diff --git a/include/linux/sound.h b/include/linux/sound.h
index 44dcf0570432..fae20ba01fbf 100644
--- a/include/linux/sound.h
+++ b/include/linux/sound.h
@@ -1,3 +1,5 @@
+#ifndef _LINUX_SOUND_H
+#define _LINUX_SOUND_H
 
 /*
  * Minor numbers for the sound driver.
@@ -42,3 +44,5 @@ extern void unregister_sound_mixer(int unit);
 extern void unregister_sound_midi(int unit);
 extern void unregister_sound_dsp(int unit);
 #endif /* __KERNEL__ */
+
+#endif /* _LINUX_SOUND_H */