Patch "route: Use ipv4_mtu instead of raw rt_pmtu" has been added to the 4.0-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    route: Use ipv4_mtu instead of raw rt_pmtu

to the 4.0-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     route-use-ipv4_mtu-instead-of-raw-rt_pmtu.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri May  8 13:16:04 CEST 2015
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Tue, 28 Apr 2015 11:43:15 +0800
Subject: route: Use ipv4_mtu instead of raw rt_pmtu

From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit cb6ccf09d6b94bec4def1ac5cf4678d12b216474 ]

The commit 3cdaa5be9e81a914e633a6be7b7d2ef75b528562 ("ipv4: Don't
increase PMTU with Datagram Too Big message") broke PMTU in cases
where the rt_pmtu value has expired but is smaller than the new
PMTU value.

This obsolete rt_pmtu then prevents the new PMTU value from being
installed.

Fixes: 3cdaa5be9e81 ("ipv4: Don't increase PMTU with Datagram Too Big message")
Reported-by: Gerd v. Egidy <gerd.von.egidy@intra2net.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/route.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -963,10 +963,7 @@ static void __ip_rt_update_pmtu(struct r
 	if (dst_metric_locked(dst, RTAX_MTU))
 		return;
 
-	if (dst->dev->mtu < mtu)
-		return;
-
-	if (rt->rt_pmtu && rt->rt_pmtu < mtu)
+	if (ipv4_mtu(dst) < mtu)
 		return;
 
 	if (mtu < ip_rt_min_pmtu)


Patches currently in stable-queue which might be from herbert@gondor.apana.org.au are

queue-4.0/route-use-ipv4_mtu-instead-of-raw-rt_pmtu.patch