drivers/acpi/utilities/utcache.c

   1 /******************************************************************************
   2  *
   3  * Module Name: utcache - local cache allocation routines
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2005, 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  */
  43
  44 #include <acpi/acpi.h>
  45
  46 #define _COMPONENT          ACPI_UTILITIES
  47 ACPI_MODULE_NAME("utcache")
  48
  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;
  70
  71         ACPI_FUNCTION_ENTRY();
  72
  73         if (!cache_name || !return_cache || (object_size < 16)) {
  74                 return (AE_BAD_PARAMETER);
  75         }
  76
  77         /* Create the cache object */
  78
  79         cache = acpi_os_allocate(sizeof(struct acpi_memory_list));
  80         if (!cache) {
  81                 return (AE_NO_MEMORY);
  82         }
  83
  84         /* Populate the cache object and return it */
  85
  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;
  91
  92         *return_cache = cache;
  93         return (AE_OK);
  94 }
  95
  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  ******************************************************************************/
 107
 108 acpi_status acpi_os_purge_cache(struct acpi_memory_list * cache)
 109 {
 110         char *next;
 111
 112         ACPI_FUNCTION_ENTRY();
 113
 114         if (!cache) {
 115                 return (AE_BAD_PARAMETER);
 116         }
 117
 118         /* Walk the list of objects in this cache */
 119
 120         while (cache->list_head) {
 121                 /* Delete and unlink one cached state object */
 122
 123                 next = *(ACPI_CAST_INDIRECT_PTR(char,
 124                                                 &(((char *)cache->
 125                                                    list_head)[cache->
 126                                                               link_offset])));
 127                 ACPI_MEM_FREE(cache->list_head);
 128
 129                 cache->list_head = next;
 130                 cache->current_depth--;
 131         }
 132
 133         return (AE_OK);
 134 }
 135
 136 /*******************************************************************************
 137  *
 138  * FUNCTION:    acpi_os_delete_cache
 139  *
 140  * PARAMETERS:  Cache           - Handle to cache object
 141  *
 142  * RETURN:      Status
 143  *
 144  * DESCRIPTION: Free all objects within the requested cache and delete the
 145  *              cache object.
 146  *
 147  ******************************************************************************/
 148
 149 acpi_status acpi_os_delete_cache(struct acpi_memory_list * cache)
 150 {
 151         acpi_status status;
 152
 153         ACPI_FUNCTION_ENTRY();
 154
 155         /* Purge all objects in the cache */
 156
 157         status = acpi_os_purge_cache(cache);
 158         if (ACPI_FAILURE(status)) {
 159                 return (status);
 160         }
 161
 162         /* Now we can delete the cache object */
 163
 164         acpi_os_free(cache);
 165         return (AE_OK);
 166 }
 167
 168 /*******************************************************************************
 169  *
 170  * FUNCTION:    acpi_os_release_object
 171  *
 172  * PARAMETERS:  Cache       - Handle to cache object
 173  *              Object      - The object to be released
 174  *
 175  * RETURN:      None
 176  *
 177  * DESCRIPTION: Release an object to the specified cache.  If cache is full,
 178  *              the object is deleted.
 179  *
 180  ******************************************************************************/
 181
 182 acpi_status
 183 acpi_os_release_object(struct acpi_memory_list * cache, void *object)
 184 {
 185         acpi_status status;
 186
 187         ACPI_FUNCTION_ENTRY();
 188
 189         if (!cache || !object) {
 190                 return (AE_BAD_PARAMETER);
 191         }
 192
 193         /* If cache is full, just free this object */
 194
 195         if (cache->current_depth >= cache->max_depth) {
 196                 ACPI_MEM_FREE(object);
 197                 ACPI_MEM_TRACKING(cache->total_freed++);
 198         }
 199
 200         /* Otherwise put this object back into the cache */
 201
 202         else {
 203                 status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
 204                 if (ACPI_FAILURE(status)) {
 205                         return (status);
 206                 }
 207
 208                 /* Mark the object as cached */
 209
 210                 ACPI_MEMSET(object, 0xCA, cache->object_size);
 211                 ACPI_SET_DESCRIPTOR_TYPE(object, ACPI_DESC_TYPE_CACHED);
 212
 213                 /* Put the object at the head of the cache list */
 214
 215                 *(ACPI_CAST_INDIRECT_PTR(char,
 216                                          &(((char *)object)[cache->
 217                                                             link_offset]))) =
 218                     cache->list_head;
 219                 cache->list_head = object;
 220                 cache->current_depth++;
 221
 222                 (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
 223         }
 224
 225         return (AE_OK);
 226 }
 227
 228 /*******************************************************************************
 229  *
 230  * FUNCTION:    acpi_os_acquire_object
 231  *
 232  * PARAMETERS:  Cache           - Handle to cache object
 233  *
 234  * RETURN:      the acquired object.  NULL on error
 235  *
 236  * DESCRIPTION: Get an object from the specified cache.  If cache is empty,
 237  *              the object is allocated.
 238  *
 239  ******************************************************************************/
 240
 241 void *acpi_os_acquire_object(struct acpi_memory_list *cache)
 242 {
 243         acpi_status status;
 244         void *object;
 245
 246         ACPI_FUNCTION_NAME("os_acquire_object");
 247
 248         if (!cache) {
 249                 return (NULL);
 250         }
 251
 252         status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
 253         if (ACPI_FAILURE(status)) {
 254                 return (NULL);
 255         }
 256
 257         ACPI_MEM_TRACKING(cache->requests++);
 258
 259         /* Check the cache first */
 260
 261         if (cache->list_head) {
 262                 /* There is an object available, use it */
 263
 264                 object = cache->list_head;
 265                 cache->list_head = *(ACPI_CAST_INDIRECT_PTR(char,
 266                                                             &(((char *)
 267                                                                object)[cache->
 268                                                                        link_offset])));
 269
 270                 cache->current_depth--;
 271
 272                 ACPI_MEM_TRACKING(cache->hits++);
 273                 ACPI_MEM_TRACKING(ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
 274                                                     "Object %p from %s cache\n",
 275                                                     object, cache->list_name)));
 276
 277                 status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
 278                 if (ACPI_FAILURE(status)) {
 279                         return (NULL);
 280                 }
 281
 282                 /* Clear (zero) the previously used Object */
 283
 284                 ACPI_MEMSET(object, 0, cache->object_size);
 285         } else {
 286                 /* The cache is empty, create a new object */
 287
 288                 ACPI_MEM_TRACKING(cache->total_allocated++);
 289
 290                 /* Avoid deadlock with ACPI_MEM_CALLOCATE */
 291
 292                 status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
 293                 if (ACPI_FAILURE(status)) {
 294                         return (NULL);
 295                 }
 296
 297                 object = ACPI_MEM_CALLOCATE(cache->object_size);
 298                 if (!object) {
 299                         return (NULL);
 300                 }
 301         }
 302
 303         return (object);
 304 }
 305 #endif                          /* ACPI_USE_LOCAL_CACHE */