Subject: [PATCH 2/2] ipv4: Don't update the pmtu on mtu locked routes

From: Steffen Klassert <[email-masked]>
Date: Thu, 17 Jan 2013 07:58:10 +0100

Routes with locked mtu should not use learned pmtu informations,
so do not update the pmtu on these routes.

Reported-by: Julian Anastasov <[email-masked]>
Signed-off-by: Steffen Klassert <[email-masked]>
---
 net/ipv4/route.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 6e4a89c..259cbee 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -912,6 +912,9 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu)
 	struct dst_entry *dst = &rt->dst;
 	struct fib_result res;
 
+	if (dst_metric_locked(dst, RTAX_MTU))
+		return;
+
 	if (dst->dev->mtu < mtu)
 		return;
 
-- 
1.7.9.5