device(&t->devices, dev);
 410         if (!dd) {
 411                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
 412                 if (!dd)
 413                         return -ENOMEM;
 414
 415                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
 416                         kfree(dd);
 417                         return r;
 418                 }
 419
 420                 atomic_set(&dd->count, 0);
 421                 list_add(&dd->list, &t->devices);
 422
 423         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
 424                 r = upgrade_mode(dd, mode, t->md);
 425                 if (r)
 426                         return r;
 427         }
 428         atomic_inc(&dd->count);
 429
 430         *result = dd->dm_dev;
 431         return 0;
 432 }
 433 EXPORT_SYMBOL(dm_get_device);
 434
 435 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
 436                                 sector_t start, sector_t len, void *data)
 437 {
 438         struct queue_limits *limits = data;
 439         struct block_device *bdev = dev->bdev;
 440         struct request_queue *q = bdev_get_queue(bdev);
 441         char b[BDEVNAME_SIZE];
 442
 443         if (unlikely(!q)) {
 444                 DMWARN("%s: Cannot set limits for nonexistent device %s",
 445                        dm_device_name(ti->table->md), bdevname(bdev, b));
 446                 return 0;
 447         }
 448
 449         if (bdev_stack_limits(limits, bdev, start) < 0)
 450                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
 451                        "physical_block_size=%u, logical_block_size=%u, "
 452                        "alignment_offset=%u, start=%llu",
 453                        dm_device_name(ti->table->md), bdevname(bdev, b),
 454                        q->limits.physical_block_size,
 455                        q->limits.logical_block_size,
 456                        q->limits.alignment_offset,
 457                        (unsigned long long) start << SECTOR_SHIFT);
 458
 459         return 0;
 460 }
 461
 462 /*
 463  * Decrement a device's use count and remove it if necessary.
 464  */
 465 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 466 {
 467         int found = 0;
 468         struct list_head *devices = &ti->table->devices;
 469         struct dm_dev_internal *dd;
 470
 471         list_for_each_entry(dd, devices, list) {
 472                 if (dd->dm_dev == d) {
 473                         found = 1;
 474                         break;
 475                 }
 476         }
 477         if (!found) {
 478                 DMWARN("%s: device %s not in table devices list",
 479                        dm_device_name(ti->table->md), d->name);
 480                 return;
 481         }
 482         if (atomic_dec_and_test(&dd->count)) {
 483                 dm_put_table_device(ti->table->md, d);
 484                 list_del(&dd->list);
 485                 kfree(dd);
 486         }
 487 }
 488 EXPORT_SYMBOL(dm_put_device);
 489
 490 /*
 491  * Checks to see if the target joins onto the end of the table.
 492  */
 493 static int adjoin(struct dm_table *table, struct dm_target *ti)
 494 {
 495         struct dm_target *prev;
 496
 497         if (!table->num_targets)
 498                 return !ti->begin;
 499
 500         prev = &table->targets[table->num_targets - 1];
 501         return (ti->begin == (prev->begin + prev->len));
 502 }
 503
 504 /*
 505  * Used to dynamically allocate the arg array.
 506  *
 507  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 508  * process messages even if some device is suspended. These messages have a
 509  * small fixed number of arguments.
 510  *
 511  * On the other hand, dm-switch needs to process bulk data using messages and
 512  * excessive use of GFP_NOIO could cause trouble.
 513  */
 514 static char **realloc_argv(unsigned *array_size, char **old_argv)
 515 {
 516         char **argv;
 517         unsigned new_size;
 518         gfp_t gfp;
 519
 520         if (*array_size) {
 521                 new_size = *array_size * 2;
 522                 gfp = GFP_KERNEL;
 523         } else {
 524                 new_size = 8;
 525                 gfp = GFP_NOIO;
 526         }
 527         argv = kmalloc(new_size * sizeof(*argv), gfp);
 528         if (argv) {
 529                 memcpy(argv, old_argv, *array_size * sizeof(*argv));
 530                 *array_size = new_size;
 531         }
 532
 533         kfree(old_argv);
 534         return argv;
 535 }
 536
 537 /*
 538  * Destructively splits up the argument list to pass to ctr.
 539  */
 540 int dm_split_args(int *argc, char ***argvp, char *input)
 541 {
 542         char *start, *end = input, *out, **argv = NULL;
 543         unsigned array_size = 0;
 544
 545         *argc = 0;
 546
 547         if (!input) {
 548                 *argvp = NULL;
 549                 return 0;
 550         }
 551
 552         argv = realloc_argv(&array_size, argv);
 553         if (!argv)
 554                 return -ENOMEM;
 555
 556         while (1) {
 557                 /* Skip whitespace */
 558                 start = skip_spaces(end);
 559
 560                 if (!*start)
 561                         break;  /* success, we hit the end */
 562
 563                 /* 'out' is used to remove any back-quotes */
 564                 end = out = start;
 565                 while (*end) {
 566                         /* Everything apart from '\0' can be quoted */
 567                         if (*end == '\\' && *(end + 1)) {
 568                                 *out++ = *(end + 1);
 569                                 end += 2;
 570                                 continue;
 571                         }
 572
 573                         if (isspace(*end))
 574                                 break;  /* end of token */
 575
 576                         *out++ = *end++;
 577                 }
 578
 579                 /* have we already filled the array ? */
 580                 if ((*argc + 1) > array_size) {
 581                         argv = realloc_argv(&array_size, argv);
 582                         if (!argv)
 583                                 return -ENOMEM;
 584                 }
 585
 586                 /* we know this is whitespace */
 587                 if (*end)
 588                         end++;
 589
 590                 /* terminate the string and put it in the array */
 591                 *out = '\0';
 592                 argv[*argc] = start;
 593                 (*argc)++;
 594         }
 595
 596         *argvp = argv;
 597         return 0;
 598 }
 599
 600 /*
 601  * Impose necessary and sufficient conditions on a devices's table such
 602  * that any incoming bio which respects its logical_block_size can be
 603  * processed successfully.  If it falls across the boundary between
 604  * two or more targets, the size of each piece it gets split into must
 605  * be compatible with the logical_block_size of the target processing it.
