dm-bio-record.h

Go to the documentation of this file.

/*
 * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the GPL.
 */

#ifndef DM_BIO_RECORD_H
#define DM_BIO_RECORD_H

#include <linux/bio.h>

/*
 * There are lots of mutable fields in the bio struct that get
 * changed by the lower levels of the block layer.  Some targets,
 * such as multipath, may wish to resubmit a bio on error.  The
 * functions in this file help the target record and restore the
 * original bio state.
 */

struct dm_bio_vec_details {
#if PAGE_SIZE < 65536
    __u16 bv_len;
    __u16 bv_offset;
#else
    unsigned bv_len;
    unsigned bv_offset;
#endif
};

struct dm_bio_details {
    sector_t bi_sector;
    struct block_device *bi_bdev;
    unsigned int bi_size;
    unsigned short bi_idx;
    unsigned long bi_flags;
    struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES];
};

static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
{
    unsigned i;

    bd->bi_sector = bio->bi_sector;
    bd->bi_bdev = bio->bi_bdev;
    bd->bi_size = bio->bi_size;
    bd->bi_idx = bio->bi_idx;
    bd->bi_flags = bio->bi_flags;

    for (i = 0; i < bio->bi_vcnt; i++) {
        bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len;
        bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset;
    }
}

static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio)
{
    unsigned i;

    bio->bi_sector = bd->bi_sector;
    bio->bi_bdev = bd->bi_bdev;
    bio->bi_size = bd->bi_size;
    bio->bi_idx = bd->bi_idx;
    bio->bi_flags = bd->bi_flags;

    for (i = 0; i < bio->bi_vcnt; i++) {
        bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len;
        bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset;
    }
}

#endif