block: handle the null_mapped flag correctly in blk_rq_map_user_iov

The tape drivers (and the sg driver in a special case that doesn't matter here) use the null_mapped flag to tell blk_rq_map_user to not copy around any data into or out of the bounce buffers. blk_rq_map_user_iov never got that treatment, which didn't matter until I refactored blk_rq_map_user to be implemented in terms of blk_rq_map_user_iov. Signed-off-by: Christoph Hellwig <[email protected]> Fixes: ddad8dd ("block: use blk_rq_map_user_iov to implement blk_rq_map_user") Signed-off-by: Jens Axboe <[email protected]>
olifre · Feb 11, 2015 · a0763b2 · a0763b2
1 parent 564e559
commit a0763b2
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/block/blk-map.c b/block/blk-map.c
@@ -93,6 +93,9 @@ int blk_rq_map_user_iov(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);
+
 	if (bio->bi_iter.bi_size != iter->count) {
 		/*
 		 * Grab an extra reference to this bio, as bio_unmap_user()