diff --git a/include/net/inet_ecn.h b/include/net/inet_ecn.h
index 0dc0a51da38f..dce2d586d9ce 100644
--- a/include/net/inet_ecn.h
+++ b/include/net/inet_ecn.h
@@ -128,7 +128,8 @@ static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
 	to = from | htonl(INET_ECN_CE << 20);
 	*(__be32 *)iph = to;
 	if (skb->ip_summed == CHECKSUM_COMPLETE)
-		skb->csum = csum_add(csum_sub(skb->csum, from), to);
+		skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
+				     (__force __wsum)to);
 	return 1;
 }