Patchwork ipvs: Fix GSO support for IPVS DR IPv6 mode

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Submitter Jesper Dangaard Brouer
Date Aug. 22, 2012, 11:11 a.m.
Message ID <20120822111040.29174.4871.stgit@dragon>
Download mbox | patch
Permalink /patch/179297/
State Superseded
Headers show


Jesper Dangaard Brouer - Aug. 22, 2012, 11:11 a.m.
The MTU check in ip_vs_dr_xmit_v6() were missing a
check for skb_is_gso().

This e.g. caused issues for KVM IPVS setups, where different
Segmentation Offloading techniques are utilized, between guests,
via the virtio driver.  This resulted in very bad performance,
due to the ICMPv6 "too big" messages didn't affect the sender.

Signed-off-by: Jesper Dangaard Brouer <>

To Simon,
This should perhaps go to stable?
The patch is based on ipvs-next, but will apply on ipvs with an offset.

 net/netfilter/ipvs/ip_vs_xmit.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

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diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 543a554..80c3006 100644
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -1113,7 +1113,7 @@  ip_vs_dr_xmit_v6(struct sk_buff *skb, struct ip_vs_conn *cp,
 	/* MTU checking */
 	mtu = dst_mtu(&rt->dst);
-	if (skb->len > mtu) {
+	if (skb->len > mtu && !skb_is_gso(skb))) {
 		if (!skb->dev) {
 			struct net *net = dev_net(skb_dst(skb)->dev);