1 /* 1 /*
2 * Header file for reservations for dma-buf an 2 * Header file for reservations for dma-buf and ttm
3 * 3 *
4 * Copyright(C) 2011 Linaro Limited. All right 4 * Copyright(C) 2011 Linaro Limited. All rights reserved.
5 * Copyright (C) 2012-2013 Canonical Ltd 5 * Copyright (C) 2012-2013 Canonical Ltd
6 * Copyright (C) 2012 Texas Instruments 6 * Copyright (C) 2012 Texas Instruments
7 * 7 *
8 * Authors: 8 * Authors:
9 * Rob Clark <robdclark@gmail.com> 9 * Rob Clark <robdclark@gmail.com>
10 * Maarten Lankhorst <maarten.lankhorst@canoni 10 * Maarten Lankhorst <maarten.lankhorst@canonical.com>
11 * Thomas Hellstrom <thellstrom-at-vmware-dot- 11 * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
12 * 12 *
13 * Based on bo.c which bears the following cop 13 * Based on bo.c which bears the following copyright notice,
14 * but is dual licensed: 14 * but is dual licensed:
15 * 15 *
16 * Copyright (c) 2006-2009 VMware, Inc., Palo 16 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
17 * All Rights Reserved. 17 * All Rights Reserved.
18 * 18 *
19 * Permission is hereby granted, free of charg 19 * Permission is hereby granted, free of charge, to any person obtaining a
20 * copy of this software and associated docume 20 * copy of this software and associated documentation files (the
21 * "Software"), to deal in the Software withou 21 * "Software"), to deal in the Software without restriction, including
22 * without limitation the rights to use, copy, 22 * without limitation the rights to use, copy, modify, merge, publish,
23 * distribute, sub license, and/or sell copies 23 * distribute, sub license, and/or sell copies of the Software, and to
24 * permit persons to whom the Software is furn 24 * permit persons to whom the Software is furnished to do so, subject to
25 * the following conditions: 25 * the following conditions:
26 * 26 *
27 * The above copyright notice and this permiss 27 * The above copyright notice and this permission notice (including the
28 * next paragraph) shall be included in all co 28 * next paragraph) shall be included in all copies or substantial portions
29 * of the Software. 29 * of the Software.
30 * 30 *
31 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT W 31 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
32 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE W 32 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
33 * FITNESS FOR A PARTICULAR PURPOSE AND NON-IN 33 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
34 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS S 34 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
35 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN A 35 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
36 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNE 36 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
37 * USE OR OTHER DEALINGS IN THE SOFTWARE. 37 * USE OR OTHER DEALINGS IN THE SOFTWARE.
38 */ 38 */
39 #ifndef _LINUX_RESERVATION_H 39 #ifndef _LINUX_RESERVATION_H
40 #define _LINUX_RESERVATION_H 40 #define _LINUX_RESERVATION_H
41 41
42 #include <linux/ww_mutex.h> 42 #include <linux/ww_mutex.h>
43 #include <linux/dma-fence.h> 43 #include <linux/dma-fence.h>
44 #include <linux/slab.h> 44 #include <linux/slab.h>
45 #include <linux/seqlock.h> 45 #include <linux/seqlock.h>
46 #include <linux/rcupdate.h> 46 #include <linux/rcupdate.h>
47 47
48 extern struct ww_class reservation_ww_class; 48 extern struct ww_class reservation_ww_class;
49 49
50 struct dma_resv_list; 50 struct dma_resv_list;
51 51
52 /** 52 /**
53 * enum dma_resv_usage - how the fences from a 53 * enum dma_resv_usage - how the fences from a dma_resv obj are used
54 * 54 *
55 * This enum describes the different use cases 55 * This enum describes the different use cases for a dma_resv object and
56 * controls which fences are returned when que 56 * controls which fences are returned when queried.
57 * 57 *
58 * An important fact is that there is the orde 58 * An important fact is that there is the order KERNEL<WRITE<READ<BOOKKEEP and
59 * when the dma_resv object is asked for fence 59 * when the dma_resv object is asked for fences for one use case the fences
60 * for the lower use case are returned as well 60 * for the lower use case are returned as well.
