[mirror_ubuntu-zesty-kernel.git] / include / linux / device-mapper.h

/*
 * Copyright (C) 2001 Sistina Software (UK) Limited.
 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the LGPL.
 */

#ifndef _LINUX_DEVICE_MAPPER_H
#define _LINUX_DEVICE_MAPPER_H

#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/math64.h>
#include <linux/ratelimit.h>

struct dm_dev;
struct dm_target;
struct dm_table;
struct mapped_device;
struct bio_vec;

typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;

union map_info {
	void *ptr;
};

/*
 * In the constructor the target parameter will already have the
 * table, type, begin and len fields filled in.
 */
typedef int (*dm_ctr_fn) (struct dm_target *target,
			  unsigned int argc, char **argv);

/*
 * The destructor doesn't need to free the dm_target, just
 * anything hidden ti->private.
 */
typedef void (*dm_dtr_fn) (struct dm_target *ti);

/*
 * The map function must return:
 * < 0: error
 * = 0: The target will handle the io by resubmitting it later
 * = 1: simple remap complete
 * = 2: The target wants to push back the io
 */
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
				  union map_info *map_context);

/*
 * Returns:
 * < 0 : error (currently ignored)
 * 0   : ended successfully
 * 1   : for some reason the io has still not completed (eg,
 *       multipath target might want to requeue a failed io).
 * 2   : The target wants to push back the io
 */
typedef int (*dm_endio_fn) (struct dm_target *ti,
			    struct bio *bio, int error);
typedef int (*dm_request_endio_fn) (struct dm_target *ti,
				    struct request *clone, int error,
				    union map_info *map_context);

typedef void (*dm_presuspend_fn) (struct dm_target *ti);
typedef void (*dm_presuspend_undo_fn) (struct dm_target *ti);
typedef void (*dm_postsuspend_fn) (struct dm_target *ti);
typedef int (*dm_preresume_fn) (struct dm_target *ti);
typedef void (*dm_resume_fn) (struct dm_target *ti);

typedef void (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
			      unsigned status_flags, char *result, unsigned maxlen);

typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);

typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd,
			    unsigned long arg);

typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm,
			    struct bio_vec *biovec, int max_size);

/*
 * These iteration functions are typically used to check (and combine)
 * properties of underlying devices.
 * E.g. Does at least one underlying device support flush?
 *      Does any underlying device not support WRITE_SAME?
 *
 * The callout function is called once for each contiguous section of
 * an underlying device.  State can be maintained in *data.
 * Return non-zero to stop iterating through any further devices.
 */
typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
					   struct dm_dev *dev,
					   sector_t start, sector_t len,
					   void *data);

/*
 * This function must iterate through each section of device used by the
 * target until it encounters a non-zero return code, which it then returns.
 * Returns zero if no callout returned non-zero.
 */
typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
				      iterate_devices_callout_fn fn,
				      void *data);

typedef void (*dm_io_hints_fn) (struct dm_target *ti,
				struct queue_limits *limits);

/*
 * Returns:
 *    0: The target can handle the next I/O immediately.
 *    1: The target can't handle the next I/O immediately.
 */
typedef int (*dm_busy_fn) (struct dm_target *ti);

void dm_error(const char *message);

struct dm_dev {
	struct block_device *bdev;
	fmode_t mode;
	char name[16];
};

/*
 * Constructors should call these functions to ensure destination devices
 * are opened/closed correctly.
 */
int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
		  struct dm_dev **result);
void dm_put_device(struct dm_target *ti, struct dm_dev *d);

/*
 * Information about a target type
 */

struct target_type {
	uint64_t features;
	const char *name;
	struct module *module;
	unsigned version[3];
	dm_ctr_fn ctr;
	dm_dtr_fn dtr;
	dm_map_fn map;
	dm_map_request_fn map_rq;
	dm_endio_fn end_io;
	dm_request_endio_fn rq_end_io;
	dm_presuspend_fn presuspend;
	dm_presuspend_undo_fn presuspend_undo;
	dm_postsuspend_fn postsuspend;
	dm_preresume_fn preresume;
	dm_resume_fn resume;
	dm_status_fn status;
	dm_message_fn message;
	dm_ioctl_fn ioctl;
	dm_merge_fn merge;
	dm_busy_fn busy;
	dm_iterate_devices_fn iterate_devices;
	dm_io_hints_fn io_hints;

	/* For internal device-mapper use. */
	struct list_head list;
};

/*
 * Target features
 */

/*
 * Any table that contains an instance of this target must have only one.
 */
#define DM_TARGET_SINGLETON		0x00000001
#define dm_target_needs_singleton(type)	((type)->features & DM_TARGET_SINGLETON)

/*
 * Indicates that a target does not support read-only devices.
 */
#define DM_TARGET_ALWAYS_WRITEABLE	0x00000002
#define dm_target_always_writeable(type) \
		((type)->features & DM_TARGET_ALWAYS_WRITEABLE)

