From: Keith Busch <keith.busch@intel.com>
Date: Mon, 14 Aug 2017 16:40:11 -0400
Subject: [PATCH] blk-mq: Fix queue usage on failed request allocation
Git-commit: 3280d66a6363af0df0441709bc0bc302bd9a2510
Patch-mainline: v4.13-rc6
References: bsc#1104967,FATE#325924
blk_mq_get_request() does not release the callers queue usage counter
when allocation fails. The caller still needs to account for its own
queue usage when it is unable to allocate a request.
Fixes: 1ad43c0078b7 ("blk-mq: don't leak preempt counter/q_usage_counter when allocating rq failed")
Reported-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-mq.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 535cbdf32aab..4603b115e234 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -360,12 +360,12 @@ struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
return ERR_PTR(ret);
rq = blk_mq_get_request(q, NULL, op, &alloc_data);
+ blk_queue_exit(q);
if (!rq)
return ERR_PTR(-EWOULDBLOCK);
blk_mq_put_ctx(alloc_data.ctx);
- blk_queue_exit(q);
rq->__data_len = 0;
rq->__sector = (sector_t) -1;
@@ -411,12 +411,11 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
alloc_data.ctx = __blk_mq_get_ctx(q, cpu);
rq = blk_mq_get_request(q, NULL, op, &alloc_data);
+ blk_queue_exit(q);
if (!rq)
return ERR_PTR(-EWOULDBLOCK);
- blk_queue_exit(q);
-
return rq;
}
EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
--
2.16.4