From: Bob Moore <robert.moore@xxxxxxxxx> Added a reader/writer locking mechanism to allow multiple concurrent namespace walks (readers), but a dynamic table unload will have exclusive access to the namespace. This fixes a problem where a table unload could delete the portion of the namespace that is currently being examined by a walk. Adds a new file, utlock.c that implements the reader/writer lock mechanism. ACPICA BZ 749. http://www.acpica.org/bugzilla/show_bug.cgi?id=749 Signed-off-by: Bob Moore <robert.moore@xxxxxxxxx> Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/acpica/Makefile | 2 +- drivers/acpi/acpica/acglobal.h | 4 + drivers/acpi/acpica/aclocal.h | 8 ++ drivers/acpi/acpica/actables.h | 2 +- drivers/acpi/acpica/acutils.h | 15 ++++ drivers/acpi/acpica/dsinit.c | 16 +++- drivers/acpi/acpica/exconfig.c | 13 ++-- drivers/acpi/acpica/nsxfeval.c | 33 ++++++-- drivers/acpi/acpica/tbinstal.c | 45 +++++++++-- drivers/acpi/acpica/utlock.c | 175 ++++++++++++++++++++++++++++++++++++++++ drivers/acpi/acpica/utmutex.c | 23 ++++-- 11 files changed, 303 insertions(+), 33 deletions(-) create mode 100644 drivers/acpi/acpica/utlock.c diff --git a/drivers/acpi/acpica/Makefile b/drivers/acpi/acpica/Makefile index 3f23298..290be74 100644 --- a/drivers/acpi/acpica/Makefile +++ b/drivers/acpi/acpica/Makefile @@ -41,4 +41,4 @@ obj-y += tbxface.o tbinstal.o tbutils.o tbfind.o tbfadt.o tbxfroot.o obj-y += utalloc.o utdebug.o uteval.o utinit.o utmisc.o utxface.o \ utcopy.o utdelete.o utglobal.o utmath.o utobject.o \ - utstate.o utmutex.o utobject.o utresrc.o + utstate.o utmutex.o utobject.o utresrc.o utlock.o diff --git a/drivers/acpi/acpica/acglobal.h b/drivers/acpi/acpica/acglobal.h index f3e87ba..f431b99 100644 --- a/drivers/acpi/acpica/acglobal.h +++ b/drivers/acpi/acpica/acglobal.h @@ -165,6 +165,10 @@ ACPI_EXTERN u8 acpi_gbl_integer_bit_width; ACPI_EXTERN u8 acpi_gbl_integer_byte_width; ACPI_EXTERN u8 acpi_gbl_integer_nybble_width; +/* Reader/Writer lock is used for namespace walk and dynamic table unload */ + +ACPI_EXTERN struct acpi_rw_lock acpi_gbl_namespace_rw_lock; + /***************************************************************************** * * Mutual exlusion within ACPICA subsystem diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h index 6feebc8..18a8d96 100644 --- a/drivers/acpi/acpica/aclocal.h +++ b/drivers/acpi/acpica/aclocal.h @@ -108,6 +108,14 @@ static char *acpi_gbl_mutex_names[ACPI_NUM_MUTEX] = { #endif #endif +/* Lock structure for reader/writer interfaces */ + +struct acpi_rw_lock { + acpi_mutex writer_mutex; + acpi_mutex reader_mutex; + u32 num_readers; +}; + /* * Predefined handles for spinlocks used within the subsystem. * These spinlocks are created by acpi_ut_mutex_initialize diff --git a/drivers/acpi/acpica/actables.h b/drivers/acpi/acpica/actables.h index d8f8c5d..01c76b8 100644 --- a/drivers/acpi/acpica/actables.h +++ b/drivers/acpi/acpica/actables.h @@ -79,7 +79,7 @@ void acpi_tb_delete_table(struct acpi_table_desc *table_desc); void acpi_tb_terminate(void); -void acpi_tb_delete_namespace_by_owner(u32 table_index); +acpi_status acpi_tb_delete_namespace_by_owner(u32 table_index); acpi_status acpi_tb_allocate_owner_id(u32 table_index); diff --git a/drivers/acpi/acpica/acutils.h b/drivers/acpi/acpica/acutils.h index 80d8813..897810b 100644 --- a/drivers/acpi/acpica/acutils.h +++ b/drivers/acpi/acpica/acutils.h @@ -346,6 +346,21 @@ acpi_status acpi_ut_execute_sxds(struct acpi_namespace_node *device_node, u8 * highest); /* + * utlock - reader/writer locks + */ +acpi_status acpi_ut_create_rw_lock(struct acpi_rw_lock *lock); + +void acpi_ut_delete_rw_lock(struct acpi_rw_lock *lock); + +acpi_status acpi_ut_acquire_read_lock(struct acpi_rw_lock *lock); + +acpi_status acpi_ut_release_read_lock(struct acpi_rw_lock *lock); + +acpi_status acpi_ut_acquire_write_lock(struct acpi_rw_lock *lock); + +void acpi_ut_release_write_lock(struct acpi_rw_lock *lock); + +/* * utobject - internal object