/*
 * Any device that contains a table with an instance of this target may never
 * have tables containing any different target type.
 */
#define DM_TARGET_IMMUTABLE		0x00000004
#define dm_target_is_immutable(type)	((type)->features & DM_TARGET_IMMUTABLE)

/*
 * Some targets need to be sent the same WRITE bio severals times so
 * that they can send copies of it to different devices.  This function
 * examines any supplied bio and returns the number of copies of it the
 * target requires.
 */
typedef unsigned (*dm_num_write_bios_fn) (struct dm_target *ti, struct bio *bio);

struct dm_target {
	struct dm_table *table;
	struct target_type *type;

	/* target limits */
	sector_t begin;
	sector_t len;

	/* If non-zero, maximum size of I/O submitted to a target. */
	uint32_t max_io_len;

	/*
	 * A number of zero-length barrier bios that will be submitted
	 * to the target for the purpose of flushing cache.
	 *
	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
	 * It is a responsibility of the target driver to remap these bios
	 * to the real underlying devices.
	 */
	unsigned num_flush_bios;

	/*
	 * The number of discard bios that will be submitted to the target.
	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
	 */
	unsigned num_discard_bios;

	/*
	 * The number of WRITE SAME bios that will be submitted to the target.
	 * The bio number can be accessed with dm_bio_get_target_bio_nr.
	 */
	unsigned num_write_same_bios;

	/*
	 * The minimum number of extra bytes allocated in each bio for the
	 * target to use.  dm_per_bio_data returns the data location.
	 */
	unsigned per_bio_data_size;

	/*
	 * If defined, this function is called to find out how many
	 * duplicate bios should be sent to the target when writing
	 * data.
	 */
	dm_num_write_bios_fn num_write_bios;

	/* target specific data */
	void *private;

	/* Used to provide an error string from the ctr */
	char *error;

	/*
	 * Set if this target needs to receive flushes regardless of
	 * whether or not its underlying devices have support.
	 */
	bool flush_supported:1;

	/*
	 * Set if this target needs to receive discards regardless of
	 * whether or not its underlying devices have support.
	 */
	bool discards_supported:1;

	/*
	 * Set if the target required discard bios to be split
	 * on max_io_len boundary.
	 */
	bool split_discard_bios:1;

	/*
	 * Set if this target does not return zeroes on discarded blocks.
	 */
	bool discard_zeroes_data_unsupported:1;
};

/* Each target can link one of these into the table */
struct dm_target_callbacks {
	struct list_head list;
	int (*congested_fn) (struct dm_target_callbacks *, int);
};

/*
 * For bio-based dm.
 * One of these is allocated for each bio.
 * This structure shouldn't be touched directly by target drivers.
 * It is here so that we can inline dm_per_bio_data and
 * dm_bio_from_per_bio_data
 */
struct dm_target_io {
	struct dm_io *io;
	struct dm_target *ti;
	unsigned target_bio_nr;
	unsigned *len_ptr;
	struct bio clone;
};

static inline void *dm_per_bio_data(struct bio *bio, size_t data_size)
{
	return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
}

static inline struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
{
	return (struct bio *)((char *)data + data_size + offsetof(struct dm_target_io, clone));
}

static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
{
	return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
}

int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);

/*
 * Target argument parsing.
 */
struct dm_arg_set {
	unsigned argc;
	char **argv;
};

/*
 * The minimum and maximum value of a numeric argument, together with
 * the error message to use if the number is found to be outside that range.
 */
struct dm_arg {
	unsigned min;
	unsigned max;
	char *error;
};

/*
 * Validate the next argument, either returning it as *value or, if invalid,
 * returning -EINVAL and setting *error.
 */
int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
		unsigned *value, char **error);

/*
 * Process the next argument as the start of a group containing between
 * arg->min and arg->max further arguments. Either return the size as
 * *num_args or, if invalid, return -EINVAL and set *error.
 */
int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
		      unsigned *num_args, char **error);

/*
 * Return the current argument and shift to the next.
 */
const char *dm_shift_arg(struct dm_arg_set *as);

/*
 * Move through num_args arguments.
 */
void dm_consume_args(struct dm_arg_set *as, unsigned num_args);

/*-----------------------------------------------------------------
 * Functions for creating and manipulating mapped devices.
 * Drop the reference with dm_put when you finish with the object.
 *---------------------------------------------------------------*/

/*
 * DM_ANY_MINOR chooses the next available minor number.
 */
#define DM_ANY_MINOR (-1)
int dm_create(int minor, struct mapped_device **md);

/*
 * Reference counting for md.
 */
struct mapped_device *dm_get_md(dev_t dev);
void dm_get(struct mapped_device *md);
void dm_put(struct mapped_device *md);

