Merge commit 'v3.4.5' into android-t114-3.4-rebased
[linux-2.6.git] / drivers / base / sync.c
1 /*
2  * drivers/base/sync.c
3  *
4  * Copyright (C) 2012 Google, Inc.
5  *
6  * This software is licensed under the terms of the GNU General Public
7  * License version 2, as published by the Free Software Foundation, and
8  * may be copied, distributed, and modified under those terms.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13  * GNU General Public License for more details.
14  *
15  */
16
17 #include <linux/debugfs.h>
18 #include <linux/export.h>
19 #include <linux/file.h>
20 #include <linux/fs.h>
21 #include <linux/kernel.h>
22 #include <linux/poll.h>
23 #include <linux/sched.h>
24 #include <linux/seq_file.h>
25 #include <linux/slab.h>
26 #include <linux/sync.h>
27 #include <linux/uaccess.h>
28
29 #include <linux/anon_inodes.h>
30
31 static void sync_fence_signal_pt(struct sync_pt *pt);
32 static int _sync_pt_has_signaled(struct sync_pt *pt);
33
34 static LIST_HEAD(sync_timeline_list_head);
35 static DEFINE_SPINLOCK(sync_timeline_list_lock);
36
37 static LIST_HEAD(sync_fence_list_head);
38 static DEFINE_SPINLOCK(sync_fence_list_lock);
39
40 struct sync_timeline *sync_timeline_create(const struct sync_timeline_ops *ops,
41                                            int size, const char *name)
42 {
43         struct sync_timeline *obj;
44         unsigned long flags;
45
46         if (size < sizeof(struct sync_timeline))
47                 return NULL;
48
49         obj = kzalloc(size, GFP_KERNEL);
50         if (obj == NULL)
51                 return NULL;
52
53         obj->ops = ops;
54         strlcpy(obj->name, name, sizeof(obj->name));
55
56         INIT_LIST_HEAD(&obj->child_list_head);
57         spin_lock_init(&obj->child_list_lock);
58
59         INIT_LIST_HEAD(&obj->active_list_head);
60         spin_lock_init(&obj->active_list_lock);
61
62         spin_lock_irqsave(&sync_timeline_list_lock, flags);
63         list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
64         spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
65
66         return obj;
67 }
68 EXPORT_SYMBOL(sync_timeline_create);
69
70 static void sync_timeline_free(struct sync_timeline *obj)
71 {
72         unsigned long flags;
73
74         if (obj->ops->release_obj)
75                 obj->ops->release_obj(obj);
76
77         spin_lock_irqsave(&sync_timeline_list_lock, flags);
78         list_del(&obj->sync_timeline_list);
79         spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
80
81         kfree(obj);
82 }
83
84 void sync_timeline_destroy(struct sync_timeline *obj)
85 {
86         unsigned long flags;
87         bool needs_freeing;
88
89         spin_lock_irqsave(&obj->child_list_lock, flags);
90         obj->destroyed = true;
91         needs_freeing = list_empty(&obj->child_list_head);
92         spin_unlock_irqrestore(&obj->child_list_lock, flags);
93
94         if (needs_freeing)
95                 sync_timeline_free(obj);
96         else
97                 sync_timeline_signal(obj);
98 }
99 EXPORT_SYMBOL(sync_timeline_destroy);
100
101 static void sync_timeline_add_pt(struct sync_timeline *obj, struct sync_pt *pt)
102 {
103         unsigned long flags;
104
105         pt->parent = obj;
106
107         spin_lock_irqsave(&obj->child_list_lock, flags);
108         list_add_tail(&pt->child_list, &obj->child_list_head);
109         spin_unlock_irqrestore(&obj->child_list_lock, flags);
110 }
111
112 static void sync_timeline_remove_pt(struct sync_pt *pt)
113 {
114         struct sync_timeline *obj = pt->parent;
115         unsigned long flags;
116         bool needs_freeing;
117
118         spin_lock_irqsave(&obj->active_list_lock, flags);
119         if (!list_empty(&pt->active_list))
120                 list_del_init(&pt->active_list);
121         spin_unlock_irqrestore(&obj->active_list_lock, flags);
122
123         spin_lock_irqsave(&obj->child_list_lock, flags);
124         list_del(&pt->child_list);
125         needs_freeing = obj->destroyed && list_empty(&obj->child_list_head);
126         spin_unlock_irqrestore(&obj->child_list_lock, flags);
127
128         if (needs_freeing)
129                 sync_timeline_free(obj);
130 }
131
132 void sync_timeline_signal(struct sync_timeline *obj)
133 {
134         unsigned long flags;
135         LIST_HEAD(signaled_pts);
136         struct list_head *pos, *n;
