Commit d7ed538a authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds
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[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: default avatarJens Axboe <>
Signed-off-by: default avatarLinus Torvalds <>
parent f7c80c9f
......@@ -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;
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