[linux-2.6-block.git] / drivers / acpi / executer / exmutex.c


/******************************************************************************
 *
 * Module Name: exmutex - ASL Mutex Acquire/Release functions
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2006, R. Byron Moore
 * 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 <acpi/acinterp.h>

#define _COMPONENT          ACPI_EXECUTER
ACPI_MODULE_NAME("exmutex")

/* Local prototypes */
static void
acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
		   struct acpi_thread_state *thread);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_unlink_mutex
 *
 * PARAMETERS:  obj_desc            - The mutex to be unlinked
 *
 * RETURN:      None
 *
 * DESCRIPTION: Remove a mutex from the "acquired_mutex" list
 *
 ******************************************************************************/

void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
{
	struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;

	if (!thread) {
		return;
	}

	/* Doubly linked list */

	if (obj_desc->mutex.next) {
		(obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
	}

	if (obj_desc->mutex.prev) {
		(obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
	} else {
		thread->acquired_mutex_list = obj_desc->mutex.next;
	}
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_link_mutex
 *
 * PARAMETERS:  obj_desc        - The mutex to be linked
 *              Thread          - Current executing thread object
 *
 * RETURN:      None
 *
 * DESCRIPTION: Add a mutex to the "acquired_mutex" list for this walk
 *
 ******************************************************************************/

static void
acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
		   struct acpi_thread_state *thread)
{
	union acpi_operand_object *list_head;

	list_head = thread->acquired_mutex_list;

	/* This object will be the first object in the list */

	obj_desc->mutex.prev = NULL;
	obj_desc->mutex.next = list_head;

	/* Update old first object to point back to this object */

	if (list_head) {
		list_head->mutex.prev = obj_desc;
	}

	/* Update list head */

	thread->acquired_mutex_list = obj_desc;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_acquire_mutex
 *
 * PARAMETERS:  time_desc           - Timeout integer
 *              obj_desc            - Mutex object
 *              walk_state          - Current method execution state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Acquire an AML mutex
 *
 ******************************************************************************/

acpi_status
acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
		      union acpi_operand_object *obj_desc,
		      struct acpi_walk_state *walk_state)
{
	acpi_status status;

	ACPI_FUNCTION_TRACE_PTR("ex_acquire_mutex", obj_desc);

	if (!obj_desc) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	/* Sanity check -- we must have a valid thread ID */

	if (!walk_state->thread) {
		ACPI_REPORT_ERROR(("Cannot acquire Mutex [%4.4s], null thread info\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
		return_ACPI_STATUS(AE_AML_INTERNAL);
	}

	/*
	 * Current Sync must be less than or equal to the sync level of the
	 * mutex.  This mechanism provides some deadlock prevention
	 */
	if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
		ACPI_REPORT_ERROR(("Cannot acquire Mutex [%4.4s], incorrect sync_level\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
		return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
	}

	/* Support for multiple acquires by the owning thread */

	if (obj_desc->mutex.owner_thread) {
		/* Special case for Global Lock, allow all threads */

		if ((obj_desc->mutex.owner_thread->thread_id ==
		     walk_state->thread->thread_id) ||
		    (obj_desc->mutex.semaphore ==
		     acpi_gbl_global_lock_semaphore)) {
			/*
			 * The mutex is already owned by this thread,
			 * just increment the acquisition depth
			 */
			obj_desc->mutex.acquisition_depth++;
			return_ACPI_STATUS(AE_OK);
		}
	}

	/* Acquire the mutex, wait if necessary */

	status = acpi_ex_system_acquire_mutex(time_desc, obj_desc);
	if (ACPI_FAILURE(status)) {
		/* Includes failure from a timeout on time_desc */

		return_ACPI_STATUS(status);
	}

	/* Have the mutex: update mutex and walk info and save the sync_level */

	obj_desc->mutex.owner_thread = walk_state->thread;
	obj_desc->mutex.acquisition_depth = 1;
	obj_desc->mutex.original_sync_level =
	    walk_state->thread->current_sync_level;

	walk_state->thread->current_sync_level = obj_desc->mutex.sync_level;

	/* Link the mutex to the current thread for force-unlock at method exit */

	acpi_ex_link_mutex(obj_desc, walk_state->thread);

	return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_release_mutex
 *
 * PARAMETERS:  obj_desc            - The object descriptor for this op
 *              walk_state          - Current method execution state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Release a previously acquired Mutex.
 *
 ******************************************************************************/

acpi_status
acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
		      struct acpi_walk_state *walk_state)
{
	acpi_status status;

