Commit d7ed538a authored Aug 02, 2005 by Jens Axboe Committed by Linus Torvalds Aug 02, 2005

[PATCH] cfq-iosched: fix problem with barriers and max_depth == 1



CFQ will currently stall when using write barriers and the default
max_depth setting of 1, since we artificially need a depth of 2 when
pre-pending the first flush. So never deny the barrier request going to
the device.

This is a regression since 2.6.12, it was found in SUSE testing.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent f7c80c9f

drivers/block/cfq-iosched.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1281,6 +1281,7 @@ static struct request cfq_next_request(request_queue_t q)
		*/
		if (!cfq_crq_in_driver(crq) &&
		!cfq_cfqq_idle_window(cfqq) &&
		!blk_barrier_rq(rq) &&
		cfqd->rq_in_driver >= cfqd->cfq_max_depth)
		return NULL;