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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
17struct dm_dev;
18struct dm_target;
19struct dm_table;
20struct dm_report_zones_args;
21struct mapped_device;
22struct bio_vec;
23
24/*
25 * Type of table, mapped_device's mempool and request_queue
26 */
27enum 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
34typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
35
36union 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 */
44typedef 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 */
51typedef 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 */
60typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
61typedef 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);
65typedef 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 */
76typedef int (*dm_endio_fn) (struct dm_target *ti,
77 struct bio *bio, blk_status_t *error);
78typedef int (*dm_request_endio_fn) (struct dm_target *ti,
79 struct request *clone, blk_status_t error,
80 union map_info *map_context);
81
82typedef void (*dm_presuspend_fn) (struct dm_target *ti);
83typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
84typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
85typedef int (*dm_preresume_fn) (struct dm_target *ti);
86typedef void (*dm_resume_fn) (struct dm_target *ti);
87
88typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
89 unsigned status_flags, char *result, unsigned maxlen);
90
91typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv,
92 char *result, unsigned maxlen);
93
94typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev);
95
96#ifdef CONFIG_BLK_DEV_ZONED
97typedef 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 */
106typedef 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 */
119typedef 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 */
129typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
130 iterate_devices_callout_fn fn,
131 void *data);
132
133typedef 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 */
141typedef 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 */
148typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
149 long nr_pages, void **kaddr, pfn_t *pfn);
150typedef size_t (*dm_dax_copy_iter_fn)(struct dm_target *ti, pgoff_t pgoff,
151 void *addr, size_t bytes, struct iov_iter *i);
152typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
153 size_t nr_pages);
154#define PAGE_SECTORS (PAGE_SIZE / 512)
155
156void dm_error(const char *message);
157
158struct dm_dev {
159 struct block_device *bdev;
160 struct dax_device *dax_dev;
161 fmode_t mode;
162 char name[16];
163};
164
165dev_t dm_get_dev_t(const char *path);
166
167/*
168 * Constructors should call these functions to ensure destination devices
169 * are opened/closed correctly.
170 */
171int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
172 struct dm_dev **result);
173void dm_put_device(struct dm_target *ti, struct dm_dev *d);
174
175/*
176 * Information about a target type
177 */
178
179struct target_type {
180 uint64_t features;
181 const char *name;
182 struct module *module;
183 unsigned version[3];
184 dm_ctr_fn ctr;
185 dm_dtr_fn dtr;
186 dm_map_fn map;
187 dm_clone_and_map_request_fn clone_and_map_rq;
188 dm_release_clone_request_fn release_clone_rq;
189 dm_endio_fn end_io;
190 dm_request_endio_fn rq_end_io;
191 dm_presuspend_fn presuspend;
192 dm_presuspend_undo_fn presuspend_undo;
193 dm_postsuspend_fn postsuspend;
194 dm_preresume_fn preresume;
195 dm_resume_fn resume;
196 dm_status_fn status;
197 dm_message_fn message;
198 dm_prepare_ioctl_fn prepare_ioctl;
199 dm_report_zones_fn report_zones;
200 dm_busy_fn busy;
201 dm_iterate_devices_fn iterate_devices;
202 dm_io_hints_fn io_hints;
203 dm_dax_direct_access_fn direct_access;
204 dm_dax_copy_iter_fn dax_copy_from_iter;
205 dm_dax_copy_iter_fn dax_copy_to_iter;
206 dm_dax_zero_page_range_fn dax_zero_page_range;
207
208 /* For internal device-mapper use. */
209 struct list_head list;
210};
211
212/*
213 * Target features
214 */
215
216/*
217 * Any table that contains an instance of this target must have only one.
218 */
219#define DM_TARGET_SINGLETON 0x00000001
220#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
221
222/*
223 * Indicates that a target does not support read-only devices.
224 */
225#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
226#define dm_target_always_writeable(type) \
227 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
228
229/*
230 * Any device that contains a table with an instance of this target may never
231 * have tables containing any different target type.
232 */
233#define DM_TARGET_IMMUTABLE 0x00000004
234#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
235
236/*
237 * Indicates that a target may replace any target; even immutable targets.
238 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
239 */
240#define DM_TARGET_WILDCARD 0x00000008
241#define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
242
243/*
244 * A target implements own bio data integrity.
245 */
246#define DM_TARGET_INTEGRITY 0x00000010
247#define dm_target_has_integrity(type) ((type)->features & DM_TARGET_INTEGRITY)
248
249/*
250 * A target passes integrity data to the lower device.
251 */
252#define DM_TARGET_PASSES_INTEGRITY 0x00000020
253#define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
254
255/*
256 * Indicates support for zoned block devices:
257 * - DM_TARGET_ZONED_HM: the target also supports host-managed zoned
258 * block devices but does not support combining different zoned models.
259 * - DM_TARGET_MIXED_ZONED_MODEL: the target supports combining multiple
260 * devices with different zoned models.