137
138         spin_lock_irqsave(&obj->active_list_lock, flags);
139
140         list_for_each_safe(pos, n, &obj->active_list_head) {
141                 struct sync_pt *pt =
142                         container_of(pos, struct sync_pt, active_list);
143
144                 if (_sync_pt_has_signaled(pt))
145                         list_move(pos, &signaled_pts);
146         }
147
148         spin_unlock_irqrestore(&obj->active_list_lock, flags);
149
150         list_for_each_safe(pos, n, &signaled_pts) {
151                 struct sync_pt *pt =
152                         container_of(pos, struct sync_pt, active_list);
153
154                 list_del_init(pos);
155                 sync_fence_signal_pt(pt);
156         }
157 }
158 EXPORT_SYMBOL(sync_timeline_signal);
159
160 struct sync_pt *sync_pt_create(struct sync_timeline *parent, int size)
161 {
162         struct sync_pt *pt;
163
164         if (size < sizeof(struct sync_pt))
165                 return NULL;
166
167         pt = kzalloc(size, GFP_KERNEL);
168         if (pt == NULL)
169                 return NULL;
170
171         INIT_LIST_HEAD(&pt->active_list);
172         sync_timeline_add_pt(parent, pt);
173
174         return pt;
175 }
176 EXPORT_SYMBOL(sync_pt_create);
177
178 void sync_pt_free(struct sync_pt *pt)
179 {
180         if (pt->parent->ops->free_pt)
181                 pt->parent->ops->free_pt(pt);
182
183         sync_timeline_remove_pt(pt);
184
185         kfree(pt);
186 }
187 EXPORT_SYMBOL(sync_pt_free);
188
189 /* call with pt->parent->active_list_lock held */
190 static int _sync_pt_has_signaled(struct sync_pt *pt)
191 {
192         int old_status = pt->status;
193
194         if (!pt->status)
195                 pt->status = pt->parent->ops->has_signaled(pt);
196
197         if (!pt->status && pt->parent->destroyed)
198                 pt->status = -ENOENT;
199
200         if (pt->status != old_status)
201                 pt->timestamp = ktime_get();
202
203         return pt->status;
204 }
205
206 static struct sync_pt *sync_pt_dup(struct sync_pt *pt)
207 {
208         return pt->parent->ops->dup(pt);
209 }
210
211 /* Adds a sync pt to the active queue.  Called when added to a fence */
212 static void sync_pt_activate(struct sync_pt *pt)
213 {
214         struct sync_timeline *obj = pt->parent;
215         unsigned long flags;
216         int err;
217
218         spin_lock_irqsave(&obj->active_list_lock, flags);
219
220         err = _sync_pt_has_signaled(pt);
221         if (err != 0)
222                 goto out;
223
224         list_add_tail(&pt->active_list, &obj->active_list_head);
225
226 out:
227         spin_unlock_irqrestore(&obj->active_list_lock, flags);
228 }
229
230 static int sync_fence_release(struct inode *inode, struct file *file);
231 static unsigned int sync_fence_poll(struct file *file, poll_table *wait);
232 static long sync_fence_ioctl(struct file *file, unsigned int cmd,
233                              unsigned long arg);
234
235
236 static const struct file_operations sync_fence_fops = {
237         .release = sync_fence_release,
238         .poll = sync_fence_poll,
239         .unlocked_ioctl = sync_fence_ioctl,
240 };
241
242 static struct sync_fence *sync_fence_alloc(const char *name)
243 {
244         struct sync_fence *fence;
245         unsigned long flags;
246
247         fence = kzalloc(sizeof(struct sync_fence), GFP_KERNEL);
248         if (fence == NULL)
249                 return NULL;
250
251         fence->file = anon_inode_getfile("sync_fence", &sync_fence_fops,
252                                          fence, 0);
253         if (fence->file == NULL)
254                 goto err;
255
256         strlcpy(fence->name, name, sizeof(fence->name));
257
258         INIT_LIST_HEAD(&fence->pt_list_head);
259         INIT_LIST_HEAD(&fence->waiter_list_head);
260         spin_lock_init(&fence->waiter_list_lock);
261
262         init_waitqueue_head(&fence->wq);
263
264         spin_lock_irqsave(&sync_fence_list_lock, flags);
265         list_add_tail(&fence->sync_fence_list, &sync_fence_list_head);
266         spin_unlock_irqrestore(&sync_fence_list_lock, flags);
267
268         return fence;
269
270 err:
271         kfree(fence);
272         return NULL;
273 }
274
275 /* TODO: implement a create which takes more that one sync_pt */
276 struct sync_fence *sync_fence_create(const char *name, struct sync_pt *pt)
