ixgbe: cleanup logic in ixgbe_change_mtu

This change is meant to just cleanup the logic in ixgbe_change_mtu since we
are making it unnecessarily complex due to a workaround required for 82599
when SR-IOV is enabled.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Stephen Ko <stephen.s.ko@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index e97ef45..db1f17c 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -5544,20 +5544,24 @@ static void ixgbe_free_all_rx_resources(struct ixgbe_adapter *adapter)
 static int ixgbe_change_mtu(struct net_device *netdev, int new_mtu)
 {
        struct ixgbe_adapter *adapter = netdev_priv(netdev);
-       struct ixgbe_hw *hw = &adapter->hw;
        int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN;
 
        /* MTU < 68 is an error and causes problems on some kernels */
-       if (adapter->flags & IXGBE_FLAG_SRIOV_ENABLED &&
-           hw->mac.type != ixgbe_mac_X540) {
-               if ((new_mtu < 68) || (max_frame > MAXIMUM_ETHERNET_VLAN_SIZE))
-                       return -EINVAL;
-       } else {
-               if ((new_mtu < 68) || (max_frame > IXGBE_MAX_JUMBO_FRAME_SIZE))
+       if ((new_mtu < 68) || (max_frame > IXGBE_MAX_JUMBO_FRAME_SIZE))
+               return -EINVAL;
+
+       /*
+        * For 82599EB we cannot allow PF to change MTU greater than 1500
+        * in SR-IOV mode as it may cause buffer overruns in guest VFs that
+        * don't allocate and chain buffers correctly.
+        */
+       if ((adapter->flags & IXGBE_FLAG_SRIOV_ENABLED) &&
+           (adapter->hw.mac.type == ixgbe_mac_82599EB) &&
+           (max_frame > MAXIMUM_ETHERNET_VLAN_SIZE))
                        return -EINVAL;
-       }
 
        e_info(probe, "changing MTU from %d to %d\n", netdev->mtu, new_mtu);
+
        /* must set new MTU before calling down or up */
        netdev->mtu = new_mtu;