 606  */
 607 static int validate_hardware_logical_block_alignment(struct dm_table *table,
 608                                                  struct queue_limits *limits)
 609 {
 610         /*
 611          * This function uses arithmetic modulo the logical_block_size
 612          * (in units of 512-byte sectors).
 613          */
 614         unsigned short device_logical_block_size_sects =
 615                 limits->logical_block_size >> SECTOR_SHIFT;
 616
 617         /*
 618          * Offset of the start of the next table entry, mod logical_block_size.
 619          */
 620         unsigned short next_target_start = 0;
 621
 622         /*
 623          * Given an aligned bio that extends beyond the end of a
 624          * target, how many sectors must the next target handle?
 625          */
 626         unsigned short remaining = 0;
 627
 628         struct dm_target *uninitialized_var(ti);
 629         struct queue_limits ti_limits;
 630         unsigned i;
 631
 632         /*
 633          * Check each entry in the table in turn.
 634          */
 635         for (i = 0; i < dm_table_get_num_targets(table); i++) {
 636                 ti = dm_table_get_target(table, i);
 637
 638                 blk_set_stacking_limits(&ti_limits);
 639
 640                 /* combine all target devices' limits */
 641                 if (ti->type->iterate_devices)
 642                         ti->type->iterate_devices(ti, dm_set_device_limits,
 643                                                   &ti_limits);
 644
 645                 /*
 646                  * If the remaining sectors fall entirely within this
 647                  * table entry are they compatible with its logical_block_size?
 648                  */
 649                 if (remaining < ti->len &&
 650                     remaining & ((ti_limits.logical_block_size >>
 651                                   SECTOR_SHIFT) - 1))
 652                         break;  /* Error */
 653
 654                 next_target_start =
 655                     (unsigned short) ((next_target_start + ti->len) &
 656                                       (device_logical_block_size_sects - 1));
 657                 remaining = next_target_start ?
 658                     device_logical_block_size_sects - next_target_start : 0;
 659         }
 660
 661         if (remaining) {
 662                 DMWARN("%s: table line %u (start sect %llu len %llu) "
 663                        "not aligned to h/w logical block size %u",
 664                        dm_device_name(table->md), i,
 665                        (unsigned long long) ti->begin,
 666                        (unsigned long long) ti->len,
 667                        limits->logical_block_size);
 668                 return -EINVAL;
 669         }
 670
 671         return 0;
 672 }
 673
 674 int dm_table_add_target(struct dm_table *t, const char *type,
 675                         sector_t start, sector_t len, char *params)
 676 {
 677         int r = -EINVAL, argc;
 678         char **argv;
 679         struct dm_target *tgt;
 680
 681         if (t->singleton) {
 682                 DMERR("%s: target type %s must appear alone in table",
 683                       dm_device_name(t->md), t->targets->type->name);
 684                 return -EINVAL;
 685         }
 686
 687         BUG_ON(t->num_targets >= t->num_allocated);
 688
 689         tgt = t->targets + t->num_targets;
 690         memset(tgt, 0, sizeof(*tgt));
 691
 692         if (!len) {
 693                 DMERR("%s: zero-length target", dm_device_name(t->md));
 694                 return -EINVAL;
 695         }
 696
 697         tgt->type = dm_get_target_type(type);
 698         if (!tgt->type) {
 699                 DMERR("%s: %s: unknown target type", dm_device_name(t->md), type);
 700                 return -EINVAL;
 701         }
 702
 703         if (dm_target_needs_singleton(tgt->type)) {
 704                 if (t->num_targets) {
 705                         tgt->error = "singleton target type must appear alone in table";
 706                         goto bad;
 707                 }
 708                 t->singleton = true;
 709         }
 710
 711         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
 712                 tgt->error = "target type may not be included in a read-only table";
 713                 goto bad;
 714         }
 715
 716         if (t->immutable_target_type) {
 717                 if (t->immutable_target_type != tgt->type) {
 718                         tgt->error = "immutable target type cannot be mixed with other target types";
 719                         goto bad;
 720                 }
 721         } else if (dm_target_is_immutable(tgt->type)) {
 722                 if (t->num_targets) {
 723                         tgt->error = "immutable target type cannot be mixed with other target types";
 724                         goto bad;
 725                 }
 726                 t->immutable_target_type = tgt->type;
 727         }
 728
 729         if (dm_target_has_integrity(tgt->type))
 730                 t->integrity_added = 1;
 731
 732         tgt->table = t;
 733         tgt->begin = start;
 734         tgt->len = len;
 735         tgt->error = "Unknown error";
 736
 737         /*
 738          * Does this target adjoin the previous one ?
