dma-resv.c

  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, i, NULL, &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(&obj->lock, &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(&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);
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(old, i, obj, &fence, &usage);
220		if (dma_fence_is_signaled(fence))
221			RCU_INIT_POINTER(new->table[--k], fence);
222		else
223			dma_resv_list_set(new, 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(fobj, i, obj, &old, &old_usage);
310		if ((old->context == fence->context && old_usage >= usage &&
311		     dma_fence_is_later_or_same(fence, old)) ||
312		    dma_fence_is_signaled(old)) {
313			dma_resv_list_set(fobj, i, fence, usage);
314			dma_fence_put(old);
315			return;
316		}
317	}
318
319	BUG_ON(fobj->num_fences >= fobj->max_fences);
320	count++;
321
322	dma_resv_list_set(fobj, 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, i, obj, &old, NULL);
357		if (old->context != context)
358			continue;
359
360		dma_resv_list_set(list, i, dma_fence_get(replacement), usage);
361		dma_fence_put(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(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(cursor->fence);
386
387		if (cursor->index >= cursor->num_fences) {
388			cursor->fence = NULL;
389			break;
390
391		}
392
393		dma_resv_list_entry(cursor->fences, cursor->index++,
394				    cursor->obj, &cursor->fence,
395				    &cursor->fence_usage);
396		cursor->fence = dma_fence_get_rcu(cursor->fence);
397		if (!cursor->fence) {
398			dma_resv_iter_restart_unlocked(cursor);
399			continue;
400		}
401
402		if (!dma_fence_is_signaled(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(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(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(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(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(cursor->fences, cursor->index++,
507				    cursor->obj, &fence, &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, src, DMA_RESV_USAGE_BOOKKEEP);
532	dma_resv_for_each_fence_unlocked(&cursor, f) {
533
534		if (dma_resv_iter_is_restarted(&cursor)) {
535			dma_resv_list_free(list);
536
537			list = dma_resv_list_alloc(cursor.num_fences);
538			if (!list) {
539				dma_resv_iter_end(&cursor);
540				return -ENOMEM;
541			}
542			list->num_fences = 0;
543		}
544
545		dma_fence_get(f);
546		dma_resv_list_set(list, list->num_fences++, f,
547				  dma_resv_iter_usage(&cursor));
548	}
549	dma_resv_iter_end(&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, obj, usage);
579	dma_resv_for_each_fence_unlocked(&cursor, fence) {
580
581		if (dma_resv_iter_is_restarted(&cursor)) {
582			struct dma_fence **new_fences;
583			unsigned int count;
584
585			while (*num_fences)
586				dma_fence_put((*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(*fences);
596				*fences = NULL;
597				*num_fences = 0;
598				dma_resv_iter_end(&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);
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(fences);
647		return 0;
648	}
649
650	array = dma_fence_array_create(count, fences,
651				       dma_fence_context_alloc(1),
652				       1, false);
653	if (!array) {
654		while (count--)
655			dma_fence_put(fences[count]);
656		kfree(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, obj, usage);
686	dma_resv_for_each_fence_unlocked(&cursor, fence) {
687
688		ret = dma_fence_wait_timeout(fence, intr, timeout);
689		if (ret <= 0)
690			break;
691
692		/* Even for zero timeout the return value is 1 */
693		if (timeout)
694			timeout = ret;
695	}
696	dma_resv_iter_end(&cursor);
697
698	return ret;
699}
700EXPORT_SYMBOL_GPL(dma_resv_wait_timeout);
701
702/**
703 * dma_resv_set_deadline - Set a deadline on reservation's objects fences
704 * @obj: the reservation object
705 * @usage: controls which fences to include, see enum dma_resv_usage.
706 * @deadline: the requested deadline (MONOTONIC)
707 *
708 * May be called without holding the dma_resv lock.  Sets @deadline on
709 * all fences filtered by @usage.
710 */
711void dma_resv_set_deadline(struct dma_resv *obj, enum dma_resv_usage usage,
712			   ktime_t deadline)
713{
714	struct dma_resv_iter cursor;
715	struct dma_fence *fence;
716
717	dma_resv_iter_begin(&cursor, obj, usage);
718	dma_resv_for_each_fence_unlocked(&cursor, fence) {
719		dma_fence_set_deadline(fence, deadline);
720	}
721	dma_resv_iter_end(&cursor);
722}
723EXPORT_SYMBOL_GPL(dma_resv_set_deadline);
724
725/**
726 * dma_resv_test_signaled - Test if a reservation object's fences have been
727 * signaled.
728 * @obj: the reservation object
729 * @usage: controls which fences to include, see enum dma_resv_usage.
730 *
731 * Callers are not required to hold specific locks, but maybe hold
732 * dma_resv_lock() already.
733 *
734 * RETURNS
735 *
736 * True if all fences signaled, else false.
737 */
738bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage)
739{
740	struct dma_resv_iter cursor;
741	struct dma_fence *fence;
742
743	dma_resv_iter_begin(&cursor, obj, usage);
744	dma_resv_for_each_fence_unlocked(&cursor, fence) {
745		dma_resv_iter_end(&cursor);
746		return false;
747	}
748	dma_resv_iter_end(&cursor);
749	return true;
750}
751EXPORT_SYMBOL_GPL(dma_resv_test_signaled);
752
753/**
754 * dma_resv_describe - Dump description of the resv object into seq_file
755 * @obj: the reservation object
756 * @seq: the seq_file to dump the description into
757 *
758 * Dump a textual description of the fences inside an dma_resv object into the
759 * seq_file.
760 */
761void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq)
762{
763	static const char *usage[] = { "kernel", "write", "read", "bookkeep" };
764	struct dma_resv_iter cursor;
765	struct dma_fence *fence;
766
767	dma_resv_for_each_fence(&cursor, obj, DMA_RESV_USAGE_READ, fence) {
768		seq_printf(seq, "\t%s fence:",
769			   usage[dma_resv_iter_usage(&cursor)]);
770		dma_fence_describe(fence, seq);
771	}
772}
773EXPORT_SYMBOL_GPL(dma_resv_describe);
774
775#if IS_ENABLED(CONFIG_LOCKDEP)
776static int __init dma_resv_lockdep(void)
777{
778	struct mm_struct *mm = mm_alloc();
779	struct ww_acquire_ctx ctx;
780	struct dma_resv obj;
781	struct address_space mapping;
782	int ret;
783
784	if (!mm)
785		return -ENOMEM;
786
787	dma_resv_init(&obj);
788	address_space_init_once(&mapping);
789
790	mmap_read_lock(mm);
791	ww_acquire_init(&ctx, &reservation_ww_class);
792	ret = dma_resv_lock(&obj, &ctx);
793	if (ret == -EDEADLK)
794		dma_resv_lock_slow(&obj, &ctx);
795	fs_reclaim_acquire(GFP_KERNEL);
796	/* for unmap_mapping_range on trylocked buffer objects in shrinkers */
797	i_mmap_lock_write(&mapping);
798	i_mmap_unlock_write(&mapping);
799#ifdef CONFIG_MMU_NOTIFIER
800	lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
801	__dma_fence_might_wait();
802	lock_map_release(&__mmu_notifier_invalidate_range_start_map);
803#else
804	__dma_fence_might_wait();
805#endif
806	fs_reclaim_release(GFP_KERNEL);
807	ww_mutex_unlock(&obj.lock);
808	ww_acquire_fini(&ctx);
809	mmap_read_unlock(mm);
810
811	mmput(mm);
812
813	return 0;
814}
815subsys_initcall(dma_resv_lockdep);
816#endif