Line data Source code
1 : // SPDX-License-Identifier: MIT
2 : /*
3 : * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
4 : *
5 : * Based on bo.c which bears the following copyright notice,
6 : * but is dual licensed:
7 : *
8 : * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
9 : * All Rights Reserved.
10 : *
11 : * Permission is hereby granted, free of charge, to any person obtaining a
12 : * copy of this software and associated documentation files (the
13 : * "Software"), to deal in the Software without restriction, including
14 : * without limitation the rights to use, copy, modify, merge, publish,
15 : * distribute, sub license, and/or sell copies of the Software, and to
16 : * permit persons to whom the Software is furnished to do so, subject to
17 : * the following conditions:
18 : *
19 : * The above copyright notice and this permission notice (including the
20 : * next paragraph) shall be included in all copies or substantial portions
21 : * of the Software.
22 : *
23 : * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 : * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 : * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
26 : * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
27 : * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
28 : * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
29 : * USE OR OTHER DEALINGS IN THE SOFTWARE.
30 : *
31 : **************************************************************************/
32 : /*
33 : * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
34 : */
35 :
36 : #include <linux/dma-resv.h>
37 : #include <linux/dma-fence-array.h>
38 : #include <linux/export.h>
39 : #include <linux/mm.h>
40 : #include <linux/sched/mm.h>
41 : #include <linux/mmu_notifier.h>
42 : #include <linux/seq_file.h>
43 :
44 : /**
45 : * DOC: Reservation Object Overview
46 : *
47 : * The reservation object provides a mechanism to manage a container of
48 : * dma_fence object associated with a resource. A reservation object
49 : * can have any number of fences attaches to it. Each fence carries an usage
50 : * parameter determining how the operation represented by the fence is using the
51 : * resource. The RCU mechanism is used to protect read access to fences from
52 : * locked write-side updates.
53 : *
54 : * See struct dma_resv for more details.
55 : */
56 :
57 : DEFINE_WD_CLASS(reservation_ww_class);
58 : EXPORT_SYMBOL(reservation_ww_class);
59 :
60 : /* Mask for the lower fence pointer bits */
61 : #define DMA_RESV_LIST_MASK 0x3
62 :
63 : struct dma_resv_list {
64 : struct rcu_head rcu;
65 : u32 num_fences, max_fences;
66 : struct dma_fence __rcu *table[];
67 : };
68 :
69 : /* Extract the fence and usage flags from an RCU protected entry in the list. */
70 : static void dma_resv_list_entry(struct dma_resv_list *list, unsigned int index,
71 : struct dma_resv *resv, struct dma_fence **fence,
72 : enum dma_resv_usage *usage)
73 : {
74 : long tmp;
75 :
76 0 : tmp = (long)rcu_dereference_check(list->table[index],
77 : resv ? dma_resv_held(resv) : true);
78 0 : *fence = (struct dma_fence *)(tmp & ~DMA_RESV_LIST_MASK);
79 0 : if (usage)
80 0 : *usage = tmp & DMA_RESV_LIST_MASK;
81 : }
82 :
83 : /* Set the fence and usage flags at the specific index in the list. */
84 : static void dma_resv_list_set(struct dma_resv_list *list,
85 : unsigned int index,
86 : struct dma_fence *fence,
87 : enum dma_resv_usage usage)
88 : {
89 0 : long tmp = ((long)fence) | usage;
90 :
91 0 : RCU_INIT_POINTER(list->table[index], (struct dma_fence *)tmp);
92 : }
93 :
94 : /*
95 : * Allocate a new dma_resv_list and make sure to correctly initialize
96 : * max_fences.