 739          */
 740         if (!adjoin(t, tgt)) {
 741                 tgt->error = "Gap in table";
 742                 goto bad;
 743         }
 744
 745         r = dm_split_args(&argc, &argv, params);
 746         if (r) {
 747                 tgt->error = "couldn't split parameters (insufficient memory)";
 748                 goto bad;
 749         }
 750
 751         r = tgt->type->ctr(tgt, argc, argv);
 752         kfree(argv);
 753         if (r)
 754                 goto bad;
 755
 756         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
 757
 758         if (!tgt->num_discard_bios && tgt->discards_supported)
 759                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
 760                        dm_device_name(t->md), type);
 761
 762         return 0;
 763
 764  bad:
 765         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 766         dm_put_target_type(tgt->type);
 767         return r;
 768 }
 769
 770 /*
 771  * Target argument parsing helpers.
 772  */
 773 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 774                              unsigned *value, char **error, unsigned grouped)
 775 {
 776         const char *arg_str = dm_shift_arg(arg_set);
 777         char dummy;
 778
 779         if (!arg_str ||
 780             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
 781             (*value < arg->min) ||
 782             (*value > arg->max) ||
 783             (grouped && arg_set->argc < *value)) {
 784                 *error = arg->error;
 785                 return -EINVAL;
 786         }
 787
 788         return 0;
 789 }
 790
 791 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
 792                 unsigned *value, char **error)
 793 {
 794         return validate_next_arg(arg, arg_set, value, error, 0);
 795 }
 796 EXPORT_SYMBOL(dm_read_arg);
 797
 798 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
 799                       unsigned *value, char **error)
 800 {
 801         return validate_next_arg(arg, arg_set, value, error, 1);
 802 }
 803 EXPORT_SYMBOL(dm_read_arg_group);
 804
 805 const char *dm_shift_arg(struct dm_arg_set *as)
 806 {
 807         char *r;
 808
 809         if (as->argc) {
 810                 as->argc--;
 811                 r = *as->argv;
 812                 as->argv++;
 813                 return r;
 814         }
 815
 816         return NULL;
 817 }
 818 EXPORT_SYMBOL(dm_shift_arg);
 819
 820 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
 821 {
 822         BUG_ON(as->argc < num_args);
 823         as->argc -= num_args;
 824         as->argv += num_args;
 825 }
 826 EXPORT_SYMBOL(dm_consume_args);
 827
 828 static bool __table_type_bio_based(enum dm_queue_mode table_type)
 829 {
 830         return (table_type == DM_TYPE_BIO_BASED ||
 831                 table_type == DM_TYPE_DAX_BIO_BASED);
 832 }
 833
 834 static bool __table_type_request_based(enum dm_queue_mode table_type)
 835 {
 836         return (table_type == DM_TYPE_REQUEST_BASED ||
 837                 table_type == DM_TYPE_MQ_REQUEST_BASED);
 838 }
 839
 840 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type)
 841 {
 842         t->type = type;
 843 }
 844 EXPORT_SYMBOL_GPL(dm_table_set_type);
 845
 846 static int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
 847                                sector_t start, sector_t len, void *data)
 848 {
 849         struct request_queue *q = bdev_get_queue(dev->bdev);
 850
 851         return q && blk_queue_dax(q);
 852 }
 853
 854 static bool dm_table_supports_dax(struct dm_table *t)
 855 {
 856         struct dm_target *ti;
 857         unsigned i;
 858
 859         /* Ensure that all targets support DAX. */
 860         for (i = 0; i < dm_table_get_num_targets(t); i++) {
 861                 ti = dm_table_get_target(t, i);
 862
 863                 if (!ti->type->direct_access)
 864                         return false;
 865
 866                 if (!ti->type->iterate_devices ||
 867                     !ti->type->iterate_devices(ti, device_supports_dax, NULL))
 868                         return false;
 869         }
 870
 871         return true;
 872 }
 873
 874 static int dm_table_determine_type(struct dm_table *t)
 875 {
 876         unsigned i;
 877         unsigned bio_based = 0, request_based = 0, hybrid = 0;
 878         unsigned sq_count = 0, mq_count = 0;
 879         struct dm_target *tgt;
 880         struct dm_dev_internal *dd;
 881         struct list_head *devices = dm_table_get_devices(t);
 882         enum dm_queue_mode live_md_type = dm_get_md_type(t->md);
 883
 884         if (t->type != DM_TYPE_NONE) {
 885                 /* target already set the table's type */
 886                 if (t->type == DM_TYPE_BIO_BASED)
 887                         return 0;
 888                 BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED);
 889                 goto verify_rq_based;
 890         }
 891
 892         for (i = 0; i < t->num_targets; i++) {
 893                 tgt = t->targets + i;
 894                 if (dm_target_hybrid(tgt))
 895                         hybrid = 1;
 896                 else if (dm_target_request_based(tgt))
 897                         request_based = 1;
 898                 else
 899                         bio_based = 1;
 900
 901                 if (bio_based && request_based) {
 902                         DMWARN("Inconsistent table: different target types"
 903                                " can't be mixed up");
 904                         return -EINVAL;
 905                 }
 906         }
 907
 908         if (hybrid && !bio_based && !request_based) {
 909                 /*
 910                  * The targets can work either way.
 911                  * Determine the type from the live device.
 912                  * Default to bio-based if device is new.
