From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:32984 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750799AbdGNIlv (ORCPT ); Fri, 14 Jul 2017 04:41:51 -0400 From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Cc: Ming Lei Subject: [PATCH] blk-mq: don't leak preempt counter/q_usage_counter when allocating rq failed Date: Fri, 14 Jul 2017 16:41:36 +0800 Message-Id: <20170714084136.24850-1-ming.lei@redhat.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org From: Ming Lei 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 --- 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..4f2561412f13 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -301,11 +301,14 @@ static struct request *blk_mq_get_request(struct request_queue *q, struct elevator_queue *e = q->elevator; struct request *rq; unsigned int tag; + bool get_cpu = false; blk_queue_enter_live(q); data->q = q; - if (likely(!data->ctx)) + if (likely(!data->ctx)) { data->ctx = blk_mq_get_ctx(q); + get_cpu = true; + } if (likely(!data->hctx)) data->hctx = blk_mq_map_queue(q, data->ctx->cpu); if (op & REQ_NOWAIT) @@ -324,6 +327,8 @@ static struct request *blk_mq_get_request(struct request_queue *q, tag = blk_mq_get_tag(data); if (tag == BLK_MQ_TAG_FAIL) { + if (get_cpu) + blk_mq_put_ctx(data->ctx); 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); -- 2.9.4