diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-05 14:16:25 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-05 14:16:25 -0400 |
| commit | 32fb6c17566ec66de87324a834c7776f40e35e78 (patch) | |
| tree | 87b8ed5d66495536fbb452255c3eacd1cfb0c43a /drivers/acpi/acpica/utlock.c | |
| parent | 45e36c1666aa6c8b0c538abcf984b336184d8c3f (diff) | |
| parent | 7ec0a7290797f57b780f792d12f4bcc19c83aa4f (diff) | |
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (140 commits)
ACPI: processor: use .notify method instead of installing handler directly
ACPI: button: use .notify method instead of installing handler directly
ACPI: support acpi_device_ops .notify methods
toshiba-acpi: remove MAINTAINERS entry
ACPI: battery: asynchronous init
acer-wmi: Update copyright notice & documentation
acer-wmi: Cleanup the failure cleanup handling
acer-wmi: Blacklist Acer Aspire One
video: build fix
thinkpad-acpi: rework brightness support
thinkpad-acpi: enhanced debugging messages for the fan subdriver
thinkpad-acpi: enhanced debugging messages for the hotkey subdriver
thinkpad-acpi: enhanced debugging messages for rfkill subdrivers
thinkpad-acpi: restrict access to some firmware LEDs
thinkpad-acpi: remove HKEY disable functionality
thinkpad-acpi: add new debug helpers and warn of deprecated atts
thinkpad-acpi: add missing log levels
thinkpad-acpi: cleanup debug helpers
thinkpad-acpi: documentation cleanup
thinkpad-acpi: drop ibm-acpi alias
...
Diffstat (limited to 'drivers/acpi/acpica/utlock.c')
| -rw-r--r-- | drivers/acpi/acpica/utlock.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/utlock.c b/drivers/acpi/acpica/utlock.c new file mode 100644 index 000000000000..25e03120686d --- /dev/null +++ b/drivers/acpi/acpica/utlock.c | |||
| @@ -0,0 +1,175 @@ | |||
| 1 | /****************************************************************************** | ||
| 2 | * | ||
| 3 | * Module Name: utlock - Reader/Writer lock interfaces | ||
| 4 | * | ||
| 5 | *****************************************************************************/ | ||
| 6 | |||
| 7 | /* | ||
| 8 | * Copyright (C) 2000 - 2009, Intel Corp. | ||
| 9 | * All rights reserved. | ||
| 10 | * | ||
| 11 | * Redistribution and use in source and binary forms, with or without | ||
| 12 | * modification, are permitted provided that the following conditions | ||
| 13 | * are met: | ||
| 14 | * 1. Redistributions of source code must retain the above copyright | ||
| 15 | * notice, this list of conditions, and the following disclaimer, | ||
| 16 | * without modification. | ||
| 17 | * 2. Redistributions in binary form must reproduce at minimum a disclaimer | ||
| 18 | * substantially similar to the "NO WARRANTY" disclaimer below | ||
| 19 | * ("Disclaimer") and any redistribution must be conditioned upon | ||
| 20 | * including a substantially similar Disclaimer requirement for further | ||
| 21 | * binary redistribution. | ||
| 22 | * 3. Neither the names of the above-listed copyright holders nor the names | ||
| 23 | * of any contributors may be used to endorse or promote products derived | ||
| 24 | * from this software without specific prior written permission. | ||
| 25 | * | ||
| 26 | * Alternatively, this software may be distributed under the terms of the | ||
| 27 | * GNU General Public License ("GPL") version 2 as published by the Free | ||
| 28 | * Software Foundation. | ||
| 29 | * | ||
| 30 | * NO WARRANTY | ||
| 31 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | ||
| 32 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | ||
| 33 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR | ||
| 34 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | ||
| 35 | * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | ||
| 36 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | ||
| 37 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
| 38 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | ||
| 39 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING | ||
| 40 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | ||
| 41 | * POSSIBILITY OF SUCH DAMAGES. | ||
| 42 | */ | ||
| 43 | |||
| 44 | #include <acpi/acpi.h> | ||
| 45 | #include "accommon.h" | ||
| 46 | |||
| 47 | #define _COMPONENT ACPI_UTILITIES | ||
| 48 | ACPI_MODULE_NAME("utlock") | ||
| 49 | |||
| 50 | /******************************************************************************* | ||
| 51 | * | ||
| 52 | * FUNCTION: acpi_ut_create_rw_lock | ||
| 53 | * acpi_ut_delete_rw_lock | ||
| 54 | * | ||
