ip: Use inline function dst_metric() instead of direct access to dst->metric[]

There are functions to refer to the value of dst->metric[THE_METRIC-1]
directly without use of a inline function "dst_metric" defined in
net/dst.h.

The following patch changes them to use the inline function
consistently.

Signed-off-by: Satoru SATOH <satoru.satoh@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9084055..92f90ae 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1468,14 +1468,14 @@
 
 					/* BSD 4.2 compatibility hack :-( */
 					if (mtu == 0 &&
-					    old_mtu >= rth->u.dst.metrics[RTAX_MTU-1] &&
+					    old_mtu >= dst_metric(&rth->u.dst, RTAX_MTU) &&
 					    old_mtu >= 68 + (iph->ihl << 2))
 						old_mtu -= iph->ihl << 2;
 
 					mtu = guess_mtu(old_mtu);
 				}
-				if (mtu <= rth->u.dst.metrics[RTAX_MTU-1]) {
-					if (mtu < rth->u.dst.metrics[RTAX_MTU-1]) {
+				if (mtu <= dst_metric(&rth->u.dst, RTAX_MTU)) {
+					if (mtu < dst_metric(&rth->u.dst, RTAX_MTU)) {
 						dst_confirm(&rth->u.dst);
 						if (mtu < ip_rt_min_pmtu) {
 							mtu = ip_rt_min_pmtu;
@@ -1497,7 +1497,7 @@
 
 static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
 {
-	if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= 68 &&
+	if (dst_metric(dst, RTAX_MTU) > mtu && mtu >= 68 &&
 	    !(dst_metric_locked(dst, RTAX_MTU))) {
 		if (mtu < ip_rt_min_pmtu) {
 			mtu = ip_rt_min_pmtu;
@@ -1624,14 +1624,14 @@
 	} else
 		rt->u.dst.metrics[RTAX_MTU-1]= rt->u.dst.dev->mtu;
 
-	if (rt->u.dst.metrics[RTAX_HOPLIMIT-1] == 0)
+	if (dst_metric(&rt->u.dst, RTAX_HOPLIMIT) == 0)
 		rt->u.dst.metrics[RTAX_HOPLIMIT-1] = sysctl_ip_default_ttl;
-	if (rt->u.dst.metrics[RTAX_MTU-1] > IP_MAX_MTU)
+	if (dst_metric(&rt->u.dst, RTAX_MTU) > IP_MAX_MTU)
 		rt->u.dst.metrics[RTAX_MTU-1] = IP_MAX_MTU;
-	if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0)
+	if (dst_metric(&rt->u.dst, RTAX_ADVMSS) == 0)
 		rt->u.dst.metrics[RTAX_ADVMSS-1] = max_t(unsigned int, rt->u.dst.dev->mtu - 40,
 				       ip_rt_min_advmss);
-	if (rt->u.dst.metrics[RTAX_ADVMSS-1] > 65535 - 40)
+	if (dst_metric(&rt->u.dst, RTAX_ADVMSS) > 65535 - 40)
 		rt->u.dst.metrics[RTAX_ADVMSS-1] = 65535 - 40;
 
 #ifdef CONFIG_NET_CLS_ROUTE