[mirror_ubuntu-artful-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;
	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 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);

/*
 * 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)

/*
 * 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;
	union map_info info;
	unsigned target_bio_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_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);
union map_info *dm_get_mapinfo(struct bio *bio);
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);

/*
 * 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;
	26	unsigned long long ll;
	27	};
	28
	29	/*
	30	* In the constructor the target parameter will already have the
	31	* table, type, begin and len fields filled in.
	32	*/
	33	typedef int (dm_ctr_fn) (struct dm_target target,
	34	unsigned int argc, char **argv);
	35
	36	/*
	37	* The destructor doesn't need to free the dm_target, just
	38	* anything hidden ti->private.
	39	*/
	40	typedef void (dm_dtr_fn) (struct dm_target ti);
	41
	42	/*
	43	* The map function must return:
	44	* < 0: error
	45	* = 0: The target will handle the io by resubmitting it later
45cbcd79	46	* = 1: simple remap complete
2e93ccc1	47	* = 2: The target wants to push back the io
1da177e4	48	*/
7de3ee57	49	typedef int (dm_map_fn) (struct dm_target ti, struct bio *bio);
7d76345d KU	50	typedef int (dm_map_request_fn) (struct dm_target ti, struct request *clone,
7d76345d KU	51	union map_info *map_context);
1da177e4 LT	52
	53	/*
	54	* Returns:
	55	* < 0 : error (currently ignored)
	56	* 0 : ended successfully
	57	* 1 : for some reason the io has still not completed (eg,
	58	* multipath target might want to requeue a failed io).
2e93ccc1	59	* 2 : The target wants to push back the io
1da177e4 LT	60	*/
1da177e4 LT	61	typedef int (dm_endio_fn) (struct dm_target ti,
7de3ee57	62	struct bio *bio, int error);
7d76345d KU	63	typedef int (dm_request_endio_fn) (struct dm_target ti,
	64	struct request *clone, int error,
	65	union map_info *map_context);
1da177e4 LT	66
	67	typedef void (dm_presuspend_fn) (struct dm_target ti);
	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
3cb40214 BR	119	/*
	120	* Combine device limits.
	121	*/
754c5fc7	122	int dm_set_device_limits(struct dm_target ti, struct dm_dev dev,
5dea271b	123	sector_t start, sector_t len, void *data);
3cb40214	124
82b1519b MP	125	struct dm_dev {
82b1519b MP	126	struct block_device *bdev;
aeb5d727	127	fmode_t mode;
82b1519b MP	128	char name[16];
	129	};
	130
1da177e4 LT	131	/*
	132	* Constructors should call these functions to ensure destination devices
	133	* are opened/closed correctly.
1da177e4	134	*/
8215d6ec NK	135	int dm_get_device(struct dm_target ti, const char path, fmode_t mode,
8215d6ec NK	136	struct dm_dev **result);
1da177e4 LT	137	void dm_put_device(struct dm_target ti, struct dm_dev d);
	138
	139	/*
	140	* Information about a target type
	141	*/
ab4c1424	142
1da177e4	143	struct target_type {
ab4c1424	144	uint64_t features;
1da177e4 LT	145	const char *name;
1da177e4 LT	146	struct module *module;
17b2f66f	147	unsigned version[3];
1da177e4 LT	148	dm_ctr_fn ctr;
	149	dm_dtr_fn dtr;
	150	dm_map_fn map;
7d76345d	151	dm_map_request_fn map_rq;
1da177e4	152	dm_endio_fn end_io;
7d76345d	153	dm_request_endio_fn rq_end_io;
1da177e4 LT	154	dm_presuspend_fn presuspend;
1da177e4 LT	155	dm_postsuspend_fn postsuspend;
8757b776	156	dm_preresume_fn preresume;
1da177e4 LT	157	dm_resume_fn resume;
	158	dm_status_fn status;
	159	dm_message_fn message;
aa129a22	160	dm_ioctl_fn ioctl;
f6fccb12	161	dm_merge_fn merge;
7d76345d	162	dm_busy_fn busy;
af4874e0	163	dm_iterate_devices_fn iterate_devices;
40bea431	164	dm_io_hints_fn io_hints;
45194e4f CR	165
	166	/* For internal device-mapper use. */
	167	struct list_head list;
1da177e4 LT	168	};
1da177e4 LT	169
3791e2fc AK	170	/*
	171	* Target features
	172	*/
	173
	174	/*
	175	* Any table that contains an instance of this target must have only one.