61 * 61 *
62 * For example when asking for WRITE fences th 62 * For example when asking for WRITE fences then the KERNEL fences are returned
63 * as well. Similar when asked for READ fences 63 * as well. Similar when asked for READ fences then both WRITE and KERNEL
64 * fences are returned as well. 64 * fences are returned as well.
65 * <<
66 * Already used fences can be promoted in the <<
67 * DMA_RESV_USAGE_BOOKKEEP could become DMA_RE <<
68 * with this usage. But fences can never be de <<
69 * with DMA_RESV_USAGE_WRITE could become DMA_ <<
70 */ 65 */
71 enum dma_resv_usage { 66 enum dma_resv_usage {
72 /** 67 /**
73 * @DMA_RESV_USAGE_KERNEL: For in kern 68 * @DMA_RESV_USAGE_KERNEL: For in kernel memory management only.
74 * 69 *
75 * This should only be used for things 70 * This should only be used for things like copying or clearing memory
76 * with a DMA hardware engine for the 71 * with a DMA hardware engine for the purpose of kernel memory
77 * management. 72 * management.
78 * 73 *
79 * Drivers *always* must wait for thos 74 * Drivers *always* must wait for those fences before accessing the
80 * resource protected by the dma_resv 75 * resource protected by the dma_resv object. The only exception for
81 * that is when the resource is known 76 * that is when the resource is known to be locked down in place by
82 * pinning it previously. 77 * pinning it previously.
83 */ 78 */
84 DMA_RESV_USAGE_KERNEL, 79 DMA_RESV_USAGE_KERNEL,
85 80
86 /** 81 /**
87 * @DMA_RESV_USAGE_WRITE: Implicit wri 82 * @DMA_RESV_USAGE_WRITE: Implicit write synchronization.
88 * 83 *
89 * This should only be used for usersp 84 * This should only be used for userspace command submissions which add
90 * an implicit write dependency. 85 * an implicit write dependency.
91 */ 86 */
92 DMA_RESV_USAGE_WRITE, 87 DMA_RESV_USAGE_WRITE,
93 88
94 /** 89 /**
95 * @DMA_RESV_USAGE_READ: Implicit read 90 * @DMA_RESV_USAGE_READ: Implicit read synchronization.
96 * 91 *
97 * This should only be used for usersp 92 * This should only be used for userspace command submissions which add
98 * an implicit read dependency. 93 * an implicit read dependency.
99 */ 94 */
100 DMA_RESV_USAGE_READ, 95 DMA_RESV_USAGE_READ,
101 96
102 /** 97 /**
103 * @DMA_RESV_USAGE_BOOKKEEP: No implic 98 * @DMA_RESV_USAGE_BOOKKEEP: No implicit sync.
104 * 99 *
105 * This should be used by submissions 100 * This should be used by submissions which don't want to participate in
106 * any implicit synchronization. !! 101 * implicit synchronization.
107 * <<
108 * The most common case are preemption <<
109 * flushes as well as explicit synced <<
110 * 102 *
111 * Explicit synced user user submissio !! 103 * The most common case are preemption fences as well as page table
112 * DMA_RESV_USAGE_READ or DMA_RESV_USA !! 104 * updates and their TLB flushes.
113 * dma_buf_import_sync_file() when imp <<
114 * become necessary after initial addi <<
115 */ 105 */
116 DMA_RESV_USAGE_BOOKKEEP 106 DMA_RESV_USAGE_BOOKKEEP
117 }; 107 };
118 108
119 /** 109 /**
120 * dma_resv_usage_rw - helper for implicit syn 110 * dma_resv_usage_rw - helper for implicit sync
121 * @write: true if we create a new implicit sy 111 * @write: true if we create a new implicit sync write
122 * 112 *
123 * This returns the implicit synchronization u 113 * This returns the implicit synchronization usage for write or read accesses,
124 * see enum dma_resv_usage and &dma_buf.resv. 114 * see enum dma_resv_usage and &dma_buf.resv.
125 */ 115 */
126 static inline enum dma_resv_usage dma_resv_usa 116 static inline enum dma_resv_usage dma_resv_usage_rw(bool write)
127 { 117 {
128 /* This looks confusing at first sight 118 /* This looks confusing at first sight, but is indeed correct.
