[PATCH v1 02/54] block: loop: comment on direct access to bvec table
From: Ming Lei <tom.leiming@gmail.com>
Date: 2016-12-27 16:09:48
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Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
Signed-off-by: Ming Lei <tom.leiming@gmail.com> --- 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));
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2.7.4