97 : */
98 0 : static struct dma_resv_list *dma_resv_list_alloc(unsigned int max_fences)
99 : {
100 : struct dma_resv_list *list;
101 : size_t size;
102 :
103 : /* Round up to the next kmalloc bucket size. */
104 0 : size = kmalloc_size_roundup(struct_size(list, table, max_fences));
105 :
106 0 : list = kmalloc(size, GFP_KERNEL);
107 0 : if (!list)
108 : return NULL;
109 :
110 : /* Given the resulting bucket size, recalculated max_fences. */
111 0 : list->max_fences = (size - offsetof(typeof(*list), table)) /
112 : sizeof(*list->table);
113 :
114 0 : return list;
115 : }
116 :
117 : /* Free a dma_resv_list and make sure to drop all references. */
118 0 : static void dma_resv_list_free(struct dma_resv_list *list)
119 : {
120 : unsigned int i;
121 :
122 0 : if (!list)
123 : return;
124 :
125 0 : for (i = 0; i < list->num_fences; ++i) {
126 : struct dma_fence *fence;
127 :
128 0 : dma_resv_list_entry(list, i, NULL, &fence, NULL);
129 0 : dma_fence_put(fence);
130 : }
131 0 : kfree_rcu(list, rcu);
132 : }
133 :
134 : /**
135 : * dma_resv_init - initialize a reservation object
136 : * @obj: the reservation object
137 : */
138 0 : void dma_resv_init(struct dma_resv *obj)
139 : {
140 0 : ww_mutex_init(&obj->lock, &reservation_ww_class);
141 :
142 0 : RCU_INIT_POINTER(obj->fences, NULL);
143 0 : }
144 : EXPORT_SYMBOL(dma_resv_init);
145 :
146 : /**
147 : * dma_resv_fini - destroys a reservation object
148 : * @obj: the reservation object
149 : */
150 0 : void dma_resv_fini(struct dma_resv *obj)
151 : {
152 : /*
153 : * This object should be dead and all references must have
154 : * been released to it, so no need to be protected with rcu.
155 : */
156 0 : dma_resv_list_free(rcu_dereference_protected(obj->fences, true));
157 0 : ww_mutex_destroy(&obj->lock);
158 0 : }
159 : EXPORT_SYMBOL(dma_resv_fini);
160 :
161 : /* Dereference the fences while ensuring RCU rules */
162 : static inline struct dma_resv_list *dma_resv_fences_list(struct dma_resv *obj)
163 : {
164 0 : return rcu_dereference_check(obj->fences, dma_resv_held(obj));
165 : }
166 :
167 : /**
168 : * dma_resv_reserve_fences - Reserve space to add fences to a dma_resv object.
169 : * @obj: reservation object
170 : * @num_fences: number of fences we want to add
171 : *
172 : * Should be called before dma_resv_add_fence(). Must be called with @obj
173 : * locked through dma_resv_lock().
174 : *
175 : * Note that the preallocated slots need to be re-reserved if @obj is unlocked
176 : * at any time before calling dma_resv_add_fence(). This is validated when
177 : * CONFIG_DEBUG_MUTEXES is enabled.
178 : *
179 : * RETURNS
180 : * Zero for success, or -errno
181 : */
182 0 : int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences)
183 : {
184 : struct dma_resv_list *old, *new;
185 : unsigned int i, j, k, max;
186 :
187 : dma_resv_assert_held(obj);
188 :
189 0 : old = dma_resv_fences_list(obj);
190 0 : if (old && old->max_fences) {
191 0 : if ((old->num_fences + num_fences) <= old->max_fences)
192 : return 0;
193 0 : max = max(old->num_fences + num_fences, old->max_fences * 2);
194 : } else {
195 0 : max = max(4ul, roundup_pow_of_two(num_fences));
196 : }
197 :
198 0 : new = dma_resv_list_alloc(max);
199 0 : if (!new)
200 : return -ENOMEM;
201 :
202 : /*
203 : * no need to bump fence refcounts, rcu_read access
204 : * requires the use of kref_get_unless_zero, and the
205 : * references from the old struct are carried over to
206 : * the new.
207 : */
208 0 : for (i = 0, j = 0, k = max; i < (old ? old->num_fences : 0); ++i) {
209 : enum dma_resv_usage usage;
210 : struct dma_fence *fence;
211 :
212 0 : dma_resv_list_entry(old, i, obj, &fence, &usage);
213 0 : if (dma_fence_is_signaled(fence))
214 0 : RCU_INIT_POINTER(new->table[--k], fence);
215 : else
216 0 : dma_resv_list_set(new, j++, fence, usage);
217 : }
218 0 : new->num_fences = j;
219 :
220 : /*
221 : * We are not changing the effective set of fences here so can
222 : * merely update the pointer to the new array; both existing
223 : * readers and new readers will see exactly the same set of
224 : * active (unsignaled) fences. Individual fences and the
225 : * old array are protected by RCU and so will not vanish under
226 : * the gaze of the rcu_read_lock() readers.
