From 1ad43c0078b79a76accd0fe64062e47b3430dc6b Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Wed, 2 Aug 2017 08:01:45 +0800 Subject: [PATCH] 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: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 041f7b7fa0d6..211ef367345f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -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); -- 2.20.1