277 {
278         struct sync_fence *fence;
279
280         if (pt->fence)
281                 return NULL;
282
283         fence = sync_fence_alloc(name);
284         if (fence == NULL)
285                 return NULL;
286
287         pt->fence = fence;
288         list_add(&pt->pt_list, &fence->pt_list_head);
289         sync_pt_activate(pt);
290
291         return fence;
292 }
293 EXPORT_SYMBOL(sync_fence_create);
294
295 static int sync_fence_copy_pts(struct sync_fence *dst, struct sync_fence *src)
296 {
297         struct list_head *pos;
298
299         list_for_each(pos, &src->pt_list_head) {
300                 struct sync_pt *orig_pt =
301                         container_of(pos, struct sync_pt, pt_list);
302                 struct sync_pt *new_pt = sync_pt_dup(orig_pt);
303
304                 if (new_pt == NULL)
305                         return -ENOMEM;
306
307                 new_pt->fence = dst;
308                 list_add(&new_pt->pt_list, &dst->pt_list_head);
309                 sync_pt_activate(new_pt);
310         }
311
312         return 0;
313 }
314
315 static void sync_fence_free_pts(struct sync_fence *fence)
316 {
317         struct list_head *pos, *n;
318
319         list_for_each_safe(pos, n, &fence->pt_list_head) {
320                 struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
321                 sync_pt_free(pt);
322         }
323 }
324
325 struct sync_fence *sync_fence_fdget(int fd)
326 {
327         struct file *file = fget(fd);
328
329         if (file == NULL)
330                 return NULL;
331
332         if (file->f_op != &sync_fence_fops)
333                 goto err;
334
335         return file->private_data;
336
337 err:
338         fput(file);
339         return NULL;
340 }
341 EXPORT_SYMBOL(sync_fence_fdget);
342
343 void sync_fence_put(struct sync_fence *fence)
344 {
345         fput(fence->file);
346 }
347 EXPORT_SYMBOL(sync_fence_put);
348
349 void sync_fence_install(struct sync_fence *fence, int fd)
350 {
351         fd_install(fd, fence->file);
352 }
353 EXPORT_SYMBOL(sync_fence_install);
354
355 static int sync_fence_get_status(struct sync_fence *fence)
356 {
357         struct list_head *pos;
358         int status = 1;
359
360         list_for_each(pos, &fence->pt_list_head) {
361                 struct sync_pt *pt = container_of(pos, struct sync_pt, pt_list);
362                 int pt_status = pt->status;
363
364                 if (pt_status < 0) {
365                         status = pt_status;
366                         break;
367                 } else if (status == 1) {
368                         status = pt_status;
369                 }
370         }
371
372         return status;
373 }
374
375 struct sync_fence *sync_fence_merge(const char *name,
376                                     struct sync_fence *a, struct sync_fence *b)
377 {
378         struct sync_fence *fence;
379         int err;
380
381         fence = sync_fence_alloc(name);
382         if (fence == NULL)
383                 return NULL;
384
385         err = sync_fence_copy_pts(fence, a);
386         if (err < 0)
387                 goto err;
388
389         err = sync_fence_copy_pts(fence, b);
390         if (err < 0)
391                 goto err;
392
393         fence->status = sync_fence_get_status(fence);
394
395         return fence;
396 err:
397         sync_fence_free_pts(fence);
398         kfree(fence);
399         return NULL;
400 }
401 EXPORT_SYMBOL(sync_fence_merge);
402
403 static void sync_fence_signal_pt(struct sync_pt *pt)
404 {
405         LIST_HEAD(signaled_waiters);
406         struct sync_fence *fence = pt->fence;
407         struct list_head *pos;
408         struct list_head *n;
409         unsigned long flags;
410         int status;
411
412         status = sync_fence_get_status(fence);
413
414         spin_lock_irqsave(&fence->waiter_list_lock, flags);
415         /*
416          * this should protect against two threads racing on the signaled
417          * false -> true transition
418          */
419         if (status && !fence->status) {
420                 list_for_each_safe(pos, n, &fence->waiter_list_head)
421                         list_move(pos, &signaled_waiters);
422
423                 fence->status = status;
424         } else {
425                 status = 0;
426         }
