PCI/ACPI: Use acpi_driver_data() rather than searching acpi_pci_roots

This patch changes the implementation of acpi_pci_find_root(). We can access acpi_pci_root without scanning acpi_pci_roots list. If hostbridge hotplug is supported, acpi_pci_roots list will be protected by mutex. We should not access acpi_pci_roots list if preventable to lessen deadlock risk. Signed-off-by: Taku Izumi <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]>
syzer · Sep 24, 2012 · cd4faf9 · cd4faf9
1 parent 6507e6e
commit cd4faf9
Showing 1 changed file with 8 additions and 5 deletions.
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
@@ -270,12 +270,15 @@ static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 {
 	struct acpi_pci_root *root;
+	struct acpi_device *device;
 
-	list_for_each_entry(root, &acpi_pci_roots, node) {
-		if (root->device->handle == handle)
-			return root;
-	}
-	return NULL;
+	if (acpi_bus_get_device(handle, &device) ||
+	    acpi_match_device_ids(device, root_device_ids))
+		return NULL;
+
+	root = acpi_driver_data(device);
+
+	return root;
 }
 EXPORT_SYMBOL_GPL(acpi_pci_find_root);