diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index 31427fb..99cfa28 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -153,7 +153,7 @@
 }
 EXPORT_SYMBOL_GPL(nf_nat_set_seq_adjust);
 
-static void nf_nat_csum(struct sk_buff *skb, struct iphdr *iph, void *data,
+static void nf_nat_csum(struct sk_buff *skb, const struct iphdr *iph, void *data,
 			int datalen, __sum16 *check, int oldlen)
 {
 	struct rtable *rt = skb_rtable(skb);