	176	*/
	177	#define DM_TARGET_SINGLETON 0x00000001
	178	#define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON)
	179
cc6cbe14 AK	180	/*
	181	* Indicates that a target does not support read-only devices.
	182	*/
	183	#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002
	184	#define dm_target_always_writeable(type) \
	185	((type)->features & DM_TARGET_ALWAYS_WRITEABLE)
	186
36a0456f AK	187	/*
	188	* Any device that contains a table with an instance of this target may never
	189	* have tables containing any different target type.
	190	*/
	191	#define DM_TARGET_IMMUTABLE 0x00000004
	192	#define dm_target_is_immutable(type) ((type)->features & DM_TARGET_IMMUTABLE)
	193
b0d8ed4d AK	194	/*
	195	* Some targets need to be sent the same WRITE bio severals times so
	196	* that they can send copies of it to different devices. This function
	197	* examines any supplied bio and returns the number of copies of it the
	198	* target requires.
	199	*/
	200	typedef unsigned (dm_num_write_bios_fn) (struct dm_target ti, struct bio *bio);
	201
1da177e4 LT	202	struct dm_target {
	203	struct dm_table *table;
	204	struct target_type *type;
	205
	206	/* target limits */
	207	sector_t begin;
	208	sector_t len;
	209
542f9038 MS	210	/* If non-zero, maximum size of I/O submitted to a target. */
542f9038 MS	211	uint32_t max_io_len;
1da177e4	212
f9ab94ce	213	/*
55a62eef	214	* A number of zero-length barrier bios that will be submitted
f9ab94ce MP	215	* to the target for the purpose of flushing cache.
f9ab94ce MP	216	*
55a62eef AK	217	* The bio number can be accessed with dm_bio_get_target_bio_nr.
55a62eef AK	218	* It is a responsibility of the target driver to remap these bios
f9ab94ce MP	219	* to the real underlying devices.
f9ab94ce MP	220	*/
55a62eef	221	unsigned num_flush_bios;
f9ab94ce	222
5ae89a87	223	/*
55a62eef AK	224	* The number of discard bios that will be submitted to the target.
55a62eef AK	225	* The bio number can be accessed with dm_bio_get_target_bio_nr.
5ae89a87	226	*/
55a62eef	227	unsigned num_discard_bios;
5ae89a87	228
d54eaa5a	229	/*
55a62eef AK	230	* The number of WRITE SAME bios that will be submitted to the target.
55a62eef AK	231	* The bio number can be accessed with dm_bio_get_target_bio_nr.
d54eaa5a	232	*/
55a62eef	233	unsigned num_write_same_bios;
d54eaa5a	234
c0820cf5 MP	235	/*
	236	* The minimum number of extra bytes allocated in each bio for the
	237	* target to use. dm_per_bio_data returns the data location.
	238	*/
	239	unsigned per_bio_data_size;
	240
b0d8ed4d AK	241	/*
	242	* If defined, this function is called to find out how many
	243	* duplicate bios should be sent to the target when writing
	244	* data.
	245	*/
	246	dm_num_write_bios_fn num_write_bios;
	247
1da177e4 LT	248	/* target specific data */
	249	void *private;
	250
	251	/* Used to provide an error string from the ctr */
	252	char *error;
4c259327	253
0e9c24ed JT	254	/*
	255	* Set if this target needs to receive flushes regardless of
	256	* whether or not its underlying devices have support.
	257	*/
	258	bool flush_supported:1;
	259
4c259327 MS	260	/*
	261	* Set if this target needs to receive discards regardless of
	262	* whether or not its underlying devices have support.