129 * 119 *
130 * The rational is that new write oper 120 * The rational is that new write operations needs to wait for the
131 * existing read and write operations 121 * existing read and write operations to finish.
132 * But a new read operation only needs 122 * But a new read operation only needs to wait for the existing write
133 * operations to finish. 123 * operations to finish.
134 */ 124 */
135 return write ? DMA_RESV_USAGE_READ : D 125 return write ? DMA_RESV_USAGE_READ : DMA_RESV_USAGE_WRITE;
136 } 126 }
137 127
138 /** 128 /**
139 * struct dma_resv - a reservation object mana 129 * struct dma_resv - a reservation object manages fences for a buffer
140 * 130 *
141 * This is a container for dma_fence objects w 131 * This is a container for dma_fence objects which needs to handle multiple use
142 * cases. 132 * cases.
143 * 133 *
144 * One use is to synchronize cross-driver acce 134 * One use is to synchronize cross-driver access to a struct dma_buf, either for
145 * dynamic buffer management or just to handle 135 * dynamic buffer management or just to handle implicit synchronization between
146 * different users of the buffer in userspace. 136 * different users of the buffer in userspace. See &dma_buf.resv for a more
147 * in-depth discussion. 137 * in-depth discussion.
148 * 138 *
149 * The other major use is to manage access and 139 * The other major use is to manage access and locking within a driver in a
150 * buffer based memory manager. struct ttm_buf 140 * buffer based memory manager. struct ttm_buffer_object is the canonical
151 * example here, since this is where reservati 141 * example here, since this is where reservation objects originated from. But
152 * use in drivers is spreading and some driver 142 * use in drivers is spreading and some drivers also manage struct
153 * drm_gem_object with the same scheme. 143 * drm_gem_object with the same scheme.
154 */ 144 */
155 struct dma_resv { 145 struct dma_resv {
156 /** 146 /**
157 * @lock: 147 * @lock:
158 * 148 *
159 * Update side lock. Don't use directl 149 * Update side lock. Don't use directly, instead use the wrapper
160 * functions like dma_resv_lock() and 150 * functions like dma_resv_lock() and dma_resv_unlock().
161 * 151 *
162 * Drivers which use the reservation o 152 * Drivers which use the reservation object to manage memory dynamically
163 * also use this lock to protect buffe 153 * also use this lock to protect buffer object state like placement,
164 * allocation policies or throughout c 154 * allocation policies or throughout command submission.
165 */ 155 */
166 struct ww_mutex lock; 156 struct ww_mutex lock;
167 157
168 /** 158 /**
169 * @fences: 159 * @fences:
170 * 160 *
171 * Array of fences which where added t 161 * Array of fences which where added to the dma_resv object
172 * 162 *
173 * A new fence is added by calling dma 163 * A new fence is added by calling dma_resv_add_fence(). Since this
174 * often needs to be done past the poi 164 * often needs to be done past the point of no return in command
175 * submission it cannot fail, and ther 165 * submission it cannot fail, and therefore sufficient slots need to be
176 * reserved by calling dma_resv_reserv 166 * reserved by calling dma_resv_reserve_fences().
177 */ 167 */
178 struct dma_resv_list __rcu *fences; 168 struct dma_resv_list __rcu *fences;
179 }; 169 };
180 170
181 /** 171 /**
182 * struct dma_resv_iter - current position int 172 * struct dma_resv_iter - current position into the dma_resv fences
183 * 173 *
184 * Don't touch this directly in the driver, us 174 * Don't touch this directly in the driver, use the accessor function instead.
185 * 175 *
186 * IMPORTANT 176 * IMPORTANT
187 * 177 *
188 * When using the lockless iterators like dma_ 178 * When using the lockless iterators like dma_resv_iter_next_unlocked() or
189 * dma_resv_for_each_fence_unlocked() beware t 179 * dma_resv_for_each_fence_unlocked() beware that the iterator can be restarted.
190 * Code which accumulates statistics or simila 180 * Code which accumulates statistics or similar needs to check for this with
191 * dma_resv_iter_is_restarted(). 181 * dma_resv_iter_is_restarted().