create/delete/cache routines */ union acpi_operand_object *acpi_ut_create_internal_object_dbg(const char diff --git a/drivers/acpi/acpica/dsinit.c b/drivers/acpi/acpica/dsinit.c index eb144b1..3aae13f 100644 --- a/drivers/acpi/acpica/dsinit.c +++ b/drivers/acpi/acpica/dsinit.c @@ -180,11 +180,23 @@ acpi_ds_initialize_objects(u32 table_index, /* Walk entire namespace from the supplied root */ - status = acpi_walk_namespace(ACPI_TYPE_ANY, start_node, ACPI_UINT32_MAX, - acpi_ds_init_one_object, &info, NULL); + status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + /* + * We don't use acpi_walk_namespace since we do not want to acquire + * the namespace reader lock. + */ + status = + acpi_ns_walk_namespace(ACPI_TYPE_ANY, start_node, ACPI_UINT32_MAX, + ACPI_NS_WALK_UNLOCK, acpi_ds_init_one_object, + &info, NULL); if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "During WalkNamespace")); } + (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE); status = acpi_get_table_by_index(table_index, &table); if (ACPI_FAILURE(status)) { diff --git a/drivers/acpi/acpica/exconfig.c b/drivers/acpi/acpica/exconfig.c index 70b39c7..3deb20a 100644 --- a/drivers/acpi/acpica/exconfig.c +++ b/drivers/acpi/acpica/exconfig.c @@ -520,13 +520,14 @@ acpi_status acpi_ex_unload_table(union acpi_operand_object *ddb_handle) } } - /* - * Delete the entire namespace under this table Node - * (Offset contains the table_id) - */ - acpi_tb_delete_namespace_by_owner(table_index); - (void)acpi_tb_release_owner_id(table_index); + /* Delete the portion of the namespace owned by this table */ + + status = acpi_tb_delete_namespace_by_owner(table_index); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + (void)acpi_tb_release_owner_id(table_index); acpi_tb_set_table_loaded_flag(table_index, FALSE); /* Table unloaded, remove a reference to the ddb_handle object */ diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c index 2583a66..0450540 100644 --- a/drivers/acpi/acpica/nsxfeval.c +++ b/drivers/acpi/acpica/nsxfeval.c @@ -475,21 +475,40 @@ acpi_walk_namespace(acpi_object_type type, } /* - * Lock the namespace around the walk. - * The namespace will be unlocked/locked around each call - * to the user function - since this function - * must be allowed to make Acpi calls itself. + * Need to acquire the namespace reader lock to prevent interference + * with any concurrent table unloads (which causes the deletion of + * namespace objects). We cannot allow the deletion of a namespace node + * while the user function is using it. The exception to this are the + * nodes created and deleted during control method execution -- these + * nodes are marked as temporary nodes and are ignored by the namespace + * walk. Thus, control methods can be executed while holding the + * namespace deletion lock (and the user function can execute control + * methods.) + */ + status = acpi_ut_acquire_read_lock(&acpi_gbl_namespace_rw_lock); + if (ACPI_FAILURE(status)) { + return status; + } + + /* + * Lock the namespace around the walk. The namespace will be + * unlocked/locked around each call to the user function - since the user + * function must be allowed to make ACPICA calls itself (for example, it + * will typically execute control methods during device enumeration.) */ status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE); if (ACPI_FAILURE(status)) { - return_ACPI_STATUS(status); + goto unlock_and_exit; } status = acpi_ns_walk_namespace(type, start_object, max_depth, - ACPI_NS_WALK_UNLOCK, - user_function, context, return_value); + ACPI_NS_WALK_UNLOCK, user_function, + context, return_value); (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE); + + unlock_and_exit: + (void)acpi_ut_release_read_lock(&acpi_gbl_namespace_rw_lock); return_ACPI_STATUS(status); } diff --git a/drivers/acpi/acpica/tbinstal.c b/drivers/acpi/acpica/tbinstal.c index c379930..f865d5a 100644 --- a/drivers/acpi/acpica/tbinstal.c +++ b/drivers/acpi/acpica/tbinstal.c @@ -434,27 +434,56 @@ void acpi_tb_terminate(void) * * PARAMETERS: table_index - Table index * - * RETURN: None + * RETURN: Status * * DESCRIPTION: Delete all namespace objects created when this table was loaded. * ******************************************************************************/ -void acpi_tb_delete_namespace_by_owner(u32 table_index) +acpi_status acpi_tb_delete_namespace_by_owner(u32 table_index) { acpi_owner_id owner_id; + acpi_status status; + + ACPI_FUNCTION_TRACE(tb_delete_namespace_by_owner); + + status = acpi_ut_acquire_mutex(ACPI_MTX_TABLES); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + if (table_index >= acpi_gbl_root_table_list.count) { + + /* The table index does not exist */ - (void)acpi_ut_acquire_mutex(ACPI_MTX_TABLES); - if (table_index < acpi_gbl_root_table_list.count) { - owner_id = - acpi_gbl_root_table_list.tables[table_index].owner_id; - } else { (void)acpi_ut_release_mutex(ACPI_MTX_TABLES); - return; + return_ACPI_STATUS(AE_NOT_EXIST); } + /* Get the owner ID for this table, used to delete namespace nodes */ + + owner_id = acpi_gbl_root_table_list.tables[table_index].owner_id; (void)acpi_ut_release_mutex(ACPI_MTX_TABLES); + + /* + * Need to acquire the namespace writer lock to prevent interference + * with any concurrent namespace walks. The interpreter must be + * released during the deletion since the acquisition of the deletion + * lock may block, and also since the execution of a namespace walk + * must be allowed to use the interpreter. + */ + acpi_ut_release_mutex(ACPI_MTX_INTERPRETER); + status = acpi_ut_acquire_write_lock(&acpi_gbl_namespace_rw_lock); + acpi_ns_delete_namespace_by_owner(owner_id); + if (ACPI_FAILURE(status)) { + return_ACPI_STATUS(status); + } + + acpi_ut_release_write_lock(&acpi_gbl_namespace_rw_lock); + + status = acpi_ut_acquire_mutex(ACPI_MTX_INTERPRETER); + return_ACPI_STATUS(status); } /******************************************************************************* diff --git a/drivers/acpi/acpica/utlock.c b/drivers/acpi/acpica/utlock.c new file mode 100644 index 0000000..25e0312 --- /dev/null +++ b/drivers/acpi/acpica/utlock.c @@ -0,0 +1,175 @@ +/****************************************************************************** + * + * Module Name: utlock - Reader/Writer lock interfaces + * + *****************************************************************************/ + +/* + * Copyright (C) 2000 - 2009, 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" + +#define _COMPONENT ACPI_UTILITIES +ACPI_MODULE_NAME("utlock") + +/******************************************************************************* + * + * FUNCTION: acpi_ut_create_rw_lock + * acpi_ut_delete_rw_lock + * + * PARAMETERS: Lock - Pointer to a valid RW lock + * + * RETURN: Status + * + * DESCRIPTION: Reader/writer lock creation and deletion interfaces. + * + ******************************************************************************/ +acpi_status acpi_ut_create_rw_lock(struct acpi_rw_lock *lock) +{ + acpi_status status; + + lock->num_readers = 0; + status = acpi_os_create_mutex(&lock->reader_mutex); + if (ACPI_FAILURE(status)) { + return status; + } + + status = acpi_os_create_mutex(&lock->writer_mutex); + return status; +} + +void acpi_ut_delete_rw_lock(struct acpi_rw_lock *lock) +{ + + acpi_os_delete_mutex(lock->reader_mutex); + acpi_os_delete_mutex(lock->writer_mutex); + + lock->num_readers = 0; + lock->reader_mutex = NULL; + lock->writer_mutex = NULL; +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_acquire_read_lock + * acpi_ut_release_read_lock + * + * PARAMETERS: Lock - Pointer to a valid RW lock + * + * RETURN: Status + * + * DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition, + * only the first reader acquires the write mutex. On release, + * only the last reader releases the write mutex. Although this + * algorithm can in theory starve writers, this should not be a + * problem with ACPICA since the subsystem is infrequently used + * in