utlock.c revision 1.1.1.2.8.2
1 1.1.1.2.8.2 jruoho /****************************************************************************** 2 1.1.1.2.8.2 jruoho * 3 1.1.1.2.8.2 jruoho * Module Name: utlock - Reader/Writer lock interfaces 4 1.1.1.2.8.2 jruoho * 5 1.1.1.2.8.2 jruoho *****************************************************************************/ 6 1.1.1.2.8.2 jruoho 7 1.1.1.2.8.2 jruoho /* 8 1.1.1.2.8.2 jruoho * Copyright (C) 2000 - 2011, Intel Corp. 9 1.1.1.2.8.2 jruoho * All rights reserved. 10 1.1.1.2.8.2 jruoho * 11 1.1.1.2.8.2 jruoho * Redistribution and use in source and binary forms, with or without 12 1.1.1.2.8.2 jruoho * modification, are permitted provided that the following conditions 13 1.1.1.2.8.2 jruoho * are met: 14 1.1.1.2.8.2 jruoho * 1. Redistributions of source code must retain the above copyright 15 1.1.1.2.8.2 jruoho * notice, this list of conditions, and the following disclaimer, 16 1.1.1.2.8.2 jruoho * without modification. 17 1.1.1.2.8.2 jruoho * 2. Redistributions in binary form must reproduce at minimum a disclaimer 18 1.1.1.2.8.2 jruoho * substantially similar to the "NO WARRANTY" disclaimer below 19 1.1.1.2.8.2 jruoho * ("Disclaimer") and any redistribution must be conditioned upon 20 1.1.1.2.8.2 jruoho * including a substantially similar Disclaimer requirement for further 21 1.1.1.2.8.2 jruoho * binary redistribution. 22 1.1.1.2.8.2 jruoho * 3. Neither the names of the above-listed copyright holders nor the names 23 1.1.1.2.8.2 jruoho * of any contributors may be used to endorse or promote products derived 24 1.1.1.2.8.2 jruoho * from this software without specific prior written permission. 25 1.1.1.2.8.2 jruoho * 26 1.1.1.2.8.2 jruoho * Alternatively, this software may be distributed under the terms of the 27 1.1.1.2.8.2 jruoho * GNU General Public License ("GPL") version 2 as published by the Free 28 1.1.1.2.8.2 jruoho * Software Foundation. 29 1.1.1.2.8.2 jruoho * 30 1.1.1.2.8.2 jruoho * NO WARRANTY 31 1.1.1.2.8.2 jruoho * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 32 1.1.1.2.8.2 jruoho * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 33 1.1.1.2.8.2 jruoho * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR 34 1.1.1.2.8.2 jruoho * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 35 1.1.1.2.8.2 jruoho * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 1.1.1.2.8.2 jruoho * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 1.1.1.2.8.2 jruoho * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 1.1.1.2.8.2 jruoho * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 39 1.1.1.2.8.2 jruoho * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 40 1.1.1.2.8.2 jruoho * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 41 1.1.1.2.8.2 jruoho * POSSIBILITY OF SUCH DAMAGES. 42 1.1.1.2.8.2 jruoho */ 43 1.1.1.2.8.2 jruoho 44 1.1.1.2.8.2 jruoho #define __UTLOCK_C__ 45 1.1.1.2.8.2 jruoho 46 1.1.1.2.8.2 jruoho #include "acpi.h" 47 1.1.1.2.8.2 jruoho #include "accommon.h" 48 1.1.1.2.8.2 jruoho 49 1.1.1.2.8.2 jruoho 50 1.1.1.2.8.2 jruoho #define _COMPONENT ACPI_UTILITIES 51 1.1.1.2.8.2 jruoho ACPI_MODULE_NAME ("utlock") 52 1.1.1.2.8.2 jruoho 53 1.1.1.2.8.2 jruoho 54 1.1.1.2.8.2 jruoho /******************************************************************************* 55 1.1.1.2.8.2 jruoho * 56 1.1.1.2.8.2 jruoho * FUNCTION: AcpiUtCreateRwLock 57 1.1.1.2.8.2 jruoho * AcpiUtDeleteRwLock 58 1.1.1.2.8.2 jruoho * 59 1.1.1.2.8.2 jruoho * PARAMETERS: Lock - Pointer to a valid RW lock 60 1.1.1.2.8.2 jruoho * 61 1.1.1.2.8.2 jruoho * RETURN: Status 62 1.1.1.2.8.2 jruoho * 63 1.1.1.2.8.2 jruoho * DESCRIPTION: Reader/writer lock creation and deletion interfaces. 