192 */ 182 */
193 struct dma_resv_iter { 183 struct dma_resv_iter {
194 /** @obj: The dma_resv object we itera 184 /** @obj: The dma_resv object we iterate over */
195 struct dma_resv *obj; 185 struct dma_resv *obj;
196 186
197 /** @usage: Return fences with this us 187 /** @usage: Return fences with this usage or lower. */
198 enum dma_resv_usage usage; 188 enum dma_resv_usage usage;
199 189
200 /** @fence: the currently handled fenc 190 /** @fence: the currently handled fence */
201 struct dma_fence *fence; 191 struct dma_fence *fence;
202 192
203 /** @fence_usage: the usage of the cur 193 /** @fence_usage: the usage of the current fence */
204 enum dma_resv_usage fence_usage; 194 enum dma_resv_usage fence_usage;
205 195
206 /** @index: index into the shared fenc 196 /** @index: index into the shared fences */
207 unsigned int index; 197 unsigned int index;
208 198
209 /** @fences: the shared fences; privat 199 /** @fences: the shared fences; private, *MUST* not dereference */
210 struct dma_resv_list *fences; 200 struct dma_resv_list *fences;
211 201
212 /** @num_fences: number of fences */ 202 /** @num_fences: number of fences */
213 unsigned int num_fences; 203 unsigned int num_fences;
214 204
215 /** @is_restarted: true if this is the 205 /** @is_restarted: true if this is the first returned fence */
216 bool is_restarted; 206 bool is_restarted;
217 }; 207 };
218 208
219 struct dma_fence *dma_resv_iter_first_unlocked 209 struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor);
220 struct dma_fence *dma_resv_iter_next_unlocked( 210 struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor);
221 struct dma_fence *dma_resv_iter_first(struct d 211 struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor);
222 struct dma_fence *dma_resv_iter_next(struct dm 212 struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor);
223 213
224 /** 214 /**
225 * dma_resv_iter_begin - initialize a dma_resv 215 * dma_resv_iter_begin - initialize a dma_resv_iter object
226 * @cursor: The dma_resv_iter object to initia 216 * @cursor: The dma_resv_iter object to initialize
227 * @obj: The dma_resv object which we want to 217 * @obj: The dma_resv object which we want to iterate over
228 * @usage: controls which fences to include, s 218 * @usage: controls which fences to include, see enum dma_resv_usage.
229 */ 219 */
230 static inline void dma_resv_iter_begin(struct 220 static inline void dma_resv_iter_begin(struct dma_resv_iter *cursor,
231 struct 221 struct dma_resv *obj,
232 enum dm 222 enum dma_resv_usage usage)
233 { 223 {
234 cursor->obj = obj; 224 cursor->obj = obj;
235 cursor->usage = usage; 225 cursor->usage = usage;
236 cursor->fence = NULL; 226 cursor->fence = NULL;
237 } 227 }
238 228
239 /** 229 /**
240 * dma_resv_iter_end - cleanup a dma_resv_iter 230 * dma_resv_iter_end - cleanup a dma_resv_iter object
241 * @cursor: the dma_resv_iter object which sho 231 * @cursor: the dma_resv_iter object which should be cleaned up
242 * 232 *
243 * Make sure that the reference to the fence i 233 * Make sure that the reference to the fence in the cursor is properly
244 * dropped. 234 * dropped.
245 */ 235 */
246 static inline void dma_resv_iter_end(struct dm 236 static inline void dma_resv_iter_end(struct dma_resv_iter *cursor)
247 { 237 {
248 dma_fence_put(cursor->fence); 238 dma_fence_put(cursor->fence);
249 } 239 }
250 240
251 /** 241 /**
252 * dma_resv_iter_usage - Return the usage of t 242 * dma_resv_iter_usage - Return the usage of the current fence
253 * @cursor: the cursor of the current position 243 * @cursor: the cursor of the current position
254 * 244 *
255 * Returns the usage of the currently processe 245 * Returns the usage of the currently processed fence.
