netns: net_identifiers should be read_mostly

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/nf_conntrack_proto_dccp.c b/net/netfilter/nf_conntrack_proto_dccp.c
index 1b816a2..80abdf2 100644
--- a/net/netfilter/nf_conntrack_proto_dccp.c
+++ b/net/netfilter/nf_conntrack_proto_dccp.c
@@ -384,7 +384,7 @@
 };
 
 /* this module per-net specifics */
-static int dccp_net_id;
+static int dccp_net_id __read_mostly;
 struct dccp_net {
 	int dccp_loose;
 	unsigned int dccp_timeout[CT_DCCP_MAX + 1];