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