 913                  */
 914                 if (__table_type_request_based(live_md_type))
 915                         request_based = 1;
 916                 else
 917                         bio_based = 1;
 918         }
 919
 920         if (bio_based) {
 921                 /* We must use this table as bio-based */
 922                 t->type = DM_TYPE_BIO_BASED;
 923                 if (dm_table_supports_dax(t) ||
 924                     (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED))
 925                         t->type = DM_TYPE_DAX_BIO_BASED;
 926                 return 0;
 927         }
 928
 929         BUG_ON(!request_based); /* No targets in this table */
 930
 931         /*
 932          * The only way to establish DM_TYPE_MQ_REQUEST_BASED is by
 933          * having a compatible target use dm_table_set_type.
 934          */
 935         t->type = DM_TYPE_REQUEST_BASED;
 936
 937 verify_rq_based:
 938         /*
 939          * Request-based dm supports only tables that have a single target now.
 940          * To support multiple targets, request splitting support is needed,
 941          * and that needs lots of changes in the block-layer.
 942          * (e.g. request completion process for partial completion.)
 943          */
 944         if (t->num_targets > 1) {
 945                 DMWARN("Request-based dm doesn't support multiple targets yet");
 946                 return -EINVAL;
 947         }
 948
 949         if (list_empty(devices)) {
 950                 int srcu_idx;
 951                 struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx);
 952
 953                 /* inherit live table's type and all_blk_mq */
 954                 if (live_table) {
 955                         t->type = live_table->type;
 956                         t->all_blk_mq = live_table->all_blk_mq;
 957                 }
 958                 dm_put_live_table(t->md, srcu_idx);
 959                 return 0;
 960         }
 961
 962         /* Non-request-stackable devices can't be used for request-based dm */
 963         list_for_each_entry(dd, devices, list) {
 964                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
 965
 966                 if (!blk_queue_stackable(q)) {
 967                         DMERR("table load rejected: including"
 968                               " non-request-stackable devices");
 969                         return -EINVAL;
 970                 }
 971
 972                 if (q->mq_ops)
 973                         mq_count++;
 974                 else
 975                         sq_count++;
 976         }
 977         if (sq_count && mq_count) {
 978                 DMERR("table load rejected: not all devices are blk-mq request-stackable");
 979                 return -EINVAL;
 980         }
 981         t->all_blk_mq = mq_count > 0;
 982
 983         if (t->type == DM_TYPE_MQ_REQUEST_BASED && !t->all_blk_mq) {
 984                 DMERR("table load rejected: all devices are not blk-mq request-stackable");
 985                 return -EINVAL;
 986         }
 987
 988         return 0;
 989 }
 990
 991 enum dm_queue_mode dm_table_get_type(struct dm_table *t)
 992 {
 993         return t->type;
 994 }
 995
 996 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
 997 {
 998         return t->immutable_target_type;
 999 }
1000
1001 struct dm_target *dm_table_get_immutable_target(struct dm_table *t)
1002 {
1003         /* Immutable target is implicitly a singleton */
1004         if (t->num_targets > 1 ||
1005             !dm_target_is_immutable(t->targets[0].type))
1006                 return NULL;
1007
1008         return t->targets;
1009 }
1010
1011 struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
1012 {
1013         struct dm_target *ti;
1014         unsigned i;
1015
1016         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1017                 ti = dm_table_get_target(t, i);
1018                 if (dm_target_is_wildcard(ti->type))
1019                         return ti;
1020         }
1021
1022         return NULL;
1023 }
1024
1025 bool dm_table_bio_based(struct dm_table *t)
1026 {
1027         return __table_type_bio_based(dm_table_get_type(t));
1028 }
1029
1030 bool dm_table_request_based(struct dm_table *t)
1031 {
1032         return __table_type_request_based(dm_table_get_type(t));
1033 }
1034
1035 bool dm_table_all_blk_mq_devices(struct dm_table *t)
1036 {
1037         return t->all_blk_mq;
1038 }
1039
1040 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
1041 {
1042         enum dm_queue_mode type = dm_table_get_type(t);
1043         unsigned per_io_data_size = 0;
1044         struct dm_target *tgt;
1045         unsigned i;
1046
1047         if (unlikely(type == DM_TYPE_NONE)) {
1048                 DMWARN("no table type is set, can't allocate mempools");
1049                 return -EINVAL;
1050         }
1051
1052         if (__table_type_bio_based(type))
1053                 for (i = 0; i < t->num_targets; i++) {
1054                         tgt = t->targets + i;
1055                         per_io_data_size = max(per_io_data_size, tgt->per_io_data_size);
1056                 }
1057
1058         t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_io_data_size);
1059         if (!t->mempools)
1060                 return -ENOMEM;
1061
1062         return 0;
1063 }
1064
1065 void dm_table_free_md_mempools(struct dm_table *t)
1066 {
1067         dm_free_md_mempools(t->mempools);
1068         t->mempools = NULL;
1069 }
1070
1071 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
1072 {
1073         return t->mempools;
1074 }
1075
1076 static int setup_indexes(struct dm_table *t)
1077 {
1078         int i;
1079         unsigned int total = 0;
1080         sector_t *indexes;
1081
1082         /* allocate the space for *all* the indexes */
1083         for (i = t->depth - 2; i >= 0; i--) {
1084                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
1085                 total += t->counts[i];
1086         }
1087
1088         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
1089         if (!indexes)
1090                 return -ENOMEM;
1091
1092         /* set up internal nodes, bottom-up */
1093         for (i = t->depth - 2; i >= 0; i--) {
1094                 t->index[i] = indexes;
1095                 indexes += (KEYS_PER_NODE * t->counts[i]);
1096                 setup_btree_index(i, t);
1097         }
1098
1099         return 0;
1100 }
1101
1102 /*
1103  * Builds the btree to index the map.