/*
 * An arbitrary pointer may be stored alongside a mapped device.
 */
void dm_set_mdptr(struct mapped_device *md, void *ptr);
void *dm_get_mdptr(struct mapped_device *md);

/*
 * A device can still be used while suspended, but I/O is deferred.
 */
int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
int dm_resume(struct mapped_device *md);

/*
 * Event functions.
 */
uint32_t dm_get_event_nr(struct mapped_device *md);
int dm_wait_event(struct mapped_device *md, int event_nr);
uint32_t dm_next_uevent_seq(struct mapped_device *md);
void dm_uevent_add(struct mapped_device *md, struct list_head *elist);

/*
 * Info functions.
 */
const char *dm_device_name(struct mapped_device *md);
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid);
struct gendisk *dm_disk(struct mapped_device *md);
int dm_suspended(struct dm_target *ti);
int dm_noflush_suspending(struct dm_target *ti);
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
union map_info *dm_get_rq_mapinfo(struct request *rq);

struct queue_limits *dm_get_queue_limits(struct mapped_device *md);

/*
 * Geometry functions.
 */
int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);

/*-----------------------------------------------------------------
 * Functions for manipulating device-mapper tables.
 *---------------------------------------------------------------*/

/*
 * First create an empty table.
 */
int dm_table_create(struct dm_table **result, fmode_t mode,
		    unsigned num_targets, struct mapped_device *md);

/*
 * Then call this once for each target.
 */
int dm_table_add_target(struct dm_table *t, const char *type,
			sector_t start, sector_t len, char *params);

/*
 * Target_ctr should call this if it needs to add any callbacks.
 */
void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);

/*
 * Finally call this to make the table ready for use.
 */
int dm_table_complete(struct dm_table *t);

/*
 * Target may require that it is never sent I/O larger than len.
 */
int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);

/*
 * Table reference counting.
 */
struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
void dm_put_live_table(struct mapped_device *md, int srcu_idx);
void dm_sync_table(struct mapped_device *md);

/*
 * Queries
 */
sector_t dm_table_get_size(struct dm_table *t);
unsigned int dm_table_get_num_targets(struct dm_table *t);
fmode_t dm_table_get_mode(struct dm_table *t);
struct mapped_device *dm_table_get_md(struct dm_table *t);

/*
 * Trigger an event.
 */
void dm_table_event(struct dm_table *t);

/*
 * Run the queue for request-based targets.
 */
void dm_table_run_md_queue_async(struct dm_table *t);

/*
 * The device must be suspended before calling this method.
 * Returns the previous table, which the caller must destroy.
 */
struct dm_table *dm_swap_table(struct mapped_device *md,
			       struct dm_table *t);

/*
 * A wrapper around vmalloc.
 */
void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);

/*-----------------------------------------------------------------
 * Macros.
 *---------------------------------------------------------------*/
#define DM_NAME "device-mapper"

#ifdef CONFIG_PRINTK
extern struct ratelimit_state dm_ratelimit_state;

#define dm_ratelimit()	__ratelimit(&dm_ratelimit_state)
#else
#define dm_ratelimit()	0
#endif

#define DMCRIT(f, arg...) \
	printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)

#define DMERR(f, arg...) \
	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMERR_LIMIT(f, arg...) \
	do { \
		if (dm_ratelimit())	\
			printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
			       f "\n", ## arg); \
	} while (0)

#define DMWARN(f, arg...) \
	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMWARN_LIMIT(f, arg...) \
	do { \
		if (dm_ratelimit())	\
			printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
			       f "\n", ## arg); \
	} while (0)

#define DMINFO(f, arg...) \
	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
#define DMINFO_LIMIT(f, arg...) \
	do { \
		if (dm_ratelimit())	\
			printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
			       "\n", ## arg); \
	} while (0)

#ifdef CONFIG_DM_DEBUG
#  define DMDEBUG(f, arg...) \
	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
#  define DMDEBUG_LIMIT(f, arg...) \
	do { \
		if (dm_ratelimit())	\
			printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
			       "\n", ## arg); \
	} while (0)
#else
#  define DMDEBUG(f, arg...) do {} while (0)
#  define DMDEBUG_LIMIT(f, arg...) do {} while (0)
#endif

#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
			  0 : scnprintf(result + sz, maxlen - sz, x))

#define SECTOR_SHIFT 9

/*
 * Definitions of return values from target end_io function.
 */
#define DM_ENDIO_INCOMPLETE	1
#define DM_ENDIO_REQUEUE	2

/*
 * Definitions of return values from target map function.
 */
#define DM_MAPIO_SUBMITTED	0
#define DM_MAPIO_REMAPPED	1
#define DM_MAPIO_REQUEUE	DM_ENDIO_REQUEUE

#define dm_sector_div64(x, y)( \
{ \
	u64 _res; \
	(x) = div64_u64_rem(x, y, &_res); \
	_res; \
} \
)

/*
 * Ceiling(n / sz)
 */
#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))