261 */
262#ifdef CONFIG_BLK_DEV_ZONED
263#define DM_TARGET_ZONED_HM 0x00000040
264#define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM)
265#else
266#define DM_TARGET_ZONED_HM 0x00000000
267#define dm_target_supports_zoned_hm(type) (false)
268#endif
269
270/*
271 * A target handles REQ_NOWAIT
272 */
273#define DM_TARGET_NOWAIT 0x00000080
274#define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT)
275
276/*
277 * A target supports passing through inline crypto support.
278 */
279#define DM_TARGET_PASSES_CRYPTO 0x00000100
280#define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO)
281
282#ifdef CONFIG_BLK_DEV_ZONED
283#define DM_TARGET_MIXED_ZONED_MODEL 0x00000200
284#define dm_target_supports_mixed_zoned_model(type) \
285 ((type)->features & DM_TARGET_MIXED_ZONED_MODEL)
286#else
287#define DM_TARGET_MIXED_ZONED_MODEL 0x00000000
288#define dm_target_supports_mixed_zoned_model(type) (false)
289#endif
290
291struct dm_target {
292 struct dm_table *table;
293 struct target_type *type;
294
295 /* target limits */
296 sector_t begin;
297 sector_t len;
298
299 /* If non-zero, maximum size of I/O submitted to a target. */
300 uint32_t max_io_len;
301
302 /*
303 * A number of zero-length barrier bios that will be submitted
304 * to the target for the purpose of flushing cache.
305 *
306 * The bio number can be accessed with dm_bio_get_target_bio_nr.
307 * It is a responsibility of the target driver to remap these bios
308 * to the real underlying devices.
309 */
310 unsigned num_flush_bios;
311
312 /*
313 * The number of discard bios that will be submitted to the target.
314 * The bio number can be accessed with dm_bio_get_target_bio_nr.
315 */
316 unsigned num_discard_bios;
317
318 /*
319 * The number of secure erase bios that will be submitted to the target.
320 * The bio number can be accessed with dm_bio_get_target_bio_nr.
321 */
322 unsigned num_secure_erase_bios;
323
324 /*
325 * The number of WRITE SAME bios that will be submitted to the target.
326 * The bio number can be accessed with dm_bio_get_target_bio_nr.
327 */
328 unsigned num_write_same_bios;
329
330 /*
331 * The number of WRITE ZEROES bios that will be submitted to the target.
332 * The bio number can be accessed with dm_bio_get_target_bio_nr.
333 */
334 unsigned num_write_zeroes_bios;
335
336 /*
337 * The minimum number of extra bytes allocated in each io for the
338 * target to use.
339 */
340 unsigned per_io_data_size;
341
342 /* target specific data */
343 void *private;
344
345 /* Used to provide an error string from the ctr */
346 char *error;
347
348 /*
349 * Set if this target needs to receive flushes regardless of
350 * whether or not its underlying devices have support.
351 */
352 bool flush_supported:1;
353
354 /*
355 * Set if this target needs to receive discards regardless of
356 * whether or not its underlying devices have support.
357 */
358 bool discards_supported:1;
359
360 /*
361 * Set if we need to limit the number of in-flight bios when swapping.
362 */
363 bool limit_swap_bios:1;
364
365 /*
366 * Set if this target implements a a zoned device and needs emulation of
367 * zone append operations using regular writes.
368 */
369 bool emulate_zone_append:1;
370};
371
372void *dm_per_bio_data(struct bio *bio, size_t data_size);
373struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size);
374unsigned dm_bio_get_target_bio_nr(const struct bio *bio);
375
376u64 dm_start_time_ns_from_clone(struct bio *bio);
377
378int dm_register_target(struct target_type *t);
379void dm_unregister_target(struct target_type *t);
380
381/*
382 * Target argument parsing.
383 */
384struct dm_arg_set {
385 unsigned argc;
386 char **argv;
387};
388
389/*
390 * The minimum and maximum value of a numeric argument, together with
391 * the error message to use if the number is found to be outside that range.
392 */
393struct dm_arg {
394 unsigned min;
395 unsigned max;
396 char *error;
397};
398
399/*
400 * Validate the next argument, either returning it as *value or, if invalid,
401 * returning -EINVAL and setting *error.
402 */
403int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
404 unsigned *value, char **error);
405
406/*
407 * Process the next argument as the start of a group containing between
408 * arg->min and arg->max further arguments. Either return the size as
409 * *num_args or, if invalid, return -EINVAL and set *error.
410 */
411int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
412 unsigned *num_args, char **error);
413
414/*
415 * Return the current argument and shift to the next.
416 */
417const char *dm_shift_arg(struct dm_arg_set *as);
418
419/*
420 * Move through num_args arguments.
421 */
422void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
423
424/*-----------------------------------------------------------------
425 * Functions for creating and manipulating mapped devices.
426 * Drop the reference with dm_put when you finish with the object.
427 *---------------------------------------------------------------*/
428
429/*
430 * DM_ANY_MINOR chooses the next available minor number.
431 */
432#define DM_ANY_MINOR (-1)
433int dm_create(int minor, struct mapped_device **md);
434
435/*
436 * Reference counting for md.
