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
57DEFINE_WD_CLASS(reservation_ww_class);
58EXPORT_SYMBOL(reservation_ww_class);
59
60/* Mask for the lower fence pointer bits */
61#define DMA_RESV_LIST_MASK 0x3
62
63struct 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. */
70static 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 tmp = (long)rcu_dereference_check(list->table[index],
77 resv ? dma_resv_held(resv) : true);
78 *fence = (struct dma_fence *)(tmp & ~DMA_RESV_LIST_MASK);
79 if (usage)
80 *usage = tmp & DMA_RESV_LIST_MASK;
81}
82
83/* Set the fence and usage flags at the specific index in the list. */
84static 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 long tmp = ((long)fence) | usage;
90
91 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 */
98static 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 size = kmalloc_size_roundup(struct_size(list, table, max_fences));
105
106 list = kmalloc(size, GFP_KERNEL);
107 if (!list)
108 return NULL;
109
110 /* Given the resulting bucket size, recalculated max_fences. */
111 list->max_fences = (size - offsetof(typeof(*list), table)) /
112 sizeof(*list->table);
113
114 return list;
115}
116
117/* Free a dma_resv_list and make sure to drop all references. */
118static void dma_resv_list_free(struct dma_resv_list *list)
119{
120 unsigned int i;
121
122 if (!list)
123 return;
124
125 for (i = 0; i < list->num_fences; ++i) {
126 struct dma_fence *fence;
127
128 dma_resv_list_entry(list, index: i, NULL, fence: &fence, NULL);
129 dma_fence_put(fence);
130 }
131 kfree_rcu(list, rcu);
132}
133
134/**
135 * dma_resv_init - initialize a reservation object
136 * @obj: the reservation object
137 */
138void dma_resv_init(struct dma_resv *obj)
139{
140 ww_mutex_init(lock: &obj->lock, ww_class: &reservation_ww_class);
141
142 RCU_INIT_POINTER(obj->fences, NULL);
143}
144EXPORT_SYMBOL(dma_resv_init);
145
146/**
147 * dma_resv_fini - destroys a reservation object
148 * @obj: the reservation object
149 */
150void 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 dma_resv_list_free(rcu_dereference_protected(obj->fences, true));
157 ww_mutex_destroy(lock: &obj->lock);
158}
159EXPORT_SYMBOL(dma_resv_fini);
160
161/* Dereference the fences while ensuring RCU rules */
162static inline struct dma_resv_list *dma_resv_fences_list(struct dma_resv *obj)
163{
164 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 */
182int 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 /* Driver and component code should never call this function with
190 * num_fences=0. If they do it usually points to bugs when calculating
191 * the number of needed fences dynamically.
192 */
193 if (WARN_ON(!num_fences))
194 return -EINVAL;
195
196 old = dma_resv_fences_list(obj);
197 if (old && old->max_fences) {
198 if ((old->num_fences + num_fences) <= old->max_fences)
199 return 0;
200 max = max(old->num_fences + num_fences, old->max_fences * 2);
201 } else {
202 max = max(4ul, roundup_pow_of_two(num_fences));
203 }
204
205 new = dma_resv_list_alloc(max_fences: max);
206 if (!new)
207 return -ENOMEM;
208
209 /*
210 * no need to bump fence refcounts, rcu_read access
211 * requires the use of kref_get_unless_zero, and the
212 * references from the old struct are carried over to
213 * the new.
214 */
215 for (i = 0, j = 0, k = max; i < (old ? old->num_fences : 0); ++i) {
216 enum dma_resv_usage usage;
217 struct dma_fence *fence;
218
219 dma_resv_list_entry(list: old, index: i, resv: obj, fence: &fence, usage: &usage);
220 if (dma_fence_is_signaled(fence))
221 RCU_INIT_POINTER(new->table[--k], fence);
222 else
223 dma_resv_list_set(list: new, index: j++, fence, usage);
224 }
225 new->num_fences = j;
226
227 /*
228 * We are not changing the effective set of fences here so can
229 * merely update the pointer to the new array; both existing
230 * readers and new readers will see exactly the same set of
231 * active (unsignaled) fences. Individual fences and the
232 * old array are protected by RCU and so will not vanish under
233 * the gaze of the rcu_read_lock() readers.
