[deliverable/linux.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/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;
	unsigned long long ll;
};

/*
 * 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_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 int (*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);

typedef int (*iterate_devices_callout_fn) (struct dm_target *ti,
					   struct dm_dev *dev,
					   sector_t start, sector_t len,
					   void *data);

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);

/*
 * Combine device limits.
 */
int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
			 sector_t start, sector_t len, void *data);

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_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)

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 requests that will be submitted
	 * to the target for the purpose of flushing cache.
	 *
	 * The request number can be accessed with dm_bio_get_target_request_nr.
	 * It is a responsibility of the target driver to remap these requests
	 * to the real underlying devices.
	 */
	unsigned num_flush_requests;

	/*
	 * The number of discard requests that will be submitted to the target.
	 * The request number can be accessed with dm_bio_get_target_request_nr.
	 */
	unsigned num_discard_requests;

	/*
	 * The number of WRITE SAME requests that will be submitted to the target.
	 * The request number can be accessed with dm_bio_get_target_request_nr.
	 */
	unsigned num_write_same_requests;

	/*
	 * 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;

	/* 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 request to be split
	 * on max_io_len boundary.
	 */
	bool split_discard_requests: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;
	union map_info info;
	unsigned target_request_nr;
	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_request_nr(const struct bio *bio)
{
	return container_of(bio, struct dm_target_io, clone)->target_request_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);
union map_info *dm_get_mapinfo(struct bio *bio);
union map_info *dm_get_rq_mapinfo(struct request *rq);

/*
 * 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);
void dm_table_get(struct dm_table *t);
void dm_table_put(struct dm_table *t);

/*
 * 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);