437 */
438struct mapped_device *dm_get_md(dev_t dev);
439void dm_get(struct mapped_device *md);
440int dm_hold(struct mapped_device *md);
441void dm_put(struct mapped_device *md);
442
443/*
444 * An arbitrary pointer may be stored alongside a mapped device.
445 */
446void dm_set_mdptr(struct mapped_device *md, void *ptr);
447void *dm_get_mdptr(struct mapped_device *md);
448
449/*
450 * A device can still be used while suspended, but I/O is deferred.
451 */
452int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
453int dm_resume(struct mapped_device *md);
454
455/*
456 * Event functions.
457 */
458uint32_t dm_get_event_nr(struct mapped_device *md);
459int dm_wait_event(struct mapped_device *md, int event_nr);
460uint32_t dm_next_uevent_seq(struct mapped_device *md);
461void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
462
463/*
464 * Info functions.
465 */
466const char *dm_device_name(struct mapped_device *md);
467int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
468struct gendisk *dm_disk(struct mapped_device *md);
469int dm_suspended(struct dm_target *ti);
470int dm_post_suspending(struct dm_target *ti);
471int dm_noflush_suspending(struct dm_target *ti);
472void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
473union map_info *dm_get_rq_mapinfo(struct request *rq);
474
475#ifdef CONFIG_BLK_DEV_ZONED
476struct dm_report_zones_args {
477 struct dm_target *tgt;
478 sector_t next_sector;
479
480 void *orig_data;
481 report_zones_cb orig_cb;
482 unsigned int zone_idx;
483
484 /* must be filled by ->report_zones before calling dm_report_zones_cb */
485 sector_t start;
486};
487int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
488 struct dm_report_zones_args *args, unsigned int nr_zones);
489#endif /* CONFIG_BLK_DEV_ZONED */
490
491/*
492 * Device mapper functions to parse and create devices specified by the
493 * parameter "dm-mod.create="
494 */
495int __init dm_early_create(struct dm_ioctl *dmi,
496 struct dm_target_spec **spec_array,
497 char **target_params_array);
498
499struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
500
501/*
502 * Geometry functions.
503 */
504int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
505int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
506
507/*-----------------------------------------------------------------
508 * Functions for manipulating device-mapper tables.
509 *---------------------------------------------------------------*/
510
511/*
512 * First create an empty table.
513 */
514int dm_table_create(struct dm_table **result, fmode_t mode,
515 unsigned num_targets, struct mapped_device *md);
516
517/*
518 * Then call this once for each target.
519 */
520int dm_table_add_target(struct dm_table *t, const char *type,
521 sector_t start, sector_t len, char *params);
522
523/*
524 * Target can use this to set the table's type.
525 * Can only ever be called from a target's ctr.
526 * Useful for "hybrid" target (supports both bio-based
527 * and request-based).
528 */
529void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
530
531/*
532 * Finally call this to make the table ready for use.
533 */
534int dm_table_complete(struct dm_table *t);
535
536/*
537 * Destroy the table when finished.
538 */
539void dm_table_destroy(struct dm_table *t);
540
541/*
542 * Target may require that it is never sent I/O larger than len.
543 */
544int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
545
546/*
547 * Table reference counting.
548 */
549struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
550void dm_put_live_table(struct mapped_device *md, int srcu_idx);
551void dm_sync_table(struct mapped_device *md);
552
553/*
554 * Queries
555 */
556sector_t dm_table_get_size(struct dm_table *t);
557unsigned int dm_table_get_num_targets(struct dm_table *t);
558fmode_t dm_table_get_mode(struct dm_table *t);
559struct mapped_device *dm_table_get_md(struct dm_table *t);
560const char *dm_table_device_name(struct dm_table *t);
561
562/*
563 * Trigger an event.
564 */
565void dm_table_event(struct dm_table *t);
566
567/*
568 * Run the queue for request-based targets.
569 */
570void dm_table_run_md_queue_async(struct dm_table *t);
571
572/*
573 * The device must be suspended before calling this method.
574 * Returns the previous table, which the caller must destroy.
575 */
576struct dm_table *dm_swap_table(struct mapped_device *md,
577 struct dm_table *t);
578
579/*
580 * Table keyslot manager functions
581 */
582void dm_destroy_keyslot_manager(struct blk_keyslot_manager *ksm);
583
584/*-----------------------------------------------------------------
585 * Macros.
586 *---------------------------------------------------------------*/
587#define DM_NAME "device-mapper"
588
589#define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n"
590
591#define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__)
592
593#define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__)
594#define DMERR_LIMIT(fmt, ...) pr_err_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
595#define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__)
596#define DMWARN_LIMIT(fmt, ...) pr_warn_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
597#define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
598#define DMINFO_LIMIT(fmt, ...) pr_info_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
599
600#define DMDEBUG(fmt, ...) pr_debug(DM_FMT(fmt), ##__VA_ARGS__)
601#define DMDEBUG_LIMIT(fmt, ...) pr_debug_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
602
603#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
604 0 : scnprintf(result + sz, maxlen - sz, x))
605
606/*
607 * Definitions of return values from target end_io function.
