ip6_tunnel: use ip_tunnel_get_stats64 as ndo_get_stats64 callback

Switch ip6_tunnel to the standard statistics pattern:
- use dev->stats for the less frequently accessed counters
- use dev->tstats for the frequently accessed counters

An additional benefit is that we now have 64bit statistics also on
32bit systems.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv6/ip6_tunnel.c

@@ -94,36 +94,6 @@ static inline int ip6_tnl_mpls_supported(void)
 	return IS_ENABLED(CONFIG_MPLS);
 }
 
-static struct net_device_stats *ip6_get_stats(struct net_device *dev)
-{
-	struct pcpu_sw_netstats tmp, sum = { 0 };
-	int i;
-
-	for_each_possible_cpu(i) {
-		unsigned int start;
-		const struct pcpu_sw_netstats *tstats =
-						   per_cpu_ptr(dev->tstats, i);
-
-		do {
-			start = u64_stats_fetch_begin_irq(&tstats->syncp);
-			tmp.rx_packets = tstats->rx_packets;
-			tmp.rx_bytes = tstats->rx_bytes;
-			tmp.tx_packets = tstats->tx_packets;
-			tmp.tx_bytes =  tstats->tx_bytes;
-		} while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
-
-		sum.rx_packets += tmp.rx_packets;
-		sum.rx_bytes   += tmp.rx_bytes;
-		sum.tx_packets += tmp.tx_packets;
-		sum.tx_bytes   += tmp.tx_bytes;
-	}
-	dev->stats.rx_packets = sum.rx_packets;
-	dev->stats.rx_bytes   = sum.rx_bytes;
-	dev->stats.tx_packets = sum.tx_packets;
-	dev->stats.tx_bytes   = sum.tx_bytes;
-	return &dev->stats;
-}
-
 #define for_each_ip6_tunnel_rcu(start) \
 	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 
@@ -1834,7 +1804,7 @@ static const struct net_device_ops ip6_tnl_netdev_ops = {
 	.ndo_start_xmit = ip6_tnl_start_xmit,
 	.ndo_do_ioctl	= ip6_tnl_ioctl,
 	.ndo_change_mtu = ip6_tnl_change_mtu,
-	.ndo_get_stats	= ip6_get_stats,
+	.ndo_get_stats64 = dev_get_tstats64,
 	.ndo_get_iflink = ip6_tnl_get_iflink,
 };