234 */
235 rcu_assign_pointer(obj->fences, new);
236
237 if (!old)
238 return 0;
239
240 /* Drop the references to the signaled fences */
241 for (i = k; i < max; ++i) {
242 struct dma_fence *fence;
243
244 fence = rcu_dereference_protected(new->table[i],
245 dma_resv_held(obj));
246 dma_fence_put(fence);
247 }
248 kfree_rcu(old, rcu);
249
250 return 0;
251}
252EXPORT_SYMBOL(dma_resv_reserve_fences);
253
254#ifdef CONFIG_DEBUG_MUTEXES
255/**
256 * dma_resv_reset_max_fences - reset fences for debugging
257 * @obj: the dma_resv object to reset
258 *
259 * Reset the number of pre-reserved fence slots to test that drivers do
260 * correct slot allocation using dma_resv_reserve_fences(). See also
261 * &dma_resv_list.max_fences.
262 */
263void dma_resv_reset_max_fences(struct dma_resv *obj)
264{
265 struct dma_resv_list *fences = dma_resv_fences_list(obj);
266
267 dma_resv_assert_held(obj);
268
269 /* Test fence slot reservation */
270 if (fences)
271 fences->max_fences = fences->num_fences;
272}
273EXPORT_SYMBOL(dma_resv_reset_max_fences);
274#endif
275
276/**
277 * dma_resv_add_fence - Add a fence to the dma_resv obj
278 * @obj: the reservation object
279 * @fence: the fence to add
280 * @usage: how the fence is used, see enum dma_resv_usage
281 *
282 * Add a fence to a slot, @obj must be locked with dma_resv_lock(), and
283 * dma_resv_reserve_fences() has been called.
284 *
285 * See also &dma_resv.fence for a discussion of the semantics.
286 */
287void dma_resv_add_fence(struct dma_resv *obj, struct dma_fence *fence,
288 enum dma_resv_usage usage)
289{
290 struct dma_resv_list *fobj;
291 struct dma_fence *old;
292 unsigned int i, count;
293
294 dma_fence_get(fence);
295
296 dma_resv_assert_held(obj);
297
298 /* Drivers should not add containers here, instead add each fence
299 * individually.
300 */
301 WARN_ON(dma_fence_is_container(fence));
302
303 fobj = dma_resv_fences_list(obj);
304 count = fobj->num_fences;
305
306 for (i = 0; i < count; ++i) {
307 enum dma_resv_usage old_usage;
308
309 dma_resv_list_entry(list: fobj, index: i, resv: obj, fence: &old, usage: &old_usage);
310 if ((old->context == fence->context && old_usage >= usage &&
311 dma_fence_is_later_or_same(f1: fence, f2: old)) ||
312 dma_fence_is_signaled(fence: old)) {
313 dma_resv_list_set(list: fobj, index: i, fence, usage);
314 dma_fence_put(fence: old);
315 return;
316 }
317 }
318
319 BUG_ON(fobj->num_fences >= fobj->max_fences);
320 count++;
321
322 dma_resv_list_set(list: fobj, index: i, fence, usage);
323 /* fence update must be visible before we extend the num_fences */
324 smp_wmb();
325 fobj->num_fences = count;
326}
327EXPORT_SYMBOL(dma_resv_add_fence);
328
329/**
330 * dma_resv_replace_fences - replace fences in the dma_resv obj
331 * @obj: the reservation object
332 * @context: the context of the fences to replace
333 * @replacement: the new fence to use instead
334 * @usage: how the new fence is used, see enum dma_resv_usage
335 *
336 * Replace fences with a specified context with a new fence. Only valid if the
337 * operation represented by the original fence has no longer access to the
338 * resources represented by the dma_resv object when the new fence completes.
339 *
340 * And example for using this is replacing a preemption fence with a page table
341 * update fence which makes the resource inaccessible.
