ReactOS 0.4.15-dev-5667-ged97270
utlock.c
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1/******************************************************************************
2 *
3 * Module Name: utlock - Reader/Writer lock interfaces
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2022, 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 MERCHANTABILITY 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.h"
45#include "accommon.h"
46
47
48#define _COMPONENT ACPI_UTILITIES
49 ACPI_MODULE_NAME ("utlock")
50
51
52/*******************************************************************************
53 *
54 * FUNCTION: AcpiUtCreateRwLock
55 * AcpiUtDeleteRwLock
56 *
57 * PARAMETERS: Lock - Pointer to a valid RW lock
58 *
59 * RETURN: Status
60 *
61 * DESCRIPTION: Reader/writer lock creation and deletion interfaces.
62 *
63 ******************************************************************************/
64
68{
70
71
72 Lock->NumReaders = 0;
73 Status = AcpiOsCreateMutex (&Lock->ReaderMutex);
74 if (ACPI_FAILURE (Status))
75 {
76 return (Status);
77 }
78
79 Status = AcpiOsCreateMutex (&Lock->WriterMutex);
80 return (Status);
81}
82
83
84void
87{
88
89 AcpiOsDeleteMutex (Lock->ReaderMutex);
90 AcpiOsDeleteMutex (Lock->WriterMutex);
91
92 Lock->NumReaders = 0;
93 Lock->ReaderMutex = NULL;
94 Lock->WriterMutex = NULL;
95}
96
97
98/*******************************************************************************
99 *
100 * FUNCTION: AcpiUtAcquireReadLock
101 * AcpiUtReleaseReadLock
102 *
103 * PARAMETERS: Lock - Pointer to a valid RW lock
104 *
105 * RETURN: Status
106 *
107 * DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition,
108 * only the first reader acquires the write mutex. On release,
109 * only the last reader releases the write mutex. Although this
110 * algorithm can in theory starve writers, this should not be a
111 * problem with ACPICA since the subsystem is infrequently used
112 * in comparison to (for example) an I/O system.
113 *
114 ******************************************************************************/
115
119{
121
122
124 if (ACPI_FAILURE (Status))
125 {
126 return (Status);
127 }
128
129 /* Acquire the write lock only for the first reader */
130
131 Lock->NumReaders++;
132 if (Lock->NumReaders == 1)
133 {
135 }
136
137 AcpiOsReleaseMutex (Lock->ReaderMutex);
138 return (Status);
139}
140
141
145{
147
148
150 if (ACPI_FAILURE (Status))
151 {
152 return (Status);
153 }
154
155 /* Release the write lock only for the very last reader */
156
157 Lock->NumReaders--;
158 if (Lock->NumReaders == 0)
159 {
160 AcpiOsReleaseMutex (Lock->WriterMutex);
161 }
162
163 AcpiOsReleaseMutex (Lock->ReaderMutex);
164 return (Status);
165}
166
167
168/*******************************************************************************
169 *
170 * FUNCTION: AcpiUtAcquireWriteLock
171 * AcpiUtReleaseWriteLock
172 *
173 * PARAMETERS: Lock - Pointer to a valid RW lock
174 *
175 * RETURN: Status
176 *
177 * DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or
178 * release the writer mutex associated with the lock. Acquisition
179 * of the lock is fully exclusive and will block all readers and
180 * writers until it is released.
181 *
182 ******************************************************************************/
183
187{
189
190
192 return (Status);
193}
194
195
196void
199{
200
201 AcpiOsReleaseMutex (Lock->WriterMutex);
202}
#define ACPI_FAILURE(a)
Definition: acexcep.h:95
#define ACPI_MODULE_NAME(Name)
Definition: acoutput.h:216
#define AcpiOsDeleteMutex(Handle)
Definition: actypes.h:275
#define AcpiOsAcquireMutex(Handle, Time)
Definition: actypes.h:276
UINT32 ACPI_STATUS
Definition: actypes.h:460
#define AcpiOsReleaseMutex(Handle)
Definition: actypes.h:277
#define ACPI_WAIT_FOREVER
Definition: actypes.h:501
#define AcpiOsCreateMutex(OutHandle)
Definition: actypes.h:274
#define NULL
Definition: types.h:112
Status
Definition: gdiplustypes.h:25
void AcpiUtReleaseWriteLock(ACPI_RW_LOCK *Lock)
Definition: utlock.c:197
ACPI_STATUS AcpiUtCreateRwLock(ACPI_RW_LOCK *Lock)
Definition: utlock.c:66
void AcpiUtDeleteRwLock(ACPI_RW_LOCK *Lock)
Definition: utlock.c:85
ACPI_STATUS AcpiUtAcquireWriteLock(ACPI_RW_LOCK *Lock)
Definition: utlock.c:185
ACPI_STATUS AcpiUtAcquireReadLock(ACPI_RW_LOCK *Lock)
Definition: utlock.c:117
ACPI_STATUS AcpiUtReleaseReadLock(ACPI_RW_LOCK *Lock)
Definition: utlock.c:143
_Must_inspect_result_ _In_opt_ PWDF_OBJECT_ATTRIBUTES _Out_ WDFWAITLOCK * Lock
Definition: wdfsync.h:127