| 55 | * PARAMETERS: Lock - Pointer to a valid RW lock | ||
| 56 | * | ||
| 57 | * RETURN: Status | ||
| 58 | * | ||
| 59 | * DESCRIPTION: Reader/writer lock creation and deletion interfaces. | ||
| 60 | * | ||
| 61 | ******************************************************************************/ | ||
| 62 | acpi_status acpi_ut_create_rw_lock(struct acpi_rw_lock *lock) | ||
| 63 | { | ||
| 64 | acpi_status status; | ||
| 65 | |||
| 66 | lock->num_readers = 0; | ||
| 67 | status = acpi_os_create_mutex(&lock->reader_mutex); | ||
| 68 | if (ACPI_FAILURE(status)) { | ||
| 69 | return status; | ||
| 70 | } | ||
| 71 | |||
| 72 | status = acpi_os_create_mutex(&lock->writer_mutex); | ||
| 73 | return status; | ||
| 74 | } | ||
| 75 | |||
| 76 | void acpi_ut_delete_rw_lock(struct acpi_rw_lock *lock) | ||
| 77 | { | ||
| 78 | |||
| 79 | acpi_os_delete_mutex(lock->reader_mutex); | ||
| 80 | acpi_os_delete_mutex(lock->writer_mutex); | ||
| 81 | |||
| 82 | lock->num_readers = 0; | ||
| 83 | lock->reader_mutex = NULL; | ||
| 84 | lock->writer_mutex = NULL; | ||
| 85 | } | ||
| 86 | |||
| 87 | /******************************************************************************* | ||
| 88 | * | ||
| 89 | * FUNCTION: acpi_ut_acquire_read_lock | ||
| 90 | * acpi_ut_release_read_lock | ||
| 91 | * | ||
| 92 | * PARAMETERS: Lock - Pointer to a valid RW lock | ||
| 93 | * | ||
| 94 | * RETURN: Status | ||
| 95 | * | ||
| 96 | * DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition, | ||
| 97 | * only the first reader acquires the write mutex. On release, | ||
| 98 | * only the last reader releases the write mutex. Although this | ||
| 99 | * algorithm can in theory starve writers, this should not be a | ||
| 100 | * problem with ACPICA since the subsystem is infrequently used | ||
| 101 | * in comparison to (for example) an I/O system. | ||
| 102 | * | ||
| 103 | ******************************************************************************/ | ||
| 104 | |||
| 105 | acpi_status acpi_ut_acquire_read_lock(struct acpi_rw_lock *lock) | ||
| 106 | { | ||
| 107 | acpi_status status; | ||
| 108 | |||
| 109 | status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER); | ||
| 110 | if (ACPI_FAILURE(status)) { | ||
| 111 | return status; | ||
| 112 | } | ||
| 113 | |||
| 114 | /* Acquire the write lock only for the first reader */ | ||
| 115 | |||
| 116 | lock->num_readers++; | ||
| 117 | if (lock->num_readers == 1) { | ||
| 118 | status = | ||
| 119 | acpi_os_acquire_mutex(lock->writer_mutex, | ||
| 120 | ACPI_WAIT_FOREVER); | ||
| 121 | } | ||
| 122 | |||
| 123 | acpi_os_release_mutex(lock->reader_mutex); | ||
| 124 | return status; | ||
| 125 | } | ||
| 126 | |||
| 127 | acpi_status acpi_ut_release_read_lock(struct acpi_rw_lock *lock) | ||
| 128 | { | ||
| 129 | acpi_status status; | ||
| 130 | |||
| 131 | status = acpi_os_acquire_mutex(lock->reader_mutex, ACPI_WAIT_FOREVER); | ||
| 132 | if (ACPI_FAILURE(status)) { | ||
| 133 | return status; | ||
| 134 | } | ||
| 135 | |||
| 136 | /* Release the write lock only for the very last reader */ | ||
| 137 | |||
| 138 | lock->num_readers--; | ||
| 139 | if (lock->num_readers == 0) { | ||
| 140 | acpi_os_release_mutex(lock->writer_mutex); | ||
| 141 | } | ||
| 142 | |||
| 143 | acpi_os_release_mutex(lock->reader_mutex); | ||
| 144 | return status; | ||
| 145 | } | ||
| 146 | |||
| 147 | /******************************************************************************* | ||
| 148 | * | ||
| 149 | * FUNCTION: acpi_ut_acquire_write_lock | ||
| 150 | * acpi_ut_release_write_lock | ||
| 151 | * | ||
| 152 | * PARAMETERS: Lock - Pointer to a valid RW lock | ||
| 153 | * | ||
| 154 | * RETURN: Status | ||
| 155 | * | ||
| 156 | * DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or | ||
| 157 | * release the writer mutex associated with the lock. Acquisition | ||
| 158 | * of the lock is fully exclusive and will block all readers and | ||
| 159 | * writers until it is released. | ||
| 160 | * | ||
| 161 | ******************************************************************************/ | ||
| 162 | |||
| 163 | acpi_status acpi_ut_acquire_write_lock(struct acpi_rw_lock *lock) | ||
| 164 | { | ||
| 165 | acpi_status status; | ||
| 166 | |||
| 167 | status = acpi_os_acquire_mutex(lock->writer_mutex, ACPI_WAIT_FOREVER); | ||
| 168 | return status; | ||
| 169 | } | ||
| 170 | |||
| 171 | void acpi_ut_release_write_lock(struct acpi_rw_lock *lock) | ||
| 172 | { | ||
| 173 | |||
| 174 | acpi_os_release_mutex(lock->writer_mutex); | ||
| 175 | } | ||
