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acpica-unix2-20130823
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--- old/usr/src/uts/intel/io/acpica/utilities/utlock.c
+++ new/usr/src/common/acpica/components/utilities/utlock.c
1 1 /******************************************************************************
2 2 *
3 3 * Module Name: utlock - Reader/Writer lock interfaces
4 4 *
5 5 *****************************************************************************/
6 6
7 7 /*
8 - * Copyright (C) 2000 - 2011, Intel Corp.
8 + * Copyright (C) 2000 - 2013, Intel Corp.
9 9 * All rights reserved.
10 10 *
11 11 * Redistribution and use in source and binary forms, with or without
12 12 * modification, are permitted provided that the following conditions
13 13 * are met:
14 14 * 1. Redistributions of source code must retain the above copyright
15 15 * notice, this list of conditions, and the following disclaimer,
16 16 * without modification.
17 17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 18 * substantially similar to the "NO WARRANTY" disclaimer below
19 19 * ("Disclaimer") and any redistribution must be conditioned upon
20 20 * including a substantially similar Disclaimer requirement for further
21 21 * binary redistribution.
22 22 * 3. Neither the names of the above-listed copyright holders nor the names
23 23 * of any contributors may be used to endorse or promote products derived
24 24 * from this software without specific prior written permission.
25 25 *
26 26 * Alternatively, this software may be distributed under the terms of the
27 27 * GNU General Public License ("GPL") version 2 as published by the Free
28 28 * Software Foundation.
29 29 *
30 30 * NO WARRANTY
31 31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 41 * POSSIBILITY OF SUCH DAMAGES.
42 42 */
43 43
44 44 #define __UTLOCK_C__
45 45
46 46 #include "acpi.h"
47 47 #include "accommon.h"
48 48
49 49
50 50 #define _COMPONENT ACPI_UTILITIES
51 51 ACPI_MODULE_NAME ("utlock")
52 52
53 53
54 54 /*******************************************************************************
55 55 *
56 56 * FUNCTION: AcpiUtCreateRwLock
57 57 * AcpiUtDeleteRwLock
58 58 *
59 59 * PARAMETERS: Lock - Pointer to a valid RW lock
60 60 *
61 61 * RETURN: Status
62 62 *
63 63 * DESCRIPTION: Reader/writer lock creation and deletion interfaces.
64 64 *
65 65 ******************************************************************************/
66 66
67 67 ACPI_STATUS
68 68 AcpiUtCreateRwLock (
69 69 ACPI_RW_LOCK *Lock)
70 70 {
71 71 ACPI_STATUS Status;
72 72
73 73
74 74 Lock->NumReaders = 0;
75 75 Status = AcpiOsCreateMutex (&Lock->ReaderMutex);
76 76 if (ACPI_FAILURE (Status))
77 77 {
78 78 return (Status);
79 79 }
80 80
81 81 Status = AcpiOsCreateMutex (&Lock->WriterMutex);
82 82 return (Status);
83 83 }
84 84
85 85
86 86 void
87 87 AcpiUtDeleteRwLock (
88 88 ACPI_RW_LOCK *Lock)
89 89 {
90 90
91 91 AcpiOsDeleteMutex (Lock->ReaderMutex);
92 92 AcpiOsDeleteMutex (Lock->WriterMutex);
93 93
94 94 Lock->NumReaders = 0;
95 95 Lock->ReaderMutex = NULL;
96 96 Lock->WriterMutex = NULL;
97 97 }
98 98
99 99
100 100 /*******************************************************************************
101 101 *
102 102 * FUNCTION: AcpiUtAcquireReadLock
103 103 * AcpiUtReleaseReadLock
104 104 *
105 105 * PARAMETERS: Lock - Pointer to a valid RW lock
106 106 *
107 107 * RETURN: Status
108 108 *
109 109 * DESCRIPTION: Reader interfaces for reader/writer locks. On acquisition,
110 110 * only the first reader acquires the write mutex. On release,
111 111 * only the last reader releases the write mutex. Although this
112 112 * algorithm can in theory starve writers, this should not be a
113 113 * problem with ACPICA since the subsystem is infrequently used
114 114 * in comparison to (for example) an I/O system.
115 115 *
116 116 ******************************************************************************/
117 117
118 118 ACPI_STATUS
119 119 AcpiUtAcquireReadLock (
120 120 ACPI_RW_LOCK *Lock)
121 121 {
122 122 ACPI_STATUS Status;
123 123
124 124
125 125 Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER);
126 126 if (ACPI_FAILURE (Status))
127 127 {
128 128 return (Status);
129 129 }
130 130
131 131 /* Acquire the write lock only for the first reader */
132 132
133 133 Lock->NumReaders++;
134 134 if (Lock->NumReaders == 1)
135 135 {
136 136 Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER);
137 137 }
138 138
139 139 AcpiOsReleaseMutex (Lock->ReaderMutex);
140 140 return (Status);
141 141 }
142 142
143 143
144 144 ACPI_STATUS
145 145 AcpiUtReleaseReadLock (
146 146 ACPI_RW_LOCK *Lock)
147 147 {
148 148 ACPI_STATUS Status;
149 149
150 150
151 151 Status = AcpiOsAcquireMutex (Lock->ReaderMutex, ACPI_WAIT_FOREVER);
152 152 if (ACPI_FAILURE (Status))
153 153 {
154 154 return (Status);
155 155 }
156 156
157 157 /* Release the write lock only for the very last reader */
158 158
159 159 Lock->NumReaders--;
160 160 if (Lock->NumReaders == 0)
161 161 {
162 162 AcpiOsReleaseMutex (Lock->WriterMutex);
163 163 }
164 164
165 165 AcpiOsReleaseMutex (Lock->ReaderMutex);
166 166 return (Status);
167 167 }
168 168
169 169
170 170 /*******************************************************************************
171 171 *
172 172 * FUNCTION: AcpiUtAcquireWriteLock
173 173 * AcpiUtReleaseWriteLock
174 174 *
175 175 * PARAMETERS: Lock - Pointer to a valid RW lock
176 176 *
177 177 * RETURN: Status
178 178 *
179 179 * DESCRIPTION: Writer interfaces for reader/writer locks. Simply acquire or
180 180 * release the writer mutex associated with the lock. Acquisition
181 181 * of the lock is fully exclusive and will block all readers and
182 182 * writers until it is released.
183 183 *
184 184 ******************************************************************************/
185 185
186 186 ACPI_STATUS
187 187 AcpiUtAcquireWriteLock (
188 188 ACPI_RW_LOCK *Lock)
189 189 {
190 190 ACPI_STATUS Status;
191 191
192 192
193 193 Status = AcpiOsAcquireMutex (Lock->WriterMutex, ACPI_WAIT_FOREVER);
194 194 return (Status);
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195 195 }
196 196
197 197
198 198 void
199 199 AcpiUtReleaseWriteLock (
200 200 ACPI_RW_LOCK *Lock)
201 201 {
202 202
203 203 AcpiOsReleaseMutex (Lock->WriterMutex);
204 204 }
205 -
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