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 <linux/kernel.h> |
35 | #include <linux/export.h> |
36 | #include <asm/bug.h> |
37 | #include <drm/drm_global.h> |
38 | |
39 | struct drm_global_item { |
40 | struct mutex mutex; |
41 | void *object; |
42 | int refcount; |
43 | }; |
44 | |
45 | static struct drm_global_item glob[DRM_GLOBAL_NUM]; |
46 | |
47 | void drm_global_init(void) |
48 | { |
49 | int i; |
50 | |
51 | for (i = 0; i < DRM_GLOBAL_NUM; ++i) { |
52 | struct drm_global_item *item = &glob[i]; |
53 | #ifdef __NetBSD__ |
54 | linux_mutex_init(&item->mutex); |
55 | #else |
56 | mutex_init(&item->mutex); |
57 | #endif |
58 | item->object = NULL; |
59 | item->refcount = 0; |
60 | } |
61 | } |
62 | |
63 | void drm_global_release(void) |
64 | { |
65 | int i; |
66 | for (i = 0; i < DRM_GLOBAL_NUM; ++i) { |
67 | struct drm_global_item *item = &glob[i]; |
68 | (void)item; /* ignore */ |
69 | BUG_ON(item->object != NULL); |
70 | BUG_ON(item->refcount != 0); |
71 | } |
72 | } |
73 | |
74 | int drm_global_item_ref(struct drm_global_reference *ref) |
75 | { |
76 | int ret; |
77 | struct drm_global_item *item = &glob[ref->global_type]; |
78 | |
79 | mutex_lock(&item->mutex); |
80 | if (item->refcount == 0) { |
81 | item->object = kzalloc(ref->size, GFP_KERNEL); |
82 | if (unlikely(item->object == NULL)) { |
83 | ret = -ENOMEM; |
84 | goto out_err; |
85 | } |
86 | |
87 | ref->object = item->object; |
88 | ret = ref->init(ref); |
89 | if (unlikely(ret != 0)) |
90 | goto out_err; |
91 | |
92 | } |
93 | ++item->refcount; |
94 | ref->object = item->object; |
95 | mutex_unlock(&item->mutex); |
96 | return 0; |
97 | out_err: |
98 | mutex_unlock(&item->mutex); |
99 | item->object = NULL; |
100 | return ret; |
101 | } |
102 | EXPORT_SYMBOL(drm_global_item_ref); |
103 | |
104 | void drm_global_item_unref(struct drm_global_reference *ref) |
105 | { |
106 | struct drm_global_item *item = &glob[ref->global_type]; |
107 | |
108 | mutex_lock(&item->mutex); |
109 | BUG_ON(item->refcount == 0); |
110 | BUG_ON(ref->object != item->object); |
111 | if (--item->refcount == 0) { |
112 | ref->release(ref); |
113 | item->object = NULL; |
114 | } |
115 | mutex_unlock(&item->mutex); |
116 | } |
117 | EXPORT_SYMBOL(drm_global_item_unref); |
118 | |
119 | |