ixgbevf: Use cached link state instead of re-reading the value for ethtool

Change the ethtool link settings call to just read the cached state out of
the adapter structure instead of trying to recheck the value from the PF.
Doing this should prevent excessive reading of the mailbox.
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: "Guilherme G. Piccoli" <gpiccoli@canonical.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbevf/ethtool.c

@@ -85,22 +85,16 @@ static int ixgbevf_get_link_ksettings(struct net_device *netdev,
 				      struct ethtool_link_ksettings *cmd)
 {
 	struct ixgbevf_adapter *adapter = netdev_priv(netdev);
-	struct ixgbe_hw *hw = &adapter->hw;
-	u32 link_speed = 0;
-	bool link_up;
 
 	ethtool_link_ksettings_zero_link_mode(cmd, supported);
 	ethtool_link_ksettings_add_link_mode(cmd, supported, 10000baseT_Full);
 	cmd->base.autoneg = AUTONEG_DISABLE;
 	cmd->base.port = -1;
 
-	hw->mac.get_link_status = 1;
-	hw->mac.ops.check_link(hw, &link_speed, &link_up, false);
-
-	if (link_up) {
+	if (adapter->link_up) {
 		__u32 speed = SPEED_10000;
 
-		switch (link_speed) {
+		switch (adapter->link_speed) {
 		case IXGBE_LINK_SPEED_10GB_FULL:
 			speed = SPEED_10000;
 			break;