ia64/linux-2.6.18-xen.hg

view drivers/acpi/utilities/utcache.c @ 0:831230e53067

Import 2.6.18 from kernel.org tarball.
author Ian Campbell <ian.campbell@xensource.com>
date Wed Apr 11 14:15:44 2007 +0100 (2007-04-11)
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1 /******************************************************************************
2 *
3 * Module Name: utcache - local cache allocation routines
4 *
5 *****************************************************************************/
7 /*
8 * Copyright (C) 2000 - 2006, R. Byron Moore
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 */
44 #include <acpi/acpi.h>
46 #define _COMPONENT ACPI_UTILITIES
47 ACPI_MODULE_NAME("utcache")
49 #ifdef ACPI_USE_LOCAL_CACHE
50 /*******************************************************************************
51 *
52 * FUNCTION: acpi_os_create_cache
53 *
54 * PARAMETERS: cache_name - Ascii name for the cache
55 * object_size - Size of each cached object
56 * max_depth - Maximum depth of the cache (in objects)
57 * return_cache - Where the new cache object is returned
58 *
59 * RETURN: Status
60 *
61 * DESCRIPTION: Create a cache object
62 *
63 ******************************************************************************/
64 acpi_status
65 acpi_os_create_cache(char *cache_name,
66 u16 object_size,
67 u16 max_depth, struct acpi_memory_list **return_cache)
68 {
69 struct acpi_memory_list *cache;
71 ACPI_FUNCTION_ENTRY();
73 if (!cache_name || !return_cache || (object_size < 16)) {
74 return (AE_BAD_PARAMETER);
75 }
77 /* Create the cache object */
79 cache = acpi_os_allocate(sizeof(struct acpi_memory_list));
80 if (!cache) {
81 return (AE_NO_MEMORY);
82 }
84 /* Populate the cache object and return it */
86 ACPI_MEMSET(cache, 0, sizeof(struct acpi_memory_list));
87 cache->link_offset = 8;
88 cache->list_name = cache_name;
89 cache->object_size = object_size;
90 cache->max_depth = max_depth;
92 *return_cache = cache;
93 return (AE_OK);
94 }
96 /*******************************************************************************
97 *
98 * FUNCTION: acpi_os_purge_cache
99 *
100 * PARAMETERS: Cache - Handle to cache object
101 *
102 * RETURN: Status
103 *
104 * DESCRIPTION: Free all objects within the requested cache.
105 *
106 ******************************************************************************/
108 acpi_status acpi_os_purge_cache(struct acpi_memory_list * cache)
109 {
110 char *next;
112 ACPI_FUNCTION_ENTRY();
114 if (!cache) {
115 return (AE_BAD_PARAMETER);
116 }
118 /* Walk the list of objects in this cache */
120 while (cache->list_head) {
122 /* Delete and unlink one cached state object */
124 next = *(ACPI_CAST_INDIRECT_PTR(char,
125 &(((char *)cache->
126 list_head)[cache->
127 link_offset])));
128 ACPI_FREE(cache->list_head);
130 cache->list_head = next;
131 cache->current_depth--;
132 }
134 return (AE_OK);
135 }
137 /*******************************************************************************
138 *
139 * FUNCTION: acpi_os_delete_cache
140 *
141 * PARAMETERS: Cache - Handle to cache object
142 *
143 * RETURN: Status
144 *
145 * DESCRIPTION: Free all objects within the requested cache and delete the
146 * cache object.
147 *
148 ******************************************************************************/
150 acpi_status acpi_os_delete_cache(struct acpi_memory_list * cache)
151 {
152 acpi_status status;
154 ACPI_FUNCTION_ENTRY();
156 /* Purge all objects in the cache */
158 status = acpi_os_purge_cache(cache);
159 if (ACPI_FAILURE(status)) {
160 return (status);
161 }
163 /* Now we can delete the cache object */
165 ACPI_FREE(cache);
166 return (AE_OK);
167 }
169 /*******************************************************************************
170 *
171 * FUNCTION: acpi_os_release_object
172 *
173 * PARAMETERS: Cache - Handle to cache object
174 * Object - The object to be released
175 *
176 * RETURN: None
177 *
178 * DESCRIPTION: Release an object to the specified cache. If cache is full,
179 * the object is deleted.
180 *
181 ******************************************************************************/
183 acpi_status
184 acpi_os_release_object(struct acpi_memory_list * cache, void *object)
185 {
186 acpi_status status;
188 ACPI_FUNCTION_ENTRY();
190 if (!cache || !object) {
191 return (AE_BAD_PARAMETER);
192 }
194 /* If cache is full, just free this object */
196 if (cache->current_depth >= cache->max_depth) {
197 ACPI_FREE(object);
198 ACPI_MEM_TRACKING(cache->total_freed++);
199 }
201 /* Otherwise put this object back into the cache */
203 else {
204 status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
205 if (ACPI_FAILURE(status)) {
206 return (status);
207 }
209 /* Mark the object as cached */
211 ACPI_MEMSET(object, 0xCA, cache->object_size);
212 ACPI_SET_DESCRIPTOR_TYPE(object, ACPI_DESC_TYPE_CACHED);
214 /* Put the object at the head of the cache list */
216 *(ACPI_CAST_INDIRECT_PTR(char,
217 &(((char *)object)[cache->
218 link_offset]))) =
219 cache->list_head;
220 cache->list_head = object;
221 cache->current_depth++;
223 (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
224 }
226 return (AE_OK);
227 }
229 /*******************************************************************************
230 *
231 * FUNCTION: acpi_os_acquire_object
232 *
233 * PARAMETERS: Cache - Handle to cache object
234 *
235 * RETURN: the acquired object. NULL on error
236 *
237 * DESCRIPTION: Get an object from the specified cache. If cache is empty,
238 * the object is allocated.
239 *
240 ******************************************************************************/
242 void *acpi_os_acquire_object(struct acpi_memory_list *cache)
243 {
244 acpi_status status;
245 void *object;
247 ACPI_FUNCTION_NAME(os_acquire_object);
249 if (!cache) {
250 return (NULL);
251 }
253 status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
254 if (ACPI_FAILURE(status)) {
255 return (NULL);
256 }
258 ACPI_MEM_TRACKING(cache->requests++);
260 /* Check the cache first */
262 if (cache->list_head) {
264 /* There is an object available, use it */
266 object = cache->list_head;
267 cache->list_head = *(ACPI_CAST_INDIRECT_PTR(char,
268 &(((char *)
269 object)[cache->
270 link_offset])));
272 cache->current_depth--;
274 ACPI_MEM_TRACKING(cache->hits++);
275 ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
276 "Object %p from %s cache\n", object,
277 cache->list_name));
279 status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
280 if (ACPI_FAILURE(status)) {
281 return (NULL);
282 }
284 /* Clear (zero) the previously used Object */
286 ACPI_MEMSET(object, 0, cache->object_size);
287 } else {
288 /* The cache is empty, create a new object */
290 ACPI_MEM_TRACKING(cache->total_allocated++);
292 /* Avoid deadlock with ACPI_ALLOCATE_ZEROED */
294 status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
295 if (ACPI_FAILURE(status)) {
296 return (NULL);
297 }
299 object = ACPI_ALLOCATE_ZEROED(cache->object_size);
300 if (!object) {
301 return (NULL);
302 }
303 }
305 return (object);
306 }
307 #endif /* ACPI_USE_LOCAL_CACHE */