427         spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
428
429         if (status) {
430                 list_for_each_safe(pos, n, &signaled_waiters) {
431                         struct sync_fence_waiter *waiter =
432                                 container_of(pos, struct sync_fence_waiter,
433                                              waiter_list);
434
435                         list_del(pos);
436                         waiter->callback(fence, waiter);
437                 }
438                 wake_up(&fence->wq);
439         }
440 }
441
442 int sync_fence_wait_async(struct sync_fence *fence,
443                           struct sync_fence_waiter *waiter)
444 {
445         unsigned long flags;
446         int err = 0;
447
448         spin_lock_irqsave(&fence->waiter_list_lock, flags);
449
450         if (fence->status) {
451                 err = fence->status;
452                 goto out;
453         }
454
455         list_add_tail(&waiter->waiter_list, &fence->waiter_list_head);
456 out:
457         spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
458
459         return err;
460 }
461 EXPORT_SYMBOL(sync_fence_wait_async);
462
463 int sync_fence_cancel_async(struct sync_fence *fence,
464                              struct sync_fence_waiter *waiter)
465 {
466         struct list_head *pos;
467         struct list_head *n;
468         unsigned long flags;
469         int ret = -ENOENT;
470
471         spin_lock_irqsave(&fence->waiter_list_lock, flags);
472         /*
473          * Make sure waiter is still in waiter_list because it is possible for
474          * the waiter to be removed from the list while the callback is still
475          * pending.
476          */
477         list_for_each_safe(pos, n, &fence->waiter_list_head) {
478                 struct sync_fence_waiter *list_waiter =
479                         container_of(pos, struct sync_fence_waiter,
480                                      waiter_list);
481                 if (list_waiter == waiter) {
482                         list_del(pos);
483                         ret = 0;
484                         break;
485                 }
486         }
487         spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
488         return ret;
489 }
490 EXPORT_SYMBOL(sync_fence_cancel_async);
491
492 int sync_fence_wait(struct sync_fence *fence, long timeout)
493 {
494         int err;
495
496         if (timeout) {
497                 timeout = msecs_to_jiffies(timeout);
498                 err = wait_event_interruptible_timeout(fence->wq,
499                                                        fence->status != 0,
500                                                        timeout);
501         } else {
502                 err = wait_event_interruptible(fence->wq, fence->status != 0);
503         }
504
505         if (err < 0)
506                 return err;
507
508         if (fence->status < 0)
509                 return fence->status;
510
511         if (fence->status == 0)
512                 return -ETIME;
513
514         return 0;
515 }
516 EXPORT_SYMBOL(sync_fence_wait);
517
518 static int sync_fence_release(struct inode *inode, struct file *file)
519 {
520         struct sync_fence *fence = file->private_data;
521         unsigned long flags;
522
523         sync_fence_free_pts(fence);
524
525         spin_lock_irqsave(&sync_fence_list_lock, flags);
526         list_del(&fence->sync_fence_list);
527         spin_unlock_irqrestore(&sync_fence_list_lock, flags);
528
529         kfree(fence);
530
531         return 0;
532 }
533
534 static unsigned int sync_fence_poll(struct file *file, poll_table *wait)
535 {
536         struct sync_fence *fence = file->private_data;
537
538         poll_wait(file, &fence->wq, wait);
539
540         if (fence->status == 1)
541                 return POLLIN;
542         else if (fence->status < 0)
543                 return POLLERR;
544         else
545                 return 0;
546 }
547
548 static long sync_fence_ioctl_wait(struct sync_fence *fence, unsigned long arg)
549 {
550         __u32 value;
551
552         if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
553                 return -EFAULT;
554
555         return sync_fence_wait(fence, value);
556 }
557
558 static long sync_fence_ioctl_merge(struct sync_fence *fence, unsigned long arg)
559 {
560         int fd = get_unused_fd();