#define dm_sector_div_up(n, sz) ( \
{ \
	sector_t _r = ((n) + (sz) - 1); \
	sector_div(_r, (sz)); \
	_r; \
} \
)

/*
 * ceiling(n / size) * size
 */
#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))

#define dm_array_too_big(fixed, obj, num) \
	((num) > (UINT_MAX - (fixed)) / (obj))

/*
 * Sector offset taken relative to the start of the target instead of
 * relative to the start of the device.
 */
#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)

static inline sector_t to_sector(unsigned long n)
{
	return (n >> SECTOR_SHIFT);
}

static inline unsigned long to_bytes(sector_t n)
{
	return (n << SECTOR_SHIFT);
}

/*-----------------------------------------------------------------
 * Helper for block layer and dm core operations
 *---------------------------------------------------------------*/
void dm_dispatch_request(struct request *rq);
void dm_requeue_unmapped_request(struct request *rq);
void dm_kill_unmapped_request(struct request *rq, int error);
int dm_underlying_device_busy(struct request_queue *q);

#endif	/* _LINUX_DEVICE_MAPPER_H */
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* Copyright (C) 2001 Sistina Software (UK) Limited.
0da336e5	3	* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
1da177e4 LT	4	*
	5	* This file is released under the LGPL.
	6	*/
	7
	8	#ifndef _LINUX_DEVICE_MAPPER_H
	9	#define _LINUX_DEVICE_MAPPER_H
	10
416cd17b	11	#include <linux/bio.h>
f6fccb12	12	#include <linux/blkdev.h>
fd2ed4d2	13	#include <linux/math64.h>
71a16736	14	#include <linux/ratelimit.h>
416cd17b	15
af4874e0	16	struct dm_dev;
1da177e4 LT	17	struct dm_target;
1da177e4 LT	18	struct dm_table;
17b2f66f	19	struct mapped_device;
f6fccb12	20	struct bio_vec;
1da177e4 LT	21
	22	typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
	23
	24	union map_info {
	25	void *ptr;
1da177e4 LT	26	};
	27
	28	/*
	29	* In the constructor the target parameter will already have the
	30	* table, type, begin and len fields filled in.
	31	*/
	32	typedef 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	*/
	39	typedef 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
45cbcd79	45	* = 1: simple remap complete
2e93ccc1	46	* = 2: The target wants to push back the io
1da177e4	47	*/
7de3ee57	48	typedef int (dm_map_fn) (struct dm_target ti, struct bio *bio);
7d76345d KU	49	typedef int (dm_map_request_fn) (struct dm_target ti, struct request *clone,
7d76345d KU	50	union map_info *map_context);
1da177e4 LT	51
	52	/*
	53	* Returns:
	54	* < 0 : error (currently ignored)
	55	* 0 : ended successfully
	56	* 1 : for some reason the io has still not completed (eg,
	57	* multipath target might want to requeue a failed io).
2e93ccc1	58	* 2 : The target wants to push back the io
1da177e4 LT	59	*/
1da177e4 LT	60	typedef int (dm_endio_fn) (struct dm_target ti,
7de3ee57	61	struct bio *bio, int error);
7d76345d KU	62	typedef int (dm_request_endio_fn) (struct dm_target ti,
	63	struct request *clone, int error,
	64	union map_info *map_context);
1da177e4 LT	65
1da177e4 LT	66	typedef void (dm_presuspend_fn) (struct dm_target ti);
d67ee213	67	typedef void (dm_presuspend_undo_fn) (struct dm_target ti);
1da177e4	68	typedef void (dm_postsuspend_fn) (struct dm_target ti);
8757b776	69	typedef int (dm_preresume_fn) (struct dm_target ti);
1da177e4 LT	70	typedef void (dm_resume_fn) (struct dm_target ti);
1da177e4 LT	71
fd7c092e MP	72	typedef void (dm_status_fn) (struct dm_target ti, status_type_t status_type,
fd7c092e MP	73	unsigned status_flags, char *result, unsigned maxlen);
1da177e4 LT	74
	75	typedef int (dm_message_fn) (struct dm_target ti, unsigned argc, char **argv);
	76
647b3d00	77	typedef int (dm_ioctl_fn) (struct dm_target ti, unsigned int cmd,
aa129a22 MB	78	unsigned long arg);
aa129a22 MB	79
f6fccb12 MB	80	typedef int (dm_merge_fn) (struct dm_target ti, struct bvec_merge_data *bvm,
	81	struct bio_vec *biovec, int max_size);
	82
058ce5ca AK	83	/*
	84	* These iteration functions are typically used to check (and combine)
	85	* properties of underlying devices.
	86	* E.g. Does at least one underlying device support flush?
	87	* Does any underlying device not support WRITE_SAME?
	88	*
	89	* The callout function is called once for each contiguous section of
	90	* an underlying device. State can be maintained in *data.
	91	* Return non-zero to stop iterating through any further devices.
