diff options
| -rw-r--r-- | block/blk-merge.c | 37 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 2 |
2 files changed, 39 insertions, 0 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index 576b68e79248..e76279e41162 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -209,6 +209,43 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq, } EXPORT_SYMBOL(blk_rq_map_sg); +/** + * blk_bio_map_sg - map a bio to a scatterlist + * @q: request_queue in question + * @bio: bio being mapped + * @sglist: scatterlist being mapped + * + * Note: + * Caller must make sure sg can hold bio->bi_phys_segments entries + * + * Will return the number of sg entries setup + */ +int blk_bio_map_sg(struct request_queue *q, struct bio *bio, + struct scatterlist *sglist) +{ + struct bio_vec *bvec, *bvprv; + struct scatterlist *sg; + int nsegs, cluster; + unsigned long i; + + nsegs = 0; + cluster = blk_queue_cluster(q); + + bvprv = NULL; + sg = NULL; + bio_for_each_segment(bvec, bio, i) { + __blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg, + &nsegs, &cluster); + } /* segments in bio */ + + if (sg) + sg_mark_end(sg); + + BUG_ON(bio->bi_phys_segments && nsegs > bio->bi_phys_segments); + return nsegs; +} +EXPORT_SYMBOL(blk_bio_map_sg); + static inline int ll_new_hw_segment(struct request_queue *q, struct request *req, struct bio *bio) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 281516ae8b4e..dc632975d54f 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -894,6 +894,8 @@ extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable); extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); +extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio, + struct scatterlist *sglist); extern void blk_dump_rq_flags(struct request *, char *); extern long nr_blockdev_pages(void); |