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
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_trylock - trylock the reservation object
171 * @obj: the reservation object
173 * Tries to lock the reservation object for exclusive access and modification.
174 * Note, that the lock is only against other writers, readers will run
175 * concurrently with a writer under RCU. The seqlock is used to notify readers
176 * if they overlap with a writer.
178 * Also note that since no context is provided, no deadlock protection is
181 * Returns true if the lock was acquired, false otherwise.
183 static inline bool __must_check
184 reservation_object_trylock(struct reservation_object
*obj
)
186 return ww_mutex_trylock(&obj
->lock
);
190 * reservation_object_unlock - unlock the reservation object
191 * @obj: the reservation object
193 * Unlocks the reservation object following exclusive access.
196 reservation_object_unlock(struct reservation_object
*obj
)
198 ww_mutex_unlock(&obj
->lock
);
202 * reservation_object_get_excl - get the reservation object's
203 * exclusive fence, with update-side lock held
204 * @obj: the reservation object
206 * Returns the exclusive fence (if any). Does NOT take a
207 * reference. The obj->lock must be held.
210 * The exclusive fence or NULL
212 static inline struct dma_fence
*
213 reservation_object_get_excl(struct reservation_object
*obj
)
215 return rcu_dereference_protected(obj
->fence_excl
,
216 reservation_object_held(obj
));
220 * reservation_object_get_excl_rcu - get the reservation object's
221 * exclusive fence, without lock held.
222 * @obj: the reservation object
224 * If there is an exclusive fence, this atomically increments it's
225 * reference count and returns it.
228 * The exclusive fence or NULL if none
230 static inline struct dma_fence
*
231 reservation_object_get_excl_rcu(struct reservation_object
*obj
)
233 struct dma_fence
*fence
;
235 if (!rcu_access_pointer(obj
->fence_excl
))
239 fence
= dma_fence_get_rcu_safe(&obj
->fence_excl
);
245 int reservation_object_reserve_shared(struct reservation_object
*obj
);
246 void reservation_object_add_shared_fence(struct reservation_object
*obj
,
247 struct dma_fence
*fence
);
249 void reservation_object_add_excl_fence(struct reservation_object
*obj
,
250 struct dma_fence
*fence
);
252 int reservation_object_get_fences_rcu(struct reservation_object
*obj
,
253 struct dma_fence
**pfence_excl
,
254 unsigned *pshared_count
,
255 struct dma_fence
***pshared
);
257 int reservation_object_copy_fences(struct reservation_object
*dst
,
258 struct reservation_object
*src
);
260 long reservation_object_wait_timeout_rcu(struct reservation_object
*obj
,
261 bool wait_all
, bool intr
,
262 unsigned long timeout
);
264 bool reservation_object_test_signaled_rcu(struct reservation_object
*obj
,
267 #endif /* _LINUX_RESERVATION_H */