summaryrefslogtreecommitdiff
path: root/drivers/dma-buf/st-dma-fence.c
blob: c8a12d7ad71ab6baef2298b60619b0d25edc2d03 (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
/* SPDX-License-Identifier: MIT */

/*
 * Copyright © 2019 Intel Corporation
 */

#include <linux/delay.h>
#include <linux/dma-fence.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include "selftest.h"

static struct kmem_cache *slab_fences;

static struct mock_fence {
	struct dma_fence base;
	struct spinlock lock;
} *to_mock_fence(struct dma_fence *f) {
	return container_of(f, struct mock_fence, base);
}

static const char *mock_name(struct dma_fence *f)
{
	return "mock";
}

static void mock_fence_release(struct dma_fence *f)
{
	kmem_cache_free(slab_fences, to_mock_fence(f));
}

struct wait_cb {
	struct dma_fence_cb cb;
	struct task_struct *task;
};

static void mock_wakeup(struct dma_fence *f, struct dma_fence_cb *cb)
{
	wake_up_process(container_of(cb, struct wait_cb, cb)->task);
}

static long mock_wait(struct dma_fence *f, bool intr, long timeout)
{
	const int state = intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;
	struct wait_cb cb = { .task = current };

	if (dma_fence_add_callback(f, &cb.cb, mock_wakeup))
		return timeout;

	while (timeout) {
		set_current_state(state);

		if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &f->flags))
			break;

		if (signal_pending_state(state, current))
			break;

		timeout = schedule_timeout(timeout);
	}
	__set_current_state(TASK_RUNNING);

	if (!dma_fence_remove_callback(f, &cb.cb))
		return timeout;

	if (signal_pending_state(state, current))
		return -ERESTARTSYS;

	return -ETIME;
}

static const struct dma_fence_ops mock_ops = {
	.get_driver_name = mock_name,
	.get_timeline_name = mock_name,
	.wait = mock_wait,
	.release = mock_fence_release,
};

static struct dma_fence *mock_fence(void)
{
	struct mock_fence *f;

	f = kmem_cache_alloc(slab_fences, GFP_KERNEL);
	if (!f)
		return NULL;

	spin_lock_init(&f->lock);
	dma_fence_init(&f->base, &mock_ops, &f->lock, 0, 0);

	return &f->base;
}

static int sanitycheck(void *arg)
{
	struct dma_fence *f;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	dma_fence_signal(f);
	dma_fence_put(f);

	return 0;
}

static int test_signaling(void *arg)
{
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	if (dma_fence_is_signaled(f)) {
		pr_err("Fence unexpectedly signaled on creation\n");
		goto err_free;
	}

	if (dma_fence_signal(f)) {
		pr_err("Fence reported being already signaled\n");
		goto err_free;
	}

	if (!dma_fence_is_signaled(f)) {
		pr_err("Fence not reporting signaled\n");
		goto err_free;
	}

	if (!dma_fence_signal(f)) {
		pr_err("Fence reported not being already signaled\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

struct simple_cb {
	struct dma_fence_cb cb;
	bool seen;
};

static void simple_callback(struct dma_fence *f, struct dma_fence_cb *cb)
{
	smp_store_mb(container_of(cb, struct simple_cb, cb)->seen, true);
}

static int test_add_callback(void *arg)
{
	struct simple_cb cb = {};
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {
		pr_err("Failed to add callback, fence already signaled!\n");
		goto err_free;
	}

	dma_fence_signal(f);
	if (!cb.seen) {
		pr_err("Callback failed!\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

static int test_late_add_callback(void *arg)
{
	struct simple_cb cb = {};
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	dma_fence_signal(f);

	if (!dma_fence_add_callback(f, &cb.cb, simple_callback)) {
		pr_err("Added callback, but fence was already signaled!\n");
		goto err_free;
	}

	dma_fence_signal(f);
	if (cb.seen) {
		pr_err("Callback called after failed attachment !\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

