PCI/ACPI: fix wrong assumption in acpi_find_root_bridge_handle

Current acpi_find_root_bridge_handle() has a assumption that
pci_bus->self is NULL on the root pci bus. But it might not be true on
some platforms. Because of this wrong assumption, current
acpi_find_root_bridge_handle() 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>

diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 3cee236..092e82e 100644 (file)
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -13,12 +13,12 @@
 #ifdef CONFIG_ACPI
 static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
 {
-       /* Find root host bridge */
-       while (pdev->bus->self)
-               pdev = pdev->bus->self;
-
-       return acpi_get_pci_rootbridge_handle(pci_domain_nr(pdev->bus),
-                       pdev->bus->number);
+       struct pci_bus *pbus = pdev->bus;
+       /* Find a PCI root bus */
+       while (pbus->parent)
+               pbus = pbus->parent;
+       return acpi_get_pci_rootbridge_handle(pci_domain_nr(pbus),
+                                             pbus->number);
 }
 
 static inline acpi_handle acpi_pci_get_bridge_handle(struct pci_bus *pbus)