227 : */
228 0 : rcu_assign_pointer(obj->fences, new);
229 :
230 0 : if (!old)
231 : return 0;
232 :
233 : /* Drop the references to the signaled fences */
234 0 : for (i = k; i < max; ++i) {
235 : struct dma_fence *fence;
236 :
237 0 : fence = rcu_dereference_protected(new->table[i],
238 : dma_resv_held(obj));
239 0 : dma_fence_put(fence);
240 : }
241 0 : kfree_rcu(old, rcu);
242 :
243 0 : return 0;
244 : }
245 : EXPORT_SYMBOL(dma_resv_reserve_fences);
246 :
247 : #ifdef CONFIG_DEBUG_MUTEXES
248 : /**
249 : * dma_resv_reset_max_fences - reset fences for debugging
250 : * @obj: the dma_resv object to reset
251 : *
252 : * Reset the number of pre-reserved fence slots to test that drivers do
253 : * correct slot allocation using dma_resv_reserve_fences(). See also
254 : * &dma_resv_list.max_fences.
255 : */
256 : void dma_resv_reset_max_fences(struct dma_resv *obj)
257 : {
258 : struct dma_resv_list *fences = dma_resv_fences_list(obj);
259 :
260 : dma_resv_assert_held(obj);
261 :
262 : /* Test fence slot reservation */
263 : if (fences)
264 : fences->max_fences = fences->num_fences;
265 : }
266 : EXPORT_SYMBOL(dma_resv_reset_max_fences);
267 : #endif
268 :
269 : /**
270 : * dma_resv_add_fence - Add a fence to the dma_resv obj
271 : * @obj: the reservation object
272 : * @fence: the fence to add
273 : * @usage: how the fence is used, see enum dma_resv_usage
274 : *
275 : * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and
276 : * dma_resv_reserve_fences() has been called.
277 : *
278 : * See also &dma_resv.fence for a discussion of the semantics.
279 : */
280 0 : void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
281 : enum dma_resv_usage usage)
282 : {
283 : struct dma_resv_list *fobj;
284 : struct dma_fence *old;
285 : unsigned int i, count;
286 :
287 0 : dma_fence_get(fence);
288 :
289 : dma_resv_assert_held(obj);
290 :
291 : /* Drivers should not add containers here, instead add each fence
292 : * individually.
293 : */
294 0 : WARN_ON(dma_fence_is_container(fence));
295 :
296 0 : fobj = dma_resv_fences_list(obj);
297 0 : count = fobj->num_fences;
298 :
299 0 : for (i = 0; i < count; ++i) {
300 : enum dma_resv_usage old_usage;
301 :
302 0 : dma_resv_list_entry(fobj, i, obj, &old, &old_usage);
303 0 : if ((old->context == fence->context && old_usage >= usage &&
304 0 : dma_fence_is_later(fence, old)) ||
305 0 : dma_fence_is_signaled(old)) {
306 0 : dma_resv_list_set(fobj, i, fence, usage);
307 0 : dma_fence_put(old);
308 : return;
309 : }
310 : }
311 :
312 0 : BUG_ON(fobj->num_fences >= fobj->max_fences);
313 0 : count++;
314 :
315 0 : dma_resv_list_set(fobj, i, fence, usage);
316 : /* pointer update must be visible before we extend the num_fences */
317 0 : smp_store_mb(fobj->num_fences, count);
318 : }
319 : EXPORT_SYMBOL(dma_resv_add_fence);
320 :
321 : /**
322 : * dma_resv_replace_fences - replace fences in the dma_resv obj
323 : * @obj: the reservation object
324 : * @context: the context of the fences to replace
325 : * @replacement: the new fence to use instead
326 : * @usage: how the new fence is used, see enum dma_resv_usage
327 : *
328 : * Replace fences with a specified context with a new fence. Only valid if the
329 : * operation represented by the original fence has no longer access to the
330 : * resources represented by the dma_resv object when the new fence completes.
