diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 9745e8f698103bc2be735c8ed9fa81d9e35ec541..8ca9915befc8caab8270281028d4eb0ee3983fbd 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -41,7 +41,7 @@ static int label_limit = (1 << 20) - 1;
 static int ttl_max = 255;
 
 #if IS_ENABLED(CONFIG_NET_IP_TUNNEL)
-size_t ipgre_mpls_encap_hlen(struct ip_tunnel_encap *e)
+static size_t ipgre_mpls_encap_hlen(struct ip_tunnel_encap *e)
 {
 	return sizeof(struct mpls_shim_hdr);
 }