In dm-crypt, it need to map one bio to scatterlist for improving the hardware engine encryption efficiency. Thus this patch introduces the blk_bio_map_sg() function to map one bio with scatterlists. Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx> --- block/blk-merge.c | 19 +++++++++++++++++++ include/linux/blkdev.h | 2 ++ 2 files changed, 21 insertions(+) diff --git a/block/blk-merge.c b/block/blk-merge.c index 2613531..bca0609 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -417,6 +417,25 @@ single_segment: } /* + * Map a bio to scatterlist, return number of sg entries setup. Caller must + * make sure sg can hold bio segments entries and detach the bio from list. + */ +int blk_bio_map_sg(struct request_queue *q, struct bio *bio, + struct scatterlist *sglist) +{ + struct scatterlist *sg = NULL; + int nsegs; + + nsegs = __blk_bios_map_sg(q, bio, sglist, &sg); + + if (sg) + sg_mark_end(sg); + + return nsegs; +} +EXPORT_SYMBOL(blk_bio_map_sg); + +/* * map a request to scatterlist, return number of sg entries setup. Caller * must make sure sg can hold rq->nr_phys_segments entries */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 3d9cf32..cbe31f9 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1024,6 +1024,8 @@ extern void blk_queue_write_cache(struct request_queue *q, bool enabled, bool fu 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); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html