ACPICA: Add post-order callback to acpi_walk_namespace

The existing interface only has a pre-order callback. This change
adds an additional parameter for a post-order callback which will
be more useful for bus scans. ACPICA BZ 779.

Also update the external calls to acpi_walk_namespace.

http://www.acpica.org/bugzilla/show_bug.cgi?id=779

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 117 insertions, 83 deletions

diff --git a/drivers/acpi/acpica/nswalk.c b/drivers/acpi/acpica/nswalk.c
index 35539df5c75d..d7e6b52b4482 100644
--- a/drivers/acpi/acpica/nswalk.c
+++ b/drivers/acpi/acpica/nswalk.c
@@ -165,24 +165,27 @@ struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,
  *              max_depth           - Depth to which search is to reach
  *              Flags               - Whether to unlock the NS before invoking
  *                                    the callback routine
- *              user_function       - Called when an object of "Type" is found
- *              Context             - Passed to user function
- *              return_value        - from the user_function if terminated early.
- *                                    Otherwise, returns NULL.
+ *              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        - from the user_function if terminated
+ *                                    early. Otherwise, returns NULL.
  * RETURNS:     Status
  *
  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
  *              starting (and ending) at the node specified by start_handle.
- *              The user_function is called whenever a node that matches
- *              the type parameter is found.  If the user function returns
+ *              The callback function is called whenever a node 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.
  *
  ******************************************************************************/
 
@@ -191,7 +194,8 @@ acpi_ns_walk_namespace(acpi_object_type type,
 		       acpi_handle start_node,
 		       u32 max_depth,
 		       u32 flags,
-		       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;
@@ -200,6 +204,7 @@ acpi_ns_walk_namespace(acpi_object_type type,
 	struct acpi_namespace_node *parent_node;
 	acpi_object_type child_type;
 	u32 level;
+	u8 node_previously_visited = FALSE;
 
 	ACPI_FUNCTION_TRACE(ns_walk_namespace);
 
@@ -212,7 +217,7 @@ acpi_ns_walk_namespace(acpi_object_type type,
 	/* Null child means "get first node" */
 
 	parent_node = start_node;
-	child_node = NULL;
+	child_node = acpi_ns_get_next_node(parent_node, NULL);
 	child_type = ACPI_TYPE_ANY;
 	level = 1;
 
@@ -221,102 +226,129 @@ acpi_ns_walk_namespace(acpi_object_type type,
 	 * started. When Level is zero, the loop is done because we have
 	 * bubbled up to (and passed) the original parent handle (start_entry)
 	 */
-	while (level > 0) {
+	while (level > 0 && child_node) {
+		status = AE_OK;
 
-		/* Get the next node in this scope.  Null if not found */
+		/* Found next child, get the type if we are not searching for ANY */
 
-		status = AE_OK;
-		child_node = acpi_ns_get_next_node(parent_node, child_node);
-		if (child_node) {
+		if (type != ACPI_TYPE_ANY) {
+			child_type = child_node->type;
+		}
 
-			/* Found next child, get the type if we are not searching for ANY */
+		/*
+		 * Ignore all temporary namespace nodes (created during control
+		 * method execution) unless told otherwise. These temporary nodes
+		 * can cause a race condition because they can be deleted during
+		 * the execution of the user function (if the namespace is
+		 * unlocked before invocation of the user function.) Only the
+		 * debugger namespace dump will examine the temporary nodes.
+		 */
+		if ((child_node->flags & ANOBJ_TEMPORARY) &&
+		    !(flags & ACPI_NS_WALK_TEMP_NODES)) {
+			status = AE_CTRL_DEPTH;
+		}
 
-			if (type != ACPI_TYPE_ANY) {
-				child_type = child_node->type;
-			}
+		/* Type must match requested type */
 
+		else if (child_type == type) {
 			/*
-			 * Ignore all temporary namespace nodes (created during control
-			 * method execution) unless told otherwise. These temporary nodes
-			 * can cause a race condition because they can be deleted during
-			 * the execution of the user function (if the namespace is
-			 * unlocked before invocation of the user function.) Only the
-			 * debugger namespace dump will examine the temporary nodes.
+			 * Found a matching node, invoke the user callback function.
+			 * Unlock the namespace if flag is set.
 			 */
-			if ((child_node->flags & ANOBJ_TEMPORARY) &&
-			    !(flags & ACPI_NS_WALK_TEMP_NODES)) {
-				status = AE_CTRL_DEPTH;
+			if (flags & ACPI_NS_WALK_UNLOCK) {
+				mutex_status =
+				    acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+				if (ACPI_FAILURE(mutex_status)) {
+					return_ACPI_STATUS(mutex_status);
+				}
 			}
 
