blk-mq: Fix queue usage on failed request allocation

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: 1ad43c0078 ("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>
This commit is contained in:
Keith Busch 2017-08-14 16:40:11 -04:00 committed by Jens Axboe
parent ef954844c7
commit 3280d66a63

View File

@ -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);