	92	*/
af4874e0 MS	93	typedef int (iterate_devices_callout_fn) (struct dm_target ti,
af4874e0 MS	94	struct dm_dev *dev,
5dea271b	95	sector_t start, sector_t len,
af4874e0 MS	96	void *data);
af4874e0 MS	97
058ce5ca AK	98	/*
	99	* This function must iterate through each section of device used by the
	100	* target until it encounters a non-zero return code, which it then returns.
	101	* Returns zero if no callout returned non-zero.
	102	*/
af4874e0 MS	103	typedef int (dm_iterate_devices_fn) (struct dm_target ti,
	104	iterate_devices_callout_fn fn,
	105	void *data);
	106
40bea431 MS	107	typedef void (dm_io_hints_fn) (struct dm_target ti,
	108	struct queue_limits *limits);
	109
7d76345d KU	110	/*
	111	* Returns:
	112	* 0: The target can handle the next I/O immediately.
	113	* 1: The target can't handle the next I/O immediately.
	114	*/
	115	typedef int (dm_busy_fn) (struct dm_target ti);
	116
1da177e4 LT	117	void dm_error(const char *message);
1da177e4 LT	118
82b1519b MP	119	struct dm_dev {
82b1519b MP	120	struct block_device *bdev;
aeb5d727	121	fmode_t mode;
82b1519b MP	122	char name[16];
	123	};
	124
1da177e4 LT	125	/*
	126	* Constructors should call these functions to ensure destination devices
	127	* are opened/closed correctly.
1da177e4	128	*/
8215d6ec	129	int dm_get_device(struct dm_target ti, const char path, fmode_t mode,
11f0431b	130	struct dm_dev **result);
1da177e4 LT	131	void dm_put_device(struct dm_target ti, struct dm_dev d);
	132
	133	/*
	134	* Information about a target type
	135	*/
ab4c1424	136
1da177e4	137	struct target_type {
ab4c1424	138	uint64_t features;
1da177e4 LT	139	const char *name;
1da177e4 LT	140	struct module *module;
17b2f66f	141	unsigned version[3];
1da177e4 LT	142	dm_ctr_fn ctr;
	143	dm_dtr_fn dtr;
	144	dm_map_fn map;
7d76345d	145	dm_map_request_fn map_rq;
1da177e4	146	dm_endio_fn end_io;
7d76345d	147	dm_request_endio_fn rq_end_io;
1da177e4	148	dm_presuspend_fn presuspend;
d67ee213	149	dm_presuspend_undo_fn presuspend_undo;
1da177e4	150	dm_postsuspend_fn postsuspend;
8757b776	151	dm_preresume_fn preresume;
1da177e4 LT	152	dm_resume_fn resume;
	153	dm_status_fn status;
	154	dm_message_fn message;
aa129a22	155	dm_ioctl_fn ioctl;
f6fccb12	156	dm_merge_fn merge;
7d76345d	157	dm_busy_fn busy;
af4874e0	158	dm_iterate_devices_fn iterate_devices;
40bea431	159	dm_io_hints_fn io_hints;
45194e4f CR	160
	161	/* For internal device-mapper use. */
	162	struct list_head list;
1da177e4 LT	163	};
1da177e4 LT	164
3791e2fc AK	165	/*
	166	* Target features
	167	*/
	168
	169	/*
	170	* Any table that contains an instance of this target must have only one.
	171	*/
	172	#define DM_TARGET_SINGLETON 0x00000001
	173	#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
	174
cc6cbe14 AK	175	/*
	176	* Indicates that a target does not support read-only devices.
	177	*/
	178	#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
	179	#define dm_target_always_writeable(type) \
	180	((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
	181
36a0456f AK	182	/*
	183	* Any device that contains a table with an instance of this target may never
	184	* have tables containing any different target type.
	185	*/
	186	#define DM_TARGET_IMMUTABLE 0x00000004
	187	#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
	188
b0d8ed4d AK	189	/*
	190	* Some targets need to be sent the same WRITE bio severals times so
	191	* that they can send copies of it to different devices. This function
	192	* examines any supplied bio and returns the number of copies of it the
	193	* target requires.
	194	*/
	195	typedef unsigned (dm_num_write_bios_fn) (struct dm_target ti, struct bio *bio);
	196
1da177e4 LT	197	struct dm_target {
	198	struct dm_table *table;
	199	struct target_type *type;
	200
	201	/* target limits */
	202	sector_t begin;
	203	sector_t len;
	204
542f9038 MS	205	/* If non-zero, maximum size of I/O submitted to a target. */
542f9038 MS	206	uint32_t max_io_len;
1da177e4	207
f9ab94ce	208	/*
55a62eef	209	* A number of zero-length barrier bios that will be submitted
f9ab94ce MP	210	* to the target for the purpose of flushing cache.
f9ab94ce MP	211	*
55a62eef AK	212	* The bio number can be accessed with dm_bio_get_target_bio_nr.
55a62eef AK	213	* It is a responsibility of the target driver to remap these bios
f9ab94ce MP	214	* to the real underlying devices.
f9ab94ce MP	215	*/
