ixgbe: fix pci device refcount leak

commit b93fb44 upstream.

As the comment of pci_get_domain_bus_and_slot() says, it
returns a PCI device with refcount incremented, when finish
using it, the caller must decrement the reference count by
calling pci_dev_put().

In ixgbe_get_first_secondary_devfn() and ixgbe_x550em_a_has_mii(),
pci_dev_put() is called to avoid leak.

Fixes: 8fa10ef ("ixgbe: register a mdiobus")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c

@@ -855,9 +855,11 @@ static struct pci_dev *ixgbe_get_first_secondary_devfn(unsigned int devfn)
 	rp_pdev = pci_get_domain_bus_and_slot(0, 0, devfn);
 	if (rp_pdev && rp_pdev->subordinate) {
 		bus = rp_pdev->subordinate->number;
+		pci_dev_put(rp_pdev);
 		return pci_get_domain_bus_and_slot(0, bus, 0);
 	}
 
+	pci_dev_put(rp_pdev);
 	return NULL;
 }
 
@@ -874,6 +876,7 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
 	struct ixgbe_adapter *adapter = hw->back;
 	struct pci_dev *pdev = adapter->pdev;
 	struct pci_dev *func0_pdev;
+	bool has_mii = false;
 
 	/* For the C3000 family of SoCs (x550em_a) the internal ixgbe devices
 	 * are always downstream of root ports @ 0000:00:16.0 & 0000:00:17.0
@@ -884,15 +887,16 @@ static bool ixgbe_x550em_a_has_mii(struct ixgbe_hw *hw)
 	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x16, 0));
 	if (func0_pdev) {
 		if (func0_pdev == pdev)
-			return true;
-		else
-			return false;
+			has_mii = true;
+		goto out;
 	}
 	func0_pdev = ixgbe_get_first_secondary_devfn(PCI_DEVFN(0x17, 0));
 	if (func0_pdev == pdev)
-		return true;
+		has_mii = true;
 
-	return false;
+out:
+	pci_dev_put(func0_pdev);
+	return has_mii;
 }
 
 /**