1 files changed, 9 insertions, 2 deletions

diff --git a/include/net/ip.h b/include/net/ip.h
index d53b5a9eae34..36f8f7811093 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -337,6 +337,13 @@ int ip_decrease_ttl(struct iphdr *iph)
         return --iph->ttl;
 }
 
+static inline int ip_mtu_locked(const struct dst_entry *dst)
+{
+        const struct rtable *rt = (const struct rtable *)dst;
+
+        return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
+}
+
 static inline
 int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 {
@@ -344,7 +351,7 @@ int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
 
         return  pmtudisc == IP_PMTUDISC_DO ||
                 (pmtudisc == IP_PMTUDISC_WANT &&
-                 !(dst_metric_locked(dst, RTAX_MTU)));
+                 !ip_mtu_locked(dst));
 }
 
 static inline bool ip_sk_accept_pmtu(const struct sock *sk)
@@ -370,7 +377,7 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
         struct net *net = dev_net(dst->dev);
 
         if (net->ipv4.sysctl_ip_fwd_use_pmtu ||
-            dst_metric_locked(dst, RTAX_MTU) ||
+            ip_mtu_locked(dst) ||
             !forwarding)
                 return dst_mtu(dst);