55a62eef	216	unsigned num_flush_bios;
f9ab94ce	217
5ae89a87	218	/*
55a62eef AK	219	* The number of discard bios that will be submitted to the target.
55a62eef AK	220	* The bio number can be accessed with dm_bio_get_target_bio_nr.
5ae89a87	221	*/
55a62eef	222	unsigned num_discard_bios;
5ae89a87	223
d54eaa5a	224	/*
55a62eef AK	225	* The number of WRITE SAME bios that will be submitted to the target.
55a62eef AK	226	* The bio number can be accessed with dm_bio_get_target_bio_nr.
d54eaa5a	227	*/
55a62eef	228	unsigned num_write_same_bios;
d54eaa5a	229
c0820cf5 MP	230	/*
	231	* The minimum number of extra bytes allocated in each bio for the
	232	* target to use. dm_per_bio_data returns the data location.
	233	*/
	234	unsigned per_bio_data_size;
	235
b0d8ed4d AK	236	/*
	237	* If defined, this function is called to find out how many
	238	* duplicate bios should be sent to the target when writing
	239	* data.
	240	*/
	241	dm_num_write_bios_fn num_write_bios;
	242
1da177e4 LT	243	/* target specific data */
	244	void *private;
	245
	246	/* Used to provide an error string from the ctr */
	247	char *error;
4c259327	248
0e9c24ed JT	249	/*
	250	* Set if this target needs to receive flushes regardless of
	251	* whether or not its underlying devices have support.
	252	*/
	253	bool flush_supported:1;
	254
4c259327 MS	255	/*
	256	* Set if this target needs to receive discards regardless of
	257	* whether or not its underlying devices have support.
	258	*/
0ac55489	259	bool discards_supported:1;
983c7db3	260
7acf0277	261	/*
55a62eef	262	* Set if the target required discard bios to be split
7acf0277 MP	263	* on max_io_len boundary.
7acf0277 MP	264	*/
55a62eef	265	bool split_discard_bios:1;
7acf0277	266
983c7db3 MB	267	/*
	268	* Set if this target does not return zeroes on discarded blocks.
	269	*/
0ac55489	270	bool discard_zeroes_data_unsupported:1;
1da177e4 LT	271	};
1da177e4 LT	272
9d357b07 N	273	/* Each target can link one of these into the table */
	274	struct dm_target_callbacks {
	275	struct list_head list;
	276	int (congested_fn) (struct dm_target_callbacks , int);
	277	};
	278
c0820cf5 MP	279	/*
	280	* For bio-based dm.
	281	* One of these is allocated for each bio.
	282	* This structure shouldn't be touched directly by target drivers.
	283	* It is here so that we can inline dm_per_bio_data and
	284	* dm_bio_from_per_bio_data
	285	*/
	286	struct dm_target_io {
	287	struct dm_io *io;
	288	struct dm_target *ti;
55a62eef	289	unsigned target_bio_nr;
1dd40c3e	290	unsigned *len_ptr;
c0820cf5 MP	291	struct bio clone;
	292	};
	293
	294	static inline void dm_per_bio_data(struct bio bio, size_t data_size)
	295	{
	296	return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
	297	}
	298
	299	static inline struct bio dm_bio_from_per_bio_data(void data, size_t data_size)
	300	{
	301	return (struct bio )((char )data + data_size + offsetof(struct dm_target_io, clone));
	302	}
	303
55a62eef	304	static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
ddbd658f	305	{
55a62eef	306	return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
ddbd658f MP	307	}
ddbd658f MP	308
1da177e4	309	int dm_register_target(struct target_type *t);
10d3bd09	310	void dm_unregister_target(struct target_type *t);
17b2f66f	311
498f0103 MS	312	/*
	313	* Target argument parsing.
	314	*/
	315	struct dm_arg_set {
	316	unsigned argc;
	317	char **argv;
	318	};
	319
	320	/*
	321	* The minimum and maximum value of a numeric argument, together with
	322	* the error message to use if the number is found to be outside that range.
	323	*/
	324	struct dm_arg {
	325	unsigned min;
	326	unsigned max;
	327	char *error;
	328	};
	329
	330	/*
	331	* Validate the next argument, either returning it as *value or, if invalid,
	332	* returning -EINVAL and setting *error.
	333	*/
	334	int dm_read_arg(struct dm_arg arg, struct dm_arg_set arg_set,
	335	unsigned value, char *error);
	336
	337	/*
	338	* Process the next argument as the start of a group containing between
	339	* arg->min and arg->max further arguments. Either return the size as
	340	* num_args or, if invalid, return -EINVAL and set error.
	341	*/
	342	int dm_read_arg_group(struct dm_arg arg, struct dm_arg_set arg_set,
	343	unsigned num_args, char *error);
	344
	345	/*
	346	* Return the current argument and shift to the next.
	347	*/
	348	const char dm_shift_arg(struct dm_arg_set as);
