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/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
*
* This file is released under the LGPL.
*/
#ifndef _LINUX_DEVICE_MAPPER_H
#define _LINUX_DEVICE_MAPPER_H
struct dm_target;
struct dm_table;
struct dm_dev;
typedef enum { STATUSTYPE_INFO, STATUSTYPE_TABLE } status_type_t;
/*
* 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
* > 0: simple remap complete
*/
typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio);
typedef void (*dm_suspend_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);
void dm_error(const char *message);
/*
* 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;
dm_ctr_fn ctr;
dm_dtr_fn dtr;
dm_map_fn map;
dm_suspend_fn suspend;
dm_resume_fn resume;
dm_status_fn status;
};
struct io_restrictions {
unsigned short max_sectors;
unsigned short max_phys_segments;
unsigned short max_hw_segments;
unsigned short hardsect_size;
unsigned int max_segment_size;
unsigned long seg_boundary_mask;
};
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 */
sector_t split_io;
/*
* These are automaticall 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);
#endif /* _LINUX_DEVICE_MAPPER_H */
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