[PATCH v2 2/2] nvme: use blk_mq_[un]quiesce_tagset

[Chao Leng]

All controller namespaces share the same tagset, so we can use this
interface which does the optimal operation for parallel quiesce based on
the tagset type(e.g. blocking tagsets and non-blocking tagsets).

Now use NVME_NS_STOPPED to ensure pairing quiescing and unquiescing.
If use blk_mq_[un]quiesce_tagset, NVME_NS_STOPPED will be invalided,
so introduce NVME_CTRL_STOPPED to replace NVME_NS_STOPPED.

nvme connect_q should be never quiesced, so set QUEUE_FLAG_NOQUIESCED
when init connect_q.

Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
Signed-off-by: Chao Leng <lengchao at huawei.com>
---
 drivers/nvme/host/core.c | 42 +++++++++++++-----------------------------
 drivers/nvme/host/nvme.h |  2 +-
 2 files changed, 14 insertions(+), 30 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 059737c1a2c1..0d07a07e02ff 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4890,6 +4890,7 @@ int nvme_alloc_io_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 			ret = PTR_ERR(ctrl->connect_q);
 			goto out_free_tag_set;
 		}
+		blk_queue_flag_set(QUEUE_FLAG_NOQUIESCED, ctrl->connect_q);
 	}
 
 	ctrl->tagset = set;
@@ -5089,20 +5090,6 @@ int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
 }
 EXPORT_SYMBOL_GPL(nvme_init_ctrl);
 
-static void nvme_start_ns_queue(struct nvme_ns *ns)
-{
-	if (test_and_clear_bit(NVME_NS_STOPPED, &ns->flags))
-		blk_mq_unquiesce_queue(ns->queue);
-}
-
-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);
-}
-
 /*
  * Prepare a queue for teardown.
  *
@@ -5111,13 +5098,14 @@ static void nvme_stop_ns_queue(struct nvme_ns *ns)
  * 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)
+static void nvme_set_queue_dying(struct nvme_ns *ns, bool start_queue)
 {
 	if (test_and_set_bit(NVME_NS_DEAD, &ns->flags))
 		return;
 
 	blk_mark_disk_dead(ns->disk);
-	nvme_start_ns_queue(ns);
+	if (start_queue)
+		blk_mq_unquiesce_queue(ns->queue);
 
 	set_capacity_and_notify(ns->disk, 0);
 }
@@ -5132,6 +5120,7 @@ static void nvme_set_queue_dying(struct nvme_ns *ns)
 void nvme_kill_queues(struct nvme_ctrl *ctrl)
 {
 	struct nvme_ns *ns;
+	bool start_queue = false;
 
 	down_read(&ctrl->namespaces_rwsem);
 
@@ -5139,8 +5128,11 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl)
 	if (ctrl->admin_q && !blk_queue_dying(ctrl->admin_q))
 		nvme_start_admin_queue(ctrl);
 
+	if (test_and_clear_bit(NVME_CTRL_STOPPED, &ctrl->flags))
+		start_queue = true;
+
 	list_for_each_entry(ns, &ctrl->namespaces, list)
-		nvme_set_queue_dying(ns);
+		nvme_set_queue_dying(ns, start_queue);
 
 	up_read(&ctrl->namespaces_rwsem);
 }
@@ -5196,23 +5188,15 @@ EXPORT_SYMBOL_GPL(nvme_start_freeze);
 
 void nvme_stop_queues(struct nvme_ctrl *ctrl)
 {
-	struct nvme_ns *ns;
-
-	down_read(&ctrl->namespaces_rwsem);
-	list_for_each_entry(ns, &ctrl->namespaces, list)
-		nvme_stop_ns_queue(ns);
-	up_read(&ctrl->namespaces_rwsem);
+	if (!test_and_set_bit(NVME_CTRL_STOPPED, &ctrl->flags))
+		blk_mq_quiesce_tagset(ctrl->tagset);
 }
 EXPORT_SYMBOL_GPL(nvme_stop_queues);
 
 void nvme_start_queues(struct nvme_ctrl *ctrl)
 {
-	struct nvme_ns *ns;
-
-	down_read(&ctrl->namespaces_rwsem);
-	list_for_each_entry(ns, &ctrl->namespaces, list)
-		nvme_start_ns_queue(ns);
-	up_read(&ctrl->namespaces_rwsem);
+	if (test_and_clear_bit(NVME_CTRL_STOPPED, &ctrl->flags))
+		blk_mq_unquiesce_tagset(ctrl->tagset);
 }
 EXPORT_SYMBOL_GPL(nvme_start_queues);
 
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index a29877217ee6..8e2f13a1e23a 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -237,6 +237,7 @@ enum nvme_ctrl_flags {
 	NVME_CTRL_FAILFAST_EXPIRED	= 0,
 	NVME_CTRL_ADMIN_Q_STOPPED	= 1,
 	NVME_CTRL_STARTED_ONCE		= 2,
+	NVME_CTRL_STOPPED		= 3,
 };
 
 struct nvme_ctrl {
@@ -487,7 +488,6 @@ struct nvme_ns {
 #define NVME_NS_ANA_PENDING	2
 #define NVME_NS_FORCE_RO	3
 #define NVME_NS_READY		4
-#define NVME_NS_STOPPED		5
 
 	struct cdev		cdev;
 	struct device		cdev_device;
-- 
2.16.4