From 410dd7bfda014a7c90bb5bd1de3274dd40ef6906 Mon Sep 17 00:00:00 2001
From: Jesse Gross <jesse@nicira.com>
Date: Tue, 2 Feb 2010 17:13:47 -0500
Subject: [PATCH 1/1] gre: Optimize tx path.

Ports commit 0bfbed "tunnels: Optimize tx path" from the mainline
kernel.
---
 .../linux-2.6/compat-2.6/include/net/ipip.h   | 19 ++++++++++++++++---
 datapath/linux-2.6/compat-2.6/ip_gre.c        |  9 ++++++++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/datapath/linux-2.6/compat-2.6/include/net/ipip.h b/datapath/linux-2.6/compat-2.6/include/net/ipip.h
index 604ece2d..7fa0b282 100644
--- a/datapath/linux-2.6/compat-2.6/include/net/ipip.h
+++ b/datapath/linux-2.6/compat-2.6/include/net/ipip.h
@@ -3,6 +3,10 @@
 
 #include <linux/version.h>
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,31)
+#define HAVE_NETDEV_QUEUE_STATS
+#endif
+
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
 
 #include <linux/if_tunnel.h>
@@ -48,6 +52,16 @@ struct ip_tunnel_prl_entry
 	spinlock_t			lock;
 };
 
+#ifdef HAVE_NETDEV_QUEUE_STATS
+#define UPDATE_TX_STATS()						\
+	txq->tx_bytes += pkt_len;					\
+	txq->tx_packets++;
+#else
+#define UPDATE_TX_STATS()						\
+	stats->tx_bytes += pkt_len;					\
+	stats->tx_packets++;
+#endif
+
 #define IPTUNNEL_XMIT() do {						\
 	int err;							\
 	int pkt_len = skb->len - skb_transport_offset(skb);		\
@@ -56,9 +70,8 @@ struct ip_tunnel_prl_entry
 	ip_select_ident(iph, &rt->u.dst, NULL);				\
 									\
 	err = ip_local_out(skb);					\
-	if (net_xmit_eval(err) == 0) {					\
-		stats->tx_bytes += pkt_len;				\
-		stats->tx_packets++;					\
+	if (likely(net_xmit_eval(err) == 0)) {				\
+		UPDATE_TX_STATS();					\
 	} else {							\
 		stats->tx_errors++;					\
 		stats->tx_aborted_errors++;				\
diff --git a/datapath/linux-2.6/compat-2.6/ip_gre.c b/datapath/linux-2.6/compat-2.6/ip_gre.c
index 05c6055b..4c47b925 100644
--- a/datapath/linux-2.6/compat-2.6/ip_gre.c
+++ b/datapath/linux-2.6/compat-2.6/ip_gre.c
@@ -696,6 +696,9 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 {
 	struct ip_tunnel *tunnel = netdev_priv(dev);
 	struct net_device_stats *stats;
+#ifdef HAVE_NETDEV_QUEUE_STATS
+	struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
+#endif
 	struct iphdr  *old_iph = ip_hdr(skb);
 	struct iphdr  *tiph;
 	u8     tos;
@@ -709,7 +712,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 	int    mtu;
 
 #ifdef HAVE_NETDEV_STATS
-	stats = &tunnel->dev->stats;
+	stats = &dev->stats;
 #else
 	stats = &tunnel->stat;
 #endif
@@ -860,7 +863,11 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
 		struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 		if (!new_skb) {
 			ip_rt_put(rt);
+#ifdef HAVE_NETDEV_QUEUE_STATS
+			txq->tx_dropped++;
+#else
 			stats->tx_dropped++;
+#endif
 			dev_kfree_skb(skb);
 			return NETDEV_TX_OK;
 		}
-- 
2.30.2