summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/ttm/ttm_object.c
blob: 4f5fa8d65fe932a7e10803d10d0e0fc3090a7d59 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
/**************************************************************************
 *
 * Copyright (c) 2009-2013 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 *
 * While no substantial code is shared, the prime code is inspired by
 * drm_prime.c, with
 * Authors:
 *      Dave Airlie <airlied@redhat.com>
 *      Rob Clark <rob.clark@linaro.org>
 */
/** @file ttm_ref_object.c
 *
 * Base- and reference object implementation for the various
 * ttm objects. Implements reference counting, minimal security checks
 * and release on file close.
 */


/**
 * struct ttm_object_file
 *
 * @tdev: Pointer to the ttm_object_device.
 *
 * @lock: Lock that protects the ref_list list and the
 * ref_hash hash tables.
 *
 * @ref_list: List of ttm_ref_objects to be destroyed at
 * file release.
 *
 * @ref_hash: Hash tables of ref objects, one per ttm_ref_type,
 * for fast lookup of ref objects given a base object.
 */

#define pr_fmt(fmt) "[TTM] " fmt

#include <drm/ttm/ttm_object.h>
#include <drm/ttm/ttm_module.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/atomic.h>

struct ttm_object_file {
	struct ttm_object_device *tdev;
	spinlock_t lock;
	struct list_head ref_list;
	struct drm_open_hash ref_hash[TTM_REF_NUM];
	struct kref refcount;
};

/**
 * struct ttm_object_device
 *
 * @object_lock: lock that protects the object_hash hash table.
 *
 * @object_hash: hash table for fast lookup of object global names.
 *
 * @object_count: Per device object count.
 *
 * This is the per-device data structure needed for ttm object management.
 */

struct ttm_object_device {
	spinlock_t object_lock;
	struct drm_open_hash object_hash;
	atomic_t object_count;
	struct ttm_mem_global *mem_glob;
	struct dma_buf_ops ops;
	void (*dmabuf_release)(struct dma_buf *dma_buf);
	size_t dma_buf_size;
};

/**
 * struct ttm_ref_object
 *
 * @hash: Hash entry for the per-file object reference hash.
 *
 * @head: List entry for the per-file list of ref-objects.
 *
 * @kref: Ref count.
 *
 * @obj: Base object this ref object is referencing.
 *
 * @ref_type: Type of ref object.
 *
 * This is similar to an idr object, but it also has a hash table entry
 * that allows lookup with a pointer to the referenced object as a key. In
 * that way, one can easily detect whether a base object is referenced by
 * a particular ttm_object_file. It also carries a ref count to avoid creating
 * multiple ref objects if a ttm_object_file references the same base
 * object more than once.
 */

struct ttm_ref_object {
	struct rcu_head rcu_head;
	struct drm_hash_item hash;
	struct list_head head;
	struct kref kref;
	enum ttm_ref_type ref_type;
	struct ttm_base_object *obj;
	struct ttm_object_file *tfile;
};

static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf);

static inline struct ttm_object_file *
ttm_object_file_ref(struct ttm_object_file *tfile)
{
	kref_get(&tfile->refcount);
	return tfile;
}

static void ttm_object_file_destroy(struct kref *kref)
{
	struct ttm_object_file *tfile =
		container_of(kref, struct ttm_object_file, refcount);

	kfree(tfile);
}


static inline void ttm_object_file_unref(struct ttm_object_file **p_tfile)
{
	struct ttm_object_file *tfile = *p_tfile;