1104  */
1105 static int dm_table_build_index(struct dm_table *t)
1106 {
1107         int r = 0;
1108         unsigned int leaf_nodes;
1109
1110         /* how many indexes will the btree have ? */
1111         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1112         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1113
1114         /* leaf layer has already been set up */
1115         t->counts[t->depth - 1] = leaf_nodes;
1116         t->index[t->depth - 1] = t->highs;
1117
1118         if (t->depth >= 2)
1119                 r = setup_indexes(t);
1120
1121         return r;
1122 }
1123
1124 static bool integrity_profile_exists(struct gendisk *disk)
1125 {
1126         return !!blk_get_integrity(disk);
1127 }
1128
1129 /*
1130  * Get a disk whose integrity profile reflects the table's profile.
1131  * Returns NULL if integrity support was inconsistent or unavailable.
1132  */
1133 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
1134 {
1135         struct list_head *devices = dm_table_get_devices(t);
1136         struct dm_dev_internal *dd = NULL;
1137         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1138         unsigned i;
1139
1140         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1141                 struct dm_target *ti = dm_table_get_target(t, i);
1142                 if (!dm_target_passes_integrity(ti->type))
1143                         goto no_integrity;
1144         }
1145
1146         list_for_each_entry(dd, devices, list) {
1147                 template_disk = dd->dm_dev->bdev->bd_disk;
1148                 if (!integrity_profile_exists(template_disk))
1149                         goto no_integrity;
1150                 else if (prev_disk &&
1151                          blk_integrity_compare(prev_disk, template_disk) < 0)
1152                         goto no_integrity;
1153                 prev_disk = template_disk;
1154         }
1155
1156         return template_disk;
1157
1158 no_integrity:
1159         if (prev_disk)
1160                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1161                        dm_device_name(t->md),
1162                        prev_disk->disk_name,
1163                        template_disk->disk_name);
1164         return NULL;
1165 }
1166
1167 /*
1168  * Register the mapped device for blk_integrity support if the
1169  * underlying devices have an integrity profile.  But all devices may
1170  * not have matching profiles (checking all devices isn't reliable
1171  * during table load because this table may use other DM device(s) which
1172  * must be resumed before they will have an initialized integity
1173  * profile).  Consequently, stacked DM devices force a 2 stage integrity
1174  * profile validation: First pass during table load, final pass during
1175  * resume.
1176  */
1177 static int dm_table_register_integrity(struct dm_table *t)
1178 {
1179         struct mapped_device *md = t->md;
1180         struct gendisk *template_disk = NULL;
1181
1182         /* If target handles integrity itself do not register it here. */
1183         if (t->integrity_added)
1184                 return 0;
1185
1186         template_disk = dm_table_get_integrity_disk(t);
1187         if (!template_disk)
1188                 return 0;
1189
1190         if (!integrity_profile_exists(dm_disk(md))) {
1191                 t->integrity_supported = true;
1192                 /*
1193                  * Register integrity profile during table load; we can do
1194                  * this because the final profile must match during resume.
1195                  */
1196                 blk_integrity_register(dm_disk(md),
1197                                        blk_get_integrity(template_disk));
1198                 return 0;
1199         }
1200
1201         /*
1202          * If DM device already has an initialized integrity
1203          * profile the new profile should not conflict.
1204          */
1205         if (blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1206                 DMWARN("%s: conflict with existing integrity profile: "
1207                        "%s profile mismatch",
1208                        dm_device_name(t->md),
1209                        template_disk->disk_name);
1210                 return 1;
1211         }
1212
1213         /* Preserve existing integrity profile */
1214         t->integrity_supported = true;
1215         return 0;
1216 }
1217
1218 /*
1219  * Prepares the table for use by building the indices,
1220  * setting the type, and allocating mempools.
1221  */
1222 int dm_table_complete(struct dm_table *t)
1223 {
1224         int r;
1225
1226         r = dm_table_determine_type(t);
1227         if (r) {
1228                 DMERR("unable to determine table type");
1229                 return r;
1230         }
1231
1232         r = dm_table_build_index(t);
1233         if (r) {
1234                 DMERR("unable to build btrees");
1235                 return r;
1236         }
1237
1238         r = dm_table_register_integrity(t);
1239         if (r) {
1240                 DMERR("could not register integrity profile.");
1241                 return r;
1242         }
1243
1244         r = dm_table_alloc_md_mempools(t, t->md);
1245         if (r)
1246                 DMERR("unable to allocate mempools");
1247
1248         return r;
1249 }
1250
1251 static DEFINE_MUTEX(_event_lock);
1252 void dm_table_event_callback(struct dm_table *t,
1253                              void (*fn)(void *), void *context)
1254 {
1255         mutex_lock(&_event_lock);
1256         t->event_fn = fn;
1257         t->event_context = context;
1258         mutex_unlock(&_event_lock);
1259 }
1260
1261 void dm_table_event(struct dm_table *t)
1262 {
1263         /*
1264          * You can no longer call dm_table_event() from interrupt
1265          * context, use a bottom half instead.
