--- zzzz-none-000/linux-4.1.52/include/linux/wait.h	2018-05-28 02:26:45.000000000 +0000
+++ bcm63-7530ax-731/linux-4.1.52/include/linux/wait.h	2022-03-02 11:37:13.000000000 +0000
@@ -140,7 +140,7 @@
 }
 
 static inline void
-__remove_wait_queue(wait_queue_head_t *head, wait_queue_t *old)
+__remove_wait_queue(wait_queue_head_t *head __maybe_unused, wait_queue_t *old)
 {
 	list_del(&old->task_list);
 }
@@ -906,6 +906,18 @@
 })
 
 /*
+ * These are the old interfaces to sleep waiting for an event.
+ * They are racy.  DO NOT use them, use the wait_event* interfaces above.
+ * We plan to remove these interfaces.
+ */
+extern void sleep_on(wait_queue_head_t *q);
+extern long sleep_on_timeout(wait_queue_head_t *q,
+				      signed long timeout);
+extern void interruptible_sleep_on(wait_queue_head_t *q);
+extern long interruptible_sleep_on_timeout(wait_queue_head_t *q,
+					   signed long timeout);
+
+/*
  * Waitqueues which are removed from the waitqueue_head at wakeup time
  */
 void prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state);