608 */
609#define DM_ENDIO_DONE 0
610#define DM_ENDIO_INCOMPLETE 1
611#define DM_ENDIO_REQUEUE 2
612#define DM_ENDIO_DELAY_REQUEUE 3
613
614/*
615 * Definitions of return values from target map function.
616 */
617#define DM_MAPIO_SUBMITTED 0
618#define DM_MAPIO_REMAPPED 1
619#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
620#define DM_MAPIO_DELAY_REQUEUE DM_ENDIO_DELAY_REQUEUE
621#define DM_MAPIO_KILL 4
622
623#define dm_sector_div64(x, y)( \
624{ \
625 u64 _res; \
626 (x) = div64_u64_rem(x, y, &_res); \
627 _res; \
628} \
629)
630
631/*
632 * Ceiling(n / sz)
633 */
634#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
635
636#define dm_sector_div_up(n, sz) ( \
637{ \
638 sector_t _r = ((n) + (sz) - 1); \
639 sector_div(_r, (sz)); \
640 _r; \
641} \
642)
643
644/*
645 * ceiling(n / size) * size
646 */
647#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
648
649/*
650 * Sector offset taken relative to the start of the target instead of
651 * relative to the start of the device.
652 */
653#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
654
655static inline sector_t to_sector(unsigned long long n)
656{
657 return (n >> SECTOR_SHIFT);
658}
659
660static inline unsigned long to_bytes(sector_t n)
661{
662 return (n << SECTOR_SHIFT);
663}
664
665#endif /* _LINUX_DEVICE_MAPPER_H */
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2001 Sistina Software (UK) Limited.
4 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 *
6 * This file is released under the LGPL.
7 */
8
9#ifndef _LINUX_DEVICE_MAPPER_H
10#define _LINUX_DEVICE_MAPPER_H
11
12#include <linux/bio.h>
13#include <linux/blkdev.h>
14#include <linux/dm-ioctl.h>
15#include <linux/math64.h>
16#include <linux/ratelimit.h>
17
18struct dm_dev;
19struct dm_target;
20struct dm_table;
21struct dm_report_zones_args;
22struct mapped_device;
23struct bio_vec;
24enum dax_access_mode;
25
26/*
27 * Type of table, mapped_device's mempool and request_queue
28 */
29enum dm_queue_mode {
30 DM_TYPE_NONE = 0,
31 DM_TYPE_BIO_BASED = 1,
32 DM_TYPE_REQUEST_BASED = 2,
33 DM_TYPE_DAX_BIO_BASED = 3,
34};
35
36typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE, STATUSTYPE_IMA } status_type_t;
37
38union map_info {
39 void *ptr;
40};
41
42/*
43 * In the constructor the target parameter will already have the
44 * table, type, begin and len fields filled in.
45 */
46typedef int (*dm_ctr_fn) (struct dm_target *target,
47 unsigned int argc, char **argv);
48
49/*
50 * The destructor doesn't need to free the dm_target, just
51 * anything hidden ti->private.
52 */
53typedef void (*dm_dtr_fn) (struct dm_target *ti);
54
55/*
56 * The map function must return:
57 * < 0: error
58 * = 0: The target will handle the io by resubmitting it later
59 * = 1: simple remap complete
60 * = 2: The target wants to push back the io
61 */
62typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
63typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
64 struct request *rq,
65 union map_info *map_context,
66 struct request **clone);
67typedef void (*dm_release_clone_request_fn) (struct request *clone,
68 union map_info *map_context);
69
70/*
71 * Returns:
72 * < 0 : error (currently ignored)
73 * 0 : ended successfully
74 * 1 : for some reason the io has still not completed (eg,
75 * multipath target might want to requeue a failed io).
76 * 2 : The target wants to push back the io
77 */
78typedef int (*dm_endio_fn) (struct dm_target *ti,
79 struct bio *bio, blk_status_t *error);
80typedef int (*dm_request_endio_fn) (struct dm_target *ti,
81 struct request *clone, blk_status_t error,
82 union map_info *map_context);
83
84typedef void (*dm_presuspend_fn) (struct dm_target *ti);
85typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
86typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
87typedef int (*dm_preresume_fn) (struct dm_target *ti);
88typedef void (*dm_resume_fn) (struct dm_target *ti);
89
90typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
91 unsigned int status_flags, char *result, unsigned int maxlen);
92
93typedef int (*dm_message_fn) (struct dm_target *ti, unsigned int argc, char **argv,
94 char *result, unsigned int maxlen);
95
96typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev);
97
98#ifdef CONFIG_BLK_DEV_ZONED
99typedef int (*dm_report_zones_fn) (struct dm_target *ti,
100 struct dm_report_zones_args *args,
101 unsigned int nr_zones);
102#else
103/*
104 * Define dm_report_zones_fn so that targets can assign to NULL if
105 * CONFIG_BLK_DEV_ZONED disabled. Otherwise each target needs to do
106 * awkward #ifdefs in their target_type, etc.
