/* * 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> 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;	unsigned flush_request;}; /* * 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,			  union map_info *map_context);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,			    union map_info *map_context);typedef int (*dm_request_endio_fn) (struct dm_target *ti,				    struct request *clone, int error,				    union map_info *map_context); typedef void (*dm_flush_fn) (struct dm_target *ti);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,			     char *result, unsigned int 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. * FIXME: too many arguments. */int dm_get_device(struct dm_target *ti, const char *path, sector_t start,		  sector_t len, fmode_t mode, struct dm_dev **result);void dm_put_device(struct dm_target *ti, struct dm_dev *d); /* * Information about a target type */ /* * Target features */ 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_flush_fn flush;	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;}; struct dm_target {	struct dm_table *table;	struct target_type *type; 	/* target limits */	sector_t begin;	sector_t len; 	/* Always a power of 2 */	sector_t split_io; 	/*	 * A number of zero-length barrier requests that will be submitted	 * to the target for the purpose of flushing cache.	 *	 * The request number will be placed in union map_info->flush_request.	 * It is a responsibility of the target driver to remap these requests	 * to the real underlying devices.	 */	unsigned num_flush_requests; 	/* target specific data */	void *private; 	/* Used to provide an error string from the ctr */	char *error;}; int dm_register_target(struct target_type *t);void dm_unregister_target(struct target_type *t); /*----------------------------------------------------------------- * 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 mapped_device *md);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); /* * Finally call this to make the table ready for use. */int dm_table_complete(struct dm_table *t); /* * Unplug all devices in a table. */void dm_table_unplug_all(struct dm_table *t); /* * Table reference counting. */struct dm_table *dm_get_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. */int 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" #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 (printk_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 (printk_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 (printk_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 (printk_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)) 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 */