From: Ming Lei <ming.lei@redhat.com>
Date: Thu, 14 Oct 2021 16:17:07 +0800
Subject: nvme: prepare for pairing quiescing and unquiescing
Patch-mainline: v5.16-rc1
Git-commit: ebc9b95260151d966728cf0063b3b4e465f934d9
References: bsc#1201651

Add two helpers so that we can prepare for pairing quiescing and
unquiescing which will be done in next patch.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211014081710.1871747-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/nvme/host/core.c |   52 ++++++++++++++++++++++++++++-------------------
 1 file changed, 31 insertions(+), 21 deletions(-)

--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -118,25 +118,6 @@ static void nvme_remove_invalid_namespac
 static void nvme_update_keep_alive(struct nvme_ctrl *ctrl,
 				   struct nvme_command *cmd);
 
-/*
- * Prepare a queue for teardown.
- *
- * This must forcibly unquiesce queues to avoid blocking dispatch, and only set
- * the capacity to 0 after that to avoid blocking dispatchers that may be
- * holding bd_butex.  This will end buffered writers dirtying pages that can't
- * be synced.
- */
-static void nvme_set_queue_dying(struct nvme_ns *ns)
-{
-	if (test_and_set_bit(NVME_NS_DEAD, &ns->flags))
-		return;
-
-	blk_set_queue_dying(ns->queue);
-	blk_mq_unquiesce_queue(ns->queue);
-
-	set_capacity_and_notify(ns->disk, 0);
-}
-
 void nvme_queue_scan(struct nvme_ctrl *ctrl)
 {
 	/*
@@ -4473,6 +4454,35 @@ int nvme_init_ctrl(struct nvme_ctrl *ctr
 }
 EXPORT_SYMBOL_GPL(nvme_init_ctrl);
 
+static void nvme_start_ns_queue(struct nvme_ns *ns)
+{
+	blk_mq_unquiesce_queue(ns->queue);
+}
+
+static void nvme_stop_ns_queue(struct nvme_ns *ns)
+{
+	blk_mq_quiesce_queue(ns->queue);
+}
+
+/*
+ * Prepare a queue for teardown.
+ *
+ * This must forcibly unquiesce queues to avoid blocking dispatch, and only set
+ * the capacity to 0 after that to avoid blocking dispatchers that may be
+ * holding bd_butex.  This will end buffered writers dirtying pages that can't
+ * be synced.
+ */
+static void nvme_set_queue_dying(struct nvme_ns *ns)
+{
+	if (test_and_set_bit(NVME_NS_DEAD, &ns->flags))
+		return;
+
+	blk_set_queue_dying(ns->queue);
+	nvme_start_ns_queue(ns);
+
+	set_capacity_and_notify(ns->disk, 0);
+}
+
 /**
  * nvme_kill_queues(): Ends all namespace queues
  * @ctrl: the dead controller that needs to end
@@ -4551,7 +4561,7 @@ void nvme_stop_queues(struct nvme_ctrl *
 
 	down_read(&ctrl->namespaces_rwsem);
 	list_for_each_entry(ns, &ctrl->namespaces, list)
-		blk_mq_quiesce_queue(ns->queue);
+		nvme_stop_ns_queue(ns);
 	up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_queues);
@@ -4562,7 +4572,7 @@ void nvme_start_queues(struct nvme_ctrl
 
 	down_read(&ctrl->namespaces_rwsem);
 	list_for_each_entry(ns, &ctrl->namespaces, list)
-		blk_mq_unquiesce_queue(ns->queue);
+		nvme_start_ns_queue(ns);
 	up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_start_queues);