107 */
108typedef int (*dm_report_zones_fn) (struct dm_target *dummy);
109#endif
110
111/*
112 * These iteration functions are typically used to check (and combine)
113 * properties of underlying devices.
114 * E.g. Does at least one underlying device support flush?
115 * Does any underlying device not support WRITE_SAME?
116 *
117 * The callout function is called once for each contiguous section of
118 * an underlying device. State can be maintained in *data.
119 * Return non-zero to stop iterating through any further devices.
120 */
121typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
122 struct dm_dev *dev,
123 sector_t start, sector_t len,
124 void *data);
125
126/*
127 * This function must iterate through each section of device used by the
128 * target until it encounters a non-zero return code, which it then returns.
129 * Returns zero if no callout returned non-zero.
130 */
131typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
132 iterate_devices_callout_fn fn,
133 void *data);
134
135typedef void (*dm_io_hints_fn) (struct dm_target *ti,
136 struct queue_limits *limits);
137
138/*
139 * Returns:
140 * 0: The target can handle the next I/O immediately.
141 * 1: The target can't handle the next I/O immediately.
142 */
143typedef int (*dm_busy_fn) (struct dm_target *ti);
144
145/*
146 * Returns:
147 * < 0 : error
148 * >= 0 : the number of bytes accessible at the address
149 */
150typedef long (*dm_dax_direct_access_fn) (struct dm_target *ti, pgoff_t pgoff,
151 long nr_pages, enum dax_access_mode node, void **kaddr,
152 pfn_t *pfn);
153typedef int (*dm_dax_zero_page_range_fn)(struct dm_target *ti, pgoff_t pgoff,
154 size_t nr_pages);
155
156/*
157 * Returns:
158 * != 0 : number of bytes transferred
159 * 0 : recovery write failed
160 */
161typedef size_t (*dm_dax_recovery_write_fn)(struct dm_target *ti, pgoff_t pgoff,
162 void *addr, size_t bytes, struct iov_iter *i);
163
164void dm_error(const char *message);
165
166struct dm_dev {
167 struct block_device *bdev;
168 struct file *bdev_file;
169 struct dax_device *dax_dev;
170 blk_mode_t mode;
171 char name[16];
172};
173
174/*
175 * Constructors should call these functions to ensure destination devices
176 * are opened/closed correctly.
177 */
178int dm_get_device(struct dm_target *ti, const char *path, blk_mode_t mode,
179 struct dm_dev **result);
180void dm_put_device(struct dm_target *ti, struct dm_dev *d);
181
182/*
183 * Helper function for getting devices
184 */
185int dm_devt_from_path(const char *path, dev_t *dev_p);
186
187/*
188 * Information about a target type
189 */
190
191struct target_type {
192 uint64_t features;
193 const char *name;
194 struct module *module;
195 unsigned int version[3];
196 dm_ctr_fn ctr;
197 dm_dtr_fn dtr;
198 dm_map_fn map;
199 dm_clone_and_map_request_fn clone_and_map_rq;
200 dm_release_clone_request_fn release_clone_rq;
201 dm_endio_fn end_io;
202 dm_request_endio_fn rq_end_io;
203 dm_presuspend_fn presuspend;
204 dm_presuspend_undo_fn presuspend_undo;
205 dm_postsuspend_fn postsuspend;
206 dm_preresume_fn preresume;
207 dm_resume_fn resume;
208 dm_status_fn status;
209 dm_message_fn message;
210 dm_prepare_ioctl_fn prepare_ioctl;
211 dm_report_zones_fn report_zones;
212 dm_busy_fn busy;
213 dm_iterate_devices_fn iterate_devices;
214 dm_io_hints_fn io_hints;
215 dm_dax_direct_access_fn direct_access;
216 dm_dax_zero_page_range_fn dax_zero_page_range;
217 dm_dax_recovery_write_fn dax_recovery_write;
218
219 /* For internal device-mapper use. */
220 struct list_head list;
221};
222
223/*
224 * Target features
225 */
226
227/*
228 * Any table that contains an instance of this target must have only one.
229 */
230#define DM_TARGET_SINGLETON 0x00000001
231#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
232
233/*
234 * Indicates that a target does not support read-only devices.
235 */
236#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
237#define dm_target_always_writeable(type) \
238 ((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
239
240/*
241 * Any device that contains a table with an instance of this target may never
242 * have tables containing any different target type.
243 */
244#define DM_TARGET_IMMUTABLE 0x00000004
245#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
246
247/*
248 * Indicates that a target may replace any target; even immutable targets.
249 * .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined.
250 */
251#define DM_TARGET_WILDCARD 0x00000008
252#define dm_target_is_wildcard(type) ((type)->features & DM_TARGET_WILDCARD)
253
254/*
255 * A target implements own bio data integrity.
256 */
257#define DM_TARGET_INTEGRITY 0x00000010
258#define dm_target_has_integrity(type) ((type)->features & DM_TARGET_INTEGRITY)
259
260/*
261 * A target passes integrity data to the lower device.