1266          */
1267         BUG_ON(in_interrupt());
1268
1269         mutex_lock(&_event_lock);
1270         if (t->event_fn)
1271                 t->event_fn(t->event_context);
1272         mutex_unlock(&_event_lock);
1273 }
1274 EXPORT_SYMBOL(dm_table_event);
1275
1276 sector_t dm_table_get_size(struct dm_table *t)
1277 {
1278         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1279 }
1280 EXPORT_SYMBOL(dm_table_get_size);
1281
1282 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1283 {
1284         if (index >= t->num_targets)
1285                 return NULL;
1286
1287         return t->targets + index;
1288 }
1289
1290 /*
1291  * Search the btree for the correct target.
1292  *
1293  * Caller should check returned pointer with dm_target_is_valid()
1294  * to trap I/O beyond end of device.
1295  */
1296 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1297 {
1298         unsigned int l, n = 0, k = 0;
1299         sector_t *node;
1300
1301         for (l = 0; l < t->depth; l++) {
1302                 n = get_child(n, k);
1303                 node = get_node(t, l, n);
1304
1305                 for (k = 0; k < KEYS_PER_NODE; k++)
1306                         if (node[k] >= sector)
1307                                 break;
1308         }
1309
1310         return &t->targets[(KEYS_PER_NODE * n) + k];
1311 }
1312
1313 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1314                         sector_t start, sector_t len, void *data)
1315 {
1316         unsigned *num_devices = data;
1317
1318         (*num_devices)++;
1319
1320         return 0;
1321 }
1322
1323 /*
1324  * Check whether a table has no data devices attached using each
1325  * target's iterate_devices method.
1326  * Returns false if the result is unknown because a target doesn't
1327  * support iterate_devices.
1328  */
1329 bool dm_table_has_no_data_devices(struct dm_table *table)
1330 {
1331         struct dm_target *ti;
1332         unsigned i, num_devices;
1333
1334         for (i = 0; i < dm_table_get_num_targets(table); i++) {
1335                 ti = dm_table_get_target(table, i);
1336
1337                 if (!ti->type->iterate_devices)
1338                         return false;
1339
1340                 num_devices = 0;
1341                 ti->type->iterate_devices(ti, count_device, &num_devices);
1342                 if (num_devices)
1343                         return false;
1344         }
1345
1346         return true;
1347 }
1348
1349 /*
1350  * Establish the new table's queue_limits and validate them.
1351  */
1352 int dm_calculate_queue_limits(struct dm_table *table,
1353                               struct queue_limits *limits)
1354 {
1355         struct dm_target *ti;
1356         struct queue_limits ti_limits;
1357         unsigned i;
1358
1359         blk_set_stacking_limits(limits);
1360
1361         for (i = 0; i < dm_table_get_num_targets(table); i++) {
1362                 blk_set_stacking_limits(&ti_limits);
1363
1364                 ti = dm_table_get_target(table, i);
1365
1366                 if (!ti->type->iterate_devices)
1367                         goto combine_limits;
1368
1369                 /*
1370                  * Combine queue limits of all the devices this target uses.
1371                  */
1372                 ti->type->iterate_devices(ti, dm_set_device_limits,
1373                                           &ti_limits);
1374
1375                 /* Set I/O hints portion of queue limits */
1376                 if (ti->type->io_hints)
1377                         ti->type->io_hints(ti, &ti_limits);
1378
1379                 /*
1380                  * Check each device area is consistent with the target's
1381                  * overall queue limits.
1382                  */
1383                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1384                                               &ti_limits))
1385                         return -EINVAL;
1386
1387 combine_limits:
1388                 /*
1389                  * Merge this target's queue limits into the overall limits
1390                  * for the table.
1391                  */
1392                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1393                         DMWARN("%s: adding target device "
1394                                "(start sect %llu len %llu) "
1395                                "caused an alignment inconsistency",
1396                                dm_device_name(table->md),
1397                                (unsigned long long) ti->begin,
1398                                (unsigned long long) ti->len);
1399         }
1400
1401         return validate_hardware_logical_block_alignment(table, limits);
1402 }
1403
1404 /*
1405  * Verify that all devices have an integrity profile that matches the
1406  * DM device's registered integrity profile.  If the profiles don't
1407  * match then unregister the DM device's integrity profile.
1408  */
1409 static void dm_table_verify_integrity(struct dm_table *t)
1410 {
1411         struct gendisk *template_disk = NULL;
1412
1413         if (t->integrity_added)
1414                 return;
1415
1416         if (t->integrity_supported) {
1417                 /*
1418                  * Verify that the original integrity profile
1419                  * matches all the devices in this table.
1420                  */
1421                 template_disk = dm_table_get_integrity_disk(t);
1422                 if (template_disk &&
1423                     blk_integrity_compare(dm_disk(t->md), template_disk) >= 0)
1424                         return;
1425         }
1426
1427         if (integrity_profile_exists(dm_disk(t->md))) {
1428                 DMWARN("%s: unable to establish an integrity profile",
1429                        dm_device_name(t->md));
1430                 blk_integrity_unregister(dm_disk(t->md));
1431         }
1432 }
1433
1434 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1435                                 sector_t start, sector_t len, void *data)
1436 {
1437         unsigned long flush = (unsigned long) data;
1438         struct request_queue *q = bdev_get_queue(dev->bdev);
1439
1440         return q && (q->queue_flags & flush);
1441 }
1442
1443 static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
1444 {
1445         struct dm_target *ti;
1446         unsigned i;
1447
1448         /*
1449          * Require at least one underlying device to support flushes.