64 1.1.1.2.8.2 jruoho * 65 1.1.1.2.8.2 jruoho ******************************************************************************/ 66 1.1.1.2.8.2 jruoho 67 1.1.1.2.8.2 jruoho ACPI_STATUS 68 1.1.1.2.8.2 jruoho AcpiUtCreateRwLock ( 69 1.1.1.2.8.2 jruoho ACPI_RW_LOCK *Lock) 70 1.1.1.2.8.2 jruoho { 71 1.1.1.2.8.2 jruoho ACPI_STATUS Status; 72 1.1.1.2.8.2 jruoho 73 1.1.1.2.8.2 jruoho 74 1.1.1.2.8.2 jruoho Lock->NumReaders = 0; 75 1.1.1.2.8.2 jruoho Status = AcpiOsCreateMutex (&Lock->ReaderMutex); 76 1.1.1.2.8.2 jruoho if (ACPI_FAILURE (Status)) 77 1.1.1.2.8.2 jruoho { 78 1.1.1.2.8.2 jruoho return (Status); 79 1.1.1.2.8.2 jruoho } 80 1.1.1.2.8.2 jruoho 81 1.1.1.2.8.2 jruoho Status = AcpiOsCreateMutex (&Lock->WriterMutex); 82 1.1.1.2.8.2 jruoho return (Status); 83 1.1.1.2.8.2 jruoho } 84 1.1.1.2.8.2 jruoho 85 1.1.1.2.8.2 jruoho 86 1.1.1.2.8.2 jruoho void 87 1.1.1.2.8.2 jruoho AcpiUtDeleteRwLock ( 88 1.1.1.2.8.2 jruoho ACPI_RW_LOCK *Lock) 89 1.1.1.2.8.2 jruoho { 90 1.1.1.2.8.2 jruoho 91 1.1.1.2.8.2 jruoho AcpiOsDeleteMutex (Lock->ReaderMutex); 92 1.1.1.2.8.2 jruoho AcpiOsDeleteMutex (Lock->WriterMutex); 93 1.1.1.2.8.2 jruoho 94 1.1.1.2.8.2 jruoho Lock->NumReaders = 0; 95 1.1.1.2.8.2 jruoho Lock->ReaderMutex = NULL; 96 1.1.1.2.8.2 jruoho Lock->WriterMutex = NULL; 97 1.1.1.2.8.2 jruoho } 98 1.1.1.2.8.2 jruoho 99 1.1.1.2.8.2 jruoho 100 1.1.1.2.8.2 jruoho /******************************************************************************* 101 1.1.1.2.8.2 jruoho * 102 1.1.1.2.8.2 jruoho * FUNCTION: AcpiUtAcquireReadLock 103 1.1.1.2.8.2 jruoho * AcpiUtReleaseReadLock 104 1.1.1.2.8.2 jruoho * 105 1.1.1.2.8.2 jruoho * PARAMETERS: Lock - Pointer to a valid RW lock 106 1.1.1.2.8.2 jruoho * 107 1.1.1.2.8.2 jruoho * RETURN: Status 108 1.1.1.2.8.2 jruoho * 109 1.1.1.2.8.2 jruoho * DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition, 110 1.1.1.2.8.2 jruoho * only the first reader acquires the write mutex. On release, 111 1.1.1.2.8.2 jruoho * only the last reader releases the write mutex. Although this 112 1.1.1.2.8.2 jruoho * algorithm can in theory starve writers, this should not be a 113 1.1.1.2.8.2 jruoho * problem with ACPICA since the subsystem is infrequently used 114 1.1.1.2.8.2 jruoho * in comparison to (for example) an I/O system. 115 1.1.1.2.8.2 jruoho * 116 1.1.1.2.8.2 jruoho ******************************************************************************/ 117 1.1.1.2.8.2 jruoho 118 1.1.1.2.8.2 jruoho ACPI_STATUS 119 1.1.1.2.8.2 jruoho AcpiUtAcquireReadLock ( 120 1.1.1.2.8.2 jruoho ACPI_RW_LOCK *Lock) 121 1.1.1.2.8.2 jruoho { 122 1.1.1.2.8.2 jruoho ACPI_STATUS Status; 123 1.1.1.2.8.2 jruoho 124 1.1.1.2.8.2 jruoho 125 1.1.1.2.8.2 jruoho Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER); 126 1.1.1.2.8.2 jruoho if (ACPI_FAILURE (Status)) 127 1.1.1.2.8.2 jruoho { 128 