forked from Minki/linux
0c9992315e
ACPICA commit b1c3656ef4950098e530be68d4b589584f06cddc
Prevent acpi_ns_walk_namespace() from crashing when called with
start_node equal to ACPI_ROOT_OBJECT if the Namespace has not been
instantiated yet and acpi_gbl_root_node is NULL.
For instance, this can happen if the kernel is run with "acpi=off"
in the command line.
Link: b1c3656ef4
Link: https://lore.kernel.org/linux-acpi/CAJZ5v0hJWW_vZ3wwajE7xT38aWjY7cZyvqMJpXHzUL98-SiCVQ@mail.gmail.com/
Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
328 lines
9.4 KiB
C
328 lines
9.4 KiB
C
// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
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/******************************************************************************
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*
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* Module Name: nswalk - Functions for walking the ACPI namespace
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*
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* Copyright (C) 2000 - 2021, Intel Corp.
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*
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*****************************************************************************/
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#include <acpi/acpi.h>
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#include "accommon.h"
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#include "acnamesp.h"
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#define _COMPONENT ACPI_NAMESPACE
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ACPI_MODULE_NAME("nswalk")
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/*******************************************************************************
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*
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* FUNCTION: acpi_ns_get_next_node
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*
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* PARAMETERS: parent_node - Parent node whose children we are
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* getting
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* child_node - Previous child that was found.
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* The NEXT child will be returned
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*
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* RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if
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* none is found.
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*
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* DESCRIPTION: Return the next peer node within the namespace. If Handle
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* is valid, Scope is ignored. Otherwise, the first node
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* within Scope is returned.
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*
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******************************************************************************/
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struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node
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*parent_node,
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struct acpi_namespace_node
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*child_node)
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{
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ACPI_FUNCTION_ENTRY();
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if (!child_node) {
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/* It's really the parent's _scope_ that we want */
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return (parent_node->child);
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}
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/* Otherwise just return the next peer */
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return (child_node->peer);
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}
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/*******************************************************************************
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*
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* FUNCTION: acpi_ns_get_next_node_typed
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*
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* PARAMETERS: type - Type of node to be searched for
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* parent_node - Parent node whose children we are
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* getting
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* child_node - Previous child that was found.
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* The NEXT child will be returned
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*
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* RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if
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* none is found.
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*
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* DESCRIPTION: Return the next peer node within the namespace. If Handle
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* is valid, Scope is ignored. Otherwise, the first node
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* within Scope is returned.
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*
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******************************************************************************/
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struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,
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struct
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acpi_namespace_node
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*parent_node,
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struct
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acpi_namespace_node
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*child_node)
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{
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struct acpi_namespace_node *next_node = NULL;
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ACPI_FUNCTION_ENTRY();
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next_node = acpi_ns_get_next_node(parent_node, child_node);
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/* If any type is OK, we are done */
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if (type == ACPI_TYPE_ANY) {
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/* next_node is NULL if we are at the end-of-list */
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return (next_node);
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}
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/* Must search for the node -- but within this scope only */
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while (next_node) {
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/* If type matches, we are done */
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if (next_node->type == type) {
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return (next_node);
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}
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/* Otherwise, move on to the next peer node */
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next_node = next_node->peer;
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}
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/* Not found */
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return (NULL);
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}
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/*******************************************************************************
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*
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* FUNCTION: acpi_ns_walk_namespace
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*
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* PARAMETERS: type - acpi_object_type to search for
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* start_node - Handle in namespace where search begins
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* max_depth - Depth to which search is to reach
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* flags - Whether to unlock the NS before invoking
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* the callback routine
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* descending_callback - Called during tree descent
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* when an object of "Type" is found
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* ascending_callback - Called during tree ascent
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* when an object of "Type" is found
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* context - Passed to user function(s) above
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* return_value - from the user_function if terminated
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* early. Otherwise, returns NULL.
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* RETURNS: Status
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*
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* DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
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* starting (and ending) at the node specified by start_handle.
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* The callback function is called whenever a node that matches
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* the type parameter is found. If the callback function returns
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* a non-zero value, the search is terminated immediately and
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* this value is returned to the caller.
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*
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* The point of this procedure is to provide a generic namespace
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* walk routine that can be called from multiple places to
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* provide multiple services; the callback function(s) can be
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* tailored to each task, whether it is a print function,
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* a compare function, etc.