1450          * t->devices includes internal dm devices such as mirror logs
1451          * so we need to use iterate_devices here, which targets
1452          * supporting flushes must provide.
1453          */
1454         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1455                 ti = dm_table_get_target(t, i);
1456
1457                 if (!ti->num_flush_bios)
1458                         continue;
1459
1460                 if (ti->flush_supported)
1461                         return true;
1462
1463                 if (ti->type->iterate_devices &&
1464                     ti->type->iterate_devices(ti, device_flush_capable, (void *) flush))
1465                         return true;
1466         }
1467
1468         return false;
1469 }
1470
1471 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1472                             sector_t start, sector_t len, void *data)
1473 {
1474         struct request_queue *q = bdev_get_queue(dev->bdev);
1475
1476         return q && blk_queue_nonrot(q);
1477 }
1478
1479 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1480                              sector_t start, sector_t len, void *data)
1481 {
1482         struct request_queue *q = bdev_get_queue(dev->bdev);
1483
1484         return q && !blk_queue_add_random(q);
1485 }
1486
1487 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1488                                    sector_t start, sector_t len, void *data)
1489 {
1490         struct request_queue *q = bdev_get_queue(dev->bdev);
1491
1492         return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1493 }
1494
1495 static bool dm_table_all_devices_attribute(struct dm_table *t,
1496                                            iterate_devices_callout_fn func)
1497 {
1498         struct dm_target *ti;
1499         unsigned i;
1500
1501         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1502                 ti = dm_table_get_target(t, i);
1503
1504                 if (!ti->type->iterate_devices ||
1505                     !ti->type->iterate_devices(ti, func, NULL))
1506                         return false;
1507         }
1508
1509         return true;
1510 }
1511
1512 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1513                                          sector_t start, sector_t len, void *data)
1514 {
1515         struct request_queue *q = bdev_get_queue(dev->bdev);
1516
1517         return q && !q->limits.max_write_same_sectors;
1518 }
1519
1520 static bool dm_table_supports_write_same(struct dm_table *t)
1521 {
1522         struct dm_target *ti;
1523         unsigned i;
1524
1525         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1526                 ti = dm_table_get_target(t, i);
1527
1528                 if (!ti->num_write_same_bios)
1529                         return false;
1530
1531                 if (!ti->type->iterate_devices ||
1532                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1533                         return false;
1534         }
1535
1536         return true;
1537 }
1538
1539 static int device_not_write_zeroes_capable(struct dm_target *ti, struct dm_dev *dev,
1540                                            sector_t start, sector_t len, void *data)
1541 {
1542         struct request_queue *q = bdev_get_queue(dev->bdev);
1543
1544         return q && !q->limits.max_write_zeroes_sectors;
1545 }
1546
1547 static bool dm_table_supports_write_zeroes(struct dm_table *t)
1548 {
1549         struct dm_target *ti;
1550         unsigned i = 0;
1551
1552         while (i < dm_table_get_num_targets(t)) {
1553                 ti = dm_table_get_target(t, i++);
1554
1555                 if (!ti->num_write_zeroes_bios)
1556                         return false;
1557
1558                 if (!ti->type->iterate_devices ||
1559                     ti->type->iterate_devices(ti, device_not_write_zeroes_capable, NULL))
1560                         return false;
1561         }
1562
1563         return true;
1564 }
1565
1566
1567 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1568                                   sector_t start, sector_t len, void *data)
1569 {
1570         struct request_queue *q = bdev_get_queue(dev->bdev);
1571
1572         return q && blk_queue_discard(q);
1573 }
1574
1575 static bool dm_table_supports_discards(struct dm_table *t)
1576 {
1577         struct dm_target *ti;
1578         unsigned i;
1579
1580         /*
1581          * Unless any target used by the table set discards_supported,
1582          * require at least one underlying device to support discards.
1583          * t->devices includes internal dm devices such as mirror logs
1584          * so we need to use iterate_devices here, which targets
1585          * supporting discard selectively must provide.
1586          */
1587         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1588                 ti = dm_table_get_target(t, i);
1589
1590                 if (!ti->num_discard_bios)
1591                         continue;
1592
1593                 if (ti->discards_supported)
1594                         return true;
1595
1596                 if (ti->type->iterate_devices &&
1597                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1598                         return true;
1599         }
1600
1601         return false;
1602 }
1603
1604 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1605                                struct queue_limits *limits)
1606 {
1607         bool wc = false, fua = false;
1608
1609         /*
1610          * Copy table's limits to the DM device's request_queue
1611          */
1612         q->limits = *limits;
1613
1614         if (!dm_table_supports_discards(t))
1615                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1616         else
1617                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1618
1619         if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
1620                 wc = true;
1621                 if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))
1622                         fua = true;
1623         }
1624         blk_queue_write_cache(q, wc, fua);
1625
1626         /* Ensure that all underlying devices are non-rotational. */
1627         if (dm_table_all_devices_attribute(t, device_is_nonrot))
1628                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1629         else
1630                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1631
1632         if (!dm_table_supports_write_same(t))
1633                 q->limits.max_write_same_sectors = 0;
1634         if (!dm_table_supports_write_zeroes(t))
1635                 q->limits.max_write_zeroes_sectors = 0;
1636
1637         if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1638                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1639         else
1640                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1641
1642         dm_table_verify_integrity(t);
1643
1644         /*
1645          * Determine whether or not this queue's I/O timings contribute
1646          * to the entropy pool, Only request-based targets use this.