/*
 * 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

/*
 * 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>
71a16736	13	#include <linux/ratelimit.h>
416cd17b	14
af4874e0	15	struct dm_dev;
1da177e4 LT	16	struct dm_target;
1da177e4 LT	17	struct dm_table;
17b2f66f	18	struct mapped_device;
f6fccb12	19	struct bio_vec;
1da177e4 LT	20
	21	typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
	22
	23	union map_info {
	24	void *ptr;
	25	unsigned long long ll;
	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
	66	typedef void (dm_presuspend_fn) (struct dm_target ti);
	67	typedef void (dm_postsuspend_fn) (struct dm_target ti);
8757b776	68	typedef int (dm_preresume_fn) (struct dm_target ti);
1da177e4 LT	69	typedef void (dm_resume_fn) (struct dm_target ti);
	70
	71	typedef int (dm_status_fn) (struct dm_target ti, status_type_t status_type,
1f4e0ff0	72	unsigned status_flags, char *result, unsigned maxlen);
1da177e4 LT	73
	74	typedef int (dm_message_fn) (struct dm_target ti, unsigned argc, char **argv);
	75
647b3d00	76	typedef int (dm_ioctl_fn) (struct dm_target ti, unsigned int cmd,
aa129a22 MB	77	unsigned long arg);
aa129a22 MB	78
f6fccb12 MB	79	typedef int (dm_merge_fn) (struct dm_target ti, struct bvec_merge_data *bvm,
	80	struct bio_vec *biovec, int max_size);
	81
af4874e0 MS	82	typedef int (iterate_devices_callout_fn) (struct dm_target ti,
af4874e0 MS	83	struct dm_dev *dev,
5dea271b	84	sector_t start, sector_t len,
af4874e0 MS	85	void *data);
	86
	87	typedef int (dm_iterate_devices_fn) (struct dm_target ti,
	88	iterate_devices_callout_fn fn,
	89	void *data);
	90
40bea431 MS	91	typedef void (dm_io_hints_fn) (struct dm_target ti,
	92	struct queue_limits *limits);
	93
7d76345d KU	94	/*
	95	* Returns:
	96	* 0: The target can handle the next I/O immediately.
	97	* 1: The target can't handle the next I/O immediately.
	98	*/
	99	typedef int (dm_busy_fn) (struct dm_target ti);
	100
1da177e4 LT	101	void dm_error(const char *message);
1da177e4 LT	102
3cb40214 BR	103	/*
	104	* Combine device limits.
	105	*/
754c5fc7	106	int dm_set_device_limits(struct dm_target ti, struct dm_dev dev,
5dea271b	107	sector_t start, sector_t len, void *data);
3cb40214	108
82b1519b MP	109	struct dm_dev {
82b1519b MP	110	struct block_device *bdev;
aeb5d727	111	fmode_t mode;
82b1519b MP	112	char name[16];
	113	};
	114
1da177e4 LT	115	/*
	116	* Constructors should call these functions to ensure destination devices
	117	* are opened/closed correctly.
1da177e4	118	*/
8215d6ec NK	119	int dm_get_device(struct dm_target ti, const char path, fmode_t mode,
8215d6ec NK	120	struct dm_dev **result);
1da177e4 LT	121	void dm_put_device(struct dm_target ti, struct dm_dev d);
	122
	123	/*
	124	* Information about a target type
	125	*/
ab4c1424	126
1da177e4	127	struct target_type {
ab4c1424	128	uint64_t features;
1da177e4 LT	129	const char *name;
1da177e4 LT	130	struct module *module;
17b2f66f	131	unsigned version[3];
1da177e4 LT	132	dm_ctr_fn ctr;
	133	dm_dtr_fn dtr;
	134	dm_map_fn map;
7d76345d	135	dm_map_request_fn map_rq;
1da177e4	136	dm_endio_fn end_io;
7d76345d	137	dm_request_endio_fn rq_end_io;
1da177e4 LT	138	dm_presuspend_fn presuspend;
1da177e4 LT	139	dm_postsuspend_fn postsuspend;
8757b776	140	dm_preresume_fn preresume;
1da177e4 LT	141	dm_resume_fn resume;
	142	dm_status_fn status;
	143	dm_message_fn message;
aa129a22	144	dm_ioctl_fn ioctl;
f6fccb12	145	dm_merge_fn merge;
7d76345d	146	dm_busy_fn busy;
af4874e0	147	dm_iterate_devices_fn iterate_devices;
40bea431	148	dm_io_hints_fn io_hints;
45194e4f CR	149
	150	/* For internal device-mapper use. */
	151	struct list_head list;
1da177e4 LT	152	};
1da177e4 LT	153
3791e2fc AK	154	/*
	155	* Target features
	156	*/
	157
	158	/*
	159	* Any table that contains an instance of this target must have only one.
	160	*/
	161	#define DM_TARGET_SINGLETON 0x00000001
	162	#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
	163
cc6cbe14 AK	164	/*
	165	* Indicates that a target does not support read-only devices.
	166	*/
	167	#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
	168	#define dm_target_always_writeable(type) \
	169	((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
	170
36a0456f AK	171	/*
	172	* Any device that contains a table with an instance of this target may never
	173	* have tables containing any different target type.
	174	*/
