include/linux/device-mapper.h

   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 LGPL.
   6  */
   7
   8 #ifndef _LINUX_DEVICE_MAPPER_H
   9 #define _LINUX_DEVICE_MAPPER_H
  10
  11 #include <linux/bio.h>
  12 #include <linux/blkdev.h>
  13 #include <linux/dm-ioctl.h>
  14 #include <linux/math64.h>
  15 #include <linux/ratelimit.h>
  16
  17 struct dm_dev;
  18 struct dm_target;
  19 struct dm_table;
  20 struct dm_report_zones_args;
  21 struct mapped_device;
  22 struct bio_vec;
  23
  24 /*
  25  * Type of table, mapped_device's mempool and request_queue
  26  */
  27 enum dm_queue_mode {
  28         DM_TYPE_NONE             = 0,
  29         DM_TYPE_BIO_BASED        = 1,
  30         DM_TYPE_REQUEST_BASED    = 2,
  31         DM_TYPE_DAX_BIO_BASED    = 3,
  32 };
  33
  34 typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE, STATUSTYPE_IMA } status_type_t;
  35
  36 union map_info {
  37         void *ptr;
  38 };
  39
  40 /*
  41  * In the constructor the target parameter will already have the
  42  * table, type, begin and len fields filled in.
  43  */
  44 typedef int (*dm_ctr_fn) (struct dm_target *target,
  45                           unsigned int argc, char **argv);
  46
  47 /*
  48  * The destructor doesn't need to free the dm_target, just
  49  * anything hidden ti->private.
  50  */
  51 typedef void (*dm_dtr_fn) (struct dm_target *ti);
  52
  53 /*
  54  * The map function must return:
  55  * < 0: error
  56  * = 0: The target will handle the io by resubmitting it later
  57  * = 1: simple remap complete
  58  * = 2: The target wants to push back the io
  59  */
  60 typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
  61 typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
  62                                             struct request *rq,
  63                                             union map_info *map_context,
  64                                             struct request **clone);
  65 typedef void (*dm_release_clone_request_fn) (struct request *clone,
  66                                              union map_info *map_context);
  67
  68 /*
  69  * Returns:
  70  * < 0 : error (currently ignored)
  71  * 0   : ended successfully
  72  * 1   : for some reason the io has still not completed (eg,
  73  *       multipath target might want to requeue a failed io).
  74  * 2   : The target wants to push back the io
  75  */
  76 typedef int (*dm_endio_fn) (struct dm_target *ti,
  77                             struct bio *bio, blk_status_t *error);
  78 typedef int (*dm_request_endio_fn) (struct dm_target *ti,
  79                                     struct request *clone, blk_status_t error,
  80                                     union map_info *map_context);
  81
  82 typedef void (*dm_presuspend_fn) (struct dm_target *ti);
  83 typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
  84 typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
  85 typedef int (*dm_preresume_fn) (struct dm_target *ti);
  86 typedef void (*dm_resume_fn) (struct dm_target *ti);
  87
  88 typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
  89                               unsigned status_flags, char *result, unsigned maxlen);
  90
  91 typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv,
  92                               char *result, unsigned maxlen);
  93
  94 typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev);
  95
  96 #ifdef CONFIG_BLK_DEV_ZONED
  97 typedef int (*dm_report_zones_fn) (struct dm_target *ti,
  98                                    struct dm_report_zones_args *args,
  99                                    unsigned int nr_zones);
 100 #else
 101 /*
 102  * Define dm_report_zones_fn so that targets can assign to NULL if
 103  * CONFIG_BLK_DEV_ZONED disabled. Otherwise each target needs to do
 104  * awkward #ifdefs in their target_type, etc.
 105  */
 106 typedef int (*dm_report_zones_fn) (struct dm_target *dummy);
 107 #endif
 108
 109 /*
 110  * These iteration functions are typically used to check (and combine)
 111  * properties of underlying devices.
 112  * E.g. Does at least one underlying device support flush?
 113  *      Does any underlying device not support WRITE_SAME?
 114  *
 115  * The callout function is called once for each contiguous section of
 116  * an underlying device.  State can be maintained in *data.
 117  * Return non-zero to stop iterating through any further devices.
 118  */
 119 typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
 120                                            struct dm_dev *dev,
 121                                            sector_t start, sector_t len,
 122                                            void *data);
 123
 124 /*
 125  * This function must iterate through each section of device used by the
 126  * target until it encounters a non-zero return code, which it then returns.
 127  * Returns zero if no callout returned non-zero.