	ACPI_FUNCTION_TRACE("ex_release_mutex");

	if (!obj_desc) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	/* The mutex must have been previously acquired in order to release it */

	if (!obj_desc->mutex.owner_thread) {
		ACPI_REPORT_ERROR(("Cannot release Mutex [%4.4s], not acquired\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
		return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
	}

	/* Sanity check -- we must have a valid thread ID */

	if (!walk_state->thread) {
		ACPI_REPORT_ERROR(("Cannot release Mutex [%4.4s], null thread info\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
		return_ACPI_STATUS(AE_AML_INTERNAL);
	}

	/*
	 * The Mutex is owned, but this thread must be the owner.
	 * Special case for Global Lock, any thread can release
	 */
	if ((obj_desc->mutex.owner_thread->thread_id !=
	     walk_state->thread->thread_id)
	    && (obj_desc->mutex.semaphore != acpi_gbl_global_lock_semaphore)) {
		ACPI_REPORT_ERROR(("Thread %X cannot release Mutex [%4.4s] acquired by thread %X\n", walk_state->thread->thread_id, acpi_ut_get_node_name(obj_desc->mutex.node), obj_desc->mutex.owner_thread->thread_id));
		return_ACPI_STATUS(AE_AML_NOT_OWNER);
	}

	/*
	 * The sync level of the mutex must be less than or
	 * equal to the current sync level
	 */
	if (obj_desc->mutex.sync_level > walk_state->thread->current_sync_level) {
		ACPI_REPORT_ERROR(("Cannot release Mutex [%4.4s], incorrect sync_level\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
		return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
	}

	/* Match multiple Acquires with multiple Releases */

	obj_desc->mutex.acquisition_depth--;
	if (obj_desc->mutex.acquisition_depth != 0) {
		/* Just decrement the depth and return */

		return_ACPI_STATUS(AE_OK);
	}

	/* Unlink the mutex from the owner's list */

	acpi_ex_unlink_mutex(obj_desc);

	/* Release the mutex */

	status = acpi_ex_system_release_mutex(obj_desc);

	/* Update the mutex and walk state, restore sync_level before acquire */

	obj_desc->mutex.owner_thread = NULL;
	walk_state->thread->current_sync_level =
	    obj_desc->mutex.original_sync_level;

	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_release_all_mutexes
 *
 * PARAMETERS:  Thread          - Current executing thread object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Release all mutexes held by this thread
 *
 ******************************************************************************/

void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
{
	union acpi_operand_object *next = thread->acquired_mutex_list;
	union acpi_operand_object *this;
	acpi_status status;

	ACPI_FUNCTION_ENTRY();

	/* Traverse the list of owned mutexes, releasing each one */

	while (next) {
		this = next;
		next = this->mutex.next;

		this->mutex.acquisition_depth = 1;
		this->mutex.prev = NULL;
		this->mutex.next = NULL;

		/* Release the mutex */

		status = acpi_ex_system_release_mutex(this);
		if (ACPI_FAILURE(status)) {
			continue;
		}

		/* Mark mutex unowned */

		this->mutex.owner_thread = NULL;

