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
,
96 * dma_resv_lock - lock the reservation object
97 * @obj: the reservation object
98 * @ctx: the locking context
100 * Locks the reservation object for exclusive access and modification. Note,
101 * that the lock is only against other writers, readers will run concurrently
102 * with a writer under RCU. The seqlock is used to notify readers if they
103 * overlap with a writer.
105 * As the reservation object may be locked by multiple parties in an
106 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
107 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
108 * object may be locked by itself by passing NULL as @ctx.
110 static inline int dma_resv_lock(struct dma_resv
*obj
,
111 struct ww_acquire_ctx
*ctx
)
113 return ww_mutex_lock(&obj
->lock
, ctx
);
117 * dma_resv_lock_interruptible - lock the reservation object
118 * @obj: the reservation object
119 * @ctx: the locking context
121 * Locks the reservation object interruptible for exclusive access and
122 * modification. Note, that the lock is only against other writers, readers
123 * will run concurrently with a writer under RCU. The seqlock is used to
124 * notify readers if they overlap with a writer.
126 * As the reservation object may be locked by multiple parties in an
127 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
128 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
129 * object may be locked by itself by passing NULL as @ctx.
131 static inline int dma_resv_lock_interruptible(struct dma_resv
*obj
,
132 struct ww_acquire_ctx
*ctx
)
134 return ww_mutex_lock_interruptible(&obj
->lock
, ctx
);
138 * dma_resv_lock_slow - slowpath lock the reservation object
139 * @obj: the reservation object
140 * @ctx: the locking context
142 * Acquires the reservation object after a die case. This function
143 * will sleep until the lock becomes available. See dma_resv_lock() as
146 static inline void dma_resv_lock_slow(struct dma_resv
*obj
,
147 struct ww_acquire_ctx
*ctx
)
149 ww_mutex_lock_slow(&obj
->lock
, ctx
);
153 * dma_resv_lock_slow_interruptible - slowpath lock the reservation
154 * object, interruptible
155 * @obj: the reservation object
156 * @ctx: the locking context
158 * Acquires the reservation object interruptible after a die case. This function
159 * will sleep until the lock becomes available. See
160 * dma_resv_lock_interruptible() as well.
162 static inline int dma_resv_lock_slow_interruptible(struct dma_resv
*obj
,
163 struct ww_acquire_ctx
*ctx
)
165 return ww_mutex_lock_slow_interruptible(&obj
->lock
, ctx
);
169 * dma_resv_trylock - trylock the reservation object
170 * @obj: the reservation object
172 * Tries to lock the reservation object for exclusive access and modification.
173 * Note, that the lock is only against other writers, readers will run
174 * concurrently with a writer under RCU. The seqlock is used to notify readers
175 * if they overlap with a writer.
177 * Also note that since no context is provided, no deadlock protection is
180 * Returns true if the lock was acquired, false otherwise.
182 static inline bool __must_check
dma_resv_trylock(struct dma_resv
*obj
)
184 return ww_mutex_trylock(&obj
->lock
);
188 * dma_resv_is_locked - is the reservation object locked
189 * @obj: the reservation object
191 * Returns true if the mutex is locked, false if unlocked.
193 static inline bool dma_resv_is_locked(struct dma_resv
*obj
)
195 return ww_mutex_is_locked(&obj
->lock
);
199 * dma_resv_locking_ctx - returns the context used to lock the object
200 * @obj: the reservation object
202 * Returns the context used to lock a reservation object or NULL if no context
203 * was used or the object is not locked at all.
205 static inline struct ww_acquire_ctx
*dma_resv_locking_ctx(struct dma_resv
*obj
)
207 return READ_ONCE(obj
->lock
.ctx
);
211 * dma_resv_unlock - unlock the reservation object
212 * @obj: the reservation object
214 * Unlocks the reservation object following exclusive access.
216 static inline void dma_resv_unlock(struct dma_resv
*obj
)
218 #ifdef CONFIG_DEBUG_MUTEXES
219 /* Test shared fence slot reservation */
220 if (rcu_access_pointer(obj
->fence
)) {
221 struct dma_resv_list
*fence
= dma_resv_get_list(obj
);
223 fence
->shared_max
= fence
->shared_count
;
226 ww_mutex_unlock(&obj
->lock
);
230 * dma_resv_get_excl - get the reservation object's
231 * exclusive fence, with update-side lock held
232 * @obj: the reservation object
234 * Returns the exclusive fence (if any). Does NOT take a
235 * reference. Writers must hold obj->lock, readers may only
236 * hold a RCU read side lock.
239 * The exclusive fence or NULL
241 static inline struct dma_fence
*
242 dma_resv_get_excl(struct dma_resv
*obj
)
244 return rcu_dereference_protected(obj
->fence_excl
,
249 * dma_resv_get_excl_rcu - get the reservation object's
250 * exclusive fence, without lock held.
251 * @obj: the reservation object
253 * If there is an exclusive fence, this atomically increments it's
254 * reference count and returns it.
257 * The exclusive fence or NULL if none
259 static inline struct dma_fence
*
260 dma_resv_get_excl_rcu(struct dma_resv
*obj
)
262 struct dma_fence
*fence
;
264 if (!rcu_access_pointer(obj
->fence_excl
))
268 fence
= dma_fence_get_rcu_safe(&obj
->fence_excl
);
274 void dma_resv_init(struct dma_resv
*obj
);
275 void dma_resv_fini(struct dma_resv
*obj
);
276 int dma_resv_reserve_shared(struct dma_resv
*obj
, unsigned int num_fences
);
277 void dma_resv_add_shared_fence(struct dma_resv
*obj
, struct dma_fence
*fence
);
279 void dma_resv_add_excl_fence(struct dma_resv
*obj
, struct dma_fence
*fence
);
281 int dma_resv_get_fences_rcu(struct dma_resv
*obj
,
282 struct dma_fence
**pfence_excl
,
283 unsigned *pshared_count
,
284 struct dma_fence
***pshared
);
286 int dma_resv_copy_fences(struct dma_resv
*dst
, struct dma_resv
*src
);
288 long dma_resv_wait_timeout_rcu(struct dma_resv
*obj
, bool wait_all
, bool intr
,
289 unsigned long timeout
);
291 bool dma_resv_test_signaled_rcu(struct dma_resv
*obj
, bool test_all
);
293 #endif /* _LINUX_RESERVATION_H */