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