static int test_rm_callback(void *arg)
{
	struct simple_cb cb = {};
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {
		pr_err("Failed to add callback, fence already signaled!\n");
		goto err_free;
	}

	if (!dma_fence_remove_callback(f, &cb.cb)) {
		pr_err("Failed to remove callback!\n");
		goto err_free;
	}

	dma_fence_signal(f);
	if (cb.seen) {
		pr_err("Callback still signaled after removal!\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

static int test_late_rm_callback(void *arg)
{
	struct simple_cb cb = {};
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {
		pr_err("Failed to add callback, fence already signaled!\n");
		goto err_free;
	}

	dma_fence_signal(f);
	if (!cb.seen) {
		pr_err("Callback failed!\n");
		goto err_free;
	}

	if (dma_fence_remove_callback(f, &cb.cb)) {
		pr_err("Callback removal succeed after being executed!\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

static int test_status(void *arg)
{
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	if (dma_fence_get_status(f)) {
		pr_err("Fence unexpectedly has signaled status on creation\n");
		goto err_free;
	}

	dma_fence_signal(f);
	if (!dma_fence_get_status(f)) {
		pr_err("Fence not reporting signaled status\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

static int test_error(void *arg)
{
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	dma_fence_set_error(f, -EIO);

	if (dma_fence_get_status(f)) {
		pr_err("Fence unexpectedly has error status before signal\n");
		goto err_free;
	}

	dma_fence_signal(f);
	if (dma_fence_get_status(f) != -EIO) {
		pr_err("Fence not reporting error status, got %d\n",
		       dma_fence_get_status(f));
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_put(f);
	return err;
}

static int test_wait(void *arg)
{
	struct dma_fence *f;
	int err = -EINVAL;

	f = mock_fence();
	if (!f)
		return -ENOMEM;

	if (dma_fence_wait_timeout(f, false, 0) != -ETIME) {
		pr_err("Wait reported complete before being signaled\n");
		goto err_free;
	}

	dma_fence_signal(f);

	if (dma_fence_wait_timeout(f, false, 0) != 0) {
		pr_err("Wait reported incomplete after being signaled\n");
		goto err_free;
	}

	err = 0;
err_free:
	dma_fence_signal(f);
	dma_fence_put(f);
	return err;
}

struct wait_timer {
	struct timer_list timer;
	struct dma_fence *f;
};

static void wait_timer(struct timer_list *timer)
{
	struct wait_timer *wt = from_timer(wt, timer, timer);

	dma_fence_signal(wt->f);
}

static int test_wait_timeout(void *arg)
{
	struct wait_timer wt;
	int err = -EINVAL;

	timer_setup_on_stack(&wt.timer, wait_timer, 0);

	wt.f = mock_fence();
	if (!wt.f)
		return -ENOMEM;

	if (dma_fence_wait_timeout(wt.f, false, 1) != -ETIME) {
		pr_err("Wait reported complete before being signaled\n");
		goto err_free;
	}

	mod_timer(&wt.timer, jiffies + 1);

	if (dma_fence_wait_timeout(wt.f, false, 2) == -ETIME) {
		if (timer_pending(&wt.timer)) {
			pr_notice("Timer did not fire within the jiffie!\n");
			err = 0; /* not our fault! */
		} else {
			pr_err("Wait reported incomplete after timeout\n");
		}
		goto err_free;
	}

	err = 0;
err_free:
	del_timer_sync(&wt.timer);
	destroy_timer_on_stack(&wt.timer);
	dma_fence_signal(wt.f);
	dma_fence_put(wt.f);
	return err;
}

static int test_stub(void *arg)
{
	struct dma_fence *f[64];
	int err = -EINVAL;
	int i;

	for (i = 0; i < ARRAY_SIZE(f); i++) {
		f[i] = dma_fence_get_stub();
		if (!dma_fence_is_signaled(f[i])) {
			pr_err("Obtained unsignaled stub fence!\n");
			goto err;
		}
	}