331 : *
332 : * And example for using this is replacing a preemption fence with a page table
333 : * update fence which makes the resource inaccessible.
334 : */
335 0 : void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
336 : struct dma_fence *replacement,
337 : enum dma_resv_usage usage)
338 : {
339 : struct dma_resv_list *list;
340 : unsigned int i;
341 :
342 : dma_resv_assert_held(obj);
343 :
344 0 : list = dma_resv_fences_list(obj);
345 0 : for (i = 0; list && i < list->num_fences; ++i) {
346 : struct dma_fence *old;
347 :
348 0 : dma_resv_list_entry(list, i, obj, &old, NULL);
349 0 : if (old->context != context)
350 0 : continue;
351 :
352 0 : dma_resv_list_set(list, i, dma_fence_get(replacement), usage);
353 0 : dma_fence_put(old);
354 : }
355 0 : }
356 : EXPORT_SYMBOL(dma_resv_replace_fences);
357 :
358 : /* Restart the unlocked iteration by initializing the cursor object. */
359 : static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor)
360 : {
361 0 : cursor->index = 0;
362 0 : cursor->num_fences = 0;
363 0 : cursor->fences = dma_resv_fences_list(cursor->obj);
364 0 : if (cursor->fences)
365 0 : cursor->num_fences = cursor->fences->num_fences;
366 0 : cursor->is_restarted = true;
367 : }
368 :
369 : /* Walk to the next not signaled fence and grab a reference to it */
370 0 : static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor)
371 : {
372 0 : if (!cursor->fences)
373 : return;
374 :
375 : do {
376 : /* Drop the reference from the previous round */
377 0 : dma_fence_put(cursor->fence);
378 :
379 0 : if (cursor->index >= cursor->num_fences) {
380 0 : cursor->fence = NULL;
381 0 : break;
382 :
383 : }
384 :
385 0 : dma_resv_list_entry(cursor->fences, cursor->index++,
386 : cursor->obj, &cursor->fence,
387 : &cursor->fence_usage);
388 0 : cursor->fence = dma_fence_get_rcu(cursor->fence);
389 0 : if (!cursor->fence) {
390 0 : dma_resv_iter_restart_unlocked(cursor);
391 0 : continue;
392 : }
393 :
394 0 : if (!dma_fence_is_signaled(cursor->fence) &&
395 0 : cursor->usage >= cursor->fence_usage)
396 : break;
397 : } while (true);
398 : }
399 :
400 : /**
401 : * dma_resv_iter_first_unlocked - first fence in an unlocked dma_resv obj.
402 : * @cursor: the cursor with the current position
403 : *
404 : * Subsequent fences are iterated with dma_resv_iter_next_unlocked().
405 : *
406 : * Beware that the iterator can be restarted. Code which accumulates statistics
407 : * or similar needs to check for this with dma_resv_iter_is_restarted(). For
408 : * this reason prefer the locked dma_resv_iter_first() whenver possible.
409 : *
410 : * Returns the first fence from an unlocked dma_resv obj.
411 : */
412 0 : struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor)
413 : {
414 : rcu_read_lock();
415 : do {
416 0 : dma_resv_iter_restart_unlocked(cursor);
417 0 : dma_resv_iter_walk_unlocked(cursor);
418 0 : } while (dma_resv_fences_list(cursor->obj) != cursor->fences);
419 : rcu_read_unlock();
420 :
421 0 : return cursor->fence;
422 : }
423 : EXPORT_SYMBOL(dma_resv_iter_first_unlocked);
424 :
425 : /**
426 : * dma_resv_iter_next_unlocked - next fence in an unlocked dma_resv obj.
427 : * @cursor: the cursor with the current position
428 : *
429 : * Beware that the iterator can be restarted. Code which accumulates statistics
430 : * or similar needs to check for this with dma_resv_iter_is_restarted(). For
431 : * this reason prefer the locked dma_resv_iter_next() whenver possible.
432 : *
433 : * Returns the next fence from an unlocked dma_resv obj.