256 */ 246 */
257 static inline enum dma_resv_usage 247 static inline enum dma_resv_usage
258 dma_resv_iter_usage(struct dma_resv_iter *curs 248 dma_resv_iter_usage(struct dma_resv_iter *cursor)
259 { 249 {
260 return cursor->fence_usage; 250 return cursor->fence_usage;
261 } 251 }
262 252
263 /** 253 /**
264 * dma_resv_iter_is_restarted - test if this i 254 * dma_resv_iter_is_restarted - test if this is the first fence after a restart
265 * @cursor: the cursor with the current positi 255 * @cursor: the cursor with the current position
266 * 256 *
267 * Return true if this is the first fence in a 257 * Return true if this is the first fence in an iteration after a restart.
268 */ 258 */
269 static inline bool dma_resv_iter_is_restarted( 259 static inline bool dma_resv_iter_is_restarted(struct dma_resv_iter *cursor)
270 { 260 {
271 return cursor->is_restarted; 261 return cursor->is_restarted;
272 } 262 }
273 263
274 /** 264 /**
275 * dma_resv_for_each_fence_unlocked - unlocked 265 * dma_resv_for_each_fence_unlocked - unlocked fence iterator
276 * @cursor: a struct dma_resv_iter pointer 266 * @cursor: a struct dma_resv_iter pointer
277 * @fence: the current fence 267 * @fence: the current fence
278 * 268 *
279 * Iterate over the fences in a struct dma_res 269 * Iterate over the fences in a struct dma_resv object without holding the
280 * &dma_resv.lock and using RCU instead. The c 270 * &dma_resv.lock and using RCU instead. The cursor needs to be initialized
281 * with dma_resv_iter_begin() and cleaned up w 271 * with dma_resv_iter_begin() and cleaned up with dma_resv_iter_end(). Inside
282 * the iterator a reference to the dma_fence i 272 * the iterator a reference to the dma_fence is held and the RCU lock dropped.
283 * 273 *
284 * Beware that the iterator can be restarted w 274 * Beware that the iterator can be restarted when the struct dma_resv for
285 * @cursor is modified. Code which accumulates 275 * @cursor is modified. Code which accumulates statistics or similar needs to
286 * check for this with dma_resv_iter_is_restar 276 * check for this with dma_resv_iter_is_restarted(). For this reason prefer the
287 * lock iterator dma_resv_for_each_fence() whe 277 * lock iterator dma_resv_for_each_fence() whenever possible.
288 */ 278 */
289 #define dma_resv_for_each_fence_unlocked(curso 279 #define dma_resv_for_each_fence_unlocked(cursor, fence) \
290 for (fence = dma_resv_iter_first_unloc 280 for (fence = dma_resv_iter_first_unlocked(cursor); \
291 fence; fence = dma_resv_iter_next 281 fence; fence = dma_resv_iter_next_unlocked(cursor))
292 282
293 /** 283 /**
294 * dma_resv_for_each_fence - fence iterator 284 * dma_resv_for_each_fence - fence iterator
295 * @cursor: a struct dma_resv_iter pointer 285 * @cursor: a struct dma_resv_iter pointer
296 * @obj: a dma_resv object pointer 286 * @obj: a dma_resv object pointer
297 * @usage: controls which fences to return 287 * @usage: controls which fences to return
298 * @fence: the current fence 288 * @fence: the current fence
299 * 289 *
300 * Iterate over the fences in a struct dma_res 290 * Iterate over the fences in a struct dma_resv object while holding the
301 * &dma_resv.lock. @all_fences controls if the 291 * &dma_resv.lock. @all_fences controls if the shared fences are returned as
302 * well. The cursor initialisation is part of 292 * well. The cursor initialisation is part of the iterator and the fence stays
303 * valid as long as the lock is held and so no 293 * valid as long as the lock is held and so no extra reference to the fence is
304 * taken. 294 * taken.
