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