434 : */
435 0 : struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor)
436 : {
437 : bool restart;
438 :
439 : rcu_read_lock();
440 0 : cursor->is_restarted = false;
441 0 : restart = dma_resv_fences_list(cursor->obj) != cursor->fences;
442 : do {
443 0 : if (restart)
444 : dma_resv_iter_restart_unlocked(cursor);
445 0 : dma_resv_iter_walk_unlocked(cursor);
446 0 : restart = true;
447 0 : } while (dma_resv_fences_list(cursor->obj) != cursor->fences);
448 : rcu_read_unlock();
449 :
450 0 : return cursor->fence;
451 : }
452 : EXPORT_SYMBOL(dma_resv_iter_next_unlocked);
453 :
454 : /**
455 : * dma_resv_iter_first - first fence from a locked dma_resv object
456 : * @cursor: cursor to record the current position
457 : *
458 : * Subsequent fences are iterated with dma_resv_iter_next_unlocked().
459 : *
460 : * Return the first fence in the dma_resv object while holding the
461 : * &dma_resv.lock.
462 : */
463 0 : struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor)
464 : {
465 : struct dma_fence *fence;
466 :
467 0 : dma_resv_assert_held(cursor->obj);
468 :
469 0 : cursor->index = 0;
470 0 : cursor->fences = dma_resv_fences_list(cursor->obj);
471 :
472 0 : fence = dma_resv_iter_next(cursor);
473 0 : cursor->is_restarted = true;
474 0 : return fence;
475 : }
476 : EXPORT_SYMBOL_GPL(dma_resv_iter_first);
477 :
478 : /**
479 : * dma_resv_iter_next - next fence from a locked dma_resv object
480 : * @cursor: cursor to record the current position
481 : *
482 : * Return the next fences from the dma_resv object while holding the
483 : * &dma_resv.lock.
484 : */
485 0 : struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor)
486 : {
487 : struct dma_fence *fence;
488 :
489 0 : dma_resv_assert_held(cursor->obj);
490 :
491 0 : cursor->is_restarted = false;
492 :
493 : do {
494 0 : if (!cursor->fences ||
495 0 : cursor->index >= cursor->fences->num_fences)
496 : return NULL;
497 :
498 0 : dma_resv_list_entry(cursor->fences, cursor->index++,
499 : cursor->obj, &fence, &cursor->fence_usage);
500 0 : } while (cursor->fence_usage > cursor->usage);
501 :
502 : return fence;
503 : }
504 : EXPORT_SYMBOL_GPL(dma_resv_iter_next);
505 :
506 : /**
507 : * dma_resv_copy_fences - Copy all fences from src to dst.
508 : * @dst: the destination reservation object
509 : * @src: the source reservation object
510 : *
511 : * Copy all fences from src to dst. dst-lock must be held.
512 : */
513 0 : int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
514 : {
515 : struct dma_resv_iter cursor;
516 : struct dma_resv_list *list;
517 : struct dma_fence *f;
518 :
519 : dma_resv_assert_held(dst);
520 :
521 0 : list = NULL;
522 :
523 0 : dma_resv_iter_begin(&cursor, src, DMA_RESV_USAGE_BOOKKEEP);
524 0 : dma_resv_for_each_fence_unlocked(&cursor, f) {
525 :
526 0 : if (dma_resv_iter_is_restarted(&cursor)) {
527 0 : dma_resv_list_free(list);
528 :
529 0 : list = dma_resv_list_alloc(cursor.num_fences);
530 0 : if (!list) {
531 0 : dma_resv_iter_end(&cursor);
532 : return -ENOMEM;
533 : }
534 0 : list->num_fences = 0;
535 : }
536 :
537 0 : dma_fence_get(f);
538 0 : dma_resv_list_set(list, list->num_fences++, f,
539 : dma_resv_iter_usage(&cursor));
540 : }
541 0 : dma_resv_iter_end(&cursor);
542 :
543 0 : list = rcu_replace_pointer(dst->fences, list, dma_resv_held(dst));
544 0 : dma_resv_list_free(list);
545 0 : return 0;
546 : }
547 : EXPORT_SYMBOL(dma_resv_copy_fences);
548 :
549 : /**
550 : * dma_resv_get_fences - Get an object's fences
551 : * fences without update side lock held
552 : * @obj: the reservation object
553 : * @usage: controls which fences to include, see enum dma_resv_usage.
