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

BugLink: https://bugs.launchpad.net/bugs/1836760

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>
(backported from commit 1e1b0c65)
[gpiccoli:
* Context adjustment for v4.4.
* Changed the patch to use the old ethtool API for get link settings
(get_link_ksettings -> get_settings); the new API was introduced in
v4.6 by commit 3f1ac7a7.]
Signed-off-by: Guilherme G. Piccoli <gpiccoli@canonical.com>
Acked-by: Khalid Elmously <khalid.elmously@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

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

@@ -95,22 +95,16 @@ static int ixgbevf_get_settings(struct net_device *netdev,
 				struct ethtool_cmd *ecmd)
 {
 	struct ixgbevf_adapter *adapter = netdev_priv(netdev);
-	struct ixgbe_hw *hw = &adapter->hw;
-	u32 link_speed = 0;
-	bool link_up;
 
 	ecmd->supported = SUPPORTED_10000baseT_Full;
 	ecmd->autoneg = AUTONEG_DISABLE;
 	ecmd->transceiver = XCVR_DUMMY1;
 	ecmd->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;