342 */
343void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
344 struct dma_fence *replacement,
345 enum dma_resv_usage usage)
346{
347 struct dma_resv_list *list;
348 unsigned int i;
349
350 dma_resv_assert_held(obj);
351
352 list = dma_resv_fences_list(obj);
353 for (i = 0; list && i < list->num_fences; ++i) {
354 struct dma_fence *old;
355
356 dma_resv_list_entry(list, index: i, resv: obj, fence: &old, NULL);
357 if (old->context != context)
358 continue;
359
360 dma_resv_list_set(list, index: i, fence: dma_fence_get(fence: replacement), usage);
361 dma_fence_put(fence: old);
362 }
363}
364EXPORT_SYMBOL(dma_resv_replace_fences);
365
366/* Restart the unlocked iteration by initializing the cursor object. */
367static void dma_resv_iter_restart_unlocked(struct dma_resv_iter *cursor)
368{
369 cursor->index = 0;
370 cursor->num_fences = 0;
371 cursor->fences = dma_resv_fences_list(obj: cursor->obj);
372 if (cursor->fences)
373 cursor->num_fences = cursor->fences->num_fences;
374 cursor->is_restarted = true;
375}
376
377/* Walk to the next not signaled fence and grab a reference to it */
378static void dma_resv_iter_walk_unlocked(struct dma_resv_iter *cursor)
379{
380 if (!cursor->fences)
381 return;
382
383 do {
384 /* Drop the reference from the previous round */
385 dma_fence_put(fence: cursor->fence);
386
387 if (cursor->index >= cursor->num_fences) {
388 cursor->fence = NULL;
389 break;
390
391 }
392
393 dma_resv_list_entry(list: cursor->fences, index: cursor->index++,
394 resv: cursor->obj, fence: &cursor->fence,
395 usage: &cursor->fence_usage);
396 cursor->fence = dma_fence_get_rcu(fence: cursor->fence);
397 if (!cursor->fence) {
398 dma_resv_iter_restart_unlocked(cursor);
399 continue;
400 }
401
402 if (!dma_fence_is_signaled(fence: cursor->fence) &&
403 cursor->usage >= cursor->fence_usage)
404 break;
405 } while (true);
406}
407
408/**
409 * dma_resv_iter_first_unlocked - first fence in an unlocked dma_resv obj.
410 * @cursor: the cursor with the current position
411 *
412 * Subsequent fences are iterated with dma_resv_iter_next_unlocked().
413 *
414 * Beware that the iterator can be restarted. Code which accumulates statistics
415 * or similar needs to check for this with dma_resv_iter_is_restarted(). For
416 * this reason prefer the locked dma_resv_iter_first() whenever possible.
417 *
418 * Returns the first fence from an unlocked dma_resv obj.
419 */
420struct dma_fence *dma_resv_iter_first_unlocked(struct dma_resv_iter *cursor)
421{
422 rcu_read_lock();
423 do {
424 dma_resv_iter_restart_unlocked(cursor);
425 dma_resv_iter_walk_unlocked(cursor);
426 } while (dma_resv_fences_list(obj: cursor->obj) != cursor->fences);
427 rcu_read_unlock();
428
429 return cursor->fence;
430}
431EXPORT_SYMBOL(dma_resv_iter_first_unlocked);
432
433/**
434 * dma_resv_iter_next_unlocked - next fence in an unlocked dma_resv obj.
435 * @cursor: the cursor with the current position
436 *
437 * Beware that the iterator can be restarted. Code which accumulates statistics
438 * or similar needs to check for this with dma_resv_iter_is_restarted(). For
439 * this reason prefer the locked dma_resv_iter_next() whenever possible.
440 *
441 * Returns the next fence from an unlocked dma_resv obj.
442 */
443struct dma_fence *dma_resv_iter_next_unlocked(struct dma_resv_iter *cursor)
444{
445 bool restart;
446
447 rcu_read_lock();
448 cursor->is_restarted = false;
449 restart = dma_resv_fences_list(obj: cursor->obj) != cursor->fences;
450 do {
451 if (restart)
452 dma_resv_iter_restart_unlocked(cursor);
453 dma_resv_iter_walk_unlocked(cursor);
454 restart = true;
455 } while (dma_resv_fences_list(obj: cursor->obj) != cursor->fences);
456 rcu_read_unlock();
457
458 return cursor->fence;
459}
460EXPORT_SYMBOL(dma_resv_iter_next_unlocked);
461
462/**
463 * dma_resv_iter_first - first fence from a locked dma_resv object
464 * @cursor: cursor to record the current position
465 *
466 * Subsequent fences are iterated with dma_resv_iter_next_unlocked().
467 *
468 * Return the first fence in the dma_resv object while holding the
469 * &dma_resv.lock.
470 */
471struct dma_fence *dma_resv_iter_first(struct dma_resv_iter *cursor)
472{
473 struct dma_fence *fence;
474
475 dma_resv_assert_held(cursor->obj);
476
477 cursor->index = 0;
478 cursor->fences = dma_resv_fences_list(obj: cursor->obj);
479
480 fence = dma_resv_iter_next(cursor);
481 cursor->is_restarted = true;
482 return fence;
483}
484EXPORT_SYMBOL_GPL(dma_resv_iter_first);
485
486/**
487 * dma_resv_iter_next - next fence from a locked dma_resv object
488 * @cursor: cursor to record the current position
489 *
490 * Return the next fences from the dma_resv object while holding the
491 * &dma_resv.lock.
492 */
493struct dma_fence *dma_resv_iter_next(struct dma_resv_iter *cursor)
494{
495 struct dma_fence *fence;
496
497 dma_resv_assert_held(cursor->obj);
498
499 cursor->is_restarted = false;
500
501 do {
502 if (!cursor->fences ||
503 cursor->index >= cursor->fences->num_fences)
504 return NULL;
505
506 dma_resv_list_entry(list: cursor->fences, index: cursor->index++,
507 resv: cursor->obj, fence: &fence, usage: &cursor->fence_usage);
508 } while (cursor->fence_usage > cursor->usage);
509
510 return fence;
511}
512EXPORT_SYMBOL_GPL(dma_resv_iter_next);
513
514/**
515 * dma_resv_copy_fences - Copy all fences from src to dst.
516 * @dst: the destination reservation object
517 * @src: the source reservation object
518 *
519 * Copy all fences from src to dst. dst-lock must be held.
520 */
521int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)
522{
523 struct dma_resv_iter cursor;
524 struct dma_resv_list *list;
525 struct dma_fence *f;
526
527 dma_resv_assert_held(dst);
528
529 list = NULL;
530
531 dma_resv_iter_begin(cursor: &cursor, obj: src, usage: DMA_RESV_USAGE_BOOKKEEP);
532 dma_resv_for_each_fence_unlocked(&cursor, f) {
533
534 if (dma_resv_iter_is_restarted(cursor: &cursor)) {
535 dma_resv_list_free(list);
536
537 list = dma_resv_list_alloc(max_fences: cursor.num_fences);
538 if (!list) {
539 dma_resv_iter_end(cursor: &cursor);
540 return -ENOMEM;
541 }
542 list->num_fences = 0;
543 }
544
545 dma_fence_get(fence: f);
546 dma_resv_list_set(list, index: list->num_fences++, fence: f,
547 usage: dma_resv_iter_usage(cursor: &cursor));
548 }
549 dma_resv_iter_end(cursor: &cursor);
550
551 list = rcu_replace_pointer(dst->fences, list, dma_resv_held(dst));
552 dma_resv_list_free(list);
553 return 0;
554}
555EXPORT_SYMBOL(dma_resv_copy_fences);
556
557/**
558 * dma_resv_get_fences - Get an object's fences
559 * fences without update side lock held
560 * @obj: the reservation object
561 * @usage: controls which fences to include, see enum dma_resv_usage.
562 * @num_fences: the number of fences returned
563 * @fences: the array of fence ptrs returned (array is krealloc'd to the
564 * required size, and must be freed by caller)
565 *
566 * Retrieve all fences from the reservation object.
567 * Returns either zero or -ENOMEM.
568 */
569int dma_resv_get_fences(struct dma_resv *obj, enum dma_resv_usage usage,
570 unsigned int *num_fences, struct dma_fence ***fences)
571{
572 struct dma_resv_iter cursor;
573 struct dma_fence *fence;
574
575 *num_fences = 0;
576 *fences = NULL;
577
578 dma_resv_iter_begin(cursor: &cursor, obj, usage);
579 dma_resv_for_each_fence_unlocked(&cursor, fence) {
580
581 if (dma_resv_iter_is_restarted(cursor: &cursor)) {
582 struct dma_fence **new_fences;
583 unsigned int count;
584
585 while (*num_fences)
586 dma_fence_put(fence: (*fences)[--(*num_fences)]);
587
588 count = cursor.num_fences + 1;
589
590 /* Eventually re-allocate the array */
591 new_fences = krealloc_array(*fences, count,
592 sizeof(void *),
593 GFP_KERNEL);
594 if (count && !new_fences) {
595 kfree(objp: *fences);
596 *fences = NULL;
597 *num_fences = 0;
598 dma_resv_iter_end(cursor: &cursor);
599 return -ENOMEM;
600 }
601 *fences = new_fences;
602 }
603
604 (*fences)[(*num_fences)++] = dma_fence_get(fence);
605 }
606 dma_resv_iter_end(cursor: &cursor);
607
608 return 0;
609}
610EXPORT_SYMBOL_GPL(dma_resv_get_fences);
611
612/**
613 * dma_resv_get_singleton - Get a single fence for all the fences
614 * @obj: the reservation object
615 * @usage: controls which fences to include, see enum dma_resv_usage.
616 * @fence: the resulting fence
617 *
618 * Get a single fence representing all the fences inside the resv object.
619 * Returns either 0 for success or -ENOMEM.
620 *
621 * Warning: This can't be used like this when adding the fence back to the resv
622 * object since that can lead to stack corruption when finalizing the
623 * dma_fence_array.
624 *
625 * Returns 0 on success and negative error values on failure.
626 */
627int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,
628 struct dma_fence **fence)
629{
630 struct dma_fence_array *array;
631 struct dma_fence **fences;
632 unsigned count;
633 int r;
634
635 r = dma_resv_get_fences(obj, usage, &count, &fences);
636 if (r)
637 return r;
638
639 if (count == 0) {
640 *fence = NULL;
641 return 0;
642 }
643
644 if (count == 1) {
645 *fence = fences[0];
646 kfree(objp: fences);
647 return 0;
648 }
649
650 array = dma_fence_array_create(num_fences: count, fences,
651 context: dma_fence_context_alloc(num: 1),
652 seqno: 1, signal_on_any: false);
653 if (!array) {
654 while (count--)
655 dma_fence_put(fence: fences[count]);
656 kfree(objp: fences);
657 return -ENOMEM;
658 }
659
660 *fence = &array->base;
661 return 0;
662}
663EXPORT_SYMBOL_GPL(dma_resv_get_singleton);
664
665/**
666 * dma_resv_wait_timeout - Wait on reservation's objects fences
667 * @obj: the reservation object
668 * @usage: controls which fences to include, see enum dma_resv_usage.
669 * @intr: if true, do interruptible wait
670 * @timeout: timeout value in jiffies or zero to return immediately
671 *
672 * Callers are not required to hold specific locks, but maybe hold
673 * dma_resv_lock() already
674 * RETURNS
675 * Returns -ERESTARTSYS if interrupted, 0 if the wait timed out, or
676 * greater than zero on success.
677 */
678long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
679 bool intr, unsigned long timeout)
680{
681 long ret = timeout ? timeout : 1;
682 struct dma_resv_iter cursor;
683 struct dma_fence *fence;
684
685 dma_resv_iter_begin(cursor: &cursor, obj, usage);
686 dma_resv_for_each_fence_unlocked(&cursor, fence) {
687
688 ret = dma_fence_wait_timeout(fence, intr, timeout: ret);
689 if (ret <= 0) {
690 dma_resv_iter_end(cursor: &cursor);
691 return ret;
692 }
693 }
694 dma_resv_iter_end(cursor: &cursor);
695
696 return ret;
697}
698EXPORT_SYMBOL_GPL(dma_resv_wait_timeout);
699
700/**
701 * dma_resv_set_deadline - Set a deadline on reservation's objects fences
702 * @obj: the reservation object
703 * @usage: controls which fences to include, see enum dma_resv_usage.
