[net 3/5] ixgbe: fix mdio bus registration

[Jeff Kirsher]

From: Ivan Vecera <ivec...@redhat.com>

The ixgbe ignores errors returned from mdiobus_register() and leaves
adapter->mii_bus non-NULL and MDIO bus state as MDIOBUS_ALLOCATED.
This triggers a BUG from mdiobus_unregister() during ixgbe_remove() call.

Fixes: 8fa10ef01260 ("ixgbe: register a mdiobus")
Signed-off-by: Ivan Vecera <ivec...@redhat.com>
Tested-by: Andrew Bowers <andrewx.bow...@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirs...@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c 
b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
index cc4907f9ff02..2fb97967961c 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c
@@ -905,13 +905,12 @@ s32 ixgbe_mii_bus_init(struct ixgbe_hw *hw)
        struct pci_dev *pdev = adapter->pdev;
        struct device *dev = &adapter->netdev->dev;
        struct mii_bus *bus;
+       int err = -ENODEV;
 
-       adapter->mii_bus = devm_mdiobus_alloc(dev);
-       if (!adapter->mii_bus)
+       bus = devm_mdiobus_alloc(dev);
+       if (!bus)
                return -ENOMEM;
 
-       bus = adapter->mii_bus;
-
        switch (hw->device_id) {
        /* C3000 SoCs */
        case IXGBE_DEV_ID_X550EM_A_KR:
@@ -949,12 +948,15 @@ s32 ixgbe_mii_bus_init(struct ixgbe_hw *hw)
         */
        hw->phy.mdio.mode_support = MDIO_SUPPORTS_C45 | MDIO_SUPPORTS_C22;
 
-       return mdiobus_register(bus);
+       err = mdiobus_register(bus);
+       if (!err) {
+               adapter->mii_bus = bus;
+               return 0;
+       }
 
 ixgbe_no_mii_bus:
        devm_mdiobus_free(dev, bus);
-       adapter->mii_bus = NULL;
-       return -ENODEV;
+       return err;
 }
 
 /**
-- 
2.20.1