1647          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1648          * have it set.
1649          */
1650         if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1651                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1652
1653         /*
1654          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1655          * visible to other CPUs because, once the flag is set, incoming bios
1656          * are processed by request-based dm, which refers to the queue
1657          * settings.
1658          * Until the flag set, bios are passed to bio-based dm and queued to
1659          * md->deferred where queue settings are not needed yet.
1660          * Those bios are passed to request-based dm at the resume time.
1661          */
1662         smp_mb();
1663         if (dm_table_request_based(t))
1664                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1665 }
1666
1667 unsigned int dm_table_get_num_targets(struct dm_table *t)
1668 {
1669         return t->num_targets;
1670 }
1671
1672 struct list_head *dm_table_get_devices(struct dm_table *t)
1673 {
1674         return &t->devices;
1675 }
1676
1677 fmode_t dm_table_get_mode(struct dm_table *t)
1678 {
1679         return t->mode;
1680 }
1681 EXPORT_SYMBOL(dm_table_get_mode);
1682
1683 enum suspend_mode {
1684         PRESUSPEND,
1685         PRESUSPEND_UNDO,
1686         POSTSUSPEND,
1687 };
1688
1689 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1690 {
1691         int i = t->num_targets;
1692         struct dm_target *ti = t->targets;
1693
1694         lockdep_assert_held(&t->md->suspend_lock);
1695
1696         while (i--) {
1697                 switch (mode) {
1698                 case PRESUSPEND:
1699                         if (ti->type->presuspend)
1700                                 ti->type->presuspend(ti);
1701                         break;
1702                 case PRESUSPEND_UNDO:
1703                         if (ti->type->presuspend_undo)
1704                                 ti->type->presuspend_undo(ti);
1705                         break;
1706                 case POSTSUSPEND:
1707                         if (ti->type->postsuspend)
1708                                 ti->type->postsuspend(ti);
1709                         break;
1710                 }
1711                 ti++;
1712         }
1713 }
1714
1715 void dm_table_presuspend_targets(struct dm_table *t)
1716 {
1717         if (!t)
1718                 return;
1719
1720         suspend_targets(t, PRESUSPEND);
1721 }
1722
1723 void dm_table_presuspend_undo_targets(struct dm_table *t)
1724 {
1725         if (!t)
1726                 return;
1727
1728         suspend_targets(t, PRESUSPEND_UNDO);
1729 }
1730
1731 void dm_table_postsuspend_targets(struct dm_table *t)
1732 {
1733         if (!t)
1734                 return;
1735
1736         suspend_targets(t, POSTSUSPEND);
1737 }
1738
1739 int dm_table_resume_targets(struct dm_table *t)
1740 {
1741         int i, r = 0;
1742
1743         lockdep_assert_held(&t->md->suspend_lock);
1744
1745         for (i = 0; i < t->num_targets; i++) {
1746                 struct dm_target *ti = t->targets + i;
1747
1748                 if (!ti->type->preresume)
1749                         continue;
1750
1751                 r = ti->type->preresume(ti);
1752                 if (r) {
1753                         DMERR("%s: %s: preresume failed, error = %d",
1754                               dm_device_name(t->md), ti->type->name, r);
1755                         return r;
1756                 }
1757         }
1758
1759         for (i = 0; i < t->num_targets; i++) {
1760                 struct dm_target *ti = t->targets + i;
1761
1762                 if (ti->type->resume)
1763                         ti->type->resume(ti);
1764         }
1765
1766         return 0;
1767 }
1768
1769 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1770 {
1771         list_add(&cb->list, &t->target_callbacks);
1772 }
1773 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1774
1775 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1776 {
1777         struct dm_dev_internal *dd;
1778         struct list_head *devices = dm_table_get_devices(t);
1779         struct dm_target_callbacks *cb;
1780         int r = 0;
1781
1782         list_for_each_entry(dd, devices, list) {
1783                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1784                 char b[BDEVNAME_SIZE];
1785
1786                 if (likely(q))
1787                         r |= bdi_congested(q->backing_dev_info, bdi_bits);
1788                 else
1789                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1790                                      dm_device_name(t->md),
1791                                      bdevname(dd->dm_dev->bdev, b));
1792         }
1793
1794         list_for_each_entry(cb, &t->target_callbacks, list)
1795                 if (cb->congested_fn)
1796                         r |= cb->congested_fn(cb, bdi_bits);
1797
1798         return r;
1799 }
1800
1801 struct mapped_device *dm_table_get_md(struct dm_table *t)
1802 {
1803         return t->md;
1804 }
1805 EXPORT_SYMBOL(dm_table_get_md);
1806
1807 void dm_table_run_md_queue_async(struct dm_table *t)
1808 {
1809         struct mapped_device *md;
1810         struct request_queue *queue;
1811         unsigned long flags;
1812
1813         if (!dm_table_request_based(t))
1814                 return;
1815
1816         md = dm_table_get_md(t);
1817         queue = dm_get_md_queue(md);
1818         if (queue) {
1819                 if (queue->mq_ops)
1820                         blk_mq_run_hw_queues(queue, true);
1821                 else {
1822                         spin_lock_irqsave(queue->queue_lock, flags);
1823                         blk_run_queue_async(queue);
1824                         spin_unlock_irqrestore(queue->queue_lock, flags);
1825                 }
1826         }
1827 }
1828 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1829