From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Lei Subject: [PATCH 1/2] blk-mq: add callback of .cleanup_rq Date: Thu, 18 Jul 2019 11:25:18 +0800 Message-ID: <20190718032519.28306-2-ming.lei@redhat.com> References: <20190718032519.28306-1-ming.lei@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190718032519.28306-1-ming.lei@redhat.com> Sender: stable-owner@vger.kernel.org To: Jens Axboe Cc: linux-block@vger.kernel.org, "James E . J . Bottomley" , "Martin K . Petersen" , linux-scsi@vger.kernel.org, Ming Lei , "Ewan D . Milne" , Bart Van Assche , Hannes Reinecke , Christoph Hellwig , Mike Snitzer , dm-devel@redhat.com, stable@vger.kernel.org List-Id: linux-scsi@vger.kernel.org dm-rq needs to free request which has been dispatched and not completed by underlying queue. However, the underlying queue may have allocated private stuff for this request in .queue_rq(), so dm-rq will leak the request private part. Add one new callback of .cleanup_rq() to fix the memory leak issue. Another use case is to free request when the hctx is dead during cpu hotplug context. Cc: Ewan D. Milne Cc: Bart Van Assche Cc: Hannes Reinecke Cc: Christoph Hellwig Cc: Mike Snitzer Cc: dm-devel@redhat.com Cc: Fixes: 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback") Signed-off-by: Ming Lei --- drivers/md/dm-rq.c | 1 + include/linux/blk-mq.h | 13 +++++++++++++ 2 files changed, 14 insertions(+) diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index c9e44ac1f9a6..21d5c1784d0c 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -408,6 +408,7 @@ static int map_request(struct dm_rq_target_io *tio) ret = dm_dispatch_clone_request(clone, rq); if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { blk_rq_unprep_clone(clone); + blk_mq_cleanup_rq(clone); tio->ti->type->release_clone_rq(clone, &tio->info); tio->clone = NULL; return DM_MAPIO_REQUEUE; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 3fa1fa59f9b2..8a7808be5d0b 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -140,6 +140,7 @@ typedef int (poll_fn)(struct blk_mq_hw_ctx *); typedef int (map_queues_fn)(struct blk_mq_tag_set *set); typedef bool (busy_fn)(struct request_queue *); typedef void (complete_fn)(struct request *); +typedef void (cleanup_rq_fn)(struct request *); struct blk_mq_ops { @@ -200,6 +201,12 @@ struct blk_mq_ops { /* Called from inside blk_get_request() */ void (*initialize_rq_fn)(struct request *rq); + /* + * Called before freeing one request which isn't completed yet, + * and usually for freeing the driver private part + */ + cleanup_rq_fn *cleanup_rq; + /* * If set, returns whether or not this queue currently is busy */ @@ -366,4 +373,10 @@ static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, BLK_QC_T_INTERNAL; } +static inline void blk_mq_cleanup_rq(struct request *rq) +{ + if (rq->q->mq_ops->cleanup_rq) + rq->q->mq_ops->cleanup_rq(rq); +} + #endif -- 2.20.1