554 : * @num_fences: the number of fences returned
555 : * @fences: the array of fence ptrs returned (array is krealloc'd to the
556 : * required size, and must be freed by caller)
557 : *
558 : * Retrieve all fences from the reservation object.
559 : * Returns either zero or -ENOMEM.
560 : */
561 0 : int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,
562 : unsigned int *num_fences, struct dma_fence ***fences)
563 : {
564 : struct dma_resv_iter cursor;
565 : struct dma_fence *fence;
566 :
567 0 : *num_fences = 0;
568 0 : *fences = NULL;
569 :
570 0 : dma_resv_iter_begin(&cursor, obj, usage);
571 0 : dma_resv_for_each_fence_unlocked(&cursor, fence) {
572 :
573 0 : if (dma_resv_iter_is_restarted(&cursor)) {
574 : unsigned int count;
575 :
576 0 : while (*num_fences)
577 0 : dma_fence_put((*fences)[--(*num_fences)]);
578 :
579 0 : count = cursor.num_fences + 1;
580 :
581 : /* Eventually re-allocate the array */
582 0 : *fences = krealloc_array(*fences, count,
583 : sizeof(void *),
584 : GFP_KERNEL);
585 0 : if (count && !*fences) {
586 0 : dma_resv_iter_end(&cursor);
587 : return -ENOMEM;
588 : }
589 : }
590 :
591 0 : (*fences)[(*num_fences)++] = dma_fence_get(fence);
592 : }
593 0 : dma_resv_iter_end(&cursor);
594 :
595 : return 0;
596 : }
597 : EXPORT_SYMBOL_GPL(dma_resv_get_fences);
598 :
599 : /**
600 : * dma_resv_get_singleton - Get a single fence for all the fences
601 : * @obj: the reservation object
602 : * @usage: controls which fences to include, see enum dma_resv_usage.
603 : * @fence: the resulting fence
604 : *
605 : * Get a single fence representing all the fences inside the resv object.
606 : * Returns either 0 for success or -ENOMEM.
607 : *
608 : * Warning: This can't be used like this when adding the fence back to the resv
609 : * object since that can lead to stack corruption when finalizing the
610 : * dma_fence_array.
611 : *
612 : * Returns 0 on success and negative error values on failure.
613 : */
614 0 : int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,
615 : struct dma_fence **fence)
616 : {
617 : struct dma_fence_array *array;
618 : struct dma_fence **fences;
619 : unsigned count;
620 : int r;
621 :
622 0 : r = dma_resv_get_fences(obj, usage, &count, &fences);
623 0 : if (r)
624 : return r;
625 :
626 0 : if (count == 0) {
627 0 : *fence = NULL;
628 0 : return 0;
629 : }
630 :
631 0 : if (count == 1) {
632 0 : *fence = fences[0];
633 0 : kfree(fences);
634 0 : return 0;
635 : }
636 :
637 0 : array = dma_fence_array_create(count, fences,
638 : dma_fence_context_alloc(1),
639 : 1, false);
640 0 : if (!array) {
641 0 : while (count--)
642 0 : dma_fence_put(fences[count]);
643 0 : kfree(fences);
644 0 : return -ENOMEM;
645 : }
646 :
647 0 : *fence = &array->base;
648 0 : return 0;
649 : }
650 : EXPORT_SYMBOL_GPL(dma_resv_get_singleton);
651 :
652 : /**
653 : * dma_resv_wait_timeout - Wait on reservation's objects fences
654 : * @obj: the reservation object
655 : * @usage: controls which fences to include, see enum dma_resv_usage.
656 : * @intr: if true, do interruptible wait
657 : * @timeout: timeout value in jiffies or zero to return immediately
658 : *
659 : * Callers are not required to hold specific locks, but maybe hold
660 : * dma_resv_lock() already
661 : * RETURNS
662 : * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
663 : * greater than zer on success.
