[PATCH v1 02/54] block: loop: comment on direct access to bvec table
From: Ming Lei
Date: Tue Dec 27 2016 - 11:09:50 EST
Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
---
drivers/block/loop.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f347285c67ec..be1cc51815ac 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -485,6 +485,11 @@ 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));
--
2.7.4