2 * Header file for reservations for dma-buf and ttm
4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Copyright (C) 2012-2013 Canonical Ltd
6 * Copyright (C) 2012 Texas Instruments
9 * Rob Clark <robdclark@gmail.com>
10 * Maarten Lankhorst <maarten.lankhorst@canonical.com>
11 * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
13 * Based on bo.c which bears the following copyright notice,
14 * but is dual licensed:
16 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
17 * All Rights Reserved.
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:
27 * The above copyright notice and this permission notice (including the
28 * next paragraph) shall be included in all copies or substantial portions
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
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39 #ifndef _LINUX_RESERVATION_H
40 #define _LINUX_RESERVATION_H
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>
48 extern struct ww_class reservation_ww_class;
49 extern struct lock_class_key reservation_seqcount_class;
50 extern const char reservation_seqcount_string[];
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
59 struct reservation_object_list {
61 u32 shared_count, shared_max;
62 struct dma_fence __rcu *shared[];
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
73 struct reservation_object {
77 struct dma_fence __rcu *fence_excl;
78 struct reservation_object_list __rcu *fence;
79 struct reservation_object_list *staged;
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)
87 * reservation_object_init - initialize a reservation object
88 * @obj: the reservation object
91 reservation_object_init(struct reservation_object *obj)
93 ww_mutex_init(&obj->lock, &reservation_ww_class);
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);
102 * reservation_object_fini - destroys a reservation object
103 * @obj: the reservation object
106 reservation_object_fini(struct reservation_object *obj)
109 struct reservation_object_list *fobj;
110 struct dma_fence *excl;
113 * This object should be dead and all references must have
114 * been released to it, so no need to be protected with rcu.
116 excl = rcu_dereference_protected(obj->fence_excl, 1);
120 fobj = rcu_dereference_protected(obj->fence, 1);
122 for (i = 0; i < fobj->shared_count; ++i)
123 dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
129 ww_mutex_destroy(&obj->lock);
133 * reservation_object_get_list - get the reservation object's
134 * shared fence list, with update-side lock held
135 * @obj: the reservation object
137 * Returns the shared fence list. Does NOT take references to
138 * the fence. The obj->lock must be held.
140 static inline struct reservation_object_list *
141 reservation_object_get_list(struct reservation_object *obj)
143 return rcu_dereference_protected(obj->fence,
144 reservation_object_held(obj));
148 * reservation_object_lock - lock the reservation object
149 * @obj: the reservation object
150 * @ctx: the locking context
152 * Locks the reservation object for exclusive access and modification. Note,
153 * that the lock is only against other writers, readers will run concurrently
154 * with a writer under RCU. The seqlock is used to notify readers if they
155 * overlap with a writer.
157 * As the reservation object may be locked by multiple parties in an
158 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
159 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
160 * object may be locked by itself by passing NULL as @ctx.
163 reservation_object_lock(struct reservation_object *obj,
164 struct ww_acquire_ctx *ctx)
166 return ww_mutex_lock(&obj->lock, ctx);
170 * reservation_object_lock_interruptible - lock the reservation object
171 * @obj: the reservation object
172 * @ctx: the locking context
174 * Locks the reservation object interruptible for exclusive access and
175 * modification. Note, that the lock is only against other writers, readers
176 * will run concurrently with a writer under RCU. The seqlock is used to
177 * notify readers if they overlap with a writer.
179 * As the reservation object may be locked by multiple parties in an
180 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
181 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
182 * object may be locked by itself by passing NULL as @ctx.
185 reservation_object_lock_interruptible(struct reservation_object *obj,
186 struct ww_acquire_ctx *ctx)
188 return ww_mutex_lock_interruptible(&obj->lock, ctx);
193 * reservation_object_trylock - trylock the reservation object
194 * @obj: the reservation object
196 * Tries to lock the reservation object for exclusive access and modification.
197 * Note, that the lock is only against other writers, readers will run
198 * concurrently with a writer under RCU. The seqlock is used to notify readers
199 * if they overlap with a writer.
201 * Also note that since no context is provided, no deadlock protection is
204 * Returns true if the lock was acquired, false otherwise.
206 static inline bool __must_check
207 reservation_object_trylock(struct reservation_object *obj)
209 return ww_mutex_trylock(&obj->lock);
213 * reservation_object_unlock - unlock the reservation object
214 * @obj: the reservation object
216 * Unlocks the reservation object following exclusive access.
219 reservation_object_unlock(struct reservation_object *obj)
221 ww_mutex_unlock(&obj->lock);
225 * reservation_object_get_excl - get the reservation object's
226 * exclusive fence, with update-side lock held
227 * @obj: the reservation object
229 * Returns the exclusive fence (if any). Does NOT take a
230 * reference. The obj->lock must be held.
233 * The exclusive fence or NULL
235 static inline struct dma_fence *
236 reservation_object_get_excl(struct reservation_object *obj)
238 return rcu_dereference_protected(obj->fence_excl,
239 reservation_object_held(obj));
243 * reservation_object_get_excl_rcu - get the reservation object's
244 * exclusive fence, without lock held.
245 * @obj: the reservation object
247 * If there is an exclusive fence, this atomically increments it's
248 * reference count and returns it.
251 * The exclusive fence or NULL if none
253 static inline struct dma_fence *
254 reservation_object_get_excl_rcu(struct reservation_object *obj)
256 struct dma_fence *fence;
258 if (!rcu_access_pointer(obj->fence_excl))
262 fence = dma_fence_get_rcu_safe(&obj->fence_excl);
268 int reservation_object_reserve_shared(struct reservation_object *obj);
269 void reservation_object_add_shared_fence(struct reservation_object *obj,
270 struct dma_fence *fence);
272 void reservation_object_add_excl_fence(struct reservation_object *obj,
273 struct dma_fence *fence);
275 int reservation_object_get_fences_rcu(struct reservation_object *obj,
276 struct dma_fence **pfence_excl,
277 unsigned *pshared_count,
278 struct dma_fence ***pshared);
280 int reservation_object_copy_fences(struct reservation_object *dst,
281 struct reservation_object *src);
283 long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
284 bool wait_all, bool intr,
285 unsigned long timeout);
287 bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
290 #endif /* _LINUX_RESERVATION_H */