Patch "nvme: avoid to use blk_mq_abort_requeue_list()" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

nvme: avoid to use blk_mq_abort_requeue_list()

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
nvme-avoid-to-use-blk_mq_abort_requeue_list.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ming Lei <[email protected]>
Date: Mon, 22 May 2017 23:05:04 +0800
Subject: nvme: avoid to use blk_mq_abort_requeue_list()

From: Ming Lei <[email protected]>

commit 986f75c876dbafed98eba7cb516c5118f155db23 upstream.

NVMe may add request into requeue list simply and not kick off the requeue if hw queues are stopped. Then blk_mq_abort_requeue_list() is called in both nvme_kill_queues() and nvme_ns_remove() for dealing with this issue.

Unfortunately blk_mq_abort_requeue_list() is absolutely a race maker, for example, one request may be requeued during the aborting. So this patch just calls blk_mq_kick_requeue_list() in nvme_kill_queues() to handle this issue like what nvme_start_queues() does. Now all requests in requeue list when queues are stopped will be handled by blk_mq_kick_requeue_list() when queues are restarted, either in nvme_start_queues() or in nvme_kill_queues().

---
 drivers/nvme/host/core.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

@@ -1725,7 +1725,6 @@ static void nvme_ns_remove(struct nvme_n
 		sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
 					&nvme_ns_attr_group);
 		del_gendisk(ns->disk);
-		blk_mq_abort_requeue_list(ns->queue);
 		blk_cleanup_queue(ns->queue);
 	}
 

@@ -2048,7 +2047,6 @@ void nvme_kill_queues(struct nvme_ctrl *
 			continue;
 		revalidate_disk(ns->disk);
 		blk_set_queue_dying(ns->queue);
-		blk_mq_abort_requeue_list(ns->queue);
 
 		/*
 		 * Forcibly start all queues to avoid having stuck requests.

@@ -2056,6 +2054,9 @@ void nvme_kill_queues(struct nvme_ctrl *
 		 * when the final removal happens.
 		 */
 		blk_mq_start_hw_queues(ns->queue);
+
+		/* draining requests in requeue list */
+		blk_mq_kick_requeue_list(ns->queue);
 	}
 	mutex_unlock(&ctrl->namespaces_mutex);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/nvme-use-blk_mq_start_hw_queues-in-nvme_kill_queues.patch queue-4.9/nvme-avoid-to-use-blk_mq_abort_requeue_list.patch