diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 6e50ccd..36936c8 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2361,6 +2361,11 @@
 	return 1;
 }
 
+static unsigned int xfrm_default_advmss(const struct dst_entry *dst)
+{
+	return dst_metric_advmss(dst->path);
+}
+
 int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)
 {
 	struct net *net;
@@ -2378,6 +2383,8 @@
 			dst_ops->kmem_cachep = xfrm_dst_cache;
 		if (likely(dst_ops->check == NULL))
 			dst_ops->check = xfrm_dst_check;
+		if (likely(dst_ops->default_advmss == NULL))
+			dst_ops->default_advmss = xfrm_default_advmss;
 		if (likely(dst_ops->negative_advice == NULL))
 			dst_ops->negative_advice = xfrm_negative_advice;
 		if (likely(dst_ops->link_failure == NULL))