		/* Update Thread sync_level (Last mutex is the important one) */

		thread->current_sync_level = this->mutex.original_sync_level;
	}
}
Commit	Line	Data
1da177e4 LT	1
	2	/******************************************************************************
	3	*
	4	* Module Name: exmutex - ASL Mutex Acquire/Release functions
	5	*
	6	*****************************************************************************/
	7
	8	/*
4a90c7e8	9	* Copyright (C) 2000 - 2006, R. Byron Moore
1da177e4 LT	10	* All rights reserved.
	11	*
	12	* Redistribution and use in source and binary forms, with or without
	13	* modification, are permitted provided that the following conditions
	14	* are met:
	15	* 1. Redistributions of source code must retain the above copyright
	16	* notice, this list of conditions, and the following disclaimer,
	17	* without modification.
	18	* 2. Redistributions in binary form must reproduce at minimum a disclaimer
	19	* substantially similar to the "NO WARRANTY" disclaimer below
	20	* ("Disclaimer") and any redistribution must be conditioned upon
	21	* including a substantially similar Disclaimer requirement for further
	22	* binary redistribution.
	23	* 3. Neither the names of the above-listed copyright holders nor the names
	24	* of any contributors may be used to endorse or promote products derived
	25	* from this software without specific prior written permission.
	26	*
	27	* Alternatively, this software may be distributed under the terms of the
	28	* GNU General Public License ("GPL") version 2 as published by the Free
	29	* Software Foundation.
	30	*
	31	* NO WARRANTY
	32	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	33	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	34	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
	35	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	36	* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	37	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	38	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	39	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	40	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	41	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	42	* POSSIBILITY OF SUCH DAMAGES.
	43	*/
	44
1da177e4 LT	45	#include <acpi/acpi.h>
	46	#include <acpi/acinterp.h>
	47
	48	#define _COMPONENT ACPI_EXECUTER
4be44fcd	49	ACPI_MODULE_NAME("exmutex")
1da177e4	50
44f6c012	51	/* Local prototypes */
44f6c012	52	static void
4be44fcd LB	53	acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
4be44fcd LB	54	struct acpi_thread_state *thread);
1da177e4 LT	55
	56	/*******************************************************************************
	57	*
	58	* FUNCTION: acpi_ex_unlink_mutex
	59	*
	60	* PARAMETERS: obj_desc - The mutex to be unlinked
	61	*
44f6c012	62	* RETURN: None
1da177e4 LT	63	*
	64	* DESCRIPTION: Remove a mutex from the "acquired_mutex" list
	65	*
	66	******************************************************************************/
	67
4be44fcd	68	void acpi_ex_unlink_mutex(union acpi_operand_object *obj_desc)
1da177e4	69	{
4be44fcd	70	struct acpi_thread_state *thread = obj_desc->mutex.owner_thread;
1da177e4 LT	71
	72	if (!thread) {
	73	return;
	74	}
	75
	76	/* Doubly linked list */
	77
	78	if (obj_desc->mutex.next) {
	79	(obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
	80	}
	81
	82	if (obj_desc->mutex.prev) {
	83	(obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
4be44fcd	84	} else {
1da177e4 LT	85	thread->acquired_mutex_list = obj_desc->mutex.next;
	86	}
	87	}
	88
1da177e4 LT	89	/*******************************************************************************
	90	*
	91	* FUNCTION: acpi_ex_link_mutex
	92	*
44f6c012 RM	93	* PARAMETERS: obj_desc - The mutex to be linked
44f6c012 RM	94	* Thread - Current executing thread object
1da177e4	95	*
44f6c012	96	* RETURN: None
1da177e4 LT	97	*
	98	* DESCRIPTION: Add a mutex to the "acquired_mutex" list for this walk
	99	*
	100	******************************************************************************/
	101
44f6c012	102	static void
4be44fcd LB	103	acpi_ex_link_mutex(union acpi_operand_object *obj_desc,
4be44fcd LB	104	struct acpi_thread_state *thread)
1da177e4	105	{
4be44fcd	106	union acpi_operand_object *list_head;
1da177e4 LT	107
