[ACPI] fix run-time error checking in acpi_pci_irq_disable()

The 'bus' field in pci_dev structure should be checked before calling
pci_read_config_byte() because pci_bus_read_config_byte() called by
pci_read_config_byte() refers to 'bus' field.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 2bbfba8e8c6d..09567c2edcfb 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -500,7 +500,7 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
 
         ACPI_FUNCTION_TRACE("acpi_pci_irq_disable");
 
-        if (!dev)
+        if (!dev || !dev->bus)
                 return_VOID;
 
         pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
@@ -508,9 +508,6 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
                 return_VOID;
         pin--;
 
-        if (!dev->bus)
-                return_VOID;
-
         /*
          * First we check the PCI IRQ routing table (PRT) for an IRQ.
          */