	349
	350	/*
	351	* Move through num_args arguments.
	352	*/
	353	void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
	354
17b2f66f AK	355	/*-----------------------------------------------------------------
	356	* Functions for creating and manipulating mapped devices.
	357	* Drop the reference with dm_put when you finish with the object.
	358	---------------------------------------------------------------/
	359
	360	/*
	361	* DM_ANY_MINOR chooses the next available minor number.
	362	*/
	363	#define DM_ANY_MINOR (-1)
	364	int dm_create(int minor, struct mapped_device **md);
	365
	366	/*
	367	* Reference counting for md.
	368	*/
	369	struct mapped_device *dm_get_md(dev_t dev);
	370	void dm_get(struct mapped_device *md);
	371	void dm_put(struct mapped_device *md);
	372
	373	/*
	374	* An arbitrary pointer may be stored alongside a mapped device.
	375	*/
	376	void dm_set_mdptr(struct mapped_device md, void ptr);
	377	void dm_get_mdptr(struct mapped_device md);
	378
	379	/*
	380	* A device can still be used while suspended, but I/O is deferred.
	381	*/
a3d77d35	382	int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
17b2f66f AK	383	int dm_resume(struct mapped_device *md);
	384
	385	/*
	386	* Event functions.
	387	*/
	388	uint32_t dm_get_event_nr(struct mapped_device *md);
	389	int dm_wait_event(struct mapped_device *md, int event_nr);
7a8c3d3b MA	390	uint32_t dm_next_uevent_seq(struct mapped_device *md);
7a8c3d3b MA	391	void dm_uevent_add(struct mapped_device md, struct list_head elist);
17b2f66f AK	392
	393	/*
	394	* Info functions.
	395	*/
72d94861	396	const char dm_device_name(struct mapped_device md);
96a1f7db	397	int dm_copy_name_and_uuid(struct mapped_device md, char name, char *uuid);
17b2f66f	398	struct gendisk dm_disk(struct mapped_device md);
64dbce58	399	int dm_suspended(struct dm_target *ti);
2e93ccc1	400	int dm_noflush_suspending(struct dm_target *ti);
1dd40c3e	401	void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
cec47e3d	402	union map_info dm_get_rq_mapinfo(struct request rq);
17b2f66f	403
f84cb8a4 MS	404	struct queue_limits dm_get_queue_limits(struct mapped_device md);
f84cb8a4 MS	405
17b2f66f AK	406	/*
	407	* Geometry functions.
	408	*/
	409	int dm_get_geometry(struct mapped_device md, struct hd_geometry geo);
	410	int dm_set_geometry(struct mapped_device md, struct hd_geometry geo);
	411
17b2f66f AK	412	/*-----------------------------------------------------------------
	413	* Functions for manipulating device-mapper tables.
	414	---------------------------------------------------------------/
	415
	416	/*
	417	* First create an empty table.
	418	*/
aeb5d727	419	int dm_table_create(struct dm_table **result, fmode_t mode,
17b2f66f AK	420	unsigned num_targets, struct mapped_device *md);
	421
	422	/*
	423	* Then call this once for each target.
	424	*/
	425	int dm_table_add_target(struct dm_table t, const char type,
	426	sector_t start, sector_t len, char *params);
	427
9d357b07 N	428	/*
	429	* Target_ctr should call this if it needs to add any callbacks.
	430	*/
	431	void dm_table_add_target_callbacks(struct dm_table t, struct dm_target_callbacks cb);
	432
17b2f66f AK	433	/*
	434	* Finally call this to make the table ready for use.
	435	*/
	436	int dm_table_complete(struct dm_table *t);
	437
542f9038 MS	438	/*
	439	* Target may require that it is never sent I/O larger than len.
	440	*/
	441	int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
	442
17b2f66f AK	443	/*
	444	* Table reference counting.
	445	*/
83d5e5b0 MP	446	struct dm_table dm_get_live_table(struct mapped_device md, int *srcu_idx);
	447	void dm_put_live_table(struct mapped_device *md, int srcu_idx);
	448	void dm_sync_table(struct mapped_device *md);
17b2f66f AK	449
	450	/*
	451	* Queries
	452	*/
	453	sector_t dm_table_get_size(struct dm_table *t);
	454	unsigned int dm_table_get_num_targets(struct dm_table *t);
aeb5d727	455	fmode_t dm_table_get_mode(struct dm_table *t);
17b2f66f AK	456	struct mapped_device dm_table_get_md(struct dm_table t);
	457
	458	/*
	459	* Trigger an event.
	460	*/
	461	void dm_table_event(struct dm_table *t);
	462
9974fa2c MS	463	/*
	464	* Run the queue for request-based targets.
	465	*/
	466	void dm_table_run_md_queue_async(struct dm_table *t);
	467
17b2f66f AK	468	/*
17b2f66f AK	469	* The device must be suspended before calling this method.