	175	#define DM_TARGET_IMMUTABLE 0x00000004
	176	#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
	177
1da177e4 LT	178	struct dm_target {
	179	struct dm_table *table;
	180	struct target_type *type;
	181
	182	/* target limits */
	183	sector_t begin;
	184	sector_t len;
	185
542f9038 MS	186	/* If non-zero, maximum size of I/O submitted to a target. */
542f9038 MS	187	uint32_t max_io_len;
1da177e4	188
f9ab94ce MP	189	/*
	190	* A number of zero-length barrier requests that will be submitted
	191	* to the target for the purpose of flushing cache.
	192	*
ddbd658f	193	* The request number can be accessed with dm_bio_get_target_request_nr.
f9ab94ce MP	194	* It is a responsibility of the target driver to remap these requests
	195	* to the real underlying devices.
	196	*/
	197	unsigned num_flush_requests;
	198
5ae89a87	199	/*
ddbd658f MP	200	* The number of discard requests that will be submitted to the target.
ddbd658f MP	201	* The request number can be accessed with dm_bio_get_target_request_nr.
5ae89a87 MS	202	*/
	203	unsigned num_discard_requests;
	204
d54eaa5a MS	205	/*
d54eaa5a MS	206	* The number of WRITE SAME requests that will be submitted to the target.
ddbd658f	207	* The request number can be accessed with dm_bio_get_target_request_nr.
d54eaa5a MS	208	*/
	209	unsigned num_write_same_requests;
	210
c0820cf5 MP	211	/*
	212	* The minimum number of extra bytes allocated in each bio for the
	213	* target to use. dm_per_bio_data returns the data location.
	214	*/
	215	unsigned per_bio_data_size;
	216
1da177e4 LT	217	/* target specific data */
	218	void *private;
	219
	220	/* Used to provide an error string from the ctr */
	221	char *error;
4c259327	222
0e9c24ed JT	223	/*
	224	* Set if this target needs to receive flushes regardless of
	225	* whether or not its underlying devices have support.
	226	*/
	227	bool flush_supported:1;
	228
4c259327 MS	229	/*
	230	* Set if this target needs to receive discards regardless of
	231	* whether or not its underlying devices have support.
	232	*/
0ac55489	233	bool discards_supported:1;
983c7db3	234
7acf0277 MP	235	/*
	236	* Set if the target required discard request to be split
	237	* on max_io_len boundary.
	238	*/
0ac55489	239	bool split_discard_requests:1;
7acf0277	240
983c7db3 MB	241	/*
	242	* Set if this target does not return zeroes on discarded blocks.
	243	*/
0ac55489	244	bool discard_zeroes_data_unsupported:1;
1da177e4 LT	245	};
1da177e4 LT	246
9d357b07 N	247	/* Each target can link one of these into the table */
	248	struct dm_target_callbacks {
	249	struct list_head list;
	250	int (congested_fn) (struct dm_target_callbacks , int);
	251	};
	252
c0820cf5 MP	253	/*
	254	* For bio-based dm.
	255	* One of these is allocated for each bio.
	256	* This structure shouldn't be touched directly by target drivers.
	257	* It is here so that we can inline dm_per_bio_data and
	258	* dm_bio_from_per_bio_data
	259	*/
	260	struct dm_target_io {
	261	struct dm_io *io;
	262	struct dm_target *ti;
	263	union map_info info;
ddbd658f	264	unsigned target_request_nr;
c0820cf5 MP	265	struct bio clone;
	266	};
	267
	268	static inline void dm_per_bio_data(struct bio bio, size_t data_size)
	269	{
	270	return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
	271	}
	272
	273	static inline struct bio dm_bio_from_per_bio_data(void data, size_t data_size)
	274	{
	275	return (struct bio )((char )data + data_size + offsetof(struct dm_target_io, clone));
	276	}
	277
ddbd658f MP	278	static inline unsigned dm_bio_get_target_request_nr(const struct bio *bio)
	279	{
	280	return container_of(bio, struct dm_target_io, clone)->target_request_nr;
	281	}
	282
1da177e4	283	int dm_register_target(struct target_type *t);
10d3bd09	284	void dm_unregister_target(struct target_type *t);
17b2f66f	285
498f0103 MS	286	/*
	287	* Target argument parsing.
	288	*/
	289	struct dm_arg_set {
	290	unsigned argc;
	291	char **argv;
	292	};
	293
	294	/*
	295	* The minimum and maximum value of a numeric argument, together with
	296	* the error message to use if the number is found to be outside that range.
	297	*/
	298	struct dm_arg {
	299	unsigned min;
	300	unsigned max;
	301	char *error;
	302	};
	303
	304	/*
	305	* Validate the next argument, either returning it as *value or, if invalid,
	306	* returning -EINVAL and setting *error.
	307	*/
	308	int dm_read_arg(struct dm_arg arg, struct dm_arg_set arg_set,
