diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 58dfa82..731f0a8 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1188,10 +1188,15 @@ static inline int xfrm_aevent_is_on(void)
 	return ret;
 }
 
+static inline int alg_len(struct xfrm_algo *alg)
+{
+	return sizeof(*alg) + ((alg->alg_key_len + 7) / 8);
+}
+
 #ifdef CONFIG_XFRM_MIGRATE
 static inline struct xfrm_algo *xfrm_algo_clone(struct xfrm_algo *orig)
 {
-	return (struct xfrm_algo *)kmemdup(orig, sizeof(*orig) + orig->alg_key_len, GFP_KERNEL);
+	return kmemdup(orig, alg_len(orig), GFP_KERNEL);
 }
 
 static inline void xfrm_states_put(struct xfrm_state **states, int n)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index e75dbdc..aa667a4 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -31,11 +31,6 @@
 #include <linux/in6.h>
 #endif
 
-static inline int alg_len(struct xfrm_algo *alg)
-{
-	return sizeof(*alg) + ((alg->alg_key_len + 7) / 8);
-}
-
 static int verify_one_alg(struct nlattr **attrs, enum xfrm_attr_type_t type)
 {
 	struct nlattr *rt = attrs[type];