r8169: add 64bit statistics.

Switch to use ndo_get_stats64 to get 64bit statistics.
Two sync entries are used (one for Rx and one for Tx).
Signed-off-by: Junchang Wang <junchangwang@gmail.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>

drivers/net/ethernet/realtek/r8169.c

@@ -675,6 +675,12 @@ enum rtl_flag {
 	RTL_FLAG_MAX
 };
 
+struct rtl8169_stats {
+	u64			packets;
+	u64			bytes;
+	struct u64_stats_sync	syncp;
+};
+
 struct rtl8169_private {
 	void __iomem *mmio_addr;	/* memory map physical address */
 	struct pci_dev *pci_dev;
@@ -687,6 +693,8 @@ struct rtl8169_private {
 	u32 cur_tx; /* Index into the Tx descriptor buffer of next Rx pkt. */
 	u32 dirty_rx;
 	u32 dirty_tx;
+	struct rtl8169_stats rx_stats;
+	struct rtl8169_stats tx_stats;
 	struct TxDesc *TxDescArray;	/* 256-aligned Tx descriptor ring */
 	struct RxDesc *RxDescArray;	/* 256-aligned Rx descriptor ring */
 	dma_addr_t TxPhyAddr;
@@ -775,7 +783,9 @@ static void rtl_hw_start(struct net_device *dev);
 static int rtl8169_close(struct net_device *dev);
 static void rtl_set_rx_mode(struct net_device *dev);
 static void rtl8169_tx_timeout(struct net_device *dev);
-static struct net_device_stats *rtl8169_get_stats(struct net_device *dev);
+static struct rtnl_link_stats64 *rtl8169_get_stats64(struct net_device *dev,
+						    struct rtnl_link_stats64
+						    *stats);
 static int rtl8169_change_mtu(struct net_device *dev, int new_mtu);
 static void rtl8169_rx_clear(struct rtl8169_private *tp);
 static int rtl8169_poll(struct napi_struct *napi, int budget);
@@ -3521,7 +3531,7 @@ static void rtl_disable_msi(struct pci_dev *pdev, struct rtl8169_private *tp)
 static const struct net_device_ops rtl8169_netdev_ops = {
 	.ndo_open		= rtl8169_open,
 	.ndo_stop		= rtl8169_close,
-	.ndo_get_stats		= rtl8169_get_stats,
+	.ndo_get_stats64	= rtl8169_get_stats64,
 	.ndo_start_xmit		= rtl8169_start_xmit,
 	.ndo_tx_timeout		= rtl8169_tx_timeout,
 	.ndo_validate_addr	= eth_validate_addr,
@@ -5658,8 +5668,10 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
 		rtl8169_unmap_tx_skb(&tp->pci_dev->dev, tx_skb,
 				     tp->TxDescArray + entry);
 		if (status & LastFrag) {
-			dev->stats.tx_packets++;
-			dev->stats.tx_bytes += tx_skb->skb->len;
+			u64_stats_update_begin(&tp->tx_stats.syncp);
+			tp->tx_stats.packets++;
+			tp->tx_stats.bytes += tx_skb->skb->len;
+			u64_stats_update_end(&tp->tx_stats.syncp);
 			dev_kfree_skb(tx_skb->skb);
 			tx_skb->skb = NULL;
 		}
@@ -5807,8 +5819,10 @@ static int rtl_rx(struct net_device *dev, struct rtl8169_private *tp, u32 budget
 
 			napi_gro_receive(&tp->napi, skb);
 
-			dev->stats.rx_bytes += pkt_size;
-			dev->stats.rx_packets++;
+			u64_stats_update_begin(&tp->rx_stats.syncp);
+			tp->rx_stats.packets++;
+			tp->rx_stats.bytes += pkt_size;
+			u64_stats_update_end(&tp->rx_stats.syncp);
 		}
 
 		/* Work around for AMD plateform. */
@@ -6069,21 +6083,38 @@ static void rtl_set_rx_mode(struct net_device *dev)
 	RTL_W32(RxConfig, tmp);
 }
 
-/**
- *  rtl8169_get_stats - Get rtl8169 read/write statistics
- *  @dev: The Ethernet Device to get statistics for
- *
- *  Get TX/RX statistics for rtl8169
- */
-static struct net_device_stats *rtl8169_get_stats(struct net_device *dev)
+static struct rtnl_link_stats64 *
+rtl8169_get_stats64(struct net_device *dev, struct rtnl_link_stats64 *stats)
 {
 	struct rtl8169_private *tp = netdev_priv(dev);
 	void __iomem *ioaddr = tp->mmio_addr;
+	unsigned int start;
 
 	if (netif_running(dev))
 		rtl8169_rx_missed(dev, ioaddr);
 
-	return &dev->stats;
+	do {
+		start = u64_stats_fetch_begin_bh(&tp->rx_stats.syncp);
+		stats->rx_packets = tp->rx_stats.packets;
+		stats->rx_bytes	= tp->rx_stats.bytes;
+	} while (u64_stats_fetch_retry_bh(&tp->rx_stats.syncp, start));
+
+
+	do {
+		start = u64_stats_fetch_begin_bh(&tp->tx_stats.syncp);
+		stats->tx_packets = tp->tx_stats.packets;
+		stats->tx_bytes	= tp->tx_stats.bytes;
+	} while (u64_stats_fetch_retry_bh(&tp->tx_stats.syncp, start));
+
+	stats->rx_dropped	= dev->stats.rx_dropped;
+	stats->tx_dropped	= dev->stats.tx_dropped;
+	stats->rx_length_errors = dev->stats.rx_length_errors;
+	stats->rx_errors	= dev->stats.rx_errors;
+	stats->rx_crc_errors	= dev->stats.rx_crc_errors;
+	stats->rx_fifo_errors	= dev->stats.rx_fifo_errors;
+	stats->rx_missed_errors = dev->stats.rx_missed_errors;
+
+	return stats;
 }
 
 static void rtl8169_net_suspend(struct net_device *dev)