diff --git a/net/mac80211/debugfs.h b/net/mac80211/debugfs.h
index 9be4e6d71d00d736db7eeee2f24a645b1c41b2bb..214ed4ecd739f10ae201e6dfa9112c0dd943f5b8 100644
--- a/net/mac80211/debugfs.h
+++ b/net/mac80211/debugfs.h
@@ -2,9 +2,9 @@
 #define __MAC80211_DEBUGFS_H
 
 #ifdef CONFIG_MAC80211_DEBUGFS
-extern void debugfs_hw_add(struct ieee80211_local *local);
-extern int mac80211_format_buffer(char __user *userbuf, size_t count,
-				  loff_t *ppos, char *fmt, ...);
+void debugfs_hw_add(struct ieee80211_local *local);
+int __printf(4, 5) mac80211_format_buffer(char __user *userbuf, size_t count,
+					  loff_t *ppos, char *fmt, ...);
 #else
 static inline void debugfs_hw_add(struct ieee80211_local *local)
 {