net: ipv6_gre: Do not use custom stat allocator

With commit 34d21de ("net: Move {l,t,d}stats allocation to core and
convert veth & vrf"), stats allocation could be done on net core
instead of in this driver.

With this new approach, the driver doesn't have to bother with error
handling (allocation failure checking, making sure free happens in the
right spot, etc). This is core responsibility now.

Remove the allocation in the ip6_gre and leverage the network
core allocation instead.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_gre.c

@@ -1444,7 +1444,6 @@ static void ip6gre_dev_free(struct net_device *dev)
 
 	gro_cells_destroy(&t->gro_cells);
 	dst_cache_destroy(&t->dst_cache);
-	free_percpu(dev->tstats);
 }
 
 static void ip6gre_tunnel_setup(struct net_device *dev)
@@ -1453,6 +1452,7 @@ static void ip6gre_tunnel_setup(struct net_device *dev)
 	dev->needs_free_netdev = true;
 	dev->priv_destructor = ip6gre_dev_free;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	dev->type = ARPHRD_IP6GRE;
 
 	dev->flags |= IFF_NOARP;
@@ -1500,13 +1500,9 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 	tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
 	if (ret)
-		goto cleanup_alloc_pcpu_stats;
+		return ret;
 
 	ret = gro_cells_init(&tunnel->gro_cells, dev);
 	if (ret)
@@ -1530,9 +1526,6 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
 
 cleanup_dst_cache_init:
 	dst_cache_destroy(&tunnel->dst_cache);
-cleanup_alloc_pcpu_stats:
-	free_percpu(dev->tstats);
-	dev->tstats = NULL;
 	return ret;
 }
 
@@ -1893,13 +1886,9 @@ static int ip6erspan_tap_init(struct net_device *dev)
 	tunnel->net = dev_net(dev);
 	strcpy(tunnel->parms.name, dev->name);
 
-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	ret = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
 	if (ret)
-		goto cleanup_alloc_pcpu_stats;
+		return ret;
 
 	ret = gro_cells_init(&tunnel->gro_cells, dev);
 	if (ret)
@@ -1921,9 +1910,6 @@ static int ip6erspan_tap_init(struct net_device *dev)
 
 cleanup_dst_cache_init:
 	dst_cache_destroy(&tunnel->dst_cache);
-cleanup_alloc_pcpu_stats:
-	free_percpu(dev->tstats);
-	dev->tstats = NULL;
 	return ret;
 }
 
@@ -1948,6 +1934,7 @@ static void ip6gre_tap_setup(struct net_device *dev)
 	dev->needs_free_netdev = true;
 	dev->priv_destructor = ip6gre_dev_free;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 	netif_keep_dst(dev);
@@ -2250,6 +2237,7 @@ static void ip6erspan_tap_setup(struct net_device *dev)
 	dev->needs_free_netdev = true;
 	dev->priv_destructor = ip6gre_dev_free;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
 	netif_keep_dst(dev);