	108	list_head = thread->acquired_mutex_list;
	109
	110	/* This object will be the first object in the list */
	111
	112	obj_desc->mutex.prev = NULL;
	113	obj_desc->mutex.next = list_head;
	114
	115	/* Update old first object to point back to this object */
	116
	117	if (list_head) {
	118	list_head->mutex.prev = obj_desc;
	119	}
	120
	121	/* Update list head */
	122
	123	thread->acquired_mutex_list = obj_desc;
	124	}
	125
1da177e4 LT	126	/*******************************************************************************
	127	*
	128	* FUNCTION: acpi_ex_acquire_mutex
	129	*
44f6c012 RM	130	* PARAMETERS: time_desc - Timeout integer
	131	* obj_desc - Mutex object
	132	* walk_state - Current method execution state
1da177e4 LT	133	*
	134	* RETURN: Status
	135	*
	136	* DESCRIPTION: Acquire an AML mutex
	137	*
	138	******************************************************************************/
	139
	140	acpi_status
4be44fcd LB	141	acpi_ex_acquire_mutex(union acpi_operand_object *time_desc,
	142	union acpi_operand_object *obj_desc,
	143	struct acpi_walk_state *walk_state)
1da177e4	144	{
4be44fcd	145	acpi_status status;
1da177e4	146
4be44fcd	147	ACPI_FUNCTION_TRACE_PTR("ex_acquire_mutex", obj_desc);
1da177e4 LT	148
1da177e4 LT	149	if (!obj_desc) {
4be44fcd	150	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	151	}
	152
	153	/* Sanity check -- we must have a valid thread ID */
	154
	155	if (!walk_state->thread) {
4be44fcd LB	156	ACPI_REPORT_ERROR(("Cannot acquire Mutex [%4.4s], null thread info\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
4be44fcd LB	157	return_ACPI_STATUS(AE_AML_INTERNAL);
1da177e4 LT	158	}
	159
	160	/*
	161	* Current Sync must be less than or equal to the sync level of the
	162	* mutex. This mechanism provides some deadlock prevention
	163	*/
	164	if (walk_state->thread->current_sync_level > obj_desc->mutex.sync_level) {
4be44fcd LB	165	ACPI_REPORT_ERROR(("Cannot acquire Mutex [%4.4s], incorrect sync_level\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
4be44fcd LB	166	return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
1da177e4 LT	167	}
	168
	169	/* Support for multiple acquires by the owning thread */
	170
	171	if (obj_desc->mutex.owner_thread) {
	172	/* Special case for Global Lock, allow all threads */
	173
44f6c012	174	if ((obj_desc->mutex.owner_thread->thread_id ==
4be44fcd LB	175	walk_state->thread->thread_id) \|\|
	176	(obj_desc->mutex.semaphore ==
	177	acpi_gbl_global_lock_semaphore)) {
1da177e4 LT	178	/*
	179	* The mutex is already owned by this thread,
	180	* just increment the acquisition depth
	181	*/
	182	obj_desc->mutex.acquisition_depth++;
4be44fcd	183	return_ACPI_STATUS(AE_OK);
1da177e4 LT	184	}
	185	}
	186
	187	/* Acquire the mutex, wait if necessary */
	188
4be44fcd LB	189	status = acpi_ex_system_acquire_mutex(time_desc, obj_desc);
4be44fcd LB	190	if (ACPI_FAILURE(status)) {
1da177e4 LT	191	/* Includes failure from a timeout on time_desc */
1da177e4 LT	192
4be44fcd	193	return_ACPI_STATUS(status);
1da177e4 LT	194	}
	195
	196	/* Have the mutex: update mutex and walk info and save the sync_level */
	197
4be44fcd	198	obj_desc->mutex.owner_thread = walk_state->thread;
1da177e4	199	obj_desc->mutex.acquisition_depth = 1;
4be44fcd LB	200	obj_desc->mutex.original_sync_level =
4be44fcd LB	201	walk_state->thread->current_sync_level;
1da177e4 LT	202
	203	walk_state->thread->current_sync_level = obj_desc->mutex.sync_level;
	204
	205	/* Link the mutex to the current thread for force-unlock at method exit */
	206
4be44fcd	207	acpi_ex_link_mutex(obj_desc, walk_state->thread);
1da177e4	208
4be44fcd	209	return_ACPI_STATUS(AE_OK);
1da177e4 LT	210	}
1da177e4 LT	211
1da177e4 LT	212	/*******************************************************************************
	213	*
	214	* FUNCTION: acpi_ex_release_mutex
	215	*
	216	* PARAMETERS: obj_desc - The object descriptor for this op
44f6c012	217	* walk_state - Current method execution state
1da177e4 LT	218	*
	219	* RETURN: Status
	220	*
	221	* DESCRIPTION: Release a previously acquired Mutex.
	222	*
	223	******************************************************************************/
	224
	225	acpi_status
4be44fcd LB	226	acpi_ex_release_mutex(union acpi_operand_object *obj_desc,
