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linux/drivers/acpi/utilities/utcache.c

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/******************************************************************************
*
* Module Name: utcache - local cache allocation routines
*
*****************************************************************************/
/*
* Copyright (C) 2000 - 2007, R. Byron Moore
* All rights reserved.
*
* 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.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* 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 MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
*/
#include <acpi/acpi.h>
#define _COMPONENT ACPI_UTILITIES
ACPI_MODULE_NAME("utcache")
#ifdef ACPI_USE_LOCAL_CACHE
/*******************************************************************************
*
* FUNCTION: acpi_os_create_cache
*
* PARAMETERS: cache_name - Ascii name for the cache
* object_size - Size of each cached object
* max_depth - Maximum depth of the cache (in objects)
* return_cache - Where the new cache object is returned
*
* RETURN: Status
*
* DESCRIPTION: Create a cache object
*
******************************************************************************/
acpi_status
acpi_os_create_cache(char *cache_name,
u16 object_size,
u16 max_depth, struct acpi_memory_list ** return_cache)
{
struct acpi_memory_list *cache;
ACPI_FUNCTION_ENTRY();
if (!cache_name || !return_cache || (object_size < 16)) {
return (AE_BAD_PARAMETER);
}
/* Create the cache object */
cache = acpi_os_allocate(sizeof(struct acpi_memory_list));
if (!cache) {
return (AE_NO_MEMORY);
}
/* Populate the cache object and return it */
ACPI_MEMSET(cache, 0, sizeof(struct acpi_memory_list));
cache->link_offset = 8;
cache->list_name = cache_name;
cache->object_size = object_size;
cache->max_depth = max_depth;
*return_cache = cache;
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_os_purge_cache
*
* PARAMETERS: Cache - Handle to cache object
*
* RETURN: Status
*
* DESCRIPTION: Free all objects within the requested cache.
*
******************************************************************************/
acpi_status acpi_os_purge_cache(struct acpi_memory_list * cache)
{
char *next;
ACPI_FUNCTION_ENTRY();
if (!cache) {
return (AE_BAD_PARAMETER);
}
/* Walk the list of objects in this cache */
while (cache->list_head) {
/* Delete and unlink one cached state object */
next = *(ACPI_CAST_INDIRECT_PTR(char,
&(((char *)cache->
list_head)[cache->
link_offset])));
ACPI_FREE(cache->list_head);
cache->list_head = next;
cache->current_depth--;
}
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_os_delete_cache
*
* PARAMETERS: Cache - Handle to cache object
*
* RETURN: Status
*
* DESCRIPTION: Free all objects within the requested cache and delete the
* cache object.
*
******************************************************************************/
acpi_status acpi_os_delete_cache(struct acpi_memory_list * cache)
{
acpi_status status;
ACPI_FUNCTION_ENTRY();
/* Purge all objects in the cache */
status = acpi_os_purge_cache(cache);
if (ACPI_FAILURE(status)) {
return (status);
}
/* Now we can delete the cache object */
ACPI_FREE(cache);
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_os_release_object
*
* PARAMETERS: Cache - Handle to cache object
* Object - The object to be released
*
* RETURN: None
*
* DESCRIPTION: Release an object to the specified cache. If cache is full,
* the object is deleted.
*
******************************************************************************/
acpi_status
acpi_os_release_object(struct acpi_memory_list * cache, void *object)
{
acpi_status status;
ACPI_FUNCTION_ENTRY();
if (!cache || !object) {
return (AE_BAD_PARAMETER);
}
/* If cache is full, just free this object */
if (cache->current_depth >= cache->max_depth) {
ACPI_FREE(object);
ACPI_MEM_TRACKING(cache->total_freed++);
}
/* Otherwise put this object back into the cache */
else {
status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
if (ACPI_FAILURE(status)) {
return (status);
}
/* Mark the object as cached */
ACPI_MEMSET(object, 0xCA, cache->object_size);
ACPI_SET_DESCRIPTOR_TYPE(object, ACPI_DESC_TYPE_CACHED);
/* Put the object at the head of the cache list */
*(ACPI_CAST_INDIRECT_PTR(char,
&(((char *)object)[cache->
link_offset]))) =
cache->list_head;
cache->list_head = object;
cache->current_depth++;
(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
}
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_os_acquire_object
*
* PARAMETERS: Cache - Handle to cache object
*
* RETURN: the acquired object. NULL on error
*
* DESCRIPTION: Get an object from the specified cache. If cache is empty,
* the object is allocated.
*
******************************************************************************/
void *acpi_os_acquire_object(struct acpi_memory_list *cache)
{
acpi_status status;
void *object;
ACPI_FUNCTION_NAME(os_acquire_object);
if (!cache) {
return (NULL);
}
status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
if (ACPI_FAILURE(status)) {
return (NULL);
}
ACPI_MEM_TRACKING(cache->requests++);
/* Check the cache first */
if (cache->list_head) {
/* There is an object available, use it */
object = cache->list_head;
cache->list_head = *(ACPI_CAST_INDIRECT_PTR(char,
&(((char *)
object)[cache->
link_offset])));
cache->current_depth--;
ACPI_MEM_TRACKING(cache->hits++);
ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
"Object %p from %s cache\n", object,
cache->list_name));
status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
if (ACPI_FAILURE(status)) {
return (NULL);
}
/* Clear (zero) the previously used Object */
ACPI_MEMSET(object, 0, cache->object_size);
} else {
/* The cache is empty, create a new object */
ACPI_MEM_TRACKING(cache->total_allocated++);
#ifdef ACPI_DBG_TRACK_ALLOCATIONS
if ((cache->total_allocated - cache->total_freed) >
cache->max_occupied) {
cache->max_occupied =
cache->total_allocated - cache->total_freed;
}
#endif
/* Avoid deadlock with ACPI_ALLOCATE_ZEROED */
status = acpi_ut_release_mutex(ACPI_MTX_CACHES);
if (ACPI_FAILURE(status)) {
return (NULL);
}
object = ACPI_ALLOCATE_ZEROED(cache->object_size);
if (!object) {
return (NULL);
}
}
return (object);
}
#endif /* ACPI_USE_LOCAL_CACHE */
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