xref: /linux/drivers/gpu/drm/drm_syncobj.c (revision c748a6d77c06a78651030e17da6beb278a1c9470)
1 /*
2  * Copyright 2017 Red Hat
3  * Parts ported from amdgpu (fence wait code).
4  * Copyright 2016 Advanced Micro Devices, Inc.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
23  * IN THE SOFTWARE.
24  *
25  * Authors:
26  *
27  */
28 
29 /**
30  * DOC: Overview
31  *
32  * DRM synchronisation objects (syncobj, see struct &drm_syncobj) provide a
33  * container for a synchronization primitive which can be used by userspace
34  * to explicitly synchronize GPU commands, can be shared between userspace
35  * processes, and can be shared between different DRM drivers.
36  * Their primary use-case is to implement Vulkan fences and semaphores.
37  * The syncobj userspace API provides ioctls for several operations:
38  *
39  *  - Creation and destruction of syncobjs
40  *  - Import and export of syncobjs to/from a syncobj file descriptor
41  *  - Import and export a syncobj's underlying fence to/from a sync file
42  *  - Reset a syncobj (set its fence to NULL)
43  *  - Signal a syncobj (set a trivially signaled fence)
44  *  - Wait for a syncobj's fence to appear and be signaled
45  *
46  * The syncobj userspace API also provides operations to manipulate a syncobj
47  * in terms of a timeline of struct &dma_fence_chain rather than a single
48  * struct &dma_fence, through the following operations:
49  *
50  *   - Signal a given point on the timeline
51  *   - Wait for a given point to appear and/or be signaled
52  *   - Import and export from/to a given point of a timeline
53  *
54  * At it's core, a syncobj is simply a wrapper around a pointer to a struct
55  * &dma_fence which may be NULL.
56  * When a syncobj is first created, its pointer is either NULL or a pointer
57  * to an already signaled fence depending on whether the
58  * &DRM_SYNCOBJ_CREATE_SIGNALED flag is passed to
59  * &DRM_IOCTL_SYNCOBJ_CREATE.
60  *
61  * If the syncobj is considered as a binary (its state is either signaled or
62  * unsignaled) primitive, when GPU work is enqueued in a DRM driver to signal
63  * the syncobj, the syncobj's fence is replaced with a fence which will be
64  * signaled by the completion of that work.
65  * If the syncobj is considered as a timeline primitive, when GPU work is
66  * enqueued in a DRM driver to signal the a given point of the syncobj, a new
67  * struct &dma_fence_chain pointing to the DRM driver's fence and also
68  * pointing to the previous fence that was in the syncobj. The new struct
69  * &dma_fence_chain fence replace the syncobj's fence and will be signaled by
70  * completion of the DRM driver's work and also any work associated with the
71  * fence previously in the syncobj.
72  *
73  * When GPU work which waits on a syncobj is enqueued in a DRM driver, at the
74  * time the work is enqueued, it waits on the syncobj's fence before
75  * submitting the work to hardware. That fence is either :
76  *
77  *    - The syncobj's current fence if the syncobj is considered as a binary
78  *      primitive.
79  *    - The struct &dma_fence associated with a given point if the syncobj is
80  *      considered as a timeline primitive.
81  *
82  * If the syncobj's fence is NULL or not present in the syncobj's timeline,
83  * the enqueue operation is expected to fail.
84  *
85  * With binary syncobj, all manipulation of the syncobjs's fence happens in
86  * terms of the current fence at the time the ioctl is called by userspace
87  * regardless of whether that operation is an immediate host-side operation
88  * (signal or reset) or or an operation which is enqueued in some driver
89  * queue. &DRM_IOCTL_SYNCOBJ_RESET and &DRM_IOCTL_SYNCOBJ_SIGNAL can be used
90  * to manipulate a syncobj from the host by resetting its pointer to NULL or
91  * setting its pointer to a fence which is already signaled.
92  *
93  * With a timeline syncobj, all manipulation of the synobj's fence happens in
94  * terms of a u64 value referring to point in the timeline. See
95  * dma_fence_chain_find_seqno() to see how a given point is found in the
96  * timeline.
97  *
98  * Note that applications should be careful to always use timeline set of
99  * ioctl() when dealing with syncobj considered as timeline. Using a binary
100  * set of ioctl() with a syncobj considered as timeline could result incorrect
101  * synchronization. The use of binary syncobj is supported through the
102  * timeline set of ioctl() by using a point value of 0, this will reproduce
103  * the behavior of the binary set of ioctl() (for example replace the
104  * syncobj's fence when signaling).
