1 /**************************************************************************
2 *
3 * Copyright 2008-2009 VMware, Inc., Palo Alto, CA., USA
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27 /*
28 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
29 */
30
31 #include <linux/mutex.h>
32 #include <linux/slab.h>
33 #include <linux/module.h>
34 #include <drm/drm_global.h>
35
36 struct drm_global_item {
37 struct mutex mutex;
38 void *object;
39 int refcount;
40 };
41
42 static struct drm_global_item glob[DRM_GLOBAL_NUM];
43
drm_global_init(void)44 void drm_global_init(void)
45 {
46 int i;
47
48 for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
49 struct drm_global_item *item = &glob[i];
50 mutex_init(&item->mutex);
51 item->object = NULL;
52 item->refcount = 0;
53 }
54 }
55
drm_global_release(void)56 void drm_global_release(void)
57 {
58 int i;
59 for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
60 struct drm_global_item *item = &glob[i];
61 BUG_ON(item->object != NULL);
62 BUG_ON(item->refcount != 0);
63 }
64 }
65
drm_global_item_ref(struct drm_global_reference * ref)66 int drm_global_item_ref(struct drm_global_reference *ref)
67 {
68 int ret = 0;
69 struct drm_global_item *item = &glob[ref->global_type];
70
71 mutex_lock(&item->mutex);
72 if (item->refcount == 0) {
73 ref->object = kzalloc(ref->size, GFP_KERNEL);
74 if (unlikely(ref->object == NULL)) {
75 ret = -ENOMEM;
76 goto error_unlock;
77 }
78 ret = ref->init(ref);
79 if (unlikely(ret != 0))
80 goto error_free;
81
82 item->object = ref->object;
83 } else {
84 ref->object = item->object;
85 }
86
87 ++item->refcount;
88 mutex_unlock(&item->mutex);
89 return 0;
90
91 error_free:
92 kfree(ref->object);
93 ref->object = NULL;
94 error_unlock:
95 mutex_unlock(&item->mutex);
96 return ret;
97 }
98 EXPORT_SYMBOL(drm_global_item_ref);
99
drm_global_item_unref(struct drm_global_reference * ref)100 void drm_global_item_unref(struct drm_global_reference *ref)
101 {
102 struct drm_global_item *item = &glob[ref->global_type];
103
104 mutex_lock(&item->mutex);
105 BUG_ON(item->refcount == 0);
106 BUG_ON(ref->object != item->object);
107 if (--item->refcount == 0) {
108 ref->release(ref);
109 item->object = NULL;
110 }
111 mutex_unlock(&item->mutex);
112 }
113 EXPORT_SYMBOL(drm_global_item_unref);
114
115