tunnels: prepare percpu accounting

Tunnels are going to use percpu for their accounting.

They are going to use a new tstats field in net_device.

skb_tunnel_rx() is changed to be a wrapper around __skb_tunnel_rx()

IPTUNNEL_XMIT() is changed to be a wrapper around __IPTUNNEL_XMIT()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/netdevice.h

@@ -1053,6 +1053,7 @@ struct net_device {
 	union {
 		void				*ml_priv;
 		struct pcpu_lstats __percpu	*lstats; /* loopback stats */
+		struct pcpu_tstats __percpu	*tstats; /* tunnel stats */
 	};
 	/* GARP */
 	struct garp_port	*garp_port;

include/net/dst.h

@@ -227,6 +227,23 @@ static inline void skb_dst_force(struct sk_buff *skb)
 }
 
 
+/**
+ *	__skb_tunnel_rx - prepare skb for rx reinsert
+ *	@skb: buffer
+ *	@dev: tunnel device
+ *
+ *	After decapsulation, packet is going to re-enter (netif_rx()) our stack,
+ *	so make some cleanups. (no accounting done)
+ */
+static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
+{
+	skb->dev = dev;
+	skb->rxhash = 0;
+	skb_set_queue_mapping(skb, 0);
+	skb_dst_drop(skb);
+	nf_reset(skb);
+}
+
 /**
  *	skb_tunnel_rx - prepare skb for rx reinsert
  *	@skb: buffer
@@ -234,17 +251,14 @@ static inline void skb_dst_force(struct sk_buff *skb)
  *
  *	After decapsulation, packet is going to re-enter (netif_rx()) our stack,
  *	so make some cleanups, and perform accounting.
+ *	Note: this accounting is not SMP safe.
  */
 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
 {
-	skb->dev = dev;
 	/* TODO : stats should be SMP safe */
 	dev->stats.rx_packets++;
 	dev->stats.rx_bytes += skb->len;
-	skb->rxhash = 0;
-	skb_set_queue_mapping(skb, 0);
-	skb_dst_drop(skb);
-	nf_reset(skb);
+	__skb_tunnel_rx(skb, dev);
 }
 
 /* Children define the path of the packet through the

include/net/ipip.h

@@ -45,7 +45,7 @@ struct ip_tunnel_prl_entry {
 	struct rcu_head			rcu_head;
 };
 
-#define IPTUNNEL_XMIT() do {						\
+#define __IPTUNNEL_XMIT(stats1, stats2) do {				\
 	int err;							\
 	int pkt_len = skb->len - skb_transport_offset(skb);		\
 									\
@@ -54,12 +54,14 @@ struct ip_tunnel_prl_entry {
 									\
 	err = ip_local_out(skb);					\
 	if (likely(net_xmit_eval(err) == 0)) {				\
-		txq->tx_bytes += pkt_len;				\
-		txq->tx_packets++;					\
+		(stats1)->tx_bytes += pkt_len;				\
+		(stats1)->tx_packets++;					\
 	} else {							\
-		stats->tx_errors++;					\
-		stats->tx_aborted_errors++;				\
+		(stats2)->tx_errors++;					\
+		(stats2)->tx_aborted_errors++;				\
 	}								\
 } while (0)
 
+#define IPTUNNEL_XMIT() __IPTUNNEL_XMIT(txq, stats)
+
 #endif