diff --git a/openbsc/src/mncc.c b/openbsc/src/mncc.c
index 328e96c..3d16d8f 100644
--- a/openbsc/src/mncc.c
+++ b/openbsc/src/mncc.c
@@ -115,7 +115,7 @@
 }
 
 
-struct gsm_call *get_call_ref(u_int32_t callref)
+static struct gsm_call *get_call_ref(u_int32_t callref)
 {
 	struct gsm_call *callt;