305 */ 295 */
306 #define dma_resv_for_each_fence(cursor, obj, u 296 #define dma_resv_for_each_fence(cursor, obj, usage, fence) \
307 for (dma_resv_iter_begin(cursor, obj, 297 for (dma_resv_iter_begin(cursor, obj, usage), \
308 fence = dma_resv_iter_first(curso 298 fence = dma_resv_iter_first(cursor); fence; \
309 fence = dma_resv_iter_next(cursor 299 fence = dma_resv_iter_next(cursor))
310 300
311 #define dma_resv_held(obj) lockdep_is_held(&(o 301 #define dma_resv_held(obj) lockdep_is_held(&(obj)->lock.base)
312 #define dma_resv_assert_held(obj) lockdep_asse 302 #define dma_resv_assert_held(obj) lockdep_assert_held(&(obj)->lock.base)
313 303
314 #ifdef CONFIG_DEBUG_MUTEXES 304 #ifdef CONFIG_DEBUG_MUTEXES
315 void dma_resv_reset_max_fences(struct dma_resv 305 void dma_resv_reset_max_fences(struct dma_resv *obj);
316 #else 306 #else
317 static inline void dma_resv_reset_max_fences(s 307 static inline void dma_resv_reset_max_fences(struct dma_resv *obj) {}
318 #endif 308 #endif
319 309
320 /** 310 /**
321 * dma_resv_lock - lock the reservation object 311 * dma_resv_lock - lock the reservation object
322 * @obj: the reservation object 312 * @obj: the reservation object
323 * @ctx: the locking context 313 * @ctx: the locking context
324 * 314 *
325 * Locks the reservation object for exclusive 315 * Locks the reservation object for exclusive access and modification. Note,
326 * that the lock is only against other writers 316 * that the lock is only against other writers, readers will run concurrently
327 * with a writer under RCU. The seqlock is use 317 * with a writer under RCU. The seqlock is used to notify readers if they
328 * overlap with a writer. 318 * overlap with a writer.
329 * 319 *
330 * As the reservation object may be locked by 320 * As the reservation object may be locked by multiple parties in an
331 * undefined order, a #ww_acquire_ctx is passe 321 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
332 * is detected. See ww_mutex_lock() and ww_acq 322 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
333 * object may be locked by itself by passing N 323 * object may be locked by itself by passing NULL as @ctx.
334 * 324 *
335 * When a die situation is indicated by return 325 * When a die situation is indicated by returning -EDEADLK all locks held by
336 * @ctx must be unlocked and then dma_resv_loc 326 * @ctx must be unlocked and then dma_resv_lock_slow() called on @obj.
337 * 327 *
338 * Unlocked by calling dma_resv_unlock(). 328 * Unlocked by calling dma_resv_unlock().
339 * 329 *
340 * See also dma_resv_lock_interruptible() for 330 * See also dma_resv_lock_interruptible() for the interruptible variant.
341 */ 331 */
342 static inline int dma_resv_lock(struct dma_res 332 static inline int dma_resv_lock(struct dma_resv *obj,
343 struct ww_acqu 333 struct ww_acquire_ctx *ctx)
344 { 334 {
345 return ww_mutex_lock(&obj->lock, ctx); 335 return ww_mutex_lock(&obj->lock, ctx);
346 } 336 }
347 337
348 /** 338 /**
349 * dma_resv_lock_interruptible - lock the rese 339 * dma_resv_lock_interruptible - lock the reservation object
350 * @obj: the reservation object 340 * @obj: the reservation object
351 * @ctx: the locking context 341 * @ctx: the locking context
352 * 342 *
353 * Locks the reservation object interruptible 343 * Locks the reservation object interruptible for exclusive access and
354 * modification. Note, that the lock is only a 344 * modification. Note, that the lock is only against other writers, readers
355 * will run concurrently with a writer under R 345 * will run concurrently with a writer under RCU. The seqlock is used to
356 * notify readers if they overlap with a write 346 * notify readers if they overlap with a writer.
357 * 347 *
358 * As the reservation object may be locked by 348 * As the reservation object may be locked by multiple parties in an
359 * undefined order, a #ww_acquire_ctx is passe 349 * undefined order, a #ww_acquire_ctx is passed to unwind if a cycle
360 * is detected. See ww_mutex_lock() and ww_acq 350 * is detected. See ww_mutex_lock() and ww_acquire_init(). A reservation
361 * object may be locked by itself by passing N 351 * object may be locked by itself by passing NULL as @ctx.
362 * 352 *
363 * When a die situation is indicated by return 353 * When a die situation is indicated by returning -EDEADLK all locks held by
364 * @ctx must be unlocked and then dma_resv_loc 354 * @ctx must be unlocked and then dma_resv_lock_slow_interruptible() called on
365 * @obj. 355 * @obj.
366 * 356 *
367 * Unlocked by calling dma_resv_unlock(). 357 * Unlocked by calling dma_resv_unlock().
368 */ 358 */
369 static inline int dma_resv_lock_interruptible( 359 static inline int dma_resv_lock_interruptible(struct dma_resv *obj,
370 360 struct ww_acquire_ctx *ctx)
371 { 361 {
372 return ww_mutex_lock_interruptible(&ob 362 return ww_mutex_lock_interruptible(&obj->lock, ctx);
373 } 363 }
374 364
375 /** 365 /**
376 * dma_resv_lock_slow - slowpath lock the rese 366 * dma_resv_lock_slow - slowpath lock the reservation object
377 * @obj: the reservation object 367 * @obj: the reservation object
378 * @ctx: the locking context 368 * @ctx: the locking context
379 * 369 *
380 * Acquires the reservation object after a die 370 * Acquires the reservation object after a die case. This function
381 * will sleep until the lock becomes available 371 * will sleep until the lock becomes available. See dma_resv_lock() as
382 * well. 372 * well.
383 * 373 *
384 * See also dma_resv_lock_slow_interruptible() 374 * See also dma_resv_lock_slow_interruptible() for the interruptible variant.
385 */ 375 */
386 static inline void dma_resv_lock_slow(struct d 376 static inline void dma_resv_lock_slow(struct dma_resv *obj,
387 struct w 377 struct ww_acquire_ctx *ctx)
388 { 378 {
389 ww_mutex_lock_slow(&obj->lock, ctx); 379 ww_mutex_lock_slow(&obj->lock, ctx);
390 } 380 }
391 381
392 /** 382 /**
393 * dma_resv_lock_slow_interruptible - slowpath 383 * dma_resv_lock_slow_interruptible - slowpath lock the reservation
394 * object, interruptible 384 * object, interruptible
395 * @obj: the reservation object 385 * @obj: the reservation object
396 * @ctx: the locking context 386 * @ctx: the locking context
397 * 387 *
398 * Acquires the reservation object interruptib 388 * Acquires the reservation object interruptible after a die case. This function
399 * will sleep until the lock becomes available 389 * will sleep until the lock becomes available. See
400 * dma_resv_lock_interruptible() as well. 390 * dma_resv_lock_interruptible() as well.
401 */ 391 */
402 static inline int dma_resv_lock_slow_interrupt 392 static inline int dma_resv_lock_slow_interruptible(struct dma_resv *obj,
403 393 struct ww_acquire_ctx *ctx)
404 { 394 {
405 return ww_mutex_lock_slow_interruptibl 395 return ww_mutex_lock_slow_interruptible(&obj->lock, ctx);
406 } 396 }
407 397
408 /** 398 /**
409 * dma_resv_trylock - trylock the reservation 399 * dma_resv_trylock - trylock the reservation object
410 * @obj: the reservation object 400 * @obj: the reservation object
411 * 401 *
412 * Tries to lock the reservation object for ex 402 * Tries to lock the reservation object for exclusive access and modification.
413 * Note, that the lock is only against other w 403 * Note, that the lock is only against other writers, readers will run
414 * concurrently with a writer under RCU. The s 404 * concurrently with a writer under RCU. The seqlock is used to notify readers
415 * if they overlap with a writer. 405 * if they overlap with a writer.
416 * 406 *
417 * Also note that since no context is provided 407 * Also note that since no context is provided, no deadlock protection is
418 * possible, which is also not needed for a tr 408 * possible, which is also not needed for a trylock.
419 * 409 *
420 * Returns true if the lock was acquired, fals 410 * Returns true if the lock was acquired, false otherwise.
421 */ 411 */
422 static inline bool __must_check dma_resv_trylo 412 static inline bool __must_check dma_resv_trylock(struct dma_resv *obj)
423 { 413 {
424 return ww_mutex_trylock(&obj->lock, NU 414 return ww_mutex_trylock(&obj->lock, NULL);
425 } 415 }
426 416
427 /** 417 /**
428 * dma_resv_is_locked - is the reservation obj 418 * dma_resv_is_locked - is the reservation object locked
429 * @obj: the reservation object 419 * @obj: the reservation object
430 * 420 *
431 * Returns true if the mutex is locked, false 421 * Returns true if the mutex is locked, false if unlocked.
432 */ 422 */
433 static inline bool dma_resv_is_locked(struct d 423 static inline bool dma_resv_is_locked(struct dma_resv *obj)
434 { 424 {
435 return ww_mutex_is_locked(&obj->lock); 425 return ww_mutex_is_locked(&obj->lock);
436 } 426 }
437 427
438 /** 428 /**
439 * dma_resv_locking_ctx - returns the context 429 * dma_resv_locking_ctx - returns the context used to lock the object
440 * @obj: the reservation object 430 * @obj: the reservation object
441 * 431 *
442 * Returns the context used to lock a reservat 432 * Returns the context used to lock a reservation object or NULL if no context
443 * was used or the object is not locked at all 433 * was used or the object is not locked at all.
444 * 434 *
445 * WARNING: This interface is pretty horrible, 435 * WARNING: This interface is pretty horrible, but TTM needs it because it
446 * doesn't pass the struct ww_acquire_ctx arou 436 * doesn't pass the struct ww_acquire_ctx around in some very long callchains.
447 * Everyone else just uses it to check whether 437 * Everyone else just uses it to check whether they're holding a reservation or
448 * not. 438 * not.
449 */ 439 */
450 static inline struct ww_acquire_ctx *dma_resv_ 440 static inline struct ww_acquire_ctx *dma_resv_locking_ctx(struct dma_resv *obj)
451 { 441 {
452 return READ_ONCE(obj->lock.ctx); 442 return READ_ONCE(obj->lock.ctx);
453 } 443 }
454 444
455 /** 445 /**
456 * dma_resv_unlock - unlock the reservation ob 446 * dma_resv_unlock - unlock the reservation object
457 * @obj: the reservation object 447 * @obj: the reservation object
458 * 448 *
459 * Unlocks the reservation object following ex 449 * Unlocks the reservation object following exclusive access.
460 */ 450 */
461 static inline void dma_resv_unlock(struct dma_ 451 static inline void dma_resv_unlock(struct dma_resv *obj)
462 { 452 {
463 dma_resv_reset_max_fences(obj); 453 dma_resv_reset_max_fences(obj);
464 ww_mutex_unlock(&obj->lock); 454 ww_mutex_unlock(&obj->lock);
465 } 455 }
466 456
467 void dma_resv_init(struct dma_resv *obj); 457 void dma_resv_init(struct dma_resv *obj);
468 void dma_resv_fini(struct dma_resv *obj); 458 void dma_resv_fini(struct dma_resv *obj);
469 int dma_resv_reserve_fences(struct dma_resv *o 459 int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences);
470 void dma_resv_add_fence(struct dma_resv *obj, 460 void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
471 enum dma_resv_usage us 461 enum dma_resv_usage usage);
472 void dma_resv_replace_fences(struct dma_resv * 462 void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
473 struct dma_fence 463 struct dma_fence *fence,
474 enum dma_resv_usa 464 enum dma_resv_usage usage);
475 int dma_resv_get_fences(struct dma_resv *obj, 465 int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,
476 unsigned int *num_fenc 466 unsigned int *num_fences, struct dma_fence ***fences);
477 int dma_resv_get_singleton(struct dma_resv *ob 467 int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,
478 struct dma_fence ** 468 struct dma_fence **fence);
479 int dma_resv_copy_fences(struct dma_resv *dst, 469 int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
480 long dma_resv_wait_timeout(struct dma_resv *ob 470 long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
481 bool intr, unsigned 471 bool intr, unsigned long timeout);
482 void dma_resv_set_deadline(struct dma_resv *ob <<
483 ktime_t deadline); <<
484 bool dma_resv_test_signaled(struct dma_resv *o 472 bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage);
485 void dma_resv_describe(struct dma_resv *obj, s 473 void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq);
486 474
487 #endif /* _LINUX_RESERVATION_H */ 475 #endif /* _LINUX_RESERVATION_H */
488 476
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