drivers/acpi/acpica/pswalk.c

/******************************************************************************
 *
 * Module Name: pswalk - Parser routines to walk parsed op tree(s)
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2017, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acparser.h"

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("pswalk")

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_delete_parse_tree
 *
 * PARAMETERS:  subtree_root        - Root of tree (or subtree) to delete
 *
 * RETURN:      None
 *
 * DESCRIPTION: Delete a portion of or an entire parse tree.
 *
 ******************************************************************************/
void acpi_ps_delete_parse_tree(union acpi_parse_object *subtree_root)
{
	union acpi_parse_object *op = subtree_root;
	union acpi_parse_object *next = NULL;
	union acpi_parse_object *parent = NULL;

	ACPI_FUNCTION_TRACE_PTR(ps_delete_parse_tree, subtree_root);

	/* Visit all nodes in the subtree */

	while (op) {

		/* Check if we are not ascending */

		if (op != parent) {

			/* Look for an argument or child of the current op */

			next = acpi_ps_get_arg(op, 0);
			if (next) {

				/* Still going downward in tree (Op is not completed yet) */

				op = next;
				continue;
			}
		}

		/* No more children, this Op is complete. */

		next = op->common.next;
		parent = op->common.parent;

		acpi_ps_free_op(op);

		/* If we are back to the starting point, the walk is complete. */

		if (op == subtree_root) {
			return_VOID;
		}

		if (next) {
			op = next;
		} else {
			op = parent;
		}
	}

	return_VOID;
}