source: svn/trunk/newcon3bcm2_21bu/toolchain/mips-linux-uclibc/include/linux/device-mapper.h

/*
 * Copyright (C) 2001 Sistina Software (UK) Limited.
 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
 *
 * 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;

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
 * > 0: simple remap complete
 */
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).
 */
typedef int (*dm_endio_fn) (struct dm_target *ti,
                            struct bio *bio, 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 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);

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;
        unsigned version[3];
        dm_ctr_fn ctr;
        dm_dtr_fn dtr;
        dm_map_fn map;
        dm_endio_fn end_io;
        dm_presuspend_fn presuspend;
        dm_postsuspend_fn postsuspend;
        dm_resume_fn resume;
        dm_status_fn status;
        dm_message_fn message;
};

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 */
        /* 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);

#endif                          /* _LINUX_DEVICE_MAPPER_H */