 128  */
 129 typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
 130                                       iterate_devices_callout_fn fn,
 131                                       void *data);
 132
 133 typedef void (*dm_io_hints_fn) (struct dm_target *ti,
 134                                 struct queue_limits *limits);
 135
 136 /*
 137  * Returns:
 138  *    0: The target can handle the next I/O immediately.
 139  *    1: The target can't handle the next I/O immediately.
 140  */
 141 typedef int (*dm_busy_fn) (struct dm_target *ti);
 142
 143 /*
 144  * Returns:
 145  *  < 0 : error
 146  * >= 0 : the number of bytes accessible at the address
 147  */
 148 typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
 149                 long nr_pages, void **kaddr, pfn_t *pfn);
 150 typedef size_t (*dm_dax_copy_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
 151                 void *addr, size_t bytes, struct iov_iter *i);
 152 typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
 153                 size_t nr_pages);
 154
 155 void dm_error(const char *message);
 156
 157 struct dm_dev {
 158         struct block_device *bdev;
 159         struct dax_device *dax_dev;
 160         fmode_t mode;
 161         char name[16];
 162 };
 163
 164 dev_t dm_get_dev_t(const char *path);
 165
 166 /*
 167  * Constructors should call these functions to ensure destination devices
 168  * are opened/closed correctly.
 169  */
 170 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
 171                   struct dm_dev **result);
 172 void dm_put_device(struct dm_target *ti, struct dm_dev *d);
 173
 174 /*
 175  * Information about a target type
 176  */
 177
 178 struct target_type {
 179         uint64_t features;
 180         const char *name;
 181         struct module *module;
 182         unsigned version[3];
 183         dm_ctr_fn ctr;
 184         dm_dtr_fn dtr;
 185         dm_map_fn map;
 186         dm_clone_and_map_request_fn clone_and_map_rq;
 187         dm_release_clone_request_fn release_clone_rq;
 188         dm_endio_fn end_io;
 189         dm_request_endio_fn rq_end_io;
 190         dm_presuspend_fn presuspend;
 191         dm_presuspend_undo_fn presuspend_undo;
 192         dm_postsuspend_fn postsuspend;
 193         dm_preresume_fn preresume;
 194         dm_resume_fn resume;
 195         dm_status_fn status;
 196         dm_message_fn message;
 197         dm_prepare_ioctl_fn prepare_ioctl;
 198         dm_report_zones_fn report_zones;
 199         dm_busy_fn busy;
 200         dm_iterate_devices_fn iterate_devices;
 201         dm_io_hints_fn io_hints;
 202         dm_dax_direct_access_fn direct_access;
 203         dm_dax_copy_iter_fn dax_copy_from_iter;
 204         dm_dax_copy_iter_fn dax_copy_to_iter;
 205         dm_dax_zero_page_range_fn dax_zero_page_range;
 206
 207         /* For internal device-mapper use. */
 208         struct list_head list;
 209 };
 210
 211 /*
 212  * Target features
 213  */
 214
 215 /*
 216  * Any table that contains an instance of this target must have only one.
 217  */
 218 #define DM_TARGET_SINGLETON             0x00000001
 219 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
 220
 221 /*
 222  * Indicates that a target does not support read-only devices.
 223  */
 224 #define DM_TARGET_ALWAYS_WRITEABLE      0x00000002
 225 #define dm_target_always_writeable(type) \
 226                 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
 227
 228 /*
 229  * Any device that contains a table with an instance of this target may never
 230  * have tables containing any different target type.
 231  */
 232 #define DM_TARGET_IMMUTABLE             0x00000004
 233 #define dm_target_is_immutable(type)    ((type)->features & DM_TARGET_IMMUTABLE)
 234
 235 /*
 236  * Indicates that a target may replace any target; even immutable targets.
 237  * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
 238  */
 239 #define DM_TARGET_WILDCARD              0x00000008
 240 #define dm_target_is_wildcard(type)     ((type)->features & DM_TARGET_WILDCARD)
 241
 242 /*
 243  * A target implements own bio data integrity.
 244  */
 245 #define DM_TARGET_INTEGRITY             0x00000010
 246 #define dm_target_has_integrity(type)   ((type)->features & DM_TARGET_INTEGRITY)
 247
 248 /*
 249  * A target passes integrity data to the lower device.
 250  */
 251 #define DM_TARGET_PASSES_INTEGRITY      0x00000020
 252 #define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
 253
 254 /*
 255  * Indicates support for zoned block devices:
 256  * - DM_TARGET_ZONED_HM: the target also supports host-managed zoned
 257  *   block devices but does not support combining different zoned models.