	err = 0;
err:
	while (i--)
		dma_fence_put(f[i]);
	return err;
}

/* Now off to the races! */

struct race_thread {
	struct dma_fence __rcu **fences;
	struct task_struct *task;
	bool before;
	int id;
};

static void __wait_for_callbacks(struct dma_fence *f)
{
	spin_lock_irq(f->lock);
	spin_unlock_irq(f->lock);
}

static int thread_signal_callback(void *arg)
{
	const struct race_thread *t = arg;
	unsigned long pass = 0;
	unsigned long miss = 0;
	int err = 0;

	while (!err && !kthread_should_stop()) {
		struct dma_fence *f1, *f2;
		struct simple_cb cb;

		f1 = mock_fence();
		if (!f1) {
			err = -ENOMEM;
			break;
		}

		rcu_assign_pointer(t->fences[t->id], f1);
		smp_wmb();

		rcu_read_lock();
		do {
			f2 = dma_fence_get_rcu_safe(&t->fences[!t->id]);
		} while (!f2 && !kthread_should_stop());
		rcu_read_unlock();

		if (t->before)
			dma_fence_signal(f1);

		smp_store_mb(cb.seen, false);
		if (!f2 ||
		    dma_fence_add_callback(f2, &cb.cb, simple_callback)) {
			miss++;
			cb.seen = true;
		}

		if (!t->before)
			dma_fence_signal(f1);

		if (!cb.seen) {
			dma_fence_wait(f2, false);
			__wait_for_callbacks(f2);
		}

		if (!READ_ONCE(cb.seen)) {
			pr_err("Callback not seen on thread %d, pass %lu (%lu misses), signaling %s add_callback; fence signaled? %s\n",
			       t->id, pass, miss,
			       t->before ? "before" : "after",
			       dma_fence_is_signaled(f2) ? "yes" : "no");
			err = -EINVAL;
		}

		dma_fence_put(f2);

		rcu_assign_pointer(t->fences[t->id], NULL);
		smp_wmb();

		dma_fence_put(f1);

		pass++;
	}

	pr_info("%s[%d] completed %lu passes, %lu misses\n",
		__func__, t->id, pass, miss);
	return err;
}

static int race_signal_callback(void *arg)
{
	struct dma_fence __rcu *f[2] = {};
	int ret = 0;
	int pass;

	for (pass = 0; !ret && pass <= 1; pass++) {
		struct race_thread t[2];
		int i;

		for (i = 0; i < ARRAY_SIZE(t); i++) {
			t[i].fences = f;
			t[i].id = i;
			t[i].before = pass;
			t[i].task = kthread_run(thread_signal_callback, &t[i],
						"dma-fence:%d", i);
			get_task_struct(t[i].task);
		}

		msleep(50);

		for (i = 0; i < ARRAY_SIZE(t); i++) {
			int err;

			err = kthread_stop(t[i].task);
			if (err && !ret)
				ret = err;

			put_task_struct(t[i].task);
		}
	}

	return ret;
}

int dma_fence(void)
{
	static const struct subtest tests[] = {
		SUBTEST(sanitycheck),
		SUBTEST(test_signaling),
		SUBTEST(test_add_callback),
		SUBTEST(test_late_add_callback),
		SUBTEST(test_rm_callback),
		SUBTEST(test_late_rm_callback),
		SUBTEST(test_status),
		SUBTEST(test_error),
		SUBTEST(test_wait),
		SUBTEST(test_wait_timeout),
		SUBTEST(test_stub),
		SUBTEST(race_signal_callback),
	};
	int ret;

	pr_info("sizeof(dma_fence)=%zu\n", sizeof(struct dma_fence));

	slab_fences = KMEM_CACHE(mock_fence,
				 SLAB_TYPESAFE_BY_RCU |
				 SLAB_HWCACHE_ALIGN);
	if (!slab_fences)
		return -ENOMEM;

	ret = subtests(tests, NULL);

	kmem_cache_destroy(slab_fences);

	return ret;
}