From: Paolo Abeni <pabeni@redhat.com>
Date: Fri, 12 Feb 2016 14:43:59 +0000 (+0100)
Subject: net/ipv4: add dst cache support for gre lwtunnels
X-Git-Tag: next-20160301~76^2~76^2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3c1cb4d2604c;p=karo-tx-linux.git

net/ipv4: add dst cache support for gre lwtunnels

In case of UDP traffic with datagram length below MTU this
gives about 4% performance increase

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Suggested-and-Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 65748db44285..917c2c1bfadd 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -540,9 +540,16 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto err_free_skb;
 
 	key = &tun_info->key;
-	rt = gre_get_rt(skb, dev, &fl, key);
-	if (IS_ERR(rt))
-		goto err_free_skb;
+	rt = !skb->mark ? dst_cache_get_ip4(&tun_info->dst_cache, &fl.saddr) :
+			 NULL;
+	if (!rt) {
+		rt = gre_get_rt(skb, dev, &fl, key);
+		if (IS_ERR(rt))
+				goto err_free_skb;
+		if (!skb->mark)
+			dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
+					  fl.saddr);
+	}
 
 	tunnel_hlen = ip_gre_calc_hlen(key->tun_flags);