[PATCH V2 4/5] nvme: quiesce namespace queue in parallel

[Ming Lei]

Chao Leng reported that in case of lots of namespaces, it may take quite a
while for nvme_stop_queues() to quiesce all namespace queues.

Improve nvme_stop_queues() by running quiesce in parallel, and just wait
once if global quiesce wait is allowed.

Link: https://lore.kernel.org/linux-block/cc732195-c053-9ce4-e1a7-e7f6dcf762ac@huawei.com/
Reported-by: Chao Leng <lengchao at huawei.com>
Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
 drivers/nvme/host/core.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 4c63564adeaa..20827a360099 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4540,9 +4540,7 @@ static void nvme_start_ns_queue(struct nvme_ns *ns)
 static void nvme_stop_ns_queue(struct nvme_ns *ns)
 {
 	if (!test_and_set_bit(NVME_NS_STOPPED, &ns->flags))
-		blk_mq_quiesce_queue(ns->queue);
-	else
-		blk_mq_wait_quiesce_done(ns->queue);
+		blk_mq_quiesce_queue_nowait(ns->queue);
 }
 
 /*
@@ -4643,6 +4641,11 @@ void nvme_stop_queues(struct nvme_ctrl *ctrl)
 	down_read(&ctrl->namespaces_rwsem);
 	list_for_each_entry(ns, &ctrl->namespaces, list)
 		nvme_stop_ns_queue(ns);
+	list_for_each_entry(ns, &ctrl->namespaces, list) {
+		blk_mq_wait_quiesce_done(ns->queue);
+		if (blk_mq_shared_quiesce_wait(ns->queue))
+			break;
+	}
 	up_read(&ctrl->namespaces_rwsem);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_queues);
-- 
2.31.1