PCI hotplug: fix wrong assumption in acpi_get_hp_params_from_firmware

Current acpi_get_hp_params_from_firmware() has a assumption that
pci_bus->self is NULL on the root pci bus. But it might not true on
some platforms. Because of this wrong assumption, current
acpi_get_hp_params_from_firmware() might cause endless loop. We must
check pci_bus->parent instead.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 6 insertions, 11 deletions

diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
index f47bc74be567..09a84402986d 100644
--- a/drivers/pci/hotplug/acpi_pcihp.c
+++ b/drivers/pci/hotplug/acpi_pcihp.c
@@ -332,19 +332,14 @@ acpi_status acpi_get_hp_params_from_firmware(struct pci_bus *bus,
 {
         acpi_status status = AE_NOT_FOUND;
         acpi_handle handle, phandle;
-        struct pci_bus *pbus = bus;
-        struct pci_dev *pdev;
+        struct pci_bus *pbus;
 
-        do {
-                pdev = pbus->self;
-                if (!pdev) {
-                        handle = acpi_get_pci_rootbridge_handle(
-                                pci_domain_nr(pbus), pbus->number);
+        handle = NULL;
+        for (pbus = bus; pbus; pbus = pbus->parent) {
+                handle = acpi_pci_get_bridge_handle(pbus);
+                if (handle)
                         break;
-                }
-                handle = DEVICE_ACPI_HANDLE(&(pdev->dev));
-                pbus = pbus->parent;
-        } while (!handle);
+        }
 
         /*
          * _HPP settings apply to all child buses, until another _HPP is