comparison to (for example) an I/O system. + * + ******************************************************************************/ + +acpi_status acpi_ut_acquire_read_lock(struct acpi_rw_lock *lock) +{ + acpi_status status; + + status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER); + if (ACPI_FAILURE(status)) { + return status; + } + + /* Acquire the write lock only for the first reader */ + + lock->num_readers++; + if (lock->num_readers == 1) { + status = + acpi_os_acquire_mutex(lock->writer_mutex, + ACPI_WAIT_FOREVER); + } + + acpi_os_release_mutex(lock->reader_mutex); + return status; +} + +acpi_status acpi_ut_release_read_lock(struct acpi_rw_lock *lock) +{ + acpi_status status; + + status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER); + if (ACPI_FAILURE(status)) { + return status; + } + + /* Release the write lock only for the very last reader */ + + lock->num_readers--; + if (lock->num_readers == 0) { + acpi_os_release_mutex(lock->writer_mutex); + } + + acpi_os_release_mutex(lock->reader_mutex); + return status; +} + +/******************************************************************************* + * + * FUNCTION: acpi_ut_acquire_write_lock + * acpi_ut_release_write_lock + * + * PARAMETERS: Lock - Pointer to a valid RW lock + * + * RETURN: Status + * + * DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or + * release the writer mutex associated with the lock. Acquisition + * of the lock is fully exclusive and will block all readers and + * writers until it is released. + * + ******************************************************************************/ + +acpi_status acpi_ut_acquire_write_lock(struct acpi_rw_lock *lock) +{ + acpi_status status; + + status = acpi_os_acquire_mutex(lock->writer_mutex, ACPI_WAIT_FOREVER); + return status; +} + +void acpi_ut_release_write_lock(struct acpi_rw_lock *lock) +{ + + acpi_os_release_mutex(lock->writer_mutex); +} diff --git a/drivers/acpi/acpica/utmutex.c b/drivers/acpi/acpica/utmutex.c index 14eb52c..26c93a7 100644 --- a/drivers/acpi/acpica/utmutex.c +++ b/drivers/acpi/acpica/utmutex.c @@ -60,7 +60,8 @@ static acpi_status acpi_ut_delete_mutex(acpi_mutex_handle mutex_id); * * RETURN: Status * - * DESCRIPTION: Create the system mutex objects. + * DESCRIPTION: Create the system mutex objects. This includes mutexes, + * spin locks, and reader/writer locks. * ******************************************************************************/ @@ -71,9 +72,8 @@ acpi_status acpi_ut_mutex_initialize(void) ACPI_FUNCTION_TRACE(ut_mutex_initialize); - /* - * Create each of the predefined mutex objects - */ + /* Create each of the predefined mutex objects */ + for (i = 0; i < ACPI_NUM_MUTEX; i++) { status = acpi_ut_create_mutex(i); if (ACPI_FAILURE(status)) { @@ -86,6 +86,9 @@ acpi_status acpi_ut_mutex_initialize(void) spin_lock_init(acpi_gbl_gpe_lock); spin_lock_init(acpi_gbl_hardware_lock); + /* Create the reader/writer lock for namespace access */ + + status = acpi_ut_create_rw_lock(&acpi_gbl_namespace_rw_lock); return_ACPI_STATUS(status); } @@ -97,7 +100,8 @@ acpi_status acpi_ut_mutex_initialize(void) * * RETURN: None. * - * DESCRIPTION: Delete all of the system mutex objects. + * DESCRIPTION: Delete all of the system mutex objects. This includes mutexes, + * spin locks, and reader/writer locks. * ******************************************************************************/ @@ -107,9 +111,8 @@ void acpi_ut_mutex_terminate(void) ACPI_FUNCTION_TRACE(ut_mutex_terminate); - /* - * Delete each predefined mutex object - */ + /* Delete each predefined mutex object */ + for (i = 0; i < ACPI_NUM_MUTEX; i++) { (void)acpi_ut_delete_mutex(i); } @@ -118,6 +121,10 @@ void acpi_ut_mutex_terminate(void) acpi_os_delete_lock(acpi_gbl_gpe_lock); acpi_os_delete_lock(acpi_gbl_hardware_lock); + + /* Delete the reader/writer lock */ + + acpi_ut_delete_rw_lock(&acpi_gbl_namespace_rw_lock); return_VOID; } -- 1.6.0.6 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