	*p_tfile = NULL;
	kref_put(&tfile->refcount, ttm_object_file_destroy);
}


int ttm_base_object_init(struct ttm_object_file *tfile,
			 struct ttm_base_object *base,
			 bool shareable,
			 enum ttm_object_type object_type,
			 void (*refcount_release) (struct ttm_base_object **),
			 void (*ref_obj_release) (struct ttm_base_object *,
						  enum ttm_ref_type ref_type))
{
	struct ttm_object_device *tdev = tfile->tdev;
	int ret;

	base->shareable = shareable;
	base->tfile = ttm_object_file_ref(tfile);
	base->refcount_release = refcount_release;
	base->ref_obj_release = ref_obj_release;
	base->object_type = object_type;
	kref_init(&base->refcount);
	spin_lock(&tdev->object_lock);
	ret = drm_ht_just_insert_please_rcu(&tdev->object_hash,
					    &base->hash,
					    (unsigned long)base, 31, 0, 0);
	spin_unlock(&tdev->object_lock);
	if (unlikely(ret != 0))
		goto out_err0;

	ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);
	if (unlikely(ret != 0))
		goto out_err1;

	ttm_base_object_unref(&base);

	return 0;
out_err1:
	spin_lock(&tdev->object_lock);
	(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
	spin_unlock(&tdev->object_lock);
out_err0:
	return ret;
}
EXPORT_SYMBOL(ttm_base_object_init);

static void ttm_release_base(struct kref *kref)
{
	struct ttm_base_object *base =
	    container_of(kref, struct ttm_base_object, refcount);
	struct ttm_object_device *tdev = base->tfile->tdev;

	spin_lock(&tdev->object_lock);
	(void)drm_ht_remove_item_rcu(&tdev->object_hash, &base->hash);
	spin_unlock(&tdev->object_lock);

	/*
	 * Note: We don't use synchronize_rcu() here because it's far
	 * too slow. It's up to the user to free the object using
	 * call_rcu() or ttm_base_object_kfree().
	 */

	ttm_object_file_unref(&base->tfile);
	if (base->refcount_release)
		base->refcount_release(&base);
}

void ttm_base_object_unref(struct ttm_base_object **p_base)
{
	struct ttm_base_object *base = *p_base;

	*p_base = NULL;

	kref_put(&base->refcount, ttm_release_base);
}
EXPORT_SYMBOL(ttm_base_object_unref);

struct ttm_base_object *ttm_base_object_lookup(struct ttm_object_file *tfile,
					       uint32_t key)
{
	struct ttm_base_object *base = NULL;
	struct drm_hash_item *hash;
	struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
	int ret;

	rcu_read_lock();
	ret = drm_ht_find_item_rcu(ht, key, &hash);

	if (likely(ret == 0)) {
		base = drm_hash_entry(hash, struct ttm_ref_object, hash)->obj;
		if (!kref_get_unless_zero(&base->refcount))
			base = NULL;
	}
	rcu_read_unlock();

	return base;
}
EXPORT_SYMBOL(ttm_base_object_lookup);

struct ttm_base_object *
ttm_base_object_lookup_for_ref(struct ttm_object_device *tdev, uint32_t key)
{
	struct ttm_base_object *base = NULL;
	struct drm_hash_item *hash;
	struct drm_open_hash *ht = &tdev->object_hash;
	int ret;

	rcu_read_lock();
	ret = drm_ht_find_item_rcu(ht, key, &hash);

	if (likely(ret == 0)) {
		base = drm_hash_entry(hash, struct ttm_base_object, hash);
		if (!kref_get_unless_zero(&base->refcount))
			base = NULL;
	}
	rcu_read_unlock();

	return base;
}
EXPORT_SYMBOL(ttm_base_object_lookup_for_ref);

/**
 * ttm_ref_object_exists - Check whether a caller has a valid ref object
 * (has opened) a base object.
 *
 * @tfile: Pointer to a struct ttm_object_file identifying the caller.
 * @base: Pointer to a struct base object.
 *
 * Checks wether the caller identified by @tfile has put a valid USAGE
 * reference object on the base object identified by @base.
 */
bool ttm_ref_object_exists(struct ttm_object_file *tfile,
			   struct ttm_base_object *base)
{
	struct drm_open_hash *ht = &tfile->ref_hash[TTM_REF_USAGE];
	struct drm_hash_item *hash;
	struct ttm_ref_object *ref;

	rcu_read_lock();
	if (unlikely(drm_ht_find_item_rcu(ht, base->hash.key, &hash) != 0))
		goto out_false;