	309	unsigned value, char *error);
	310
	311	/*
	312	* Process the next argument as the start of a group containing between
	313	* arg->min and arg->max further arguments. Either return the size as
	314	* num_args or, if invalid, return -EINVAL and set error.
	315	*/
	316	int dm_read_arg_group(struct dm_arg arg, struct dm_arg_set arg_set,
	317	unsigned num_args, char *error);
	318
	319	/*
	320	* Return the current argument and shift to the next.
	321	*/
	322	const char dm_shift_arg(struct dm_arg_set as);
	323
	324	/*
	325	* Move through num_args arguments.
	326	*/
	327	void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
	328
17b2f66f AK	329	/*-----------------------------------------------------------------
	330	* Functions for creating and manipulating mapped devices.
	331	* Drop the reference with dm_put when you finish with the object.
	332	---------------------------------------------------------------/
	333
	334	/*
	335	* DM_ANY_MINOR chooses the next available minor number.
	336	*/
	337	#define DM_ANY_MINOR (-1)
	338	int dm_create(int minor, struct mapped_device **md);
	339
	340	/*
	341	* Reference counting for md.
	342	*/
	343	struct mapped_device *dm_get_md(dev_t dev);
	344	void dm_get(struct mapped_device *md);
	345	void dm_put(struct mapped_device *md);
	346
	347	/*
	348	* An arbitrary pointer may be stored alongside a mapped device.
	349	*/
	350	void dm_set_mdptr(struct mapped_device md, void ptr);
	351	void dm_get_mdptr(struct mapped_device md);
	352
	353	/*
	354	* A device can still be used while suspended, but I/O is deferred.
	355	*/
a3d77d35	356	int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
17b2f66f AK	357	int dm_resume(struct mapped_device *md);
	358
	359	/*
	360	* Event functions.
	361	*/
	362	uint32_t dm_get_event_nr(struct mapped_device *md);
	363	int dm_wait_event(struct mapped_device *md, int event_nr);
7a8c3d3b MA	364	uint32_t dm_next_uevent_seq(struct mapped_device *md);
7a8c3d3b MA	365	void dm_uevent_add(struct mapped_device md, struct list_head elist);
17b2f66f AK	366
	367	/*
	368	* Info functions.
	369	*/
72d94861	370	const char dm_device_name(struct mapped_device md);
96a1f7db	371	int dm_copy_name_and_uuid(struct mapped_device md, char name, char *uuid);
17b2f66f	372	struct gendisk dm_disk(struct mapped_device md);
64dbce58	373	int dm_suspended(struct dm_target *ti);
2e93ccc1	374	int dm_noflush_suspending(struct dm_target *ti);
89343da0	375	union map_info dm_get_mapinfo(struct bio bio);
cec47e3d	376	union map_info dm_get_rq_mapinfo(struct request rq);
17b2f66f AK	377
	378	/*
	379	* Geometry functions.
	380	*/
	381	int dm_get_geometry(struct mapped_device md, struct hd_geometry geo);
	382	int dm_set_geometry(struct mapped_device md, struct hd_geometry geo);
	383
	384
	385	/*-----------------------------------------------------------------
	386	* Functions for manipulating device-mapper tables.
	387	---------------------------------------------------------------/
	388
	389	/*
	390	* First create an empty table.
	391	*/
aeb5d727	392	int dm_table_create(struct dm_table **result, fmode_t mode,
17b2f66f AK	393	unsigned num_targets, struct mapped_device *md);
	394
	395	/*
	396	* Then call this once for each target.
	397	*/
	398	int dm_table_add_target(struct dm_table t, const char type,
	399	sector_t start, sector_t len, char *params);
	400
9d357b07 N	401	/*
	402	* Target_ctr should call this if it needs to add any callbacks.
	403	*/
	404	void dm_table_add_target_callbacks(struct dm_table t, struct dm_target_callbacks cb);
	405
17b2f66f AK	406	/*
	407	* Finally call this to make the table ready for use.
	408	*/
	409	int dm_table_complete(struct dm_table *t);
	410
542f9038 MS	411	/*
	412	* Target may require that it is never sent I/O larger than len.
	413	*/
	414	int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
	415
17b2f66f AK	416	/*
	417	* Table reference counting.
	418	*/
7c666411	419	struct dm_table dm_get_live_table(struct mapped_device md);
17b2f66f AK	420	void dm_table_get(struct dm_table *t);
	421	void dm_table_put(struct dm_table *t);
	422
	423	/*
	424	* Queries
	425	*/
	426	sector_t dm_table_get_size(struct dm_table *t);
	427	unsigned int dm_table_get_num_targets(struct dm_table *t);
aeb5d727	428	fmode_t dm_table_get_mode(struct dm_table *t);
17b2f66f AK	429	struct mapped_device dm_table_get_md(struct dm_table t);
