vlan: lockless transmit path

vlan is a stacked device, like tunnels. We should use the lockless
mechanism we are using in tunnels and loopback.

This patch completely removes locking in TX path.

tx stat counters are added into existing percpu stat structure, renamed
from vlan_rx_stats to vlan_pcpu_stats.

Note : this partially reverts commit 2e59af3dcbdf (vlan: multiqueue vlan
device)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/8021q/vlan.h b/net/8021q/vlan.h
index 4625ba6..5687c9b 100644
--- a/net/8021q/vlan.h
+++ b/net/8021q/vlan.h
@@ -19,19 +19,25 @@
 
 
 /**
- *	struct vlan_rx_stats - VLAN percpu rx stats
+ *	struct vlan_pcpu_stats - VLAN percpu rx/tx stats
  *	@rx_packets: number of received packets
  *	@rx_bytes: number of received bytes
  *	@rx_multicast: number of received multicast packets
+ *	@tx_packets: number of transmitted packets
+ *	@tx_bytes: number of transmitted bytes
  *	@syncp: synchronization point for 64bit counters
- *	@rx_errors: number of errors
+ *	@rx_errors: number of rx errors
+ *	@tx_dropped: number of tx drops
  */
-struct vlan_rx_stats {
+struct vlan_pcpu_stats {
 	u64			rx_packets;
 	u64			rx_bytes;
 	u64			rx_multicast;
+	u64			tx_packets;
+	u64			tx_bytes;
 	struct u64_stats_sync	syncp;
-	unsigned long		rx_errors;
+	u32			rx_errors;
+	u32			tx_dropped;
 };
 
 /**
@@ -45,7 +51,7 @@
  *	@real_dev: underlying netdevice
  *	@real_dev_addr: address of underlying netdevice
  *	@dent: proc dir entry
- *	@vlan_rx_stats: ptr to percpu rx stats
+ *	@vlan_pcpu_stats: ptr to percpu rx stats
  */
 struct vlan_dev_info {
 	unsigned int				nr_ingress_mappings;
@@ -60,7 +66,7 @@
 	unsigned char				real_dev_addr[ETH_ALEN];
 
 	struct proc_dir_entry			*dent;
-	struct vlan_rx_stats __percpu		*vlan_rx_stats;
+	struct vlan_pcpu_stats __percpu		*vlan_pcpu_stats;
 };
 
 static inline struct vlan_dev_info *vlan_dev_info(const struct net_device *dev)