iov_iter is implemented with bvec itererator, so it is safe to pass multipage bvec to it, and this way is much more efficient than passing one page in each bvec.
Cc: Dave Chinner <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: Mike Snitzer <[email protected]> Cc: [email protected] Cc: Alexander Viro <[email protected]> Cc: [email protected] Cc: Shaohua Li <[email protected]> Cc: [email protected] Cc: [email protected] Cc: David Sterba <[email protected]> Cc: [email protected] Cc: Darrick J. Wong <[email protected]> Cc: [email protected] Cc: Gao Xiang <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Theodore Ts'o <[email protected]> Cc: [email protected] Cc: Coly Li <[email protected]> Cc: [email protected] Cc: Boaz Harrosh <[email protected]> Cc: Bob Peterson <[email protected]> Cc: [email protected] Signed-off-by: Ming Lei <[email protected]> --- drivers/block/loop.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index bf6bc35aaf88..a3fd418ec637 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -515,16 +515,16 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, struct bio *bio = rq->bio; struct file *file = lo->lo_backing_file; unsigned int offset; - int segments = 0; + int nr_bvec = 0; int ret; if (rq->bio != rq->biotail) { - struct req_iterator iter; + struct bvec_iter iter; struct bio_vec tmp; __rq_for_each_bio(bio, rq) - segments += bio_segments(bio); - bvec = kmalloc_array(segments, sizeof(struct bio_vec), + nr_bvec += bio_bvecs(bio); + bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec), GFP_NOIO); if (!bvec) return -EIO; @@ -533,13 +533,14 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, /* * The bios of the request may be started from the middle of * the 'bvec' because of bio splitting, so we can't directly - * copy bio->bi_iov_vec to new bvec. The rq_for_each_segment + * copy bio->bi_iov_vec to new bvec. The bio_for_each_bvec * API will take care of all details for us. */ - rq_for_each_segment(tmp, rq, iter) { - *bvec = tmp; - bvec++; - } + __rq_for_each_bio(bio, rq) + bio_for_each_bvec(tmp, bio, iter) { + *bvec = tmp; + bvec++; + } bvec = cmd->bvec; offset = 0; } else { @@ -550,11 +551,11 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, */ offset = bio->bi_iter.bi_bvec_done; bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); - segments = bio_segments(bio); + nr_bvec = bio_bvecs(bio); } atomic_set(&cmd->ref, 2); - iov_iter_bvec(&iter, rw, bvec, segments, blk_rq_bytes(rq)); + iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); iter.iov_offset = offset; cmd->iocb.ki_pos = pos; -- 2.9.5