 258  * - DM_TARGET_MIXED_ZONED_MODEL: the target supports combining multiple
 259  *   devices with different zoned models.
 260  */
 261 #ifdef CONFIG_BLK_DEV_ZONED
 262 #define DM_TARGET_ZONED_HM              0x00000040
 263 #define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM)
 264 #else
 265 #define DM_TARGET_ZONED_HM              0x00000000
 266 #define dm_target_supports_zoned_hm(type) (false)
 267 #endif
 268
 269 /*
 270  * A target handles REQ_NOWAIT
 271  */
 272 #define DM_TARGET_NOWAIT                0x00000080
 273 #define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT)
 274
 275 /*
 276  * A target supports passing through inline crypto support.
 277  */
 278 #define DM_TARGET_PASSES_CRYPTO         0x00000100
 279 #define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO)
 280
 281 #ifdef CONFIG_BLK_DEV_ZONED
 282 #define DM_TARGET_MIXED_ZONED_MODEL     0x00000200
 283 #define dm_target_supports_mixed_zoned_model(type) \
 284         ((type)->features & DM_TARGET_MIXED_ZONED_MODEL)
 285 #else
 286 #define DM_TARGET_MIXED_ZONED_MODEL     0x00000000
 287 #define dm_target_supports_mixed_zoned_model(type) (false)
 288 #endif
 289
 290 struct dm_target {
 291         struct dm_table *table;
 292         struct target_type *type;
 293
 294         /* target limits */
 295         sector_t begin;
 296         sector_t len;
 297
 298         /* If non-zero, maximum size of I/O submitted to a target. */
 299         uint32_t max_io_len;
 300
 301         /*
 302          * A number of zero-length barrier bios that will be submitted
 303          * to the target for the purpose of flushing cache.
 304          *
 305          * The bio number can be accessed with dm_bio_get_target_bio_nr.
 306          * It is a responsibility of the target driver to remap these bios
 307          * to the real underlying devices.
 308          */
 309         unsigned num_flush_bios;
 310
 311         /*
 312          * The number of discard bios that will be submitted to the target.
 313          * The bio number can be accessed with dm_bio_get_target_bio_nr.
 314          */
 315         unsigned num_discard_bios;
 316
 317         /*
 318          * The number of secure erase bios that will be submitted to the target.
 319          * The bio number can be accessed with dm_bio_get_target_bio_nr.
 320          */
 321         unsigned num_secure_erase_bios;
 322
 323         /*
 324          * The number of WRITE SAME bios that will be submitted to the target.
 325          * The bio number can be accessed with dm_bio_get_target_bio_nr.
 326          */
 327         unsigned num_write_same_bios;
 328
 329         /*
 330          * The number of WRITE ZEROES bios that will be submitted to the target.
 331          * The bio number can be accessed with dm_bio_get_target_bio_nr.
 332          */
 333         unsigned num_write_zeroes_bios;
 334
 335         /*
 336          * The minimum number of extra bytes allocated in each io for the
 337          * target to use.
 338          */
 339         unsigned per_io_data_size;
 340
 341         /* target specific data */
 342         void *private;
 343
 344         /* Used to provide an error string from the ctr */
 345         char *error;
 346
 347         /*
 348          * Set if this target needs to receive flushes regardless of
 349          * whether or not its underlying devices have support.
 350          */
 351         bool flush_supported:1;
 352
 353         /*
 354          * Set if this target needs to receive discards regardless of
 355          * whether or not its underlying devices have support.
 356          */
 357         bool discards_supported:1;
 358
 359         /*
 360          * Set if we need to limit the number of in-flight bios when swapping.
 361          */
 362         bool limit_swap_bios:1;
 363
 364         /*
 365          * Set if this target implements a a zoned device and needs emulation of
 366          * zone append operations using regular writes.
 367          */
 368         bool emulate_zone_append:1;
 369 };
 370
 371 void *dm_per_bio_data(struct bio *bio, size_t data_size);
 372 struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size);
 373 unsigned dm_bio_get_target_bio_nr(const struct bio *bio);
 374
 375 u64 dm_start_time_ns_from_clone(struct bio *bio);
 376
 377 int dm_register_target(struct target_type *t);
 378 void dm_unregister_target(struct target_type *t);
 379
 380 /*
 381  * Target argument parsing.
 382  */
 383 struct dm_arg_set {
 384         unsigned argc;
 385         char **argv;
 386 };
 387
 388 /*
 389  * The minimum and maximum value of a numeric argument, together with
 390  * the error message to use if the number is found to be outside that range.
