/****************************************************************************** * * Module Name: utlock - Reader/Writer lock interfaces * *****************************************************************************/ /****************************************************************************** * * 1. Copyright Notice * * Some or all of this work - Copyright (c) 1999 - 2022, Intel Corp. * All rights reserved. * * 2. License * * 2.1. This is your license from Intel Corp. under its intellectual property * rights. You may have additional license terms from the party that provided * you this software, covering your right to use that party's intellectual * property rights. * * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a * copy of the source code appearing in this file ("Covered Code") an * irrevocable, perpetual, worldwide license under Intel's copyrights in the * base code distributed originally by Intel ("Original Intel Code") to copy, * make derivatives, distribute, use and display any portion of the Covered * Code in any form, with the right to sublicense such rights; and * * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent * license (with the right to sublicense), under only those claims of Intel * patents that are infringed by the Original Intel Code, to make, use, sell, * offer to sell, and import the Covered Code and derivative works thereof * solely to the minimum extent necessary to exercise the above copyright * license, and in no event shall the patent license extend to any additions * to or modifications of the Original Intel Code. No other license or right * is granted directly or by implication, estoppel or otherwise; * * The above copyright and patent license is granted only if the following * conditions are met: * * 3. Conditions * * 3.1. Redistribution of Source with Rights to Further Distribute Source. * Redistribution of source code of any substantial portion of the Covered * Code or modification with rights to further distribute source must include * the above Copyright Notice, the above License, this list of Conditions, * and the following Disclaimer and Export Compliance provision. In addition, * Licensee must cause all Covered Code to which Licensee contributes to * contain a file documenting the changes Licensee made to create that Covered * Code and the date of any change. Licensee must include in that file the * documentation of any changes made by any predecessor Licensee. Licensee * must include a prominent statement that the modification is derived, * directly or indirectly, from Original Intel Code. * * 3.2. Redistribution of Source with no Rights to Further Distribute Source. * Redistribution of source code of any substantial portion of the Covered * Code or modification without rights to further distribute source must * include the following Disclaimer and Export Compliance provision in the * documentation and/or other materials provided with distribution. In * addition, Licensee may not authorize further sublicense of source of any * portion of the Covered Code, and must include terms to the effect that the * license from Licensee to its licensee is limited to the intellectual * property embodied in the software Licensee provides to its licensee, and * not to intellectual property embodied in modifications its licensee may * make. * * 3.3. Redistribution of Executable. Redistribution in executable form of any * substantial portion of the Covered Code or modification must reproduce the * above Copyright Notice, and the following Disclaimer and Export Compliance * provision in the documentation and/or other materials provided with the * distribution. * * 3.4. Intel retains all right, title, and interest in and to the Original * Intel Code. * * 3.5. Neither the name Intel nor any other trademark owned or controlled by * Intel shall be used in advertising or otherwise to promote the sale, use or * other dealings in products derived from or relating to the Covered Code * without prior written authorization from Intel. * * 4. Disclaimer and Export Compliance * * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE, * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A * PARTICULAR PURPOSE. * * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT, * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY * LIMITED REMEDY. * * 4.3. Licensee shall not export, either directly or indirectly, any of this * software or system incorporating such software without first obtaining any * required license or other approval from the U. S. Department of Commerce or * any other agency or department of the United States Government. In the * event Licensee exports any such software from the United States or * re-exports any such software from a foreign destination, Licensee shall * ensure that the distribution and export/re-export of the software is in * compliance with all laws, regulations, orders, or other restrictions of the * U.S. Export Administration Regulations. Licensee agrees that neither it nor * any of its subsidiaries will export/re-export any technical data, process, * software, or service, directly or indirectly, to any country for which the * United States government or any agency thereof requires an export license, * other governmental approval, or letter of assurance, without first obtaining * such license, approval or letter. * ***************************************************************************** * * Alternatively, you may choose to be licensed under the terms of the * following license: * * 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. * * 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 MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * 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 DAMAGE. * * Alternatively, you may choose to be licensed under the terms of the * GNU General Public License ("GPL") version 2 as published by the Free * Software Foundation. * *****************************************************************************/ #include #include #define _COMPONENT ACPI_UTILITIES ACPI_MODULE_NAME ("utlock") /******************************************************************************* * * FUNCTION: AcpiUtCreateRwLock * AcpiUtDeleteRwLock * * PARAMETERS: Lock - Pointer to a valid RW lock * * RETURN: Status * * DESCRIPTION: Reader/writer lock creation and deletion interfaces. * ******************************************************************************/ ACPI_STATUS AcpiUtCreateRwLock ( ACPI_RW_LOCK *Lock) { ACPI_STATUS Status; Lock->NumReaders = 0; Status = AcpiOsCreateMutex (&Lock->ReaderMutex); if (ACPI_FAILURE (Status)) { return (Status); } Status = AcpiOsCreateMutex (&Lock->WriterMutex); return (Status); } void AcpiUtDeleteRwLock ( ACPI_RW_LOCK *Lock) { AcpiOsDeleteMutex (Lock->ReaderMutex); AcpiOsDeleteMutex (Lock->WriterMutex); Lock->NumReaders = 0; Lock->ReaderMutex = NULL; Lock->WriterMutex = NULL; } /******************************************************************************* * * FUNCTION: AcpiUtAcquireReadLock * AcpiUtReleaseReadLock * * 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 AcpiUtAcquireReadLock ( ACPI_RW_LOCK *Lock) { ACPI_STATUS Status; Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER); if (ACPI_FAILURE (Status)) { return (Status); } /* Acquire the write lock only for the first reader */ Lock->NumReaders++; if (Lock->NumReaders == 1) { Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER); } AcpiOsReleaseMutex (Lock->ReaderMutex); return (Status); } ACPI_STATUS AcpiUtReleaseReadLock ( ACPI_RW_LOCK *Lock) { ACPI_STATUS Status; Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER); if (ACPI_FAILURE (Status)) { return (Status); } /* Release the write lock only for the very last reader */ Lock->NumReaders--; if (Lock->NumReaders == 0) { AcpiOsReleaseMutex (Lock->WriterMutex); } AcpiOsReleaseMutex (Lock->ReaderMutex); return (Status); } /******************************************************************************* * * FUNCTION: AcpiUtAcquireWriteLock * AcpiUtReleaseWriteLock * * 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 AcpiUtAcquireWriteLock ( ACPI_RW_LOCK *Lock) { ACPI_STATUS Status; Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER); return (Status); } void AcpiUtReleaseWriteLock ( ACPI_RW_LOCK *Lock) { AcpiOsReleaseMutex (Lock->WriterMutex); }