net: Move free of dst_metrics to helper

Move the refcounting and potential free of dst metrics associated
for ipv4 and ipv6 to a common helper.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip.h

@@ -441,6 +441,15 @@ void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
 	}
 }
 
+static inline
+void ip_dst_metrics_put(struct dst_entry *dst)
+{
+	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
+
+	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
+		kfree(p);
+}
+
 u32 ip_idents_reserve(u32 hash, int segs);
 void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
 

net/ipv4/route.c

@@ -1476,12 +1476,9 @@ void rt_del_uncached_list(struct rtable *rt)
 
 static void ipv4_dst_destroy(struct dst_entry *dst)
 {
-	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
 	struct rtable *rt = (struct rtable *)dst;
 
-	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
-		kfree(p);
-
+	ip_dst_metrics_put(dst);
 	rt_del_uncached_list(rt);
 }
 

net/ipv6/route.c

@@ -364,14 +364,11 @@ EXPORT_SYMBOL(ip6_dst_alloc);
 
 static void ip6_dst_destroy(struct dst_entry *dst)
 {
-	struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
 	struct rt6_info *rt = (struct rt6_info *)dst;
 	struct fib6_info *from;
 	struct inet6_dev *idev;
 
-	if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
-		kfree(p);
-
+	ip_dst_metrics_put(dst);
 	rt6_uncached_list_del(rt);
 
 	idev = rt->rt6i_idev;