[PATCH 7/8] blk-map: let blk_rq_map_user_iov() support null mapping

[Tejun Heo <tj@kernel.org>]

Impact: API expansion

Till now, only blk_rq_map() supported null mapping.  Add null mapping
support to blk_rq_map_user_iov() by moving BIO_NULL_MAPPED setting to
bio_copy_user_iov().

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 block/blk-map.c |    3 ---
 fs/bio.c        |    4 +++-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index 6718021..ac1961d 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -63,9 +63,6 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
 	if (IS_ERR(bio))
 		return PTR_ERR(bio);
 
-	if (map_data && map_data->null_mapped)
-		bio->bi_flags |= (1 << BIO_NULL_MAPPED);
-
 	orig_bio = bio;
 	blk_queue_bounce(q, &bio);
 
diff --git a/fs/bio.c b/fs/bio.c
index 8ad9784..728bef9 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -869,7 +869,9 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
 	/*
 	 * success
 	 */
-	if (!write_to_vm && (!map_data || !map_data->null_mapped)) {
+	if (unlikely(map_data && map_data->null_mapped))
+		bio->bi_flags |= (1 << BIO_NULL_MAPPED);
+	else if (!write_to_vm) {
 		ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 0);
 		if (ret)
 			goto cleanup;
-- 
1.6.0.2