Also make them static.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
        write_unlock_bh(&nf_nat_lock);
 }
 
-struct nf_ct_ext_type nat_extend = {
+static struct nf_ct_ext_type nat_extend __read_mostly = {
        .len            = sizeof(struct nf_conn_nat),
        .align          = __alignof__(struct nf_conn_nat),
        .destroy        = nf_nat_cleanup_conntrack,
 
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
 
-struct nf_ct_ext_type helper_extend = {
+static struct nf_ct_ext_type helper_extend __read_mostly = {
        .len    = sizeof(struct nf_conn_help),
        .align  = __alignof__(struct nf_conn_help),
        .id     = NF_CT_EXT_HELPER,