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Commit 1ad43c00 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
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blk-mq: don't leak preempt counter/q_usage_counter when allocating rq failed 



When blk_mq_get_request() failed, preempt counter isn't
released, and blk_mq_make_request() doesn't release the counter
too.

This patch fixes the issue, and makes sure that preempt counter
is only held if rq is allocated successfully. The same policy is
applied on .q_usage_counter too.

Signed-off-by: default avatarMing Lei <minlei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 46d556e6

block/blk-mq.c

+11 −6
Original line number Diff line number Diff line
@@ -301,11 +301,12 @@ static struct request *blk_mq_get_request(struct request_queue *q, 
	struct elevator_queue *e = q->elevator;

	struct request *rq;

	unsigned int tag;

	struct blk_mq_ctx *local_ctx = NULL;



	blk_queue_enter_live(q);

	data->q = q;

	if (likely(!data->ctx))

		data->ctx = blk_mq_get_ctx(q);

		data->ctx = local_ctx = blk_mq_get_ctx(q);

	if (likely(!data->hctx))

		data->hctx = blk_mq_map_queue(q, data->ctx->cpu);

	if (op & REQ_NOWAIT)
@@ -324,6 +325,10 @@ static struct request *blk_mq_get_request(struct request_queue *q, 


	tag = blk_mq_get_tag(data);

	if (tag == BLK_MQ_TAG_FAIL) {

		if (local_ctx) {

			blk_mq_put_ctx(local_ctx);

			data->ctx = NULL;

		}

		blk_queue_exit(q);

		return NULL;

	}
@@ -356,12 +361,12 @@ struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op, 


	rq = blk_mq_get_request(q, NULL, op, &alloc_data);



	blk_mq_put_ctx(alloc_data.ctx);

	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;

	rq->bio = rq->biotail = NULL;
@@ -407,11 +412,11 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, 


	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);