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* Copyright (C) 2001 Sistina Software (UK) Limited.
* Copyright (C) 2004 Red Hat, Inc. All rights reserved.
* This file is released under the LGPL.
#ifdef __KERNEL__
struct dm_target;
struct dm_table;
struct dm_dev;
struct mapped_device;
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,
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 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, struct inode *inode,
struct file *filp, unsigned int cmd,
unsigned long arg);
void dm_error(const char *message);
* Combine device limits.
void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
* 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, int 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 {
const char *name;
struct module *module;
unsigned version[3];
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
dm_endio_fn 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;
struct io_restrictions {
unsigned int max_sectors;
unsigned short max_phys_segments;
unsigned short max_hw_segments;
unsigned short hardsect_size;
unsigned int max_segment_size;
unsigned int max_hw_sectors;
unsigned long seg_boundary_mask;
unsigned long bounce_pfn;
unsigned char no_cluster; /* inverted so that 0 is default */
struct dm_target {
struct dm_table *table;
struct target_type *type;
/* target limits */
sector_t begin;
sector_t len;
/* FIXME: turn this into a mask, and merge with io_restrictions */
/* Always a power of 2 */
sector_t split_io;
* These are automatically filled in by
* dm_table_get_device.
struct io_restrictions limits;
/* target specific data */
void *private;
/* Used to provide an error string from the ctr */
char *error;
int dm_register_target(struct target_type *t);
int 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);
* 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, int 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);
* 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);
int 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);
* Prepare a table for a device that will error all I/O.
* To make it active, call dm_suspend(), dm_swap_table() then dm_resume().
int dm_create_error_table(struct dm_table **result, struct mapped_device *md);
#endif /* __KERNEL__ */