-			/* Type must match requested type */
-
-			else if (child_type == type) {
-				/*
-				 * Found a matching node, invoke the user callback function.
-				 * Unlock the namespace if flag is set.
-				 */
-				if (flags & ACPI_NS_WALK_UNLOCK) {
-					mutex_status =
-					    acpi_ut_release_mutex
-					    (ACPI_MTX_NAMESPACE);
-					if (ACPI_FAILURE(mutex_status)) {
-						return_ACPI_STATUS
-						    (mutex_status);
-					}
+			/*
+			 * Invoke the user function, either pre-order or post-order
+			 * or both.
+			 */
+			if (!node_previously_visited) {
+				if (pre_order_visit) {
+					status =
+					    pre_order_visit(child_node, level,
+							    context,
+							    return_value);
 				}
+			} else {
+				if (post_order_visit) {
+					status =
+					    post_order_visit(child_node, level,
+							     context,
+							     return_value);
+				}
+			}
 
-				status =
-				    user_function(child_node, level, context,
-						  return_value);
-
-				if (flags & ACPI_NS_WALK_UNLOCK) {
-					mutex_status =
-					    acpi_ut_acquire_mutex
-					    (ACPI_MTX_NAMESPACE);
-					if (ACPI_FAILURE(mutex_status)) {
-						return_ACPI_STATUS
-						    (mutex_status);
-					}
+			if (flags & ACPI_NS_WALK_UNLOCK) {
+				mutex_status =
+				    acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
+				if (ACPI_FAILURE(mutex_status)) {
+					return_ACPI_STATUS(mutex_status);
 				}
+			}
 
-				switch (status) {
-				case AE_OK:
-				case AE_CTRL_DEPTH:
+			switch (status) {
+			case AE_OK:
+			case AE_CTRL_DEPTH:
 
-					/* Just keep going */
-					break;
+				/* Just keep going */
+				break;
 
-				case AE_CTRL_TERMINATE:
+			case AE_CTRL_TERMINATE:
 
-					/* Exit now, with OK status */
+				/* Exit now, with OK status */
 
-					return_ACPI_STATUS(AE_OK);
+				return_ACPI_STATUS(AE_OK);
 
-				default:
+			default:
 
-					/* All others are valid exceptions */
+				/* All others are valid exceptions */
 
-					return_ACPI_STATUS(status);
-				}
+				return_ACPI_STATUS(status);
+			}
+		}
+
+		/*
+		 * Depth first search: Attempt to go down another level in the
+		 * namespace if we are allowed to.  Don't go any further if we have
+		 * reached the caller specified maximum depth or if the user
+		 * function has specified that the maximum depth has been reached.
+		 */
+		if (!node_previously_visited &&
+		    (level < max_depth) && (status != AE_CTRL_DEPTH)) {
+			if (child_node->child) {
+
+				/* There is at least one child of this node, visit it */
+
+				level++;
+				parent_node = child_node;
+				child_node =
+				    acpi_ns_get_next_node(parent_node, NULL);
+				continue;
 			}
+		}
 
-			/*
-			 * Depth first search: Attempt to go down another level in the
-			 * namespace if we are allowed to.  Don't go any further if we have
-			 * reached the caller specified maximum depth or if the user
-			 * function has specified that the maximum depth has been reached.
-			 */
-			if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
-				if (child_node->child) {
+		/* No more children, re-visit this node */
 
-					/* There is at least one child of this node, visit it */
+		if (!node_previously_visited) {
+			node_previously_visited = TRUE;
+			continue;
+		}
 
-					level++;
-					parent_node = child_node;
-					child_node = NULL;
-				}
-			}
-		} else {
+		/* No more children, visit peers */
+
+		child_node = acpi_ns_get_next_node(parent_node, child_node);
+		if (child_node) {
+			node_previously_visited = FALSE;
+		}
+
+		/* No peers, re-visit parent */
+
+		else {
 			/*
 			 * No more children of this node (acpi_ns_get_next_node failed), go
 			 * back upwards in the namespace tree to the node's parent.
@@ -324,6 +356,8 @@ acpi_ns_walk_namespace(acpi_object_type type,
 			level--;
 			child_node = parent_node;
 			parent_node = acpi_ns_get_parent_node(parent_node);
+
+			node_previously_visited = TRUE;
 		}
 	}