042d2a9b	470	* Returns the previous table, which the caller must destroy.
17b2f66f	471	*/
042d2a9b AK	472	struct dm_table dm_swap_table(struct mapped_device md,
042d2a9b AK	473	struct dm_table *t);
17b2f66f	474
54160904 MP	475	/*
	476	* A wrapper around vmalloc.
	477	*/
	478	void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
	479
0da336e5 AK	480	/*-----------------------------------------------------------------
	481	* Macros.
	482	---------------------------------------------------------------/
	483	#define DM_NAME "device-mapper"
	484
71a16736 NK	485	#ifdef CONFIG_PRINTK
	486	extern struct ratelimit_state dm_ratelimit_state;
	487
	488	#define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
	489	#else
	490	#define dm_ratelimit() 0
	491	#endif
	492
10d3bd09 MP	493	#define DMCRIT(f, arg...) \
	494	printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	495
0da336e5 AK	496	#define DMERR(f, arg...) \
	497	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	498	#define DMERR_LIMIT(f, arg...) \
	499	do { \
71a16736	500	if (dm_ratelimit()) \
0da336e5 AK	501	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
	502	f "\n", ## arg); \
	503	} while (0)
	504
	505	#define DMWARN(f, arg...) \
	506	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	507	#define DMWARN_LIMIT(f, arg...) \
	508	do { \
71a16736	509	if (dm_ratelimit()) \
0da336e5 AK	510	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
	511	f "\n", ## arg); \
	512	} while (0)
	513
	514	#define DMINFO(f, arg...) \
	515	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	516	#define DMINFO_LIMIT(f, arg...) \
	517	do { \
71a16736	518	if (dm_ratelimit()) \
0da336e5 AK	519	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
	520	"\n", ## arg); \
	521	} while (0)
	522
	523	#ifdef CONFIG_DM_DEBUG
	524	# define DMDEBUG(f, arg...) \
	525	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
	526	# define DMDEBUG_LIMIT(f, arg...) \
	527	do { \
71a16736	528	if (dm_ratelimit()) \
0da336e5 AK	529	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
	530	"\n", ## arg); \
	531	} while (0)
	532	#else
	533	# define DMDEBUG(f, arg...) do {} while (0)
	534	# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
	535	#endif
	536
	537	#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
	538	0 : scnprintf(result + sz, maxlen - sz, x))
	539
	540	#define SECTOR_SHIFT 9
	541
	542	/*
	543	* Definitions of return values from target end_io function.
	544	*/
	545	#define DM_ENDIO_INCOMPLETE 1
	546	#define DM_ENDIO_REQUEUE 2
	547
	548	/*
	549	* Definitions of return values from target map function.
	550	*/
	551	#define DM_MAPIO_SUBMITTED 0
	552	#define DM_MAPIO_REMAPPED 1
	553	#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
	554
fd2ed4d2 MP	555	#define dm_sector_div64(x, y)( \
	556	{ \
	557	u64 _res; \
	558	(x) = div64_u64_rem(x, y, &_res); \
	559	_res; \
	560	} \
	561	)
	562
0da336e5 AK	563	/*
	564	* Ceiling(n / sz)
	565	*/
	566	#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
	567
	568	#define dm_sector_div_up(n, sz) ( \
	569	{ \
	570	sector_t _r = ((n) + (sz) - 1); \
	571	sector_div(_r, (sz)); \
	572	_r; \
	573	} \
	574	)
	575
	576	/*
	577	* ceiling(n / size) * size
	578	*/
	579	#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
	580
d63a5ce3 MP	581	#define dm_array_too_big(fixed, obj, num) \
	582	((num) > (UINT_MAX - (fixed)) / (obj))
	583
56a67df7 MS	584	/*
	585	* Sector offset taken relative to the start of the target instead of
	586	* relative to the start of the device.
	587	*/
	588	#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
	589
0da336e5 AK	590	static inline sector_t to_sector(unsigned long n)
	591	{
	592	return (n >> SECTOR_SHIFT);
	593	}
	594
	595	static inline unsigned long to_bytes(sector_t n)
	596	{
	597	return (n << SECTOR_SHIFT);
	598	}
	599
cec47e3d KU	600	/*-----------------------------------------------------------------
	601	* Helper for block layer and dm core operations
	602	---------------------------------------------------------------/
	603	void dm_dispatch_request(struct request *rq);
	604	void dm_requeue_unmapped_request(struct request *rq);
	605	void dm_kill_unmapped_request(struct request *rq, int error);
	606	int dm_underlying_device_busy(struct request_queue *q);
	607
17b2f66f	608	#endif /* _LINUX_DEVICE_MAPPER_H */