workqueue: Register sysfs after the whole creation of the new wq

workqueue creation includes adding it to the workqueue list.

Prepare for moving the whole workqueue initializing procedure into
wq_pool_mutex and cpu hotplug locks.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/workqueue.c

@@ -5684,9 +5684,6 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 	if (wq_online && init_rescuer(wq) < 0)
 		goto err_destroy;
 
-	if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
-		goto err_destroy;
-
 	/*
 	 * wq_pool_mutex protects global freeze state and workqueues list.
 	 * Grab it, adjust max_active and add the new @wq to workqueues
@@ -5702,6 +5699,9 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
 
 	mutex_unlock(&wq_pool_mutex);
 
+	if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
+		goto err_destroy;
+
 	return wq;
 
 err_free_node_nr_active: