Merge branches 'acpi-tables', 'acpi-osl', 'acpi-misc' and 'acpi-tools'
[linux-2.6-microblaze.git] / include / linux / reservation.h
1 /*
2  * Header file for reservations for dma-buf and ttm
3  *
4  * Copyright(C) 2011 Linaro Limited. All rights reserved.
5  * Copyright (C) 2012-2013 Canonical Ltd
6  * Copyright (C) 2012 Texas Instruments
7  *
8  * Authors:
9  * Rob Clark <robdclark@gmail.com>
10  * Maarten Lankhorst <maarten.lankhorst@canonical.com>
11  * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
12  *
13  * Based on bo.c which bears the following copyright notice,
14  * but is dual licensed:
15  *
16  * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
17  * All Rights Reserved.
18  *
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:
26  *
27  * The above copyright notice and this permission notice (including the
28  * next paragraph) shall be included in all copies or substantial portions
29  * of the Software.
30  *
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.
38  */
39 #ifndef _LINUX_RESERVATION_H
40 #define _LINUX_RESERVATION_H
41
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>
47
48 extern struct ww_class reservation_ww_class;
49 extern struct lock_class_key reservation_seqcount_class;
50 extern const char reservation_seqcount_string[];
51
52 /**
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
58  */
59 struct reservation_object_list {
60         struct rcu_head rcu;
61         u32 shared_count, shared_max;
62         struct dma_fence __rcu *shared[];
63 };
64
65 /**
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  */
72 struct reservation_object {
73         struct ww_mutex lock;
74         seqcount_t seq;
75
76         struct dma_fence __rcu *fence_excl;
77         struct reservation_object_list __rcu *fence;
78 };
79
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)
83
84 /**
85  * reservation_object_init - initialize a reservation object
86  * @obj: the reservation object
87  */
88 static inline void
89 reservation_object_init(struct reservation_object *obj)
90 {
91         ww_mutex_init(&obj->lock, &reservation_ww_class);
92
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);
96 }
97
98 /**
99  * reservation_object_fini - destroys a reservation object
100  * @obj: the reservation object
101  */
102 static inline void
103 reservation_object_fini(struct reservation_object *obj)
104 {
105         int i;
106         struct reservation_object_list *fobj;
107         struct dma_fence *excl;
108
109         /*
110          * This object should be dead and all references must have
111          * been released to it, so no need to be protected with rcu.
112          */
113         excl = rcu_dereference_protected(obj->fence_excl, 1);
114         if (excl)
115                 dma_fence_put(excl);
116
117         fobj = rcu_dereference_protected(obj->fence, 1);
118         if (fobj) {
119                 for (i = 0; i < fobj->shared_count; ++i)
120                         dma_fence_put(rcu_dereference_protected(fobj->shared[i], 1));
121
122                 kfree(fobj);
123         }
124
125         ww_mutex_destroy(&obj->lock);
126 }
127
128 /**
129  * reservation_object_get_list - get the reservation object's
130  * shared fence list, with update-side lock held
131  * @obj: the reservation object
132  *
133  * Returns the shared fence list.  Does NOT take references to
134  * the fence.  The obj->lock must be held.
135  */
136 static inline struct reservation_object_list *
137 reservation_object_get_list(struct reservation_object *obj)
138 {
139         return rcu_dereference_protected(obj->fence,
140                                          reservation_object_held(obj));
141 }
142
143 /**
144  * reservation_object_lock - lock the reservation object
145  * @obj: the reservation object
146  * @ctx: the locking context
147  *
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.
152  *
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.
157  */
158 static inline int
159 reservation_object_lock(struct reservation_object *obj,
160                         struct ww_acquire_ctx *ctx)
161 {
162         return ww_mutex_lock(&obj->lock, ctx);
163 }
164
165 /**
166  * reservation_object_lock_interruptible - lock the reservation object
167  * @obj: the reservation object
168  * @ctx: the locking context
169  *
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.
174  *
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.
179  */
180 static inline int
181 reservation_object_lock_interruptible(struct reservation_object *obj,
182                                       struct ww_acquire_ctx *ctx)
183 {
184         return ww_mutex_lock_interruptible(&obj->lock, ctx);
185 }
186
187
188 /**
189  * reservation_object_trylock - trylock the reservation object
190  * @obj: the reservation object
191  *
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.
196  *
197  * Also note that since no context is provided, no deadlock protection is
198  * possible.
199  *
200  * Returns true if the lock was acquired, false otherwise.
201  */
202 static inline bool __must_check
203 reservation_object_trylock(struct reservation_object *obj)
204 {
205         return ww_mutex_trylock(&obj->lock);
206 }
207
208 /**
209  * reservation_object_unlock - unlock the reservation object
210  * @obj: the reservation object
211  *
212  * Unlocks the reservation object following exclusive access.
213  */
214 static inline void
215 reservation_object_unlock(struct reservation_object *obj)
216 {
217 #ifdef CONFIG_DEBUG_MUTEXES
218         /* Test shared fence slot reservation */
219         if (obj->fence)
220                 obj->fence->shared_max = obj->fence->shared_count;
221 #endif
222         ww_mutex_unlock(&obj->lock);
223 }
224
225 /**
226  * reservation_object_get_excl - get the reservation object's
227  * exclusive fence, with update-side lock held
228  * @obj: the reservation object
229  *
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.
233  *
234  * RETURNS
235  * The exclusive fence or NULL
236  */
237 static inline struct dma_fence *
238 reservation_object_get_excl(struct reservation_object *obj)
239 {
240         return rcu_dereference_protected(obj->fence_excl,
241                                          reservation_object_held(obj));
242 }
243
244 /**
245  * reservation_object_get_excl_rcu - get the reservation object's
246  * exclusive fence, without lock held.
247  * @obj: the reservation object
248  *
249  * If there is an exclusive fence, this atomically increments it's
250  * reference count and returns it.
251  *
252  * RETURNS
253  * The exclusive fence or NULL if none
254  */
255 static inline struct dma_fence *
256 reservation_object_get_excl_rcu(struct reservation_object *obj)
257 {
258         struct dma_fence *fence;
259
260         if (!rcu_access_pointer(obj->fence_excl))
261                 return NULL;
262
263         rcu_read_lock();
264         fence = dma_fence_get_rcu_safe(&obj->fence_excl);
265         rcu_read_unlock();
266
267         return fence;
268 }
269
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);
274
275 void reservation_object_add_excl_fence(struct reservation_object *obj,
276                                        struct dma_fence *fence);
277
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);
282
283 int reservation_object_copy_fences(struct reservation_object *dst,
284                                    struct reservation_object *src);
285
286 long reservation_object_wait_timeout_rcu(struct reservation_object *obj,
287                                          bool wait_all, bool intr,
288                                          unsigned long timeout);
289
290 bool reservation_object_test_signaled_rcu(struct reservation_object *obj,
291                                           bool test_all);
292
293 #endif /* _LINUX_RESERVATION_H */