4be44fcd LB	227	struct acpi_walk_state *walk_state)
1da177e4	228	{
4be44fcd	229	acpi_status status;
1da177e4	230
4be44fcd	231	ACPI_FUNCTION_TRACE("ex_release_mutex");
1da177e4 LT	232
1da177e4 LT	233	if (!obj_desc) {
4be44fcd	234	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	235	}
	236
	237	/* The mutex must have been previously acquired in order to release it */
	238
	239	if (!obj_desc->mutex.owner_thread) {
4be44fcd LB	240	ACPI_REPORT_ERROR(("Cannot release Mutex [%4.4s], not acquired\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
4be44fcd LB	241	return_ACPI_STATUS(AE_AML_MUTEX_NOT_ACQUIRED);
1da177e4 LT	242	}
	243
	244	/* Sanity check -- we must have a valid thread ID */
	245
	246	if (!walk_state->thread) {
4be44fcd LB	247	ACPI_REPORT_ERROR(("Cannot release Mutex [%4.4s], null thread info\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
4be44fcd LB	248	return_ACPI_STATUS(AE_AML_INTERNAL);
1da177e4 LT	249	}
	250
	251	/*
	252	* The Mutex is owned, but this thread must be the owner.
	253	* Special case for Global Lock, any thread can release
	254	*/
4be44fcd LB	255	if ((obj_desc->mutex.owner_thread->thread_id !=
	256	walk_state->thread->thread_id)
	257	&& (obj_desc->mutex.semaphore != acpi_gbl_global_lock_semaphore)) {
	258	ACPI_REPORT_ERROR(("Thread %X cannot release Mutex [%4.4s] acquired by thread %X\n", walk_state->thread->thread_id, acpi_ut_get_node_name(obj_desc->mutex.node), obj_desc->mutex.owner_thread->thread_id));
	259	return_ACPI_STATUS(AE_AML_NOT_OWNER);
1da177e4 LT	260	}
	261
	262	/*
	263	* The sync level of the mutex must be less than or
	264	* equal to the current sync level
	265	*/
	266	if (obj_desc->mutex.sync_level > walk_state->thread->current_sync_level) {
4be44fcd LB	267	ACPI_REPORT_ERROR(("Cannot release Mutex [%4.4s], incorrect sync_level\n", acpi_ut_get_node_name(obj_desc->mutex.node)));
4be44fcd LB	268	return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
1da177e4 LT	269	}
	270
	271	/* Match multiple Acquires with multiple Releases */
	272
	273	obj_desc->mutex.acquisition_depth--;
	274	if (obj_desc->mutex.acquisition_depth != 0) {
	275	/* Just decrement the depth and return */
	276
4be44fcd	277	return_ACPI_STATUS(AE_OK);
1da177e4 LT	278	}
	279
	280	/* Unlink the mutex from the owner's list */
	281
4be44fcd	282	acpi_ex_unlink_mutex(obj_desc);
1da177e4 LT	283
	284	/* Release the mutex */
	285
4be44fcd	286	status = acpi_ex_system_release_mutex(obj_desc);
1da177e4 LT	287
	288	/* Update the mutex and walk state, restore sync_level before acquire */
	289
	290	obj_desc->mutex.owner_thread = NULL;
4be44fcd LB	291	walk_state->thread->current_sync_level =
4be44fcd LB	292	obj_desc->mutex.original_sync_level;
1da177e4	293
4be44fcd	294	return_ACPI_STATUS(status);
1da177e4 LT	295	}
1da177e4 LT	296
1da177e4 LT	297	/*******************************************************************************
	298	*
	299	* FUNCTION: acpi_ex_release_all_mutexes
	300	*
44f6c012	301	* PARAMETERS: Thread - Current executing thread object
1da177e4 LT	302	*
	303	* RETURN: Status
	304	*
44f6c012	305	* DESCRIPTION: Release all mutexes held by this thread
1da177e4 LT	306	*
	307	******************************************************************************/
	308
4be44fcd	309	void acpi_ex_release_all_mutexes(struct acpi_thread_state *thread)
1da177e4	310	{
4be44fcd LB	311	union acpi_operand_object *next = thread->acquired_mutex_list;
	312	union acpi_operand_object *this;
	313	acpi_status status;
1da177e4	314
4be44fcd	315	ACPI_FUNCTION_ENTRY();
1da177e4 LT	316
	317	/* Traverse the list of owned mutexes, releasing each one */
	318
	319	while (next) {
	320	this = next;
	321	next = this->mutex.next;
	322
	323	this->mutex.acquisition_depth = 1;
4be44fcd LB	324	this->mutex.prev = NULL;
4be44fcd LB	325	this->mutex.next = NULL;
1da177e4	326
4be44fcd	327	/* Release the mutex */
1da177e4	328
4be44fcd LB	329	status = acpi_ex_system_release_mutex(this);
4be44fcd LB	330	if (ACPI_FAILURE(status)) {
1da177e4 LT	331	continue;
	332	}
	333
	334	/* Mark mutex unowned */
	335
	336	this->mutex.owner_thread = NULL;
	337
	338	/* Update Thread sync_level (Last mutex is the important one) */
	339
	340	thread->current_sync_level = this->mutex.original_sync_level;
	341	}
	342	}