	/*
	 * Verify that the ref object is really pointing to our base object.
	 * Our base object could actually be dead, and the ref object pointing
	 * to another base object with the same handle.
	 */
	ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
	if (unlikely(base != ref->obj))
		goto out_false;

	/*
	 * Verify that the ref->obj pointer was actually valid!
	 */
	rmb();
	if (unlikely(atomic_read(&ref->kref.refcount) == 0))
		goto out_false;

	rcu_read_unlock();
	return true;

 out_false:
	rcu_read_unlock();
	return false;
}
EXPORT_SYMBOL(ttm_ref_object_exists);

int ttm_ref_object_add(struct ttm_object_file *tfile,
		       struct ttm_base_object *base,
		       enum ttm_ref_type ref_type, bool *existed)
{
	struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
	struct ttm_ref_object *ref;
	struct drm_hash_item *hash;
	struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;
	int ret = -EINVAL;

	if (base->tfile != tfile && !base->shareable)
		return -EPERM;

	if (existed != NULL)
		*existed = true;

	while (ret == -EINVAL) {
		rcu_read_lock();
		ret = drm_ht_find_item_rcu(ht, base->hash.key, &hash);

		if (ret == 0) {
			ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
			if (kref_get_unless_zero(&ref->kref)) {
				rcu_read_unlock();
				break;
			}
		}

		rcu_read_unlock();
		ret = ttm_mem_global_alloc(mem_glob, sizeof(*ref),
					   false, false);
		if (unlikely(ret != 0))
			return ret;
		ref = kmalloc(sizeof(*ref), GFP_KERNEL);
		if (unlikely(ref == NULL)) {
			ttm_mem_global_free(mem_glob, sizeof(*ref));
			return -ENOMEM;
		}

		ref->hash.key = base->hash.key;
		ref->obj = base;
		ref->tfile = tfile;
		ref->ref_type = ref_type;
		kref_init(&ref->kref);

		spin_lock(&tfile->lock);
		ret = drm_ht_insert_item_rcu(ht, &ref->hash);

		if (likely(ret == 0)) {
			list_add_tail(&ref->head, &tfile->ref_list);
			kref_get(&base->refcount);
			spin_unlock(&tfile->lock);
			if (existed != NULL)
				*existed = false;
			break;
		}

		spin_unlock(&tfile->lock);
		BUG_ON(ret != -EINVAL);

		ttm_mem_global_free(mem_glob, sizeof(*ref));
		kfree(ref);
	}

	return ret;
}
EXPORT_SYMBOL(ttm_ref_object_add);

static void ttm_ref_object_release(struct kref *kref)
{
	struct ttm_ref_object *ref =
	    container_of(kref, struct ttm_ref_object, kref);
	struct ttm_base_object *base = ref->obj;
	struct ttm_object_file *tfile = ref->tfile;
	struct drm_open_hash *ht;
	struct ttm_mem_global *mem_glob = tfile->tdev->mem_glob;

	ht = &tfile->ref_hash[ref->ref_type];
	(void)drm_ht_remove_item_rcu(ht, &ref->hash);
	list_del(&ref->head);
	spin_unlock(&tfile->lock);

	if (ref->ref_type != TTM_REF_USAGE && base->ref_obj_release)
		base->ref_obj_release(base, ref->ref_type);

	ttm_base_object_unref(&ref->obj);
	ttm_mem_global_free(mem_glob, sizeof(*ref));
	kfree_rcu(ref, rcu_head);
	spin_lock(&tfile->lock);
}

int ttm_ref_object_base_unref(struct ttm_object_file *tfile,
			      unsigned long key, enum ttm_ref_type ref_type)
{
	struct drm_open_hash *ht = &tfile->ref_hash[ref_type];
	struct ttm_ref_object *ref;
	struct drm_hash_item *hash;
	int ret;

