1 /*
2  * Header file for reservations for dma-buf and ttm
3  *
4  * Copyright(C) 2011 Linaro Limited. All rights reserved.
5  * Copyright (C) 2012-2013 Canonical Ltd
6  * Copyright (C) 2012 Texas Instruments
7  *
8  * Authors:
9  * Rob Clark <rob.clark@linaro.org>
10  * Maarten Lankhorst <maarten.lankhorst@canonical.com>
11  * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
12  *
13  * Based on bo.c which bears the following copyright notice,
14  * but is dual licensed:
15  *
16  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
17  * All Rights Reserved.
18  *
19  * Permission is hereby granted, free of charge, to any person obtaining a
20  * copy of this software and associated documentation files (the
21  * "Software"), to deal in the Software without restriction, including
22  * without limitation the rights to use, copy, modify, merge, publish,
23  * distribute, sub license, and/or sell copies of the Software, and to
24  * permit persons to whom the Software is furnished to do so, subject to
25  * the following conditions:
26  *
27  * The above copyright notice and this permission notice (including the
28  * next paragraph) shall be included in all copies or substantial portions
29  * of the Software.
30  *
31  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
32  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
33  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
34  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
35  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
36  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
37  * USE OR OTHER DEALINGS IN THE SOFTWARE.
38  */
39 #ifndef _LINUX_RESERVATION_H
40 #define _LINUX_RESERVATION_H
41 
42 #include <linux/ww_mutex.h>
43 #include <linux/fence.h>
44 #include <linux/slab.h>
45 #include <linux/seqlock.h>
46 #include <linux/rcupdate.h>
47 
48 extern struct ww_class reservation_ww_class;
49 extern struct lock_class_key reservation_seqcount_class;
50 extern const char reservation_seqcount_string[];
51 
52 struct reservation_object {
53 	struct ww_mutex lock;
54 	seqcount_t seq;
55 
56 	struct fence *fence_excl;
57 };
58 
59 #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
60 #define reservation_object_assert_held(obj) \
61 	lockdep_assert_held(&(obj)->lock.base)
62 
63 /**
64  * reservation_object_init - initialize a reservation object
65  * @obj: the reservation object
66  */
67 static inline void
68 reservation_object_init(struct reservation_object *obj)
69 {
70 	ww_mutex_init(&obj->lock, &reservation_ww_class);
71 
72 	__seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
73 }
74 
75 /**
76  * reservation_object_fini - destroys a reservation object
77  * @obj: the reservation object
78  */
79 static inline void
80 reservation_object_fini(struct reservation_object *obj)
81 {
82 	ww_mutex_destroy(&obj->lock);
83 }
84 
85 #endif /* _LINUX_RESERVATION_H */
86