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