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,
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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;
51 * struct dma_resv_list - a list of shared fences
52 * @rcu: for internal use
53 * @shared_count: table of shared fences
54 * @shared_max: for growing shared fence table
55 * @shared: shared fence table
57 struct dma_resv_list {
59 u32 shared_count, shared_max;
60 struct dma_fence __rcu *shared[];
64 * struct dma_resv - a reservation object manages fences for a buffer
65 * @lock: update side lock
66 * @seq: sequence count for managing RCU read-side synchronization
67 * @fence_excl: the exclusive fence, if there is one currently
68 * @fence: list of current shared fences
72 seqcount_ww_mutex_t seq;
74 struct dma_fence __rcu *fence_excl;
75 struct dma_resv_list __rcu *fence;
78 #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
79 #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
82 * dma_resv_get_list - get the reservation object's
83 * shared fence list, with update-side lock held
84 * @obj: the reservation object
86 * Returns the shared fence list. Does NOT take references to
87 * the fence. The obj->lock must be held.
89 static inline struct dma_resv_list *dma_resv_get_list(struct dma_resv *obj)
91 return rcu_dereference_protected(obj->fence,
95 #ifdef CONFIG_DEBUG_MUTEXES
96 void dma_resv_reset_shared_max(struct dma_resv *obj);
98 static inline void dma_resv_reset_shared_max(struct dma_resv *obj) {}
102 * dma_resv_lock - lock the reservation object
103 * @obj: the reservation object
104 * @ctx: the locking context
106 * Locks the reservation object for exclusive access and modification. Note,
107 * that the lock is only against other writers, readers will run concurrently
108 * with a writer under RCU. The seqlock is used to notify readers if they
109 * overlap with a writer.
111 * As the reservation object may be locked by multiple parties in an
112 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
113 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
114 * object may be locked by itself by passing NULL as @ctx.
116 static inline int dma_resv_lock(struct dma_resv *obj,
117 struct ww_acquire_ctx *ctx)
119 return ww_mutex_lock(&obj->lock, ctx);
123 * dma_resv_lock_interruptible - lock the reservation object
124 * @obj: the reservation object
125 * @ctx: the locking context
127 * Locks the reservation object interruptible for exclusive access and
128 * modification. Note, that the lock is only against other writers, readers
129 * will run concurrently with a writer under RCU. The seqlock is used to
130 * notify readers if they overlap with a writer.
132 * As the reservation object may be locked by multiple parties in an
133 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
134 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
135 * object may be locked by itself by passing NULL as @ctx.
137 static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
138 struct ww_acquire_ctx *ctx)
140 return ww_mutex_lock_interruptible(&obj->lock, ctx);
144 * dma_resv_lock_slow - slowpath lock the reservation object
145 * @obj: the reservation object
146 * @ctx: the locking context
148 * Acquires the reservation object after a die case. This function
149 * will sleep until the lock becomes available. See dma_resv_lock() as
152 static inline void dma_resv_lock_slow(struct dma_resv *obj,
153 struct ww_acquire_ctx *ctx)
155 ww_mutex_lock_slow(&obj->lock, ctx);
159 * dma_resv_lock_slow_interruptible - slowpath lock the reservation
160 * object, interruptible
161 * @obj: the reservation object
162 * @ctx: the locking context
164 * Acquires the reservation object interruptible after a die case. This function
165 * will sleep until the lock becomes available. See
166 * dma_resv_lock_interruptible() as well.
168 static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
169 struct ww_acquire_ctx *ctx)
171 return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
175 * dma_resv_trylock - trylock the reservation object
176 * @obj: the reservation object
178 * Tries to lock the reservation object for exclusive access and modification.
179 * Note, that the lock is only against other writers, readers will run
180 * concurrently with a writer under RCU. The seqlock is used to notify readers
181 * if they overlap with a writer.
183 * Also note that since no context is provided, no deadlock protection is
186 * Returns true if the lock was acquired, false otherwise.
188 static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
190 return ww_mutex_trylock(&obj->lock);
194 * dma_resv_is_locked - is the reservation object locked
195 * @obj: the reservation object
197 * Returns true if the mutex is locked, false if unlocked.
199 static inline bool dma_resv_is_locked(struct dma_resv *obj)
201 return ww_mutex_is_locked(&obj->lock);
205 * dma_resv_locking_ctx - returns the context used to lock the object
206 * @obj: the reservation object
208 * Returns the context used to lock a reservation object or NULL if no context
209 * was used or the object is not locked at all.
211 static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
213 return READ_ONCE(obj->lock.ctx);
217 * dma_resv_unlock - unlock the reservation object
218 * @obj: the reservation object
220 * Unlocks the reservation object following exclusive access.
222 static inline void dma_resv_unlock(struct dma_resv *obj)
224 dma_resv_reset_shared_max(obj);
225 ww_mutex_unlock(&obj->lock);
229 * dma_resv_get_excl - get the reservation object's
230 * exclusive fence, with update-side lock held
231 * @obj: the reservation object
233 * Returns the exclusive fence (if any). Does NOT take a
234 * reference. Writers must hold obj->lock, readers may only
235 * hold a RCU read side lock.
238 * The exclusive fence or NULL
240 static inline struct dma_fence *
241 dma_resv_get_excl(struct dma_resv *obj)
243 return rcu_dereference_protected(obj->fence_excl,
248 * dma_resv_get_excl_rcu - get the reservation object's
249 * exclusive fence, without lock held.
250 * @obj: the reservation object
252 * If there is an exclusive fence, this atomically increments it's
253 * reference count and returns it.
256 * The exclusive fence or NULL if none
258 static inline struct dma_fence *
259 dma_resv_get_excl_rcu(struct dma_resv *obj)
261 struct dma_fence *fence;
263 if (!rcu_access_pointer(obj->fence_excl))
267 fence = dma_fence_get_rcu_safe(&obj->fence_excl);
273 void dma_resv_init(struct dma_resv *obj);
274 void dma_resv_fini(struct dma_resv *obj);
275 int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
276 void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);
278 void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);
280 int dma_resv_get_fences_rcu(struct dma_resv *obj,
281 struct dma_fence **pfence_excl,
282 unsigned *pshared_count,
283 struct dma_fence ***pshared);
285 int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
287 long dma_resv_wait_timeout_rcu(struct dma_resv *obj, bool wait_all, bool intr,
288 unsigned long timeout);
290 bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all);
292 #endif /* _LINUX_RESERVATION_H */