Hi Greg,
first, we need to cherry-pick another patch first:
> From 52a589d51f1008f62569bf89e95b26221ee76690 Mon Sep 17 00:00:00 2001
> From: Xin Long <lucien.xin@xxxxxxxxx>
> Date: Mon, 25 Dec 2017 14:43:58 +0800
> Subject: [PATCH] geneve: update skb dst pmtu on tx path
>
> Commit a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path") has fixed
> a performance issue caused by the change of lower dev's mtu for vxlan.
>
> The same thing needs to be done for geneve as well.
>
> Note that geneve cannot adjust it's mtu according to lower dev's mtu
> when creating it. The performance is very low later when netperfing
> over it without fixing the mtu manually. This patch could also avoid
> this issue.
>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Then you can apply the following backport. A backport is required
because v4.15 has commit 77552cfa39c48e695c39d0553afc8c6018e411ce
which rewrote
> skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
into
> skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2,
> rel_info);
in net/ipv6/ip6_tunnel.c which is missing:
>From b2fb9a8178660f92c6ab29d3171bc44e2cb1b618 Mon Sep 17 00:00:00 2001
From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Date: Thu, 25 Jan 2018 19:03:03 +0100
Subject: net: don't call update_pmtu unconditionally
commit f15ca723c1ebe6c1a06bc95fda6b62cd87b44559 upstream.
Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
"BUG: unable to handle kernel NULL pointer dereference at (null)"
Let's add a helper to check if update_pmtu is available before calling it.
Fixes: 52a589d51f10 ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff4490 ("vxlan: update skb dst pmtu on tx path")
CC: Roman Kapl <code@xxxxxxxx>
CC: Xin Long <lucien.xin@xxxxxxxxx>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
---
drivers/infiniband/ulp/ipoib/ipoib_cm.c | 3 +--
drivers/net/geneve.c | 4 ++--
drivers/net/vxlan.c | 6 ++----
include/net/dst.h | 8 ++++++++
net/ipv4/ip_tunnel.c | 3 +--
net/ipv4/ip_vti.c | 2 +-
net/ipv6/ip6_tunnel.c | 5 ++---
net/ipv6/ip6_vti.c | 2 +-
net/ipv6/sit.c | 4 ++--
9 files changed, 20 insertions(+), 17 deletions(-)
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_cm.c b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
index 7774654c2ccb..7a5ed5a5391e 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_cm.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_cm.c
@@ -1447,8 +1447,7 @@ void ipoib_cm_skb_too_long(struct net_device *dev, struct sk_buff *skb,
struct ipoib_dev_priv *priv = ipoib_priv(dev);
int e = skb_queue_empty(&priv->cm.skb_queue);
- if (skb_dst(skb))
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
skb_queue_tail(&priv->cm.skb_queue, skb);
if (e)
diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 1b0fcf0b2afa..fbc825ac97ab 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -829,7 +829,7 @@ static int geneve_xmit_skb(struct sk_buff *skb, struct net_device *dev,
int mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr) -
GENEVE_BASE_HLEN - info->options_len - 14;
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
}
sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
@@ -875,7 +875,7 @@ static int geneve6_xmit_skb(struct sk_buff *skb, struct net_device *dev,
int mtu = dst_mtu(dst) - sizeof(struct ipv6hdr) -
GENEVE_BASE_HLEN - info->options_len - 14;
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
}
sport = udp_flow_src_port(geneve->net, skb, 1, USHRT_MAX, true);
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index bb44f0c6891f..3d9c5b35a4a7 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2158,8 +2158,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
if (skb_dst(skb)) {
int mtu = dst_mtu(ndst) - VXLAN_HEADROOM;
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL,
- skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
}
tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
@@ -2200,8 +2199,7 @@ static void vxlan_xmit_one(struct sk_buff *skb, struct net_device *dev,
if (skb_dst(skb)) {
int mtu = dst_mtu(ndst) - VXLAN6_HEADROOM;
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL,
- skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
}
tos = ip_tunnel_ecn_encap(tos, old_iph, skb);
diff --git a/include/net/dst.h b/include/net/dst.h
index 694c2e6ae618..ebfb4328fdb1 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -520,4 +520,12 @@ static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
}
#endif
+static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
+{
+ struct dst_entry *dst = skb_dst(skb);
+
+ if (dst && dst->ops->update_pmtu)
+ dst->ops->update_pmtu(dst, NULL, skb, mtu);
+}
+
#endif /* _NET_DST_H */
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 13f7bbc0168d..a2fcc20774a6 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -521,8 +521,7 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
else
mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
- if (skb_dst(skb))
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
if (skb->protocol == htons(ETH_P_IP)) {
if (!skb_is_gso(skb) &&
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 89453cf62158..c9cd891f69c2 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -209,7 +209,7 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
mtu = dst_mtu(dst);
if (skb->len > mtu) {
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
if (skb->protocol == htons(ETH_P_IP)) {
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
htonl(mtu));
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 7e11f6a811f5..d61a82fd4b60 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -652,7 +652,7 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
if (rel_info > dst_mtu(skb_dst(skb2)))
goto out;
- skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
+ skb_dst_update_pmtu(skb2, rel_info);
}
if (rel_type == ICMP_REDIRECT)
skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
@@ -1141,8 +1141,7 @@ int ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev, __u8 dsfield,
mtu = 576;
}
- if (skb_dst(skb) && !t->parms.collect_md)
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
if (skb->len - t->tun_hlen - eth_hlen > mtu && !skb_is_gso(skb)) {
*pmtu = mtu;
err = -EMSGSIZE;
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 7c0f647b5195..2493a40bc4b1 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -486,7 +486,7 @@ vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
mtu = dst_mtu(dst);
if (!skb->ignore_df && skb->len > mtu) {
- skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu);
+ skb_dst_update_pmtu(skb, mtu);
if (skb->protocol == htons(ETH_P_IPV6)) {
if (mtu < IPV6_MIN_MTU)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index f03c1a562135..b35d8905794c 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -925,8 +925,8 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
df = 0;
}
- if (tunnel->parms.iph.daddr && skb_dst(skb))
- skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
+ if (tunnel->parms.iph.daddr)
+ skb_dst_update_pmtu(skb, mtu);
if (skb->len > mtu && !skb_is_gso(skb)) {
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
--
2.17.0