561         int err;
562         struct sync_fence *fence2, *fence3;
563         struct sync_merge_data data;
564
565         if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
566                 return -EFAULT;
567
568         fence2 = sync_fence_fdget(data.fd2);
569         if (fence2 == NULL) {
570                 err = -ENOENT;
571                 goto err_put_fd;
572         }
573
574         data.name[sizeof(data.name) - 1] = '\0';
575         fence3 = sync_fence_merge(data.name, fence, fence2);
576         if (fence3 == NULL) {
577                 err = -ENOMEM;
578                 goto err_put_fence2;
579         }
580
581         data.fence = fd;
582         if (copy_to_user((void __user *)arg, &data, sizeof(data))) {
583                 err = -EFAULT;
584                 goto err_put_fence3;
585         }
586
587         sync_fence_install(fence3, fd);
588         sync_fence_put(fence2);
589         return 0;
590
591 err_put_fence3:
592         sync_fence_put(fence3);
593
594 err_put_fence2:
595         sync_fence_put(fence2);
596
597 err_put_fd:
598         put_unused_fd(fd);
599         return err;
600 }
601
602 static int sync_fill_pt_info(struct sync_pt *pt, void *data, int size)
603 {
604         struct sync_pt_info *info = data;
605         int ret;
606
607         if (size < sizeof(struct sync_pt_info))
608                 return -ENOMEM;
609
610         info->len = sizeof(struct sync_pt_info);
611
612         if (pt->parent->ops->fill_driver_data) {
613                 ret = pt->parent->ops->fill_driver_data(pt, info->driver_data,
614                                                         size - sizeof(*info));
615                 if (ret < 0)
616                         return ret;
617
618                 info->len += ret;
619         }
620
621         strlcpy(info->obj_name, pt->parent->name, sizeof(info->obj_name));
622         strlcpy(info->driver_name, pt->parent->ops->driver_name,
623                 sizeof(info->driver_name));
624         info->status = pt->status;
625         info->timestamp_ns = ktime_to_ns(pt->timestamp);
626
627         return info->len;
628 }
629
630 static long sync_fence_ioctl_fence_info(struct sync_fence *fence,
631                                         unsigned long arg)
632 {
633         struct sync_fence_info_data *data;
634         struct list_head *pos;
635         __u32 size;
636         __u32 len = 0;
637         int ret;
638
639         if (copy_from_user(&size, (void __user *)arg, sizeof(size)))
640                 return -EFAULT;
641
642         if (size < sizeof(struct sync_fence_info_data))
643                 return -EINVAL;
644
645         if (size > 4096)
646                 size = 4096;
647
648         data = kzalloc(size, GFP_KERNEL);
649         if (data == NULL)
650                 return -ENOMEM;
651
652         strlcpy(data->name, fence->name, sizeof(data->name));
653         data->status = fence->status;
654         len = sizeof(struct sync_fence_info_data);
655
656         list_for_each(pos, &fence->pt_list_head) {
657                 struct sync_pt *pt =
658                         container_of(pos, struct sync_pt, pt_list);
659
660                 ret = sync_fill_pt_info(pt, (u8 *)data + len, size - len);
661
662                 if (ret < 0)
663                         goto out;
664
665                 len += ret;
666         }
667
668         data->len = len;
669
670         if (copy_to_user((void __user *)arg, data, len))
671                 ret = -EFAULT;
672         else
673                 ret = 0;
674
675 out:
676         kfree(data);
677
678         return ret;
679 }
680
681 static long sync_fence_ioctl(struct file *file, unsigned int cmd,
682                              unsigned long arg)
683 {
684         struct sync_fence *fence = file->private_data;
685         switch (cmd) {
686         case SYNC_IOC_WAIT:
687                 return sync_fence_ioctl_wait(fence, arg);
688
689         case SYNC_IOC_MERGE:
690                 return sync_fence_ioctl_merge(fence, arg);
691
692         case SYNC_IOC_FENCE_INFO:
693                 return sync_fence_ioctl_fence_info(fence, arg);
694
695         default:
696                 return -ENOTTY;
697         }
698 }
699
700 #ifdef CONFIG_DEBUG_FS
701 static const char *sync_status_str(int status)
702 {
703         if (status > 0)
704                 return "signaled";
