From 06eb061f48594aa369f6e852b352410298b317a8 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 7 Apr 2017 16:50:44 -0700 Subject: dm mpath: requeue after a small delay if blk_get_request() fails If blk_get_request() returns ENODEV then multipath_clone_and_map() causes a request to be requeued immediately. This can cause a kworker thread to spend 100% of the CPU time of a single core in __blk_mq_run_hw_queue() and also can cause device removal to never finish. Avoid this by only requeuing after a delay if blk_get_request() fails. Additionally, reduce the requeue delay. Cc: stable@vger.kernel.org # 4.9+ Signed-off-by: Bart Van Assche Signed-off-by: Mike Snitzer --- drivers/md/dm-rq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/md/dm-rq.c') diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 28955b94d2b2..90756a56c4d3 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -280,7 +280,7 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_ if (!rq->q->mq_ops) dm_old_requeue_request(rq); else - dm_mq_delay_requeue_request(rq, delay_requeue ? 5000 : 0); + dm_mq_delay_requeue_request(rq, delay_requeue ? 100/*ms*/ : 0); rq_completed(md, rw, false); } -- cgit v1.2.3 From 23a601248958fa4142d49294352fe8d1fdf3e509 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 27 Apr 2017 10:11:19 -0700 Subject: dm rq: check blk_mq_register_dev() return value in dm_mq_init_request_queue() Otherwise the request-based DM blk-mq request_queue will be put into service without being properly exported via sysfs. Cc: stable@vger.kernel.org Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinecke Cc: Christoph Hellwig Signed-off-by: Mike Snitzer --- drivers/md/dm-rq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-rq.c') diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index 90756a56c4d3..a6e8da9da7a4 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -809,10 +809,14 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) dm_init_md_queue(md); /* backfill 'mq' sysfs registration normally done in blk_register_queue */ - blk_mq_register_dev(disk_to_dev(md->disk), q); + err = blk_mq_register_dev(disk_to_dev(md->disk), q); + if (err) + goto out_cleanup_queue; return 0; +out_cleanup_queue: + blk_cleanup_queue(q); out_tag_set: blk_mq_free_tag_set(md->tag_set); out_kfree_tag_set: -- cgit v1.2.3