drivers/md/dm-bio-record.h

   1 /*
   2  * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #ifndef DM_BIO_RECORD_H
   8 #define DM_BIO_RECORD_H
   9
  10 #include <linux/bio.h>
  11
  12 /*
  13  * There are lots of mutable fields in the bio struct that get
  14  * changed by the lower levels of the block layer.  Some targets,
  15  * such as multipath, may wish to resubmit a bio on error.  The
  16  * functions in this file help the target record and restore the
  17  * original bio state.
  18  */
  19
  20 struct dm_bio_vec_details {
  21 #if PAGE_SIZE < 65536
  22         __u16 bv_len;
  23         __u16 bv_offset;
  24 #else
  25         unsigned bv_len;
  26         unsigned bv_offset;
  27 #endif
  28 };
  29
  30 struct dm_bio_details {
  31         sector_t bi_sector;
  32         struct block_device *bi_bdev;
  33         unsigned int bi_size;
  34         unsigned short bi_idx;
  35         unsigned long bi_flags;
  36         struct dm_bio_vec_details bi_io_vec[BIO_MAX_PAGES];
  37 };
  38
  39 static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
  40 {
  41         unsigned i;
  42
  43         bd->bi_sector = bio->bi_sector;
  44         bd->bi_bdev = bio->bi_bdev;
  45         bd->bi_size = bio->bi_size;
  46         bd->bi_idx = bio->bi_idx;
  47         bd->bi_flags = bio->bi_flags;
  48
  49         for (i = 0; i < bio->bi_vcnt; i++) {
  50                 bd->bi_io_vec[i].bv_len = bio->bi_io_vec[i].bv_len;
  51                 bd->bi_io_vec[i].bv_offset = bio->bi_io_vec[i].bv_offset;
  52         }
  53 }
  54
  55 static inline void dm_bio_restore(struct dm_bio_details *bd, struct bio *bio)
  56 {
  57         unsigned i;
  58
  59         bio->bi_sector = bd->bi_sector;
  60         bio->bi_bdev = bd->bi_bdev;
  61         bio->bi_size = bd->bi_size;
  62         bio->bi_idx = bd->bi_idx;
  63         bio->bi_flags = bd->bi_flags;
  64
  65         for (i = 0; i < bio->bi_vcnt; i++) {
  66                 bio->bi_io_vec[i].bv_len = bd->bi_io_vec[i].bv_len;
  67                 bio->bi_io_vec[i].bv_offset = bd->bi_io_vec[i].bv_offset;
  68         }
  69 }
  70
  71 #endif