262 */
263#define DM_TARGET_PASSES_INTEGRITY 0x00000020
264#define dm_target_passes_integrity(type) ((type)->features & DM_TARGET_PASSES_INTEGRITY)
265
266/*
267 * Indicates support for zoned block devices:
268 * - DM_TARGET_ZONED_HM: the target also supports host-managed zoned
269 * block devices but does not support combining different zoned models.
270 * - DM_TARGET_MIXED_ZONED_MODEL: the target supports combining multiple
271 * devices with different zoned models.
272 */
273#ifdef CONFIG_BLK_DEV_ZONED
274#define DM_TARGET_ZONED_HM 0x00000040
275#define dm_target_supports_zoned_hm(type) ((type)->features & DM_TARGET_ZONED_HM)
276#else
277#define DM_TARGET_ZONED_HM 0x00000000
278#define dm_target_supports_zoned_hm(type) (false)
279#endif
280
281/*
282 * A target handles REQ_NOWAIT
283 */
284#define DM_TARGET_NOWAIT 0x00000080
285#define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT)
286
287/*
288 * A target supports passing through inline crypto support.
289 */
290#define DM_TARGET_PASSES_CRYPTO 0x00000100
291#define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO)
292
293#ifdef CONFIG_BLK_DEV_ZONED
294#define DM_TARGET_MIXED_ZONED_MODEL 0x00000200
295#define dm_target_supports_mixed_zoned_model(type) \
296 ((type)->features & DM_TARGET_MIXED_ZONED_MODEL)
297#else
298#define DM_TARGET_MIXED_ZONED_MODEL 0x00000000
299#define dm_target_supports_mixed_zoned_model(type) (false)
300#endif
301
302struct dm_target {
303 struct dm_table *table;
304 struct target_type *type;
305
306 /* target limits */
307 sector_t begin;
308 sector_t len;
309
310 /* If non-zero, maximum size of I/O submitted to a target. */
311 uint32_t max_io_len;
312
313 /*
314 * A number of zero-length barrier bios that will be submitted
315 * to the target for the purpose of flushing cache.
316 *
317 * The bio number can be accessed with dm_bio_get_target_bio_nr.
318 * It is a responsibility of the target driver to remap these bios
319 * to the real underlying devices.
320 */
321 unsigned int num_flush_bios;
322
323 /*
324 * The number of discard 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 int num_discard_bios;
328
329 /*
330 * The number of secure erase 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 int num_secure_erase_bios;
334
335 /*
336 * The number of WRITE ZEROES bios that will be submitted to the target.
337 * The bio number can be accessed with dm_bio_get_target_bio_nr.
338 */
339 unsigned int num_write_zeroes_bios;
340
341 /*
342 * The minimum number of extra bytes allocated in each io for the
343 * target to use.
344 */
345 unsigned int per_io_data_size;
346
347 /* target specific data */
348 void *private;
349
350 /* Used to provide an error string from the ctr */
351 char *error;
352
353 /*
354 * Set if this target needs to receive flushes regardless of
355 * whether or not its underlying devices have support.
356 */
357 bool flush_supported:1;
358
359 /*
360 * Set if this target needs to receive discards regardless of
361 * whether or not its underlying devices have support.
362 */
363 bool discards_supported:1;
364
365 /*
366 * Automatically set by dm-core if this target supports
367 * REQ_OP_ZONE_RESET_ALL. Otherwise, this operation will be emulated
368 * using REQ_OP_ZONE_RESET. Target drivers must not set this manually.
369 */
370 bool zone_reset_all_supported:1;
371
372 /*
373 * Set if this target requires that discards be split on
374 * 'max_discard_sectors' boundaries.
375 */
376 bool max_discard_granularity:1;
377
378 /*
379 * Set if we need to limit the number of in-flight bios when swapping.
380 */
381 bool limit_swap_bios:1;
382
383 /*
384 * Set if this target implements a zoned device and needs emulation of
385 * zone append operations using regular writes.
386 */
387 bool emulate_zone_append:1;
388
389 /*
390 * Set if the target will submit IO using dm_submit_bio_remap()
391 * after returning DM_MAPIO_SUBMITTED from its map function.
392 */
393 bool accounts_remapped_io:1;
394
395 /*
396 * Set if the target will submit the DM bio without first calling
397 * bio_set_dev(). NOTE: ideally a target should _not_ need this.
398 */
399 bool needs_bio_set_dev:1;
400
401 /*
402 * Set if the target supports flush optimization. If all the targets in
403 * a table have flush_bypasses_map set, the dm core will not send
404 * flushes to the targets via a ->map method. It will iterate over
405 * dm_table->devices and send flushes to the devices directly. This
406 * optimization reduces the number of flushes being sent when multiple
407 * targets in a table use the same underlying device.
408 *
409 * This optimization may be enabled on targets that just pass the
410 * flushes to the underlying devices without performing any other
411 * actions on the flush request. Currently, dm-linear and dm-stripe
412 * support it.
413 */
414 bool flush_bypasses_map:1;
415
416 /*
417 * Set if the target calls bio_integrity_alloc on bios received
418 * in the map method.
