Patchwork [1/2] ipv4: Remove output route check in ipv4_mtu

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Submitter Steffen Klassert
Date Jan. 17, 2013, 6:55 a.m.
Message ID <20130117065500.GG18940@secunet.com>
Download mbox | patch
Permalink /patch/213147/
State Accepted
Delegated to: David Miller
Headers show

Comments

Steffen Klassert - Jan. 17, 2013, 6:55 a.m.
The output route check was introduced with git commit 261663b0
(ipv4: Don't use the cached pmtu informations for input routes)
during times when we cached the pmtu informations on the
inetpeer. Now the pmtu informations are back in the routes,
so this check is obsolete. It also had some unwanted side effects,
as reported by Timo Teras and Lukas Tribus.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/route.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Timo Teräs - Jan. 17, 2013, 8:35 a.m.
On Thu, 17 Jan 2013 07:55:01 +0100 Steffen Klassert
<steffen.klassert@secunet.com> wrote:

> The output route check was introduced with git commit 261663b0
> (ipv4: Don't use the cached pmtu informations for input routes)
> during times when we cached the pmtu informations on the
> inetpeer. Now the pmtu informations are back in the routes,
> so this check is obsolete. It also had some unwanted side effects,
> as reported by Timo Teras and Lukas Tribus.
> 
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
> ---

Acked-by: Timo Teräs <timo.teras@iki.fi>

I think this should also go to stable queues which are applicable, since
the original commit caused CLAMPMSS and XFRM pmtu regressions.

The original thread of this is:
http://marc.info/?t=134208398500001&r=1&w=2

My original revert request is at:
http://marc.info/?l=linux-netdev&m=134242561624266&w=2

and additional reasoning at:
http://marc.info/?l=linux-netdev&m=134243626627716&w=2

Thanks,
 Timo
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David Miller - Jan. 17, 2013, 8:40 a.m.
From: Steffen Klassert <steffen.klassert@secunet.com>
Date: Thu, 17 Jan 2013 07:55:01 +0100

> The output route check was introduced with git commit 261663b0
> (ipv4: Don't use the cached pmtu informations for input routes)
> during times when we cached the pmtu informations on the
> inetpeer. Now the pmtu informations are back in the routes,
> so this check is obsolete. It also had some unwanted side effects,
> as reported by Timo Teras and Lukas Tribus.
> 
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Applied and queued up for -stable.
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Patch

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 844a9ef..6e4a89c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1120,7 +1120,7 @@  static unsigned int ipv4_mtu(const struct dst_entry *dst)
 	if (!mtu || time_after_eq(jiffies, rt->dst.expires))
 		mtu = dst_metric_raw(dst, RTAX_MTU);
 
-	if (mtu && rt_is_output_route(rt))
+	if (mtu)
 		return mtu;
 
 	mtu = dst->dev->mtu;