[PATCH v3 02/49] block: loop: comment on direct access to bvec table

[Ming Lei]

Signed-off-by: Ming Lei <ming....@redhat.com>
---
 drivers/block/loop.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index ef8334949b42..58df9ed70328 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -487,6 +487,11 @@ static int lo_rw_aio(struct loop_device *lo, struct 
loop_cmd *cmd,
        /* nomerge for loop request queue */
        WARN_ON(cmd->rq->bio != cmd->rq->biotail);
 
+       /*
+        * For multipage bvec support, it is safe to pass the bvec
+        * table to iov iterator, because iov iter still uses bvec
+        * iter helpers to travese bvec.
+        */
        bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
        iov_iter_bvec(&iter, ITER_BVEC | rw, bvec,
                      bio_segments(bio), blk_rq_bytes(cmd->rq));
-- 
2.9.4