	263	*/
0ac55489	264	bool discards_supported:1;
983c7db3	265
7acf0277	266	/*
55a62eef	267	* Set if the target required discard bios to be split
7acf0277 MP	268	* on max_io_len boundary.
7acf0277 MP	269	*/
55a62eef	270	bool split_discard_bios:1;
7acf0277	271
983c7db3 MB	272	/*
	273	* Set if this target does not return zeroes on discarded blocks.
	274	*/
0ac55489	275	bool discard_zeroes_data_unsupported:1;
1da177e4 LT	276	};
1da177e4 LT	277
9d357b07 N	278	/* Each target can link one of these into the table */
	279	struct dm_target_callbacks {
	280	struct list_head list;
	281	int (congested_fn) (struct dm_target_callbacks , int);
	282	};
	283
c0820cf5 MP	284	/*
	285	* For bio-based dm.
	286	* One of these is allocated for each bio.
	287	* This structure shouldn't be touched directly by target drivers.
	288	* It is here so that we can inline dm_per_bio_data and
	289	* dm_bio_from_per_bio_data
	290	*/
	291	struct dm_target_io {
	292	struct dm_io *io;
	293	struct dm_target *ti;
	294	union map_info info;
55a62eef	295	unsigned target_bio_nr;
c0820cf5 MP	296	struct bio clone;
	297	};
	298
	299	static inline void dm_per_bio_data(struct bio bio, size_t data_size)
	300	{
	301	return (char *)bio - offsetof(struct dm_target_io, clone) - data_size;
	302	}
	303
	304	static inline struct bio dm_bio_from_per_bio_data(void data, size_t data_size)
	305	{
	306	return (struct bio )((char )data + data_size + offsetof(struct dm_target_io, clone));
	307	}
	308
55a62eef	309	static inline unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
ddbd658f	310	{
55a62eef	311	return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
ddbd658f MP	312	}
ddbd658f MP	313
1da177e4	314	int dm_register_target(struct target_type *t);
10d3bd09	315	void dm_unregister_target(struct target_type *t);
17b2f66f	316
498f0103 MS	317	/*
	318	* Target argument parsing.
	319	*/
	320	struct dm_arg_set {
	321	unsigned argc;
	322	char **argv;
	323	};
	324
	325	/*
	326	* The minimum and maximum value of a numeric argument, together with
	327	* the error message to use if the number is found to be outside that range.
	328	*/
	329	struct dm_arg {
	330	unsigned min;
	331	unsigned max;
	332	char *error;
	333	};
	334
	335	/*
	336	* Validate the next argument, either returning it as *value or, if invalid,
	337	* returning -EINVAL and setting *error.
	338	*/
	339	int dm_read_arg(struct dm_arg arg, struct dm_arg_set arg_set,
	340	unsigned value, char *error);
	341
	342	/*
	343	* Process the next argument as the start of a group containing between
	344	* arg->min and arg->max further arguments. Either return the size as
	345	* num_args or, if invalid, return -EINVAL and set error.
	346	*/
	347	int dm_read_arg_group(struct dm_arg arg, struct dm_arg_set arg_set,
	348	unsigned num_args, char *error);
	349
	350	/*
	351	* Return the current argument and shift to the next.
	352	*/
	353	const char dm_shift_arg(struct dm_arg_set as);
	354
	355	/*
	356	* Move through num_args arguments.
	357	*/
	358	void dm_consume_args(struct dm_arg_set *as, unsigned num_args);
	359
17b2f66f AK	360	/*-----------------------------------------------------------------
	361	* Functions for creating and manipulating mapped devices.
	362	* Drop the reference with dm_put when you finish with the object.
	363	---------------------------------------------------------------/
	364
	365	/*
	366	* DM_ANY_MINOR chooses the next available minor number.
	367	*/
	368	#define DM_ANY_MINOR (-1)
	369	int dm_create(int minor, struct mapped_device **md);
	370
	371	/*
	372	* Reference counting for md.