1.1.1.2.8.2 jruoho return (Status); 129 1.1.1.2.8.2 jruoho } 130 1.1.1.2.8.2 jruoho 131 1.1.1.2.8.2 jruoho /* Acquire the write lock only for the first reader */ 132 1.1.1.2.8.2 jruoho 133 1.1.1.2.8.2 jruoho Lock->NumReaders++; 134 1.1.1.2.8.2 jruoho if (Lock->NumReaders == 1) 135 1.1.1.2.8.2 jruoho { 136 1.1.1.2.8.2 jruoho Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER); 137 1.1.1.2.8.2 jruoho } 138 1.1.1.2.8.2 jruoho 139 1.1.1.2.8.2 jruoho AcpiOsReleaseMutex (Lock->ReaderMutex); 140 1.1.1.2.8.2 jruoho return (Status); 141 1.1.1.2.8.2 jruoho } 142 1.1.1.2.8.2 jruoho 143 1.1.1.2.8.2 jruoho 144 1.1.1.2.8.2 jruoho ACPI_STATUS 145 1.1.1.2.8.2 jruoho AcpiUtReleaseReadLock ( 146 1.1.1.2.8.2 jruoho ACPI_RW_LOCK *Lock) 147 1.1.1.2.8.2 jruoho { 148 1.1.1.2.8.2 jruoho ACPI_STATUS Status; 149 1.1.1.2.8.2 jruoho 150 1.1.1.2.8.2 jruoho 151 1.1.1.2.8.2 jruoho Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER); 152 1.1.1.2.8.2 jruoho if (ACPI_FAILURE (Status)) 153 1.1.1.2.8.2 jruoho { 154 1.1.1.2.8.2 jruoho return (Status); 155 1.1.1.2.8.2 jruoho } 156 1.1.1.2.8.2 jruoho 157 1.1.1.2.8.2 jruoho /* Release the write lock only for the very last reader */ 158 1.1.1.2.8.2 jruoho 159 1.1.1.2.8.2 jruoho Lock->NumReaders--; 160 1.1.1.2.8.2 jruoho if (Lock->NumReaders == 0) 161 1.1.1.2.8.2 jruoho { 162 1.1.1.2.8.2 jruoho AcpiOsReleaseMutex (Lock->WriterMutex); 163 1.1.1.2.8.2 jruoho } 164 1.1.1.2.8.2 jruoho 165 1.1.1.2.8.2 jruoho AcpiOsReleaseMutex (Lock->ReaderMutex); 166 1.1.1.2.8.2 jruoho return (Status); 167 1.1.1.2.8.2 jruoho } 168 1.1.1.2.8.2 jruoho 169 1.1.1.2.8.2 jruoho 170 1.1.1.2.8.2 jruoho /******************************************************************************* 171 1.1.1.2.8.2 jruoho * 172 1.1.1.2.8.2 jruoho * FUNCTION: AcpiUtAcquireWriteLock 173 1.1.1.2.8.2 jruoho * AcpiUtReleaseWriteLock 174 1.1.1.2.8.2 jruoho * 175 1.1.1.2.8.2 jruoho * PARAMETERS: Lock - Pointer to a valid RW lock 176 1.1.1.2.8.2 jruoho * 177 1.1.1.2.8.2 jruoho * RETURN: Status 178 1.1.1.2.8.2 jruoho * 179 1.1.1.2.8.2 jruoho * DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or 180 1.1.1.2.8.2 jruoho * release the writer mutex associated with the lock. Acquisition 181 1.1.1.2.8.2 jruoho * of the lock is fully exclusive and will block all readers and 182 1.1.1.2.8.2 jruoho * writers until it is released. 183 1.1.1.2.8.2 jruoho * 184 1.1.1.2.8.2 jruoho ******************************************************************************/ 185 1.1.1.2.8.2 jruoho 186 1.1.1.2.8.2 jruoho ACPI_STATUS 187 1.1.1.2.8.2 jruoho AcpiUtAcquireWriteLock ( 188 1.1.1.2.8.2 jruoho ACPI_RW_LOCK *Lock) 189 1.1.1.2.8.2 jruoho { 190 1.1.1.2.8.2 jruoho ACPI_STATUS Status; 191 1.1.1.2.8.2 jruoho 192 1.1.1.2.8.2 jruoho 193 1.1.1.2.8.2 jruoho Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER); 194 1.1.1.2.8.2 jruoho return (Status); 195 1.1.1.2.8.2 jruoho } 196 1.1.1.2.8.2 jruoho 197 1.1.1.2.8.2 jruoho 198 1.1.1.2.8.2 jruoho void 199 1.1.1.2.8.2 jruoho AcpiUtReleaseWriteLock ( 200 1.1.1.2.8.2 jruoho ACPI_RW_LOCK *Lock) 201 1.1.1.2.8.2 jruoho { 202 1.1.1.2.8.2 jruoho 203 1.1.1.2.8.2 jruoho AcpiOsReleaseMutex (Lock->WriterMutex); 204 1.1.1.2.8.2 jruoho } 205 1.1.1.2.8.2 jruoho 206
Indexes created Thu Oct 23 22:10:10 GMT 2025