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>

1 files changed, 6 insertions, 6 deletions

diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 3cee2367459f..092e82e0048c 100644
--- 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)