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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 <robdclark@gmail.com>
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/dma-fence.h>
44#include <linux/slab.h>
45#include <linux/seqlock.h>
46#include <linux/rcupdate.h>
47
48extern struct ww_class reservation_ww_class;
49extern struct lock_class_key reservation_seqcount_class;
50extern const char reservation_seqcount_string[];
51
52/**
53 * struct reservation_object_list - a list of shared fences
54 * @rcu: for internal use
55 * @shared_count: table of shared fences
56 * @shared_max: for growing shared fence table
57 * @shared: shared fence table
58 */
59struct reservation_object_list {
60 struct rcu_head rcu;
61 u32 shared_count, shared_max;
62 struct dma_fence __rcu *shared[];
63};
64
65/**
66 * struct reservation_object - a reservation object manages fences for a buffer
67 * @lock: update side lock
68 * @seq: sequence count for managing RCU read-side synchronization
69 * @fence_excl: the exclusive fence, if there is one currently
70 * @fence: list of current shared fences
71 * @staged: staged copy of shared fences for RCU updates
72 */
73struct reservation_object {
74 struct ww_mutex lock;
75 seqcount_t seq;
76
77 struct dma_fence __rcu *fence_excl;
78 struct reservation_object_list __rcu *fence;
79 struct reservation_object_list *staged;
80};
81
82#define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
83#define reservation_object_assert_held(obj) \
84 lockdep_assert_held(&(obj)->lock.base)
85
86/**
87 * reservation_object_init - initialize a reservation object
88 * @obj: the reservation object
89 */
90static inline void
91reservation_object_init(struct reservation_object *obj)
92{
93 ww_mutex_init(&obj->lock, &reservation_ww_class);
94
95 __seqcount_init(&obj->seq, reservation_seqcount_string, &reservation_seqcount_class);
96 RCU_INIT_POINTER(obj->fence, NULL);
97 RCU_INIT_POINTER(obj->fence_excl, NULL);
98 obj->staged = NULL;
99}
100
101/**
102 * reservation_object_fini - destroys a reservation object
103 * @obj: the reservation object
104 */
105static inline void
106reservation_object_fini(struct reservation_object *obj)
107{
108 int i;
109 struct reservation_object_list *fobj;
110 struct dma_fence *excl;
111
112 /*
113 * This object should be dead and all references must have
114 * been released to it, so no need to be protected with rcu.
115 */
116 excl = rcu_dereference_protected(obj->fence_excl, 1);
117 if (excl)
118 dma_fence_put(excl);
119
120 fobj = rcu_dereference_protected(obj->fence, 1);
121 if (fobj) {
122 for (i = 0; i < fobj->shared_count; ++i)
123 dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
124
125 kfree(fobj);
126 }
127 kfree(obj->staged);
128
129 ww_mutex_destroy(&obj->lock);
130}
131
132/**
133 * reservation_object_get_list - get the reservation object's
134 * shared fence list, with update-side lock held
135 * @obj: the reservation object
136 *
137 * Returns the shared fence list. Does NOT take references to
138 * the fence. The obj->lock must be held.
139 */
140static inline struct reservation_object_list *
141reservation_object_get_list(struct reservation_object *obj)
142{
143 return rcu_dereference_protected(obj->fence,
144 reservation_object_held(obj));
145}
146
147/**
148 * reservation_object_get_excl - get the reservation object's
149 * exclusive fence, with update-side lock held
150 * @obj: the reservation object
151 *
152 * Returns the exclusive fence (if any). Does NOT take a
153 * reference. The obj->lock must be held.
154 *
155 * RETURNS
156 * The exclusive fence or NULL
157 */
158static inline struct dma_fence *
159reservation_object_get_excl(struct reservation_object *obj)
160{
161 return rcu_dereference_protected(obj->fence_excl,
162 reservation_object_held(obj));
163}
164
165/**
166 * reservation_object_get_excl_rcu - get the reservation object's
167 * exclusive fence, without lock held.
168 * @obj: the reservation object
169 *
170 * If there is an exclusive fence, this atomically increments it's
171 * reference count and returns it.
172 *
173 * RETURNS
174 * The exclusive fence or NULL if none
175 */
176static inline struct dma_fence *
177reservation_object_get_excl_rcu(struct reservation_object *obj)
178{
179 struct dma_fence *fence;
180
181 if (!rcu_access_pointer(obj->fence_excl))
182 return NULL;
183
184 rcu_read_lock();
185 fence = dma_fence_get_rcu_safe(&obj->fence_excl);
186 rcu_read_unlock();
187
188 return fence;
189}
190
191int reservation_object_reserve_shared(struct reservation_object *obj);
192void reservation_object_add_shared_fence(struct reservation_object *obj,
193 struct dma_fence *fence);
194
195void reservation_object_add_excl_fence(struct reservation_object *obj,
196 struct dma_fence *fence);
197
198int reservation_object_get_fences_rcu(struct reservation_object *obj,
199 struct dma_fence **pfence_excl,
200 unsigned *pshared_count,
201 struct dma_fence ***pshared);
202
203long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
204 bool wait_all, bool intr,
205 unsigned long timeout);
206
207bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
208 bool test_all);
209
210#endif /* _LINUX_RESERVATION_H */