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| author | Martin K. Petersen <martin.petersen@oracle.com> | 2008-10-01 22:42:53 -0400 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:22 +0200 |
| commit | ad3316bf4eeb53c89164f759767f911072b56203 (patch) | |
| tree | 12caa0194f385c58e4543ad864a58dff02f33a47 | |
| parent | b02739b01c5309d74a59859f2ce92c931d1f1955 (diff) | |
| download | linux-ad3316bf4eeb53c89164f759767f911072b56203.tar.bz2 | |
block: Find bio sector offset given idx and offset
Helper function to find the sector offset in a bio given bvec index
and page offset.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
| -rw-r--r-- | fs/bio.c | 36 | ||||
| -rw-r--r-- | include/linux/bio.h | 1 |
2 files changed, 37 insertions, 0 deletions
@@ -1300,6 +1300,42 @@ struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors) return bp; } +/** + * bio_sector_offset - Find hardware sector offset in bio + * @bio: bio to inspect + * @index: bio_vec index + * @offset: offset in bv_page + * + * Return the number of hardware sectors between beginning of bio + * and an end point indicated by a bio_vec index and an offset + * within that vector's page. + */ +sector_t bio_sector_offset(struct bio *bio, unsigned short index, + unsigned int offset) +{ + unsigned int sector_sz = queue_hardsect_size(bio->bi_bdev->bd_disk->queue); + struct bio_vec *bv; + sector_t sectors; + int i; + + sectors = 0; + + if (index >= bio->bi_idx) + index = bio->bi_vcnt - 1; + + __bio_for_each_segment(bv, bio, i, 0) { + if (i == index) { + if (offset > bv->bv_offset) + sectors += (offset - bv->bv_offset) / sector_sz; + break; + } + + sectors += bv->bv_len / sector_sz; + } + + return sectors; +} +EXPORT_SYMBOL(bio_sector_offset); /* * create memory pools for biovec's in a bio_set. diff --git a/include/linux/bio.h b/include/linux/bio.h index d86d39d490e6..fe12d0f9ebaa 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -327,6 +327,7 @@ extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, unsigned int, unsigned int); extern int bio_get_nr_vecs(struct block_device *); +extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int); extern struct bio *bio_map_user(struct request_queue *, struct block_device *, unsigned long, unsigned int, int, gfp_t); struct sg_iovec; |