diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c
index 4929dbd..f2bd1da 100644
--- a/drivers/acpi/acpica/nsxfeval.c
+++ b/drivers/acpi/acpica/nsxfeval.c
@@ -433,8 +433,11 @@
  * PARAMETERS:  Type                - acpi_object_type to search for
  *              start_object        - Handle in namespace where search begins
  *              max_depth           - Depth to which search is to reach
- *              user_function       - Called when an object of "Type" is found
- *              Context             - Passed to user function
+ *              pre_order_visit     - Called during tree pre-order visit
+ *                                    when an object of "Type" is found
+ *              post_order_visit    - Called during tree post-order visit
+ *                                    when an object of "Type" is found
+ *              Context             - Passed to user function(s) above
  *              return_value        - Location where return value of
  *                                    user_function is put if terminated early
  *
@@ -443,16 +446,16 @@
  *
  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
  *              starting (and ending) at the object specified by start_handle.
- *              The user_function is called whenever an object that matches
- *              the type parameter is found.  If the user function returns
+ *              The callback function is called whenever an object that matches
+ *              the type parameter is found. If the callback function returns
  *              a non-zero value, the search is terminated immediately and this
  *              value is returned to the caller.
  *
  *              The point of this procedure is to provide a generic namespace
  *              walk routine that can be called from multiple places to
- *              provide multiple services;  the User Function can be tailored
- *              to each task, whether it is a print function, a compare
- *              function, etc.
+ *              provide multiple services; the callback function(s) can be
+ *              tailored to each task, whether it is a print function,
+ *              a compare function, etc.
  *
  ******************************************************************************/
 
@@ -460,7 +463,8 @@
 acpi_walk_namespace(acpi_object_type type,
 		    acpi_handle start_object,
 		    u32 max_depth,
-		    acpi_walk_callback user_function,
+		    acpi_walk_callback pre_order_visit,
+		    acpi_walk_callback post_order_visit,
 		    void *context, void **return_value)
 {
 	acpi_status status;
@@ -469,7 +473,8 @@
 
 	/* Parameter validation */
 
-	if ((type > ACPI_TYPE_LOCAL_MAX) || (!max_depth) || (!user_function)) {
+	if ((type > ACPI_TYPE_LOCAL_MAX) ||
+	    (!max_depth) || (!pre_order_visit && !post_order_visit)) {
 		return_ACPI_STATUS(AE_BAD_PARAMETER);
 	}
 
@@ -501,8 +506,9 @@
 	}
 
 	status = acpi_ns_walk_namespace(type, start_object, max_depth,
-					ACPI_NS_WALK_UNLOCK, user_function,
-					context, return_value);
+					ACPI_NS_WALK_UNLOCK, pre_order_visit,
+					post_order_visit, context,
+					return_value);
 
 	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 
@@ -681,8 +687,8 @@
 
 	status = acpi_ns_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 					ACPI_UINT32_MAX, ACPI_NS_WALK_UNLOCK,
-					acpi_ns_get_device_callback, &info,
-					return_value);
+					acpi_ns_get_device_callback, NULL,
+					&info, return_value);
 
 	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 	return_ACPI_STATUS(status);