igc: Fix returning wrong statistics

'igc_update_stats()' was not updating 'netdev->stats', so the returned
statistics, for example, requested by:

$ ip -s link show dev enp3s0

were not being updated and were always zero.

Fix by returning a set of statistics that are actually being
updated (adapter->stats64).

Fixes: c9a11c23 ("igc: Add netdev")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/igc/igc_main.c

@@ -3891,21 +3891,23 @@ static int igc_change_mtu(struct net_device *netdev, int new_mtu)
 }
 
 /**
- * igc_get_stats - Get System Network Statistics
+ * igc_get_stats64 - Get System Network Statistics
  * @netdev: network interface device structure
+ * @stats: rtnl_link_stats64 pointer
  *
  * Returns the address of the device statistics structure.
  * The statistics are updated here and also from the timer callback.
  */
-static struct net_device_stats *igc_get_stats(struct net_device *netdev)
+static void igc_get_stats64(struct net_device *netdev,
+			    struct rtnl_link_stats64 *stats)
 {
 	struct igc_adapter *adapter = netdev_priv(netdev);
 
+	spin_lock(&adapter->stats64_lock);
 	if (!test_bit(__IGC_RESETTING, &adapter->state))
 		igc_update_stats(adapter);
-
-	/* only return the current stats */
-	return &netdev->stats;
+	memcpy(stats, &adapter->stats64, sizeof(*stats));
+	spin_unlock(&adapter->stats64_lock);
 }
 
 static netdev_features_t igc_fix_features(struct net_device *netdev,
@@ -4855,7 +4857,7 @@ static const struct net_device_ops igc_netdev_ops = {
 	.ndo_set_rx_mode	= igc_set_rx_mode,
 	.ndo_set_mac_address	= igc_set_mac,
 	.ndo_change_mtu		= igc_change_mtu,
-	.ndo_get_stats		= igc_get_stats,
+	.ndo_get_stats64	= igc_get_stats64,
 	.ndo_fix_features	= igc_fix_features,
 	.ndo_set_features	= igc_set_features,
 	.ndo_features_check	= igc_features_check,