path: root/mm/bounce.c
diff options
authorJens Axboe <>2007-09-27 13:01:25 +0200
committerJens Axboe <>2007-10-16 11:03:56 +0200
commitbf2de6f5a4faf0197268f18d08969b003b87b6e8 (patch)
tree16830a15a7effea352445a7aba5dbb433314d3eb /mm/bounce.c
parentc07e2b41291853b19fff11ceee3657df252a4e42 (diff)
block: Initial support for data-less (or empty) barrier support
This implements functionality to pass down or insert a barrier in a queue, without having data attached to it. The ->prepare_flush_fn() infrastructure from data barriers are reused to provide this functionality. Signed-off-by: Jens Axboe <>
Diffstat (limited to 'mm/bounce.c')
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/bounce.c b/mm/bounce.c
index 3b549bf31f7d..b6d2d0f1019b 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -265,6 +265,12 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
mempool_t *pool;
+ * Data-less bio, nothing to bounce
+ */
+ if (bio_empty_barrier(*bio_orig))
+ return;
+ /*
* for non-isa bounce case, just check if the bounce pfn is equal
* to or bigger than the highest pfn in the system -- in that case,
* don't waste time iterating over bio segments