nvme: use blk_mq_start_hw_queues() in nvme_kill_queues()

Inside nvme_kill_queues(), we have to start hw queues for
draining requests in sw queues, .dispatch list and requeue list,
so use blk_mq_start_hw_queues() instead of blk_mq_start_stopped_hw_queues()
which only run queues if queues are stopped, but the queues may have
been started already, for example nvme_start_queues() is called in reset work
function.

blk_mq_start_hw_queues() run hw queues in current context, instead
of running asynchronously like before. Given nvme_kill_queues() is
run from either remove context or reset worker context, both are fine
to run hw queue directly. And the mutex of namespaces_mutex isn't a
problem too becasue nvme_start_freeze() runs hw queue in this way
already.

Cc: [email protected]
Reported-by: Zhang Yi <[email protected]>
Reviewed-by: Keith Busch <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

drivers/nvme/host/core.c

@@ -2437,7 +2437,13 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl)
 		revalidate_disk(ns->disk);
 		blk_set_queue_dying(ns->queue);
 		blk_mq_abort_requeue_list(ns->queue);
-		blk_mq_start_stopped_hw_queues(ns->queue, true);
+
+		/*
+		 * Forcibly start all queues to avoid having stuck requests.
+		 * Note that we must ensure the queues are not stopped
+		 * when the final removal happens.
+		 */
+		blk_mq_start_hw_queues(ns->queue);
 	}
 	mutex_unlock(&ctrl->namespaces_mutex);
 }