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;
                 }
         }