ipv6: introduce ip6tunnel_xmit() helper

Similar to iptunnel_xmit(), group these operations into a
helper function.

This by the way fixes the missing u64_stats_update_begin()
and u64_stats_update_end() for 32 bit arch.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Pravin B Shelar <pshelar@nicira.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index e03047f..ebdef7f 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -68,4 +68,24 @@
 __u32 ip6_tnl_get_cap(struct ip6_tnl *t, const struct in6_addr *laddr,
 			     const struct in6_addr *raddr);
 
+static inline void ip6tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct net_device_stats *stats = &dev->stats;
+	int pkt_len, err;
+
+	nf_reset(skb);
+	pkt_len = skb->len;
+	err = ip6_local_out(skb);
+
+	if (net_xmit_eval(err) == 0) {
+		struct pcpu_tstats *tstats = this_cpu_ptr(dev->tstats);
+		u64_stats_update_begin(&tstats->syncp);
+		tstats->tx_bytes += pkt_len;
+		tstats->tx_packets++;
+		u64_stats_update_end(&tstats->syncp);
+	} else {
+		stats->tx_errors++;
+		stats->tx_aborted_errors++;
+	}
+}
 #endif