704 * @deadline: the requested deadline (MONOTONIC)
705 *
706 * May be called without holding the dma_resv lock. Sets @deadline on
707 * all fences filtered by @usage.
708 */
709void dma_resv_set_deadline(struct dma_resv *obj, enum dma_resv_usage usage,
710 ktime_t deadline)
711{
712 struct dma_resv_iter cursor;
713 struct dma_fence *fence;
714
715 dma_resv_iter_begin(cursor: &cursor, obj, usage);
716 dma_resv_for_each_fence_unlocked(&cursor, fence) {
717 dma_fence_set_deadline(fence, deadline);
718 }
719 dma_resv_iter_end(cursor: &cursor);
720}
721EXPORT_SYMBOL_GPL(dma_resv_set_deadline);
722
723/**
724 * dma_resv_test_signaled - Test if a reservation object's fences have been
725 * signaled.
726 * @obj: the reservation object
727 * @usage: controls which fences to include, see enum dma_resv_usage.
728 *
729 * Callers are not required to hold specific locks, but maybe hold
730 * dma_resv_lock() already.
731 *
732 * RETURNS
733 *
734 * True if all fences signaled, else false.
735 */
736bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage)
737{
738 struct dma_resv_iter cursor;
739 struct dma_fence *fence;
740
741 dma_resv_iter_begin(cursor: &cursor, obj, usage);
742 dma_resv_for_each_fence_unlocked(&cursor, fence) {
743 dma_resv_iter_end(cursor: &cursor);
744 return false;
745 }
746 dma_resv_iter_end(cursor: &cursor);
747 return true;
748}
749EXPORT_SYMBOL_GPL(dma_resv_test_signaled);
750
751/**
752 * dma_resv_describe - Dump description of the resv object into seq_file
753 * @obj: the reservation object
754 * @seq: the seq_file to dump the description into
755 *
756 * Dump a textual description of the fences inside an dma_resv object into the
757 * seq_file.
758 */
759void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq)
760{
761 static const char *usage[] = { "kernel", "write", "read", "bookkeep" };
762 struct dma_resv_iter cursor;
763 struct dma_fence *fence;
764
765 dma_resv_for_each_fence(&cursor, obj, DMA_RESV_USAGE_READ, fence) {
766 seq_printf(m: seq, fmt: "\t%s fence:",
767 usage[dma_resv_iter_usage(cursor: &cursor)]);
768 dma_fence_describe(fence, seq);
769 }
770}
771EXPORT_SYMBOL_GPL(dma_resv_describe);
772
773#if IS_ENABLED(CONFIG_LOCKDEP)
774static int __init dma_resv_lockdep(void)
775{
776 struct mm_struct *mm = mm_alloc();
777 struct ww_acquire_ctx ctx;
778 struct dma_resv obj;
779 struct address_space mapping;
780 int ret;
781
782 if (!mm)
783 return -ENOMEM;
784
785 dma_resv_init(&obj);
786 address_space_init_once(mapping: &mapping);
787
788 mmap_read_lock(mm);
789 ww_acquire_init(ctx: &ctx, ww_class: &reservation_ww_class);
790 ret = dma_resv_lock(obj: &obj, ctx: &ctx);
791 if (ret == -EDEADLK)
792 dma_resv_lock_slow(obj: &obj, ctx: &ctx);
793 fs_reclaim_acquire(GFP_KERNEL);
794 /* for unmap_mapping_range on trylocked buffer objects in shrinkers */
795 i_mmap_lock_write(mapping: &mapping);
796 i_mmap_unlock_write(mapping: &mapping);
797#ifdef CONFIG_MMU_NOTIFIER
798 lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
799 __dma_fence_might_wait();
800 lock_map_release(&__mmu_notifier_invalidate_range_start_map);
801#else
802 __dma_fence_might_wait();
803#endif
804 fs_reclaim_release(GFP_KERNEL);
805 ww_mutex_unlock(lock: &obj.lock);
806 ww_acquire_fini(ctx: &ctx);
807 mmap_read_unlock(mm);
808
809 mmput(mm);
810
811 return 0;
812}
813subsys_initcall(dma_resv_lockdep);
814#endif
815

source code of linux/drivers/dma-buf/dma-resv.c