 391  */
 392 struct dm_arg {
 393         unsigned min;
 394         unsigned max;
 395         char *error;
 396 };
 397
 398 /*
 399  * Validate the next argument, either returning it as *value or, if invalid,
 400  * returning -EINVAL and setting *error.
 401  */
 402 int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
 403                 unsigned *value, char **error);
 404
 405 /*
 406  * Process the next argument as the start of a group containing between
 407  * arg->min and arg->max further arguments. Either return the size as
 408  * *num_args or, if invalid, return -EINVAL and set *error.
 409  */
 410 int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
 411                       unsigned *num_args, char **error);
 412
 413 /*
 414  * Return the current argument and shift to the next.
 415  */
 416 const char *dm_shift_arg(struct dm_arg_set *as);
 417
 418 /*
 419  * Move through num_args arguments.
 420  */
 421 void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
 422
 423 /*-----------------------------------------------------------------
 424  * Functions for creating and manipulating mapped devices.
 425  * Drop the reference with dm_put when you finish with the object.
 426  *---------------------------------------------------------------*/
 427
 428 /*
 429  * DM_ANY_MINOR chooses the next available minor number.
 430  */
 431 #define DM_ANY_MINOR (-1)
 432 int dm_create(int minor, struct mapped_device **md);
 433
 434 /*
 435  * Reference counting for md.
 436  */
 437 struct mapped_device *dm_get_md(dev_t dev);
 438 void dm_get(struct mapped_device *md);
 439 int dm_hold(struct mapped_device *md);
 440 void dm_put(struct mapped_device *md);
 441
 442 /*
 443  * An arbitrary pointer may be stored alongside a mapped device.
 444  */
 445 void dm_set_mdptr(struct mapped_device *md, void *ptr);
 446 void *dm_get_mdptr(struct mapped_device *md);
 447
 448 /*
 449  * A device can still be used while suspended, but I/O is deferred.
 450  */
 451 int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
 452 int dm_resume(struct mapped_device *md);
 453
 454 /*
 455  * Event functions.
 456  */
 457 uint32_t dm_get_event_nr(struct mapped_device *md);
 458 int dm_wait_event(struct mapped_device *md, int event_nr);
 459 uint32_t dm_next_uevent_seq(struct mapped_device *md);
 460 void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
 461
 462 /*
 463  * Info functions.
 464  */
 465 const char *dm_device_name(struct mapped_device *md);
 466 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
 467 struct gendisk *dm_disk(struct mapped_device *md);
 468 int dm_suspended(struct dm_target *ti);
 469 int dm_post_suspending(struct dm_target *ti);
 470 int dm_noflush_suspending(struct dm_target *ti);
 471 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
 472 union map_info *dm_get_rq_mapinfo(struct request *rq);
 473
 474 #ifdef CONFIG_BLK_DEV_ZONED
 475 struct dm_report_zones_args {
 476         struct dm_target *tgt;
 477         sector_t next_sector;
 478
 479         void *orig_data;
 480         report_zones_cb orig_cb;
 481         unsigned int zone_idx;
 482
 483         /* must be filled by ->report_zones before calling dm_report_zones_cb */
 484         sector_t start;
 485 };
 486 int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
 487                     struct dm_report_zones_args *args, unsigned int nr_zones);
 488 #endif /* CONFIG_BLK_DEV_ZONED */
 489
 490 /*
 491  * Device mapper functions to parse and create devices specified by the
 492  * parameter "dm-mod.create="
 493  */
 494 int __init dm_early_create(struct dm_ioctl *dmi,
 495                            struct dm_target_spec **spec_array,
 496                            char **target_params_array);
 497
 498 struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
 499
 500 /*
 501  * Geometry functions.
 502  */
 503 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
 504 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
 505
 506 /*-----------------------------------------------------------------
 507  * Functions for manipulating device-mapper tables.
 508  *---------------------------------------------------------------*/
 509
 510 /*
 511  * First create an empty table.
 512  */
 513 int dm_table_create(struct dm_table **result, fmode_t mode,
 514                     unsigned num_targets, struct mapped_device *md);
 515
 516 /*
 517  * Then call this once for each target.
 518  */
 519 int dm_table_add_target(struct dm_table *t, const char *type,
 520                         sector_t start, sector_t len, char *params);
 521
 522 /*
 523  * Target can use this to set the table's type.
 524  * Can only ever be called from a target's ctr.
 525  * Useful for "hybrid" target (supports both bio-based
 526  * and request-based).
 527  */
 528 void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
 529
 530 /*
 531  * Finally call this to make the table ready for use.
