aboutsummaryrefslogtreecommitdiff
path: root/include/linux/dma-resv.h
blob: d44a77e8a7e34a3333e61a714028beee76fa297b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
/*
 * Header file for reservations for dma-buf and ttm
 *
 * Copyright(C) 2011 Linaro Limited. All rights reserved.
 * Copyright (C) 2012-2013 Canonical Ltd
 * Copyright (C) 2012 Texas Instruments
 *
 * Authors:
 * Rob Clark <robdclark@gmail.com>
 * Maarten Lankhorst <maarten.lankhorst@canonical.com>
 * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 *
 * Based on bo.c which bears the following copyright notice,
 * but is dual licensed:
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#ifndef _LINUX_RESERVATION_H
#define _LINUX_RESERVATION_H

#include <linux/ww_mutex.h>
#include <linux/dma-fence.h>
#include <linux/slab.h>
#include <linux/seqlock.h>
#include <linux/rcupdate.h>

extern struct ww_class reservation_ww_class;

/**
 * struct dma_resv_list - a list of shared fences
 * @rcu: for internal use
 * @shared_count: table of shared fences
 * @shared_max: for growing shared fence table
 * @shared: shared fence table
 */
struct dma_resv_list {
	struct rcu_head rcu;
	u32 shared_count, shared_max;
	struct dma_fence __rcu *shared[];
};

/**
 * struct dma_resv - a reservation object manages fences for a buffer
 * @lock: update side lock
 * @seq: sequence count for managing RCU read-side synchronization
 * @fence_excl: the exclusive fence, if there is one currently
 * @fence: list of current shared fences
 */
struct dma_resv {
	struct ww_mutex lock;
	seqcount_ww_mutex_t seq;

	struct dma_fence __rcu *fence_excl;
	struct dma_resv_list __rcu *fence;
};

#define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
#define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)

/**
 * dma_resv_get_list - get the reservation object's
 * shared fence list, with update-side lock held
 * @obj: the reservation object
 *
 * Returns the shared fence list.  Does NOT take references to
 * the fence.  The obj->lock must be held.
 */
static inline struct dma_resv_list *dma_resv_get_list(struct dma_resv *obj)
{
	return rcu_dereference_protected(obj->fence,
					 dma_resv_held(obj));
}

/**
 * dma_resv_lock - lock the reservation object
 * @obj: the reservation object
 * @ctx: the locking context
 *
 * Locks the reservation object for exclusive access and modification. Note,
 * that the lock is only against other writers, readers will run concurrently
 * with a writer under RCU. The seqlock is used to notify readers if they
 * overlap with a writer.
 *
 * As the reservation object may be locked by multiple parties in an
 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
 * object may be locked by itself by passing NULL as @ctx.
 */
static inline int dma_resv_lock(struct dma_resv *obj,
				struct ww_acquire_ctx *ctx)
{
	return ww_mutex_lock(&obj->lock, ctx);
}

/**
 * dma_resv_lock_interruptible - lock the reservation object
 * @obj: the reservation object
 * @ctx: the locking context
 *
 * Locks the reservation object interruptible for exclusive access and
 * modification. Note, that the lock is only against other writers, readers
 * will run concurrently with a writer under RCU. The seqlock is used to
 * notify readers if they overlap with a writer.
 *
 * As the reservation object may be locked by multiple parties in an
 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
 * object may be locked by itself by passing NULL as @ctx.
 */
static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
					      struct ww_acquire_ctx *ctx)
{
	return ww_mutex_lock_interruptible(&obj->lock, ctx);
}

/**
 * dma_resv_lock_slow - slowpath lock the reservation object
 * @obj: the reservation object
 * @ctx: the locking context
 *
 * Acquires the reservation object after a die case. This function
 * will sleep until the lock becomes available. See dma_resv_lock() as
 * well.
 */
static inline void dma_resv_lock_slow(struct dma_resv *obj,
				      struct ww_acquire_ctx *ctx)
{
	ww_mutex_lock_slow(&obj->lock, ctx);
}

/**
 * dma_resv_lock_slow_interruptible - slowpath lock the reservation
 * object, interruptible
 * @obj: the reservation object
 * @ctx: the locking context
 *
 * Acquires the reservation object interruptible after a die case. This function
 * will sleep until the lock becomes available. See
 * dma_resv_lock_interruptible() as well.
 */
static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
						   struct ww_acquire_ctx *ctx)
{
	return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
}

/**
 * dma_resv_trylock - trylock the reservation object
 * @obj: the reservation object
 *
 * Tries to lock the reservation object for exclusive access and modification.
 * Note, that the lock is only against other writers, readers will run
 * concurrently with a writer under RCU. The seqlock is used to notify readers
 * if they overlap with a writer.
 *
 * Also note that since no context is provided, no deadlock protection is
 * possible.
 *
 * Returns true if the lock was acquired, false otherwise.
 */
static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
{
	return ww_mutex_trylock(&obj->lock);
}

/**
 * dma_resv_is_locked - is the reservation object locked
 * @obj: the reservation object
 *
 * Returns true if the mutex is locked, false if unlocked.
 */
static inline bool dma_resv_is_locked(struct dma_resv *obj)
{
	return ww_mutex_is_locked(&obj->lock);
}

/**
 * dma_resv_locking_ctx - returns the context used to lock the object
 * @obj: the reservation object
 *
 * Returns the context used to lock a reservation object or NULL if no context
 * was used or the object is not locked at all.
 */
static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
{
	return READ_ONCE(obj->lock.ctx);
}

/**
 * dma_resv_unlock - unlock the reservation object
 * @obj: the reservation object
 *
 * Unlocks the reservation object following exclusive access.
 */
static inline void dma_resv_unlock(struct dma_resv *obj)
{
#ifdef CONFIG_DEBUG_MUTEXES
	/* Test shared fence slot reservation */
	if (rcu_access_pointer(obj->fence)) {
		struct dma_resv_list *fence = dma_resv_get_list(obj);

		fence->shared_max = fence->shared_count;
	}
#endif
	ww_mutex_unlock(&obj->lock);
}

/**
 * dma_resv_get_excl - get the reservation object's
 * exclusive fence, with update-side lock held
 * @obj: the reservation object
 *
 * Returns the exclusive fence (if any).  Does NOT take a
 * reference. Writers must hold obj->lock, readers may only
 * hold a RCU read side lock.
 *
 * RETURNS
 * The exclusive fence or NULL
 */
static inline struct dma_fence *
dma_resv_get_excl(struct dma_resv *obj)
{
	return rcu_dereference_protected(obj->fence_excl,
					 dma_resv_held(obj));
}

/**
 * dma_resv_get_excl_rcu - get the reservation object's
 * exclusive fence, without lock held.
 * @obj: the reservation object
 *
 * If there is an exclusive fence, this atomically increments it's
 * reference count and returns it.
 *
 * RETURNS
 * The exclusive fence or NULL if none
 */
static inline struct dma_fence *
dma_resv_get_excl_rcu(struct dma_resv *obj)
{
	struct dma_fence *fence;

	if (!rcu_access_pointer(obj->fence_excl))
		return NULL;

	rcu_read_lock();
	fence = dma_fence_get_rcu_safe(&obj->fence_excl);
	rcu_read_unlock();

	return fence;
}

void dma_resv_init(struct dma_resv *obj);
void dma_resv_fini(struct dma_resv *obj);
int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);

void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);

int dma_resv_get_fences_rcu(struct dma_resv *obj,
			    struct dma_fence **pfence_excl,
			    unsigned *pshared_count,
			    struct dma_fence ***pshared);

int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);

long dma_resv_wait_timeout_rcu(struct dma_resv *obj, bool wait_all, bool intr,
			       unsigned long timeout);

bool dma_resv_test_signaled_rcu(struct dma_resv *obj, bool test_all);

#endif /* _LINUX_RESERVATION_H */