e1000e: avoid polling h/w registers during link negotiation

Avoid touching hardware registers when possible, otherwise link negotiation
can get messed up when user-level scripts are rapidly polling the driver to
see if/when link is up.  Use the saved link state information instead when
possible.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 26 deletions

diff --git a/drivers/net/e1000e/ethtool.c b/drivers/net/e1000e/ethtool.c
index db86850b1636..77c5829ab945 100644
--- a/drivers/net/e1000e/ethtool.c
+++ b/drivers/net/e1000e/ethtool.c
@@ -118,7 +118,6 @@ static int e1000_get_settings(struct net_device *netdev,
 {
         struct e1000_adapter *adapter = netdev_priv(netdev);
         struct e1000_hw *hw = &adapter->hw;
-        u32 status;
 
         if (hw->phy.media_type == e1000_media_type_copper) {
 
@@ -156,22 +155,29 @@ static int e1000_get_settings(struct net_device *netdev,
                 ecmd->transceiver = XCVR_EXTERNAL;
         }
 
-        status = er32(STATUS);
-        if (status & E1000_STATUS_LU) {
-                if (status & E1000_STATUS_SPEED_1000)
-                        ecmd->speed = 1000;
-                else if (status & E1000_STATUS_SPEED_100)
-                        ecmd->speed = 100;
-                else
-                        ecmd->speed = 10;
+        ecmd->speed = -1;
+        ecmd->duplex = -1;
 
-                if (status & E1000_STATUS_FD)
-                        ecmd->duplex = DUPLEX_FULL;
-                else
-                        ecmd->duplex = DUPLEX_HALF;
+        if (netif_running(netdev)) {
+                if (netif_carrier_ok(netdev)) {
+                        ecmd->speed = adapter->link_speed;
+                        ecmd->duplex = adapter->link_duplex - 1;
+                }
         } else {
-                ecmd->speed = -1;
-                ecmd->duplex = -1;
+                u32 status = er32(STATUS);
+                if (status & E1000_STATUS_LU) {
+                        if (status & E1000_STATUS_SPEED_1000)
+                                ecmd->speed = 1000;
+                        else if (status & E1000_STATUS_SPEED_100)
+                                ecmd->speed = 100;
+                        else
+                                ecmd->speed = 10;
+
+                        if (status & E1000_STATUS_FD)
+                                ecmd->duplex = DUPLEX_FULL;
+                        else
+                                ecmd->duplex = DUPLEX_HALF;
+                }
         }
 
         ecmd->autoneg = ((hw->phy.media_type == e1000_media_type_fiber) ||
@@ -179,7 +185,7 @@ static int e1000_get_settings(struct net_device *netdev,
 
         /* MDI-X => 2; MDI =>1; Invalid =>0 */
         if ((hw->phy.media_type == e1000_media_type_copper) &&
-            !hw->mac.get_link_status)
+            netif_carrier_ok(netdev))
                 ecmd->eth_tp_mdix = hw->phy.is_mdix ? ETH_TP_MDI_X :
                                                       ETH_TP_MDI;
         else
@@ -191,19 +197,15 @@ static int e1000_get_settings(struct net_device *netdev,
 static u32 e1000_get_link(struct net_device *netdev)
 {
         struct e1000_adapter *adapter = netdev_priv(netdev);
-        struct e1000_mac_info *mac = &adapter->hw.mac;
+        struct e1000_hw *hw = &adapter->hw;
 
         /*
-         * If the link is not reported up to netdev, interrupts are disabled,
-         * and so the physical link state may have changed since we last
-         * looked. Set get_link_status to make sure that the true link
-         * state is interrogated, rather than pulling a cached and possibly
-         * stale link state from the driver.
+         * Avoid touching hardware registers when possible, otherwise
+         * link negotiation can get messed up when user-level scripts
+         * are rapidly polling the driver to see if link is up.
          */
-        if (!netif_carrier_ok(netdev))
-                mac->get_link_status = 1;
-
-        return e1000e_has_link(adapter);
+        return netif_running(netdev) ? netif_carrier_ok(netdev) :
+            !!(er32(STATUS) & E1000_STATUS_LU);
 }
 
 static int e1000_set_spd_dplx(struct e1000_adapter *adapter, u16 spddplx)