	430
	431	/*
	432	* Trigger an event.
	433	*/
	434	void dm_table_event(struct dm_table *t);
	435
	436	/*
	437	* The device must be suspended before calling this method.
042d2a9b	438	* Returns the previous table, which the caller must destroy.
17b2f66f	439	*/
042d2a9b AK	440	struct dm_table dm_swap_table(struct mapped_device md,
042d2a9b AK	441	struct dm_table *t);
17b2f66f	442
54160904 MP	443	/*
	444	* A wrapper around vmalloc.
	445	*/
	446	void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size);
	447
0da336e5 AK	448	/*-----------------------------------------------------------------
	449	* Macros.
	450	---------------------------------------------------------------/
	451	#define DM_NAME "device-mapper"
	452
71a16736 NK	453	#ifdef CONFIG_PRINTK
	454	extern struct ratelimit_state dm_ratelimit_state;
	455
	456	#define dm_ratelimit() __ratelimit(&dm_ratelimit_state)
	457	#else
	458	#define dm_ratelimit() 0
	459	#endif
	460
10d3bd09 MP	461	#define DMCRIT(f, arg...) \
	462	printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	463
0da336e5 AK	464	#define DMERR(f, arg...) \
	465	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	466	#define DMERR_LIMIT(f, arg...) \
	467	do { \
71a16736	468	if (dm_ratelimit()) \
0da336e5 AK	469	printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " \
	470	f "\n", ## arg); \
	471	} while (0)
	472
	473	#define DMWARN(f, arg...) \
	474	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	475	#define DMWARN_LIMIT(f, arg...) \
	476	do { \
71a16736	477	if (dm_ratelimit()) \
0da336e5 AK	478	printk(KERN_WARNING DM_NAME ": " DM_MSG_PREFIX ": " \
	479	f "\n", ## arg); \
	480	} while (0)
	481
	482	#define DMINFO(f, arg...) \
	483	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg)
	484	#define DMINFO_LIMIT(f, arg...) \
	485	do { \
71a16736	486	if (dm_ratelimit()) \
0da336e5 AK	487	printk(KERN_INFO DM_NAME ": " DM_MSG_PREFIX ": " f \
	488	"\n", ## arg); \
	489	} while (0)
	490
	491	#ifdef CONFIG_DM_DEBUG
	492	# define DMDEBUG(f, arg...) \
	493	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX " DEBUG: " f "\n", ## arg)
	494	# define DMDEBUG_LIMIT(f, arg...) \
	495	do { \
71a16736	496	if (dm_ratelimit()) \
0da336e5 AK	497	printk(KERN_DEBUG DM_NAME ": " DM_MSG_PREFIX ": " f \
	498	"\n", ## arg); \
	499	} while (0)
	500	#else
	501	# define DMDEBUG(f, arg...) do {} while (0)
	502	# define DMDEBUG_LIMIT(f, arg...) do {} while (0)
	503	#endif
	504
	505	#define DMEMIT(x...) sz += ((sz >= maxlen) ? \
	506	0 : scnprintf(result + sz, maxlen - sz, x))
	507
	508	#define SECTOR_SHIFT 9
	509
	510	/*
	511	* Definitions of return values from target end_io function.
	512	*/
	513	#define DM_ENDIO_INCOMPLETE 1
	514	#define DM_ENDIO_REQUEUE 2
	515
	516	/*
	517	* Definitions of return values from target map function.
	518	*/
	519	#define DM_MAPIO_SUBMITTED 0
	520	#define DM_MAPIO_REMAPPED 1
	521	#define DM_MAPIO_REQUEUE DM_ENDIO_REQUEUE
	522
	523	/*
	524	* Ceiling(n / sz)
	525	*/
	526	#define dm_div_up(n, sz) (((n) + (sz) - 1) / (sz))
	527
	528	#define dm_sector_div_up(n, sz) ( \
	529	{ \
	530	sector_t _r = ((n) + (sz) - 1); \
	531	sector_div(_r, (sz)); \
	532	_r; \
	533	} \
	534	)
	535
	536	/*
	537	* ceiling(n / size) * size
	538	*/
	539	#define dm_round_up(n, sz) (dm_div_up((n), (sz)) * (sz))
	540
d63a5ce3 MP	541	#define dm_array_too_big(fixed, obj, num) \
	542	((num) > (UINT_MAX - (fixed)) / (obj))
	543
56a67df7 MS	544	/*
	545	* Sector offset taken relative to the start of the target instead of
	546	* relative to the start of the device.
	547	*/
	548	#define dm_target_offset(ti, sector) ((sector) - (ti)->begin)
	549
0da336e5 AK	550	static inline sector_t to_sector(unsigned long n)
	551	{
	552	return (n >> SECTOR_SHIFT);
	553	}
	554
	555	static inline unsigned long to_bytes(sector_t n)
	556	{
	557	return (n << SECTOR_SHIFT);
	558	}
	559
cec47e3d KU	560	/*-----------------------------------------------------------------
	561	* Helper for block layer and dm core operations
	562	---------------------------------------------------------------/
	563	void dm_dispatch_request(struct request *rq);
	564	void dm_requeue_unmapped_request(struct request *rq);
	565	void dm_kill_unmapped_request(struct request *rq, int error);
	566	int dm_underlying_device_busy(struct request_queue *q);
	567
17b2f66f	568	#endif /* _LINUX_DEVICE_MAPPER_H */