419 */
420 bool mempool_needs_integrity:1;
421};
422
423void *dm_per_bio_data(struct bio *bio, size_t data_size);
424struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size);
425unsigned int dm_bio_get_target_bio_nr(const struct bio *bio);
426
427u64 dm_start_time_ns_from_clone(struct bio *bio);
428
429int dm_register_target(struct target_type *t);
430void dm_unregister_target(struct target_type *t);
431
432/*
433 * Target argument parsing.
434 */
435struct dm_arg_set {
436 unsigned int argc;
437 char **argv;
438};
439
440/*
441 * The minimum and maximum value of a numeric argument, together with
442 * the error message to use if the number is found to be outside that range.
443 */
444struct dm_arg {
445 unsigned int min;
446 unsigned int max;
447 char *error;
448};
449
450/*
451 * Validate the next argument, either returning it as *value or, if invalid,
452 * returning -EINVAL and setting *error.
453 */
454int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
455 unsigned int *value, char **error);
456
457/*
458 * Process the next argument as the start of a group containing between
459 * arg->min and arg->max further arguments. Either return the size as
460 * *num_args or, if invalid, return -EINVAL and set *error.
461 */
462int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
463 unsigned int *num_args, char **error);
464
465/*
466 * Return the current argument and shift to the next.
467 */
468const char *dm_shift_arg(struct dm_arg_set *as);
469
470/*
471 * Move through num_args arguments.
472 */
473void dm_consume_args(struct dm_arg_set *as, unsigned int num_args);
474
475/*
476 *----------------------------------------------------------------
477 * Functions for creating and manipulating mapped devices.
478 * Drop the reference with dm_put when you finish with the object.
479 *----------------------------------------------------------------
480 */
481
482/*
483 * DM_ANY_MINOR chooses the next available minor number.
484 */
485#define DM_ANY_MINOR (-1)
486int dm_create(int minor, struct mapped_device **md);
487
488/*
489 * Reference counting for md.
490 */
491struct mapped_device *dm_get_md(dev_t dev);
492void dm_get(struct mapped_device *md);
493int dm_hold(struct mapped_device *md);
494void dm_put(struct mapped_device *md);
495
496/*
497 * An arbitrary pointer may be stored alongside a mapped device.
498 */
499void dm_set_mdptr(struct mapped_device *md, void *ptr);
500void *dm_get_mdptr(struct mapped_device *md);
501
502/*
503 * A device can still be used while suspended, but I/O is deferred.
504 */
505int dm_suspend(struct mapped_device *md, unsigned int suspend_flags);
506int dm_resume(struct mapped_device *md);
507
508/*
509 * Event functions.
510 */
511uint32_t dm_get_event_nr(struct mapped_device *md);
512int dm_wait_event(struct mapped_device *md, int event_nr);
513uint32_t dm_next_uevent_seq(struct mapped_device *md);
514void dm_uevent_add(struct mapped_device *md, struct list_head *elist);
515
516/*
517 * Info functions.
518 */
519const char *dm_device_name(struct mapped_device *md);
520int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
521struct gendisk *dm_disk(struct mapped_device *md);
522int dm_suspended(struct dm_target *ti);
523int dm_post_suspending(struct dm_target *ti);
524int dm_noflush_suspending(struct dm_target *ti);
525void dm_accept_partial_bio(struct bio *bio, unsigned int n_sectors);
526void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone);
527
528#ifdef CONFIG_BLK_DEV_ZONED
529struct dm_report_zones_args {
530 struct dm_target *tgt;
531 sector_t next_sector;
532
533 void *orig_data;
534 report_zones_cb orig_cb;
535 unsigned int zone_idx;
536
537 /* must be filled by ->report_zones before calling dm_report_zones_cb */
538 sector_t start;
539};
540int dm_report_zones(struct block_device *bdev, sector_t start, sector_t sector,
541 struct dm_report_zones_args *args, unsigned int nr_zones);
542#endif /* CONFIG_BLK_DEV_ZONED */
543
544/*
545 * Device mapper functions to parse and create devices specified by the
546 * parameter "dm-mod.create="
547 */
548int __init dm_early_create(struct dm_ioctl *dmi,
549 struct dm_target_spec **spec_array,
550 char **target_params_array);
551
552/*
553 * Geometry functions.
554 */
555int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
556int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
557
558/*
559 *---------------------------------------------------------------
560 * Functions for manipulating device-mapper tables.
561 *---------------------------------------------------------------
562 */
563
564/*
565 * First create an empty table.
566 */
567int dm_table_create(struct dm_table **result, blk_mode_t mode,
568 unsigned int num_targets, struct mapped_device *md);
569
570/*
571 * Then call this once for each target.
572 */
573int dm_table_add_target(struct dm_table *t, const char *type,
574 sector_t start, sector_t len, char *params);
575
576/*
577 * Target can use this to set the table's type.
578 * Can only ever be called from a target's ctr.
579 * Useful for "hybrid" target (supports both bio-based
580 * and request-based).
581 */
582void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type);
583
584/*
585 * Finally call this to make the table ready for use.
586 */
587int dm_table_complete(struct dm_table *t);
588
589/*
590 * Destroy the table when finished.
