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// SPDX-License-Identifier: GPL-2.0 OR MIT
/**************************************************************************
*
* Copyright 2008-2009 VMware, Inc., Palo Alto, CA., USA
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/*
* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
*/
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <drm/drm_global.h>
struct drm_global_item {
struct mutex mutex;
void *object;
int refcount;
};
static struct drm_global_item glob[DRM_GLOBAL_NUM];
void drm_global_init(void)
{
int i;
for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
struct drm_global_item *item = &glob[i];
mutex_init(&item->mutex);
item->object = NULL;
item->refcount = 0;
}
}
void drm_global_release(void)
{
int i;
for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
struct drm_global_item *item = &glob[i];
BUG_ON(item->object != NULL);
BUG_ON(item->refcount != 0);
}
}
/**
* drm_global_item_ref - Initialize and acquire reference to memory
* object
* @ref: Object for initialization
*
* This initializes a memory object, allocating memory and calling the
* .init() hook. Further calls will increase the reference count for
* that item.
*
* Returns:
* Zero on success, non-zero otherwise.
*/
int drm_global_item_ref(struct drm_global_reference *ref)
{
int ret = 0;
struct drm_global_item *item = &glob[ref->global_type];
mutex_lock(&item->mutex);
if (item->refcount == 0) {
ref->object = kzalloc(ref->size, GFP_KERNEL);
if (unlikely(ref->object == NULL)) {
ret = -ENOMEM;
goto error_unlock;
}
ret = ref->init(ref);
if (unlikely(ret != 0))
goto error_free;
item->object = ref->object;
} else {
ref->object = item->object;
}
++item->refcount;
mutex_unlock(&item->mutex);
return 0;
error_free:
kfree(ref->object);
ref->object = NULL;
error_unlock:
mutex_unlock(&item->mutex);
return ret;
}
EXPORT_SYMBOL(drm_global_item_ref);
/**
* drm_global_item_unref - Drop reference to memory
* object
* @ref: Object being removed
*
* Drop a reference to the memory object and eventually call the
* release() hook. The allocated object should be dropped in the
* release() hook or before calling this function
*
*/
void drm_global_item_unref(struct drm_global_reference *ref)
{
struct drm_global_item *item = &glob[ref->global_type];
mutex_lock(&item->mutex);
BUG_ON(item->refcount == 0);
BUG_ON(ref->object != item->object);
if (--item->refcount == 0) {
ref->release(ref);
item->object = NULL;
}
mutex_unlock(&item->mutex);
}
EXPORT_SYMBOL(drm_global_item_unref);
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