diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index a7de9e3..c5f6af5 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -125,7 +125,7 @@
 
 #define HASH_SIZE  16
 
-static int ipgre_net_id;
+static int ipgre_net_id __read_mostly;
 struct ipgre_net {
 	struct ip_tunnel *tunnels[4][HASH_SIZE];