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#ifndef _MULTIPATH_H

#define _MULTIPATH_H

#include <linux/raid/md.h>

struct multipath_info {

        int             number;

        int             raid_disk;

        kdev_t          dev;

        /*

         * State bits:

         */

        int             operational;

        int             spare;

        int             used_slot;

};

struct multipath_private_data {

        mddev_t                 *mddev;

        struct multipath_info   multipaths[MD_SB_DISKS];

        int                     nr_disks;

        int                     raid_disks;

        int                     working_disks;

        mdk_thread_t            *thread;

        struct multipath_info   *spare;

        md_spinlock_t           device_lock;

        /* buffer pool */

        /* buffer_heads that we have pre-allocated have b_pprev -> &freebh

         * and are linked into a stack using b_next

         * multipath_bh that are pre-allocated have MPBH_PreAlloc set.

         * All these variable are protected by device_lock

         */

        struct multipath_bh     *freer1;

        int                     freer1_blocked;

        int                     freer1_cnt;

        md_wait_queue_head_t    wait_buffer;

};

typedef struct multipath_private_data multipath_conf_t;

/*

 * this is the only point in the RAID code where we violate

 * C type safety. mddev->private is an 'opaque' pointer.

 */

#define mddev_to_conf(mddev) ((multipath_conf_t *) mddev->private)

/*

 * this is our 'private' 'collective' MULTIPATH buffer head.

 * it contains information about what kind of IO operations were started

 * for this MULTIPATH operation, and about their status:

 */

struct multipath_bh {

        atomic_t                remaining; /* 'have we finished' count,

                                            * used from IRQ handlers

                                            */

        int                     cmd;

        unsigned long           state;

        mddev_t                 *mddev;

        struct buffer_head      *master_bh;

        struct buffer_head      bh_req;

        struct multipath_bh     *next_mp; /* next for retry or in free list */

};

/* bits for multipath_bh.state */

#define MPBH_Uptodate   1

#define MPBH_SyncPhase  2

#define MPBH_PreAlloc   3       /* this was pre-allocated, add to free list */

#endif