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*
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******************************************************************************/
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acpi_status
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acpi_ns_walk_namespace(acpi_object_type type,
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acpi_handle start_node,
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u32 max_depth,
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u32 flags,
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acpi_walk_callback descending_callback,
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acpi_walk_callback ascending_callback,
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void *context, void **return_value)
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{
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acpi_status status;
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acpi_status mutex_status;
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struct acpi_namespace_node *child_node;
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struct acpi_namespace_node *parent_node;
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acpi_object_type child_type;
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u32 level;
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u8 node_previously_visited = FALSE;
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ACPI_FUNCTION_TRACE(ns_walk_namespace);
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/* Special case for the namespace Root Node */
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if (start_node == ACPI_ROOT_OBJECT) {
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start_node = acpi_gbl_root_node;
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if (!start_node) {
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return_ACPI_STATUS(AE_NO_NAMESPACE);
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}
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}
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/* Null child means "get first node" */
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parent_node = start_node;
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child_node = acpi_ns_get_next_node(parent_node, NULL);
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child_type = ACPI_TYPE_ANY;
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level = 1;
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/*
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* Traverse the tree of nodes until we bubble back up to where we
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* started. When Level is zero, the loop is done because we have
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* bubbled up to (and passed) the original parent handle (start_entry)
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*/
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while (level > 0 && child_node) {
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status = AE_OK;
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/* Found next child, get the type if we are not searching for ANY */
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if (type != ACPI_TYPE_ANY) {
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child_type = child_node->type;
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}
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/*
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* Ignore all temporary namespace nodes (created during control
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* method execution) unless told otherwise. These temporary nodes
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* can cause a race condition because they can be deleted during
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* the execution of the user function (if the namespace is
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* unlocked before invocation of the user function.) Only the
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* debugger namespace dump will examine the temporary nodes.
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*/
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if ((child_node->flags & ANOBJ_TEMPORARY) &&
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!(flags & ACPI_NS_WALK_TEMP_NODES)) {
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status = AE_CTRL_DEPTH;
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}
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/* Type must match requested type */
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else if (child_type == type) {
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/*
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* Found a matching node, invoke the user callback function.
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* Unlock the namespace if flag is set.
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*/
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if (flags & ACPI_NS_WALK_UNLOCK) {
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mutex_status =
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acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
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if (ACPI_FAILURE(mutex_status)) {
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return_ACPI_STATUS(mutex_status);
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}
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}
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/*
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* Invoke the user function, either descending, ascending,
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* or both.
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*/
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if (!node_previously_visited) {
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if (descending_callback) {
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status =
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descending_callback(child_node,
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level, context,
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return_value);
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}
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} else {
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if (ascending_callback) {
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status =
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ascending_callback(child_node,
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level, context,
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return_value);
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}
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}
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if (flags & ACPI_NS_WALK_UNLOCK) {
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mutex_status =
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acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
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if (ACPI_FAILURE(mutex_status)) {
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return_ACPI_STATUS(mutex_status);
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}
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}
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switch (status) {
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case AE_OK:
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case AE_CTRL_DEPTH:
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/* Just keep going */
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break;
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case AE_CTRL_TERMINATE:
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/* Exit now, with OK status */
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return_ACPI_STATUS(AE_OK);
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default:
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/* All others are valid exceptions */
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return_ACPI_STATUS(status);
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}
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}
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/*
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* Depth first search: Attempt to go down another level in the
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* namespace if we are allowed to. Don't go any further if we have
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* reached the caller specified maximum depth or if the user
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* function has specified that the maximum depth has been reached.
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*/
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if (!node_previously_visited &&
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(level < max_depth) && (status != AE_CTRL_DEPTH)) {
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if (child_node->child) {
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/* There is at least one child of this node, visit it */
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level++;
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parent_node = child_node;
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child_node =
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acpi_ns_get_next_node(parent_node, NULL);
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continue;
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}
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}
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/* No more children, re-visit this node */
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if (!node_previously_visited) {
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node_previously_visited = TRUE;
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continue;
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}
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/* No more children, visit peers */
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child_node = acpi_ns_get_next_node(parent_node, child_node);
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if (child_node) {
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node_previously_visited = FALSE;
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}
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/* No peers, re-visit parent */
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else {
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/*
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* No more children of this node (acpi_ns_get_next_node failed), go
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* back upwards in the namespace tree to the node's parent.
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*/
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level--;
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child_node = parent_node;
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parent_node = parent_node->parent;
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node_previously_visited = TRUE;
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}
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}
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/* Complete walk, not terminated by user function */
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return_ACPI_STATUS(AE_OK);
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}
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