	spin_lock(&tfile->lock);
	ret = drm_ht_find_item(ht, key, &hash);
	if (unlikely(ret != 0)) {
		spin_unlock(&tfile->lock);
		return -EINVAL;
	}
	ref = drm_hash_entry(hash, struct ttm_ref_object, hash);
	kref_put(&ref->kref, ttm_ref_object_release);
	spin_unlock(&tfile->lock);
	return 0;
}
EXPORT_SYMBOL(ttm_ref_object_base_unref);

void ttm_object_file_release(struct ttm_object_file **p_tfile)
{
	struct ttm_ref_object *ref;
	struct list_head *list;
	unsigned int i;
	struct ttm_object_file *tfile = *p_tfile;

	*p_tfile = NULL;
	spin_lock(&tfile->lock);

	/*
	 * Since we release the lock within the loop, we have to
	 * restart it from the beginning each time.
	 */

	while (!list_empty(&tfile->ref_list)) {
		list = tfile->ref_list.next;
		ref = list_entry(list, struct ttm_ref_object, head);
		ttm_ref_object_release(&ref->kref);
	}

	for (i = 0; i < TTM_REF_NUM; ++i)
		drm_ht_remove(&tfile->ref_hash[i]);

	spin_unlock(&tfile->lock);
	ttm_object_file_unref(&tfile);
}
EXPORT_SYMBOL(ttm_object_file_release);

struct ttm_object_file *ttm_object_file_init(struct ttm_object_device *tdev,
					     unsigned int hash_order)
{
	struct ttm_object_file *tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
	unsigned int i;
	unsigned int j = 0;
	int ret;

	if (unlikely(tfile == NULL))
		return NULL;

	spin_lock_init(&tfile->lock);
	tfile->tdev = tdev;
	kref_init(&tfile->refcount);
	INIT_LIST_HEAD(&tfile->ref_list);

	for (i = 0; i < TTM_REF_NUM; ++i) {
		ret = drm_ht_create(&tfile->ref_hash[i], hash_order);
		if (ret) {
			j = i;
			goto out_err;
		}
	}

	return tfile;
out_err:
	for (i = 0; i < j; ++i)
		drm_ht_remove(&tfile->ref_hash[i]);

	kfree(tfile);

	return NULL;
}
EXPORT_SYMBOL(ttm_object_file_init);

struct ttm_object_device *
ttm_object_device_init(struct ttm_mem_global *mem_glob,
		       unsigned int hash_order,
		       const struct dma_buf_ops *ops)
{
	struct ttm_object_device *tdev = kmalloc(sizeof(*tdev), GFP_KERNEL);
	int ret;

	if (unlikely(tdev == NULL))
		return NULL;

	tdev->mem_glob = mem_glob;
	spin_lock_init(&tdev->object_lock);
	atomic_set(&tdev->object_count, 0);
	ret = drm_ht_create(&tdev->object_hash, hash_order);
	if (ret != 0)
		goto out_no_object_hash;

	tdev->ops = *ops;
	tdev->dmabuf_release = tdev->ops.release;
	tdev->ops.release = ttm_prime_dmabuf_release;
	tdev->dma_buf_size = ttm_round_pot(sizeof(struct dma_buf)) +
		ttm_round_pot(sizeof(struct file));
	return tdev;

out_no_object_hash:
	kfree(tdev);
	return NULL;
}
EXPORT_SYMBOL(ttm_object_device_init);

void ttm_object_device_release(struct ttm_object_device **p_tdev)
{
	struct ttm_object_device *tdev = *p_tdev;

	*p_tdev = NULL;

	spin_lock(&tdev->object_lock);
	drm_ht_remove(&tdev->object_hash);
	spin_unlock(&tdev->object_lock);

	kfree(tdev);
}
EXPORT_SYMBOL(ttm_object_device_release);