591 */
592void dm_table_destroy(struct dm_table *t);
593
594/*
595 * Target may require that it is never sent I/O larger than len.
596 */
597int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
598
599/*
600 * Table reference counting.
601 */
602struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
603void dm_put_live_table(struct mapped_device *md, int srcu_idx);
604void dm_sync_table(struct mapped_device *md);
605
606/*
607 * Queries
608 */
609sector_t dm_table_get_size(struct dm_table *t);
610blk_mode_t dm_table_get_mode(struct dm_table *t);
611struct mapped_device *dm_table_get_md(struct dm_table *t);
612const char *dm_table_device_name(struct dm_table *t);
613
614/*
615 * Trigger an event.
616 */
617void dm_table_event(struct dm_table *t);
618
619/*
620 * Run the queue for request-based targets.
621 */
622void dm_table_run_md_queue_async(struct dm_table *t);
623
624/*
625 * The device must be suspended before calling this method.
626 * Returns the previous table, which the caller must destroy.
627 */
628struct dm_table *dm_swap_table(struct mapped_device *md,
629 struct dm_table *t);
630
631/*
632 * Table blk_crypto_profile functions
633 */
634void dm_destroy_crypto_profile(struct blk_crypto_profile *profile);
635
636/*
637 *---------------------------------------------------------------
638 * Macros.
639 *---------------------------------------------------------------
640 */
641#define DM_NAME "device-mapper"
642
643#define DM_FMT(fmt) DM_NAME ": " DM_MSG_PREFIX ": " fmt "\n"
644
645#define DMCRIT(fmt, ...) pr_crit(DM_FMT(fmt), ##__VA_ARGS__)
646
647#define DMERR(fmt, ...) pr_err(DM_FMT(fmt), ##__VA_ARGS__)
648#define DMERR_LIMIT(fmt, ...) pr_err_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
649#define DMWARN(fmt, ...) pr_warn(DM_FMT(fmt), ##__VA_ARGS__)
650#define DMWARN_LIMIT(fmt, ...) pr_warn_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
651#define DMINFO(fmt, ...) pr_info(DM_FMT(fmt), ##__VA_ARGS__)
652#define DMINFO_LIMIT(fmt, ...) pr_info_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
653
654#define DMDEBUG(fmt, ...) pr_debug(DM_FMT(fmt), ##__VA_ARGS__)
655#define DMDEBUG_LIMIT(fmt, ...) pr_debug_ratelimited(DM_FMT(fmt), ##__VA_ARGS__)
656
657#define DMEMIT(x...) (sz += ((sz >= maxlen) ? 0 : scnprintf(result + sz, maxlen - sz, x)))
658
659#define DMEMIT_TARGET_NAME_VERSION(y) \
660 DMEMIT("target_name=%s,target_version=%u.%u.%u", \
661 (y)->name, (y)->version[0], (y)->version[1], (y)->version[2])
662
663/**
664 * module_dm() - Helper macro for DM targets that don't do anything
665 * special in their module_init and module_exit.
666 * Each module may only use this macro once, and calling it replaces
667 * module_init() and module_exit().
668 *
669 * @name: DM target's name
670 */
671#define module_dm(name) \
672static int __init dm_##name##_init(void) \
673{ \
674 return dm_register_target(&(name##_target)); \
675} \
676module_init(dm_##name##_init) \
677static void __exit dm_##name##_exit(void) \
678{ \
679 dm_unregister_target(&(name##_target)); \
680} \
681module_exit(dm_##name##_exit)
682
683/*
684 * Definitions of return values from target end_io function.
685 */
686#define DM_ENDIO_DONE 0
687#define DM_ENDIO_INCOMPLETE 1
688#define DM_ENDIO_REQUEUE 2
689#define DM_ENDIO_DELAY_REQUEUE 3
690
691/*
692 * Definitions of return values from target map function.
693 */
694#define DM_MAPIO_SUBMITTED 0
695#define DM_MAPIO_REMAPPED 1
696#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
697#define DM_MAPIO_DELAY_REQUEUE DM_ENDIO_DELAY_REQUEUE
698#define DM_MAPIO_KILL 4
699
700#define dm_sector_div64(x, y)( \
701{ \
702 u64 _res; \
703 (x) = div64_u64_rem(x, y, &_res); \
704 _res; \
705} \
706)
707
708/*
709 * Ceiling(n / sz)
710 */
711#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
712
713#define dm_sector_div_up(n, sz) ( \
714{ \
715 sector_t _r = ((n) + (sz) - 1); \
716 sector_div(_r, (sz)); \
717 _r; \
718} \
719)
720
721/*
722 * ceiling(n / size) * size
723 */
724#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
725
726/*
727 * Sector offset taken relative to the start of the target instead of
728 * relative to the start of the device.
729 */
730#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
731
732static inline sector_t to_sector(unsigned long long n)
733{
734 return (n >> SECTOR_SHIFT);
735}
736
737static inline unsigned long to_bytes(sector_t n)
738{
739 return (n << SECTOR_SHIFT);
740}
741
742#endif /* _LINUX_DEVICE_MAPPER_H */