ACPI PCI hotplug: harden against panic regression

ACPI hotplug panic with current git head
http://lkml.org/lkml/2009/1/10/136

Rather than reverting the entire commit that causes the crash:
e8c331e963c58b83db24b7d0e39e8c07f687dbc6
"PCI hotplug: introduce functions for ACPI slot detection"

simply harden against it while the changes to
the hotplug code on this particularl machine are understood.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index f09b1010d477..803d9ddd6e75 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -266,6 +266,8 @@ static int detect_ejectable_slots(struct pci_bus *pbus)
         int found = acpi_pci_detect_ejectable(pbus);
         if (!found) {
                 acpi_handle bridge_handle = acpi_pci_get_bridge_handle(pbus);
+                if (!bridge_handle)
+                        return 0;
                 acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge_handle, (u32)1,
                                     is_pci_dock_device, (void *)&found, NULL);
         }