664 : */
665 0 : long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
666 : bool intr, unsigned long timeout)
667 : {
668 0 : long ret = timeout ? timeout : 1;
669 : struct dma_resv_iter cursor;
670 : struct dma_fence *fence;
671 :
672 0 : dma_resv_iter_begin(&cursor, obj, usage);
673 0 : dma_resv_for_each_fence_unlocked(&cursor, fence) {
674 :
675 0 : ret = dma_fence_wait_timeout(fence, intr, ret);
676 0 : if (ret <= 0) {
677 0 : dma_resv_iter_end(&cursor);
678 : return ret;
679 : }
680 : }
681 0 : dma_resv_iter_end(&cursor);
682 :
683 : return ret;
684 : }
685 : EXPORT_SYMBOL_GPL(dma_resv_wait_timeout);
686 :
687 :
688 : /**
689 : * dma_resv_test_signaled - Test if a reservation object's fences have been
690 : * signaled.
691 : * @obj: the reservation object
692 : * @usage: controls which fences to include, see enum dma_resv_usage.
693 : *
694 : * Callers are not required to hold specific locks, but maybe hold
695 : * dma_resv_lock() already.
696 : *
697 : * RETURNS
698 : *
699 : * True if all fences signaled, else false.
700 : */
701 0 : bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage)
702 : {
703 : struct dma_resv_iter cursor;
704 : struct dma_fence *fence;
705 :
706 0 : dma_resv_iter_begin(&cursor, obj, usage);
707 0 : dma_resv_for_each_fence_unlocked(&cursor, fence) {
708 0 : dma_resv_iter_end(&cursor);
709 : return false;
710 : }
711 0 : dma_resv_iter_end(&cursor);
712 : return true;
713 : }
714 : EXPORT_SYMBOL_GPL(dma_resv_test_signaled);
715 :
716 : /**
717 : * dma_resv_describe - Dump description of the resv object into seq_file
718 : * @obj: the reservation object
719 : * @seq: the seq_file to dump the description into
720 : *
721 : * Dump a textual description of the fences inside an dma_resv object into the
722 : * seq_file.
723 : */
724 0 : void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq)
725 : {
726 : static const char *usage[] = { "kernel", "write", "read", "bookkeep" };
727 : struct dma_resv_iter cursor;
728 : struct dma_fence *fence;
729 :
730 0 : dma_resv_for_each_fence(&cursor, obj, DMA_RESV_USAGE_READ, fence) {
731 0 : seq_printf(seq, "\t%s fence:",
732 0 : usage[dma_resv_iter_usage(&cursor)]);
733 0 : dma_fence_describe(fence, seq);
734 : }
735 0 : }
736 : EXPORT_SYMBOL_GPL(dma_resv_describe);
737 :
738 : #if IS_ENABLED(CONFIG_LOCKDEP)
739 : static int __init dma_resv_lockdep(void)
740 : {
741 : struct mm_struct *mm = mm_alloc();
742 : struct ww_acquire_ctx ctx;
743 : struct dma_resv obj;
744 : struct address_space mapping;
745 : int ret;
746 :
747 : if (!mm)
748 : return -ENOMEM;
749 :
750 : dma_resv_init(&obj);
751 : address_space_init_once(&mapping);
752 :
753 : mmap_read_lock(mm);
754 : ww_acquire_init(&ctx, &reservation_ww_class);
755 : ret = dma_resv_lock(&obj, &ctx);
756 : if (ret == -EDEADLK)
757 : dma_resv_lock_slow(&obj, &ctx);
758 : fs_reclaim_acquire(GFP_KERNEL);
759 : /* for unmap_mapping_range on trylocked buffer objects in shrinkers */
760 : i_mmap_lock_write(&mapping);
761 : i_mmap_unlock_write(&mapping);
762 : #ifdef CONFIG_MMU_NOTIFIER
763 : lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
764 : __dma_fence_might_wait();
765 : lock_map_release(&__mmu_notifier_invalidate_range_start_map);
766 : #else
767 : __dma_fence_might_wait();
768 : #endif
769 : fs_reclaim_release(GFP_KERNEL);
770 : ww_mutex_unlock(&obj.lock);
771 : ww_acquire_fini(&ctx);
772 : mmap_read_unlock(mm);
773 :
774 : mmput(mm);
775 :
776 : return 0;
777 : }
778 : subsys_initcall(dma_resv_lockdep);
779 : #endif
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