	373	*/
	374	struct mapped_device *dm_get_md(dev_t dev);
	375	void dm_get(struct mapped_device *md);
	376	void dm_put(struct mapped_device *md);
	377
	378	/*
	379	* An arbitrary pointer may be stored alongside a mapped device.
	380	*/
	381	void dm_set_mdptr(struct mapped_device md, void ptr);
	382	void dm_get_mdptr(struct mapped_device md);
	383
	384	/*
	385	* A device can still be used while suspended, but I/O is deferred.
	386	*/
a3d77d35	387	int dm_suspend(struct mapped_device *md, unsigned suspend_flags);
17b2f66f AK	388	int dm_resume(struct mapped_device *md);
	389
	390	/*
	391	* Event functions.
	392	*/
	393	uint32_t dm_get_event_nr(struct mapped_device *md);
	394	int dm_wait_event(struct mapped_device *md, int event_nr);
7a8c3d3b MA	395	uint32_t dm_next_uevent_seq(struct mapped_device *md);
7a8c3d3b MA	396	void dm_uevent_add(struct mapped_device md, struct list_head elist);
17b2f66f AK	397
	398	/*
	399	* Info functions.
	400	*/
72d94861	401	const char dm_device_name(struct mapped_device md);
96a1f7db	402	int dm_copy_name_and_uuid(struct mapped_device md, char name, char *uuid);
17b2f66f	403	struct gendisk dm_disk(struct mapped_device md);
64dbce58	404	int dm_suspended(struct dm_target *ti);
2e93ccc1	405	int dm_noflush_suspending(struct dm_target *ti);
89343da0	406	union map_info dm_get_mapinfo(struct bio bio);
cec47e3d	407	union map_info dm_get_rq_mapinfo(struct request rq);
17b2f66f	408
f84cb8a4 MS	409	struct queue_limits dm_get_queue_limits(struct mapped_device md);
f84cb8a4 MS	410
17b2f66f AK	411	/*
	412	* Geometry functions.
	413	*/
	414	int dm_get_geometry(struct mapped_device md, struct hd_geometry geo);
	415	int dm_set_geometry(struct mapped_device md, struct hd_geometry geo);
	416
17b2f66f AK	417	/*-----------------------------------------------------------------
	418	* Functions for manipulating device-mapper tables.
	419	---------------------------------------------------------------/
	420
	421	/*
	422	* First create an empty table.
	423	*/
aeb5d727	424	int dm_table_create(struct dm_table **result, fmode_t mode,
17b2f66f AK	425	unsigned num_targets, struct mapped_device *md);
	426
	427	/*
	428	* Then call this once for each target.
	429	*/
	430	int dm_table_add_target(struct dm_table t, const char type,
	431	sector_t start, sector_t len, char *params);
	432
9d357b07 N	433	/*
	434	* Target_ctr should call this if it needs to add any callbacks.
	435	*/
	436	void dm_table_add_target_callbacks(struct dm_table t, struct dm_target_callbacks cb);
	437
17b2f66f AK	438	/*
	439	* Finally call this to make the table ready for use.
	440	*/
	441	int dm_table_complete(struct dm_table *t);
	442
542f9038 MS	443	/*
	444	* Target may require that it is never sent I/O larger than len.
	445	*/
	446	int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
	447
17b2f66f AK	448	/*
	449	* Table reference counting.
	450	*/
83d5e5b0 MP	451	struct dm_table dm_get_live_table(struct mapped_device md, int *srcu_idx);
	452	void dm_put_live_table(struct mapped_device *md, int srcu_idx);
	453	void dm_sync_table(struct mapped_device *md);
17b2f66f AK	454
	455	/*
	456	* Queries
	457	*/
	458	sector_t dm_table_get_size(struct dm_table *t);
	459	unsigned int dm_table_get_num_targets(struct dm_table *t);
aeb5d727	460	fmode_t dm_table_get_mode(struct dm_table *t);
17b2f66f AK	461	struct mapped_device dm_table_get_md(struct dm_table t);
	462
	463	/*
	464	* Trigger an event.
	465	*/
	466	void dm_table_event(struct dm_table *t);
	467
	468	/*
	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 */