705         else if (status == 0)
706                 return "active";
707         else
708                 return "error";
709 }
710
711 static void sync_print_pt(struct seq_file *s, struct sync_pt *pt, bool fence)
712 {
713         int status = pt->status;
714         seq_printf(s, "  %s%spt %s",
715                    fence ? pt->parent->name : "",
716                    fence ? "_" : "",
717                    sync_status_str(status));
718         if (pt->status) {
719                 struct timeval tv = ktime_to_timeval(pt->timestamp);
720                 seq_printf(s, "@%ld.%06ld", tv.tv_sec, tv.tv_usec);
721         }
722
723         if (pt->parent->ops->print_pt) {
724                 seq_printf(s, ": ");
725                 pt->parent->ops->print_pt(s, pt);
726         }
727
728         seq_printf(s, "\n");
729 }
730
731 static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
732 {
733         struct list_head *pos;
734         unsigned long flags;
735
736         seq_printf(s, "%s %s", obj->name, obj->ops->driver_name);
737
738         if (obj->ops->print_obj) {
739                 seq_printf(s, ": ");
740                 obj->ops->print_obj(s, obj);
741         }
742
743         seq_printf(s, "\n");
744
745         spin_lock_irqsave(&obj->child_list_lock, flags);
746         list_for_each(pos, &obj->child_list_head) {
747                 struct sync_pt *pt =
748                         container_of(pos, struct sync_pt, child_list);
749                 sync_print_pt(s, pt, false);
750         }
751         spin_unlock_irqrestore(&obj->child_list_lock, flags);
752 }
753
754 static void sync_print_fence(struct seq_file *s, struct sync_fence *fence)
755 {
756         struct list_head *pos;
757         unsigned long flags;
758
759         seq_printf(s, "%s: %s\n", fence->name, sync_status_str(fence->status));
760
761         list_for_each(pos, &fence->pt_list_head) {
762                 struct sync_pt *pt =
763                         container_of(pos, struct sync_pt, pt_list);
764                 sync_print_pt(s, pt, true);
765         }
766
767         spin_lock_irqsave(&fence->waiter_list_lock, flags);
768         list_for_each(pos, &fence->waiter_list_head) {
769                 struct sync_fence_waiter *waiter =
770                         container_of(pos, struct sync_fence_waiter,
771                                      waiter_list);
772
773                 seq_printf(s, "waiter %pF\n", waiter->callback);
774         }
775         spin_unlock_irqrestore(&fence->waiter_list_lock, flags);
776 }
777
778 static int sync_debugfs_show(struct seq_file *s, void *unused)
779 {
780         unsigned long flags;
781         struct list_head *pos;
782
783         seq_printf(s, "objs:\n--------------\n");
784
785         spin_lock_irqsave(&sync_timeline_list_lock, flags);
786         list_for_each(pos, &sync_timeline_list_head) {
787                 struct sync_timeline *obj =
788                         container_of(pos, struct sync_timeline,
789                                      sync_timeline_list);
790
791                 sync_print_obj(s, obj);
792                 seq_printf(s, "\n");
793         }
794         spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
795
796         seq_printf(s, "fences:\n--------------\n");
797
798         spin_lock_irqsave(&sync_fence_list_lock, flags);
799         list_for_each(pos, &sync_fence_list_head) {
800                 struct sync_fence *fence =
801                         container_of(pos, struct sync_fence, sync_fence_list);
802
803                 sync_print_fence(s, fence);
804                 seq_printf(s, "\n");
805         }
806         spin_unlock_irqrestore(&sync_fence_list_lock, flags);
807         return 0;
808 }
809
810 static int sync_debugfs_open(struct inode *inode, struct file *file)
811 {
812         return single_open(file, sync_debugfs_show, inode->i_private);
813 }
814
815 static const struct file_operations sync_debugfs_fops = {
816         .open           = sync_debugfs_open,
817         .read           = seq_read,
818         .llseek         = seq_lseek,
819         .release        = single_release,
820 };
821
822 static __init int sync_debugfs_init(void)
823 {
824         debugfs_create_file("sync", S_IRUGO, NULL, NULL, &sync_debugfs_fops);
825         return 0;
826 }
827
828 late_initcall(sync_debugfs_init);
829
830 #endif