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
36 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
37 * USE OR OTHER DEALINGS IN THE SOFTWARE.
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
72 struct reservation_object
{
76 struct dma_fence __rcu
*fence_excl
;
77 struct reservation_object_list __rcu
*fence
;
80 #define reservation_object_held(obj) lockdep_is_held(&(obj)->lock.base)
81 #define reservation_object_assert_held(obj) \
82 lockdep_assert_held(&(obj)->lock.base)
85 * reservation_object_init - initialize a reservation object
86 * @obj: the reservation object
89 reservation_object_init(struct reservation_object
*obj
)
91 ww_mutex_init(&obj
->lock
, &reservation_ww_class
);
93 __seqcount_init(&obj
->seq
, reservation_seqcount_string
, &reservation_seqcount_class
);
94 RCU_INIT_POINTER(obj
->fence
, NULL
);
95 RCU_INIT_POINTER(obj
->fence_excl
, NULL
);
99 * reservation_object_fini - destroys a reservation object
100 * @obj: the reservation object
103 reservation_object_fini(struct reservation_object
*obj
)
106 struct reservation_object_list
*fobj
;
107 struct dma_fence
*excl
;
110 * This object should be dead and all references must have
111 * been released to it, so no need to be protected with rcu.
113 excl
= rcu_dereference_protected(obj
->fence_excl
, 1);
117 fobj
= rcu_dereference_protected(obj
->fence
, 1);
119 for (i
= 0; i
< fobj
->shared_count
; ++i
)
120 dma_fence_put(rcu_dereference_protected(fobj
->shared
[i
], 1));
125 ww_mutex_destroy(&obj
->lock
);
129 * reservation_object_get_list - get the reservation object's
130 * shared fence list, with update-side lock held
131 * @obj: the reservation object
133 * Returns the shared fence list. Does NOT take references to
134 * the fence. The obj->lock must be held.
136 static inline struct reservation_object_list
*
137 reservation_object_get_list(struct reservation_object
*obj
)
139 return rcu_dereference_protected(obj
->fence
,
140 reservation_object_held(obj
));
144 * reservation_object_lock - lock the reservation object
145 * @obj: the reservation object
146 * @ctx: the locking context
148 * Locks the reservation object for exclusive access and modification. Note,
149 * that the lock is only against other writers, readers will run concurrently
150 * with a writer under RCU. The seqlock is used to notify readers if they
151 * overlap with a writer.
153 * As the reservation object may be locked by multiple parties in an
154 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
155 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
156 * object may be locked by itself by passing NULL as @ctx.
159 reservation_object_lock(struct reservation_object
*obj
,
160 struct ww_acquire_ctx
*ctx
)
162 return ww_mutex_lock(&obj
->lock
, ctx
);
166 * reservation_object_lock_interruptible - lock the reservation object
167 * @obj: the reservation object
168 * @ctx: the locking context
170 * Locks the reservation object interruptible for exclusive access and
171 * modification. Note, that the lock is only against other writers, readers
172 * will run concurrently with a writer under RCU. The seqlock is used to
173 * notify readers if they overlap with a writer.
175 * As the reservation object may be locked by multiple parties in an
176 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
177 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
178 * object may be locked by itself by passing NULL as @ctx.
181 reservation_object_lock_interruptible(struct reservation_object
*obj
,
182 struct ww_acquire_ctx
*ctx
)
184 return ww_mutex_lock_interruptible(&obj
->lock
, ctx
);
189 * reservation_object_trylock - trylock the reservation object
190 * @obj: the reservation object
192 * Tries to lock the reservation object for exclusive access and modification.
193 * Note, that the lock is only against other writers, readers will run
194 * concurrently with a writer under RCU. The seqlock is used to notify readers
195 * if they overlap with a writer.
197 * Also note that since no context is provided, no deadlock protection is
200 * Returns true if the lock was acquired, false otherwise.
202 static inline bool __must_check
203 reservation_object_trylock(struct reservation_object
*obj
)
205 return ww_mutex_trylock(&obj
->lock
);
209 * reservation_object_unlock - unlock the reservation object
210 * @obj: the reservation object
212 * Unlocks the reservation object following exclusive access.
215 reservation_object_unlock(struct reservation_object
*obj
)
217 #ifdef CONFIG_DEBUG_MUTEXES
218 /* Test shared fence slot reservation */
220 obj
->fence
->shared_max
= obj
->fence
->shared_count
;
222 ww_mutex_unlock(&obj
->lock
);
226 * reservation_object_get_excl - get the reservation object's
227 * exclusive fence, with update-side lock held
228 * @obj: the reservation object
230 * Returns the exclusive fence (if any). Does NOT take a
231 * reference. Writers must hold obj->lock, readers may only
232 * hold a RCU read side lock.
235 * The exclusive fence or NULL
237 static inline struct dma_fence
*
238 reservation_object_get_excl(struct reservation_object
*obj
)
240 return rcu_dereference_protected(obj
->fence_excl
,
241 reservation_object_held(obj
));
245 * reservation_object_get_excl_rcu - get the reservation object's
246 * exclusive fence, without lock held.
247 * @obj: the reservation object
249 * If there is an exclusive fence, this atomically increments it's
250 * reference count and returns it.
253 * The exclusive fence or NULL if none
255 static inline struct dma_fence
*
256 reservation_object_get_excl_rcu(struct reservation_object
*obj
)
258 struct dma_fence
*fence
;
260 if (!rcu_access_pointer(obj
->fence_excl
))
264 fence
= dma_fence_get_rcu_safe(&obj
->fence_excl
);
270 int reservation_object_reserve_shared(struct reservation_object
*obj
,
271 unsigned int num_fences
);
272 void reservation_object_add_shared_fence(struct reservation_object
*obj
,
273 struct dma_fence
*fence
);
275 void reservation_object_add_excl_fence(struct reservation_object
*obj
,
276 struct dma_fence
*fence
);
278 int reservation_object_get_fences_rcu(struct reservation_object
*obj
,
279 struct dma_fence
**pfence_excl
,
280 unsigned *pshared_count
,
281 struct dma_fence
***pshared
);
283 int reservation_object_copy_fences(struct reservation_object
*dst
,
284 struct reservation_object
*src
);
286 long reservation_object_wait_timeout_rcu(struct reservation_object
*obj
,
287 bool wait_all
, bool intr
,
288 unsigned long timeout
);
290 bool reservation_object_test_signaled_rcu(struct reservation_object
*obj
,
293 #endif /* _LINUX_RESERVATION_H */