/**
 * get_dma_buf_unless_doomed - get a dma_buf reference if possible.
 *
 * @dma_buf: Non-refcounted pointer to a struct dma-buf.
 *
 * Obtain a file reference from a lookup structure that doesn't refcount
 * the file, but synchronizes with its release method to make sure it has
 * not been freed yet. See for example kref_get_unless_zero documentation.
 * Returns true if refcounting succeeds, false otherwise.
 *
 * Nobody really wants this as a public API yet, so let it mature here
 * for some time...
 */
static bool __must_check get_dma_buf_unless_doomed(struct dma_buf *dmabuf)
{
	return atomic_long_inc_not_zero(&dmabuf->file->f_count) != 0L;
}

/**
 * ttm_prime_refcount_release - refcount release method for a prime object.
 *
 * @p_base: Pointer to ttm_base_object pointer.
 *
 * This is a wrapper that calls the refcount_release founction of the
 * underlying object. At the same time it cleans up the prime object.
 * This function is called when all references to the base object we
 * derive from are gone.
 */
static void ttm_prime_refcount_release(struct ttm_base_object **p_base)
{
	struct ttm_base_object *base = *p_base;
	struct ttm_prime_object *prime;

	*p_base = NULL;
	prime = container_of(base, struct ttm_prime_object, base);
	BUG_ON(prime->dma_buf != NULL);
	mutex_destroy(&prime->mutex);
	if (prime->refcount_release)
		prime->refcount_release(&base);
}

/**
 * ttm_prime_dmabuf_release - Release method for the dma-bufs we export
 *
 * @dma_buf:
 *
 * This function first calls the dma_buf release method the driver
 * provides. Then it cleans up our dma_buf pointer used for lookup,
 * and finally releases the reference the dma_buf has on our base
 * object.
 */
static void ttm_prime_dmabuf_release(struct dma_buf *dma_buf)
{
	struct ttm_prime_object *prime =
		(struct ttm_prime_object *) dma_buf->priv;
	struct ttm_base_object *base = &prime->base;
	struct ttm_object_device *tdev = base->tfile->tdev;

	if (tdev->dmabuf_release)
		tdev->dmabuf_release(dma_buf);
	mutex_lock(&prime->mutex);
	if (prime->dma_buf == dma_buf)
		prime->dma_buf = NULL;
	mutex_unlock(&prime->mutex);
	ttm_mem_global_free(tdev->mem_glob, tdev->dma_buf_size);
	ttm_base_object_unref(&base);
}

/**
 * ttm_prime_fd_to_handle - Get a base object handle from a prime fd
 *
 * @tfile: A struct ttm_object_file identifying the caller.
 * @fd: The prime / dmabuf fd.
 * @handle: The returned handle.
 *
 * This function returns a handle to an object that previously exported
 * a dma-buf. Note that we don't handle imports yet, because we simply
 * have no consumers of that implementation.
 */
int ttm_prime_fd_to_handle(struct ttm_object_file *tfile,
			   int fd, u32 *handle)
{
	struct ttm_object_device *tdev = tfile->tdev;
	struct dma_buf *dma_buf;
	struct ttm_prime_object *prime;
	struct ttm_base_object *base;
	int ret;

	dma_buf = dma_buf_get(fd);
	if (IS_ERR(dma_buf))
		return PTR_ERR(dma_buf);

	if (dma_buf->ops != &tdev->ops)
		return -ENOSYS;

	prime = (struct ttm_prime_object *) dma_buf->priv;
	base = &prime->base;
	*handle = base->hash.key;
	ret = ttm_ref_object_add(tfile, base, TTM_REF_USAGE, NULL);

	dma_buf_put(dma_buf);

	return ret;
}
EXPORT_SYMBOL_GPL(ttm_prime_fd_to_handle);