 532  */
 533 int dm_table_complete(struct dm_table *t);
 534
 535 /*
 536  * Destroy the table when finished.
 537  */
 538 void dm_table_destroy(struct dm_table *t);
 539
 540 /*
 541  * Target may require that it is never sent I/O larger than len.
 542  */
 543 int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
 544
 545 /*
 546  * Table reference counting.
 547  */
 548 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
 549 void dm_put_live_table(struct mapped_device *md, int srcu_idx);
 550 void dm_sync_table(struct mapped_device *md);
 551
 552 /*
 553  * Queries
 554  */
 555 sector_t dm_table_get_size(struct dm_table *t);
 556 unsigned int dm_table_get_num_targets(struct dm_table *t);
 557 fmode_t dm_table_get_mode(struct dm_table *t);
 558 struct mapped_device *dm_table_get_md(struct dm_table *t);
 559 const char *dm_table_device_name(struct dm_table *t);
 560
 561 /*
 562  * Trigger an event.
 563  */
 564 void dm_table_event(struct dm_table *t);
 565
 566 /*
 567  * Run the queue for request-based targets.
 568  */
 569 void dm_table_run_md_queue_async(struct dm_table *t);
 570
 571 /*
 572  * The device must be suspended before calling this method.
 573  * Returns the previous table, which the caller must destroy.
 574  */
 575 struct dm_table *dm_swap_table(struct mapped_device *md,
 576                                struct dm_table *t);
 577
 578 /*
 579  * Table keyslot manager functions
 580  */
 581 void dm_destroy_keyslot_manager(struct blk_keyslot_manager *ksm);
 582
 583 /*-----------------------------------------------------------------
 584  * Macros.
 585  *---------------------------------------------------------------*/
 586 #define DM_NAME "device-mapper"
 587
 588 #define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n"
 589
 590 #define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__)
 591
 592 #define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__)
 593 #define DMERR_LIMIT(fmt, ...) pr_err_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 594 #define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__)
 595 #define DMWARN_LIMIT(fmt, ...) pr_warn_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 596 #define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
 597 #define DMINFO_LIMIT(fmt, ...) pr_info_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 598
 599 #define DMDEBUG(fmt, ...) pr_debug(DM_FMT(fmt), ##__VA_ARGS__)
 600 #define DMDEBUG_LIMIT(fmt, ...) pr_debug_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
 601
 602 #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
 603                           0 : scnprintf(result + sz, maxlen - sz, x))
 604
 605 #define DMEMIT_TARGET_NAME_VERSION(y) \
 606                 DMEMIT("target_name=%s,target_version=%u.%u.%u", \
 607                        (y)->name, (y)->version[0], (y)->version[1], (y)->version[2])
 608
 609 /*
 610  * Definitions of return values from target end_io function.
 611  */
 612 #define DM_ENDIO_DONE           0
 613 #define DM_ENDIO_INCOMPLETE     1
 614 #define DM_ENDIO_REQUEUE        2
 615 #define DM_ENDIO_DELAY_REQUEUE  3
 616
 617 /*
 618  * Definitions of return values from target map function.
 619  */
 620 #define DM_MAPIO_SUBMITTED      0
 621 #define DM_MAPIO_REMAPPED       1
 622 #define DM_MAPIO_REQUEUE        DM_ENDIO_REQUEUE
 623 #define DM_MAPIO_DELAY_REQUEUE  DM_ENDIO_DELAY_REQUEUE
 624 #define DM_MAPIO_KILL           4
 625
 626 #define dm_sector_div64(x, y)( \
 627 { \
 628         u64 _res; \
 629         (x) = div64_u64_rem(x, y, &_res); \
 630         _res; \
 631 } \
 632 )
 633
 634 /*
 635  * Ceiling(n / sz)
 636  */
 637 #define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
 638
 639 #define dm_sector_div_up(n, sz) ( \
 640 { \
 641         sector_t _r = ((n) + (sz) - 1); \
 642         sector_div(_r, (sz)); \
 643         _r; \
 644 } \
 645 )
 646
 647 /*
 648  * ceiling(n / size) * size
 649  */
 650 #define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
 651
 652 /*
 653  * Sector offset taken relative to the start of the target instead of
 654  * relative to the start of the device.
 655  */
 656 #define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
 657
 658 static inline sector_t to_sector(unsigned long long n)
 659 {
 660         return (n >> SECTOR_SHIFT);
 661 }
 662
 663 static inline unsigned long to_bytes(sector_t n)
 664 {
 665         return (n << SECTOR_SHIFT);
 666 }
 667
 668 #endif  /* _LINUX_DEVICE_MAPPER_H */