xref: /linux/drivers/md/dm-bio-record.h (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
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
72