/**
 * ttm_prime_handle_to_fd - Return a dma_buf fd from a ttm prime object
 *
 * @tfile: Struct ttm_object_file identifying the caller.
 * @handle: Handle to the object we're exporting from.
 * @flags: flags for dma-buf creation. We just pass them on.
 * @prime_fd: The returned file descriptor.
 *
 */
int ttm_prime_handle_to_fd(struct ttm_object_file *tfile,
			   uint32_t handle, uint32_t flags,
			   int *prime_fd)
{
	struct ttm_object_device *tdev = tfile->tdev;
	struct ttm_base_object *base;
	struct dma_buf *dma_buf;
	struct ttm_prime_object *prime;
	int ret;

	base = ttm_base_object_lookup(tfile, handle);
	if (unlikely(base == NULL ||
		     base->object_type != ttm_prime_type)) {
		ret = -ENOENT;
		goto out_unref;
	}

	prime = container_of(base, struct ttm_prime_object, base);
	if (unlikely(!base->shareable)) {
		ret = -EPERM;
		goto out_unref;
	}

	ret = mutex_lock_interruptible(&prime->mutex);
	if (unlikely(ret != 0)) {
		ret = -ERESTARTSYS;
		goto out_unref;
	}

	dma_buf = prime->dma_buf;
	if (!dma_buf || !get_dma_buf_unless_doomed(dma_buf)) {
		DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

		exp_info.ops = &tdev->ops;
		exp_info.size = prime->size;
		exp_info.flags = flags;
		exp_info.priv = prime;

		/*
		 * Need to create a new dma_buf, with memory accounting.
		 */
		ret = ttm_mem_global_alloc(tdev->mem_glob, tdev->dma_buf_size,
					   false, true);
		if (unlikely(ret != 0)) {
			mutex_unlock(&prime->mutex);
			goto out_unref;
		}

		dma_buf = dma_buf_export(&exp_info);
		if (IS_ERR(dma_buf)) {
			ret = PTR_ERR(dma_buf);
			ttm_mem_global_free(tdev->mem_glob,
					    tdev->dma_buf_size);
			mutex_unlock(&prime->mutex);
			goto out_unref;
		}

		/*
		 * dma_buf has taken the base object reference
		 */
		base = NULL;
		prime->dma_buf = dma_buf;
	}
	mutex_unlock(&prime->mutex);

	ret = dma_buf_fd(dma_buf, flags);
	if (ret >= 0) {
		*prime_fd = ret;
		ret = 0;
	} else
		dma_buf_put(dma_buf);

out_unref:
	if (base)
		ttm_base_object_unref(&base);
	return ret;
}
EXPORT_SYMBOL_GPL(ttm_prime_handle_to_fd);

/**
 * ttm_prime_object_init - Initialize a ttm_prime_object
 *
 * @tfile: struct ttm_object_file identifying the caller
 * @size: The size of the dma_bufs we export.
 * @prime: The object to be initialized.
 * @shareable: See ttm_base_object_init
 * @type: See ttm_base_object_init
 * @refcount_release: See ttm_base_object_init
 * @ref_obj_release: See ttm_base_object_init
 *
 * Initializes an object which is compatible with the drm_prime model
 * for data sharing between processes and devices.
 */
int ttm_prime_object_init(struct ttm_object_file *tfile, size_t size,
			  struct ttm_prime_object *prime, bool shareable,
			  enum ttm_object_type type,
			  void (*refcount_release) (struct ttm_base_object **),
			  void (*ref_obj_release) (struct ttm_base_object *,
						   enum ttm_ref_type ref_type))
{
	mutex_init(&prime->mutex);
	prime->size = PAGE_ALIGN(size);
	prime->real_type = type;
	prime->dma_buf = NULL;
	prime->refcount_release = refcount_release;
	return ttm_base_object_init(tfile, &prime->base, shareable,
				    ttm_prime_type,
				    ttm_prime_refcount_release,
				    ref_obj_release);
}
EXPORT_SYMBOL(ttm_prime_object_init);
OpenPOWER on IntegriCloud