105  *
106  *
107  * Host-side wait on syncobjs
108  * --------------------------
109  *
110  * &DRM_IOCTL_SYNCOBJ_WAIT takes an array of syncobj handles and does a
111  * host-side wait on all of the syncobj fences simultaneously.
112  * If &DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL is set, the wait ioctl will wait on
113  * all of the syncobj fences to be signaled before it returns.
114  * Otherwise, it returns once at least one syncobj fence has been signaled
115  * and the index of a signaled fence is written back to the client.
116  *
117  * Unlike the enqueued GPU work dependencies which fail if they see a NULL
118  * fence in a syncobj, if &DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT is set,
119  * the host-side wait will first wait for the syncobj to receive a non-NULL
120  * fence and then wait on that fence.
121  * If &DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT is not set and any one of the
122  * syncobjs in the array has a NULL fence, -EINVAL will be returned.
123  * Assuming the syncobj starts off with a NULL fence, this allows a client
124  * to do a host wait in one thread (or process) which waits on GPU work
125  * submitted in another thread (or process) without having to manually
126  * synchronize between the two.
127  * This requirement is inherited from the Vulkan fence API.
128  *
129  * Similarly, &DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT takes an array of syncobj
130  * handles as well as an array of u64 points and does a host-side wait on all
131  * of syncobj fences at the given points simultaneously.
132  *
133  * &DRM_IOCTL_SYNCOBJ_TIMELINE_WAIT also adds the ability to wait for a given
134  * fence to materialize on the timeline without waiting for the fence to be
135  * signaled by using the &DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE flag. This
136  * requirement is inherited from the wait-before-signal behavior required by
137  * the Vulkan timeline semaphore API.
138  *
139  * Alternatively, &DRM_IOCTL_SYNCOBJ_EVENTFD can be used to wait without
140  * blocking: an eventfd will be signaled when the syncobj is. This is useful to
141  * integrate the wait in an event loop.
142  *
143  *
144  * Import/export of syncobjs
145  * -------------------------
146  *
147  * &DRM_IOCTL_SYNCOBJ_FD_TO_HANDLE and &DRM_IOCTL_SYNCOBJ_HANDLE_TO_FD
148  * provide two mechanisms for import/export of syncobjs.
149  *
150  * The first lets the client import or export an entire syncobj to a file
151  * descriptor.
152  * These fd's are opaque and have no other use case, except passing the
153  * syncobj between processes.
154  * All exported file descriptors and any syncobj handles created as a
155  * result of importing those file descriptors own a reference to the
156  * same underlying struct &drm_syncobj and the syncobj can be used
157  * persistently across all the processes with which it is shared.
158  * The syncobj is freed only once the last reference is dropped.
159  * Unlike dma-buf, importing a syncobj creates a new handle (with its own
160  * reference) for every import instead of de-duplicating.
161  * The primary use-case of this persistent import/export is for shared
162  * Vulkan fences and semaphores.
163  *
164  * The second import/export mechanism, which is indicated by
165  * &DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE or
166  * &DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE lets the client
167  * import/export the syncobj's current fence from/to a &sync_file.
168  * When a syncobj is exported to a sync file, that sync file wraps the
169  * sycnobj's fence at the time of export and any later signal or reset
170  * operations on the syncobj will not affect the exported sync file.
171  * When a sync file is imported into a syncobj, the syncobj's fence is set
172  * to the fence wrapped by that sync file.
173  * Because sync files are immutable, resetting or signaling the syncobj
174  * will not affect any sync files whose fences have been imported into the
175  * syncobj.
176  *
177  *
178  * Import/export of timeline points in timeline syncobjs
179  * -----------------------------------------------------
180  *
181  * &DRM_IOCTL_SYNCOBJ_TRANSFER provides a mechanism to transfer a struct
182  * &dma_fence_chain of a syncobj at a given u64 point to another u64 point
183  * into another syncobj.
184  *
185  * Note that if you want to transfer a struct &dma_fence_chain from a given
186  * point on a timeline syncobj from/into a binary syncobj, you can use the
187  * point 0 to mean take/replace the fence in the syncobj.
188  */
189 
190 #include <linux/anon_inodes.h>
191 #include <linux/dma-fence-unwrap.h>
192 #include <linux/eventfd.h>
193 #include <linux/file.h>
194 #include <linux/fs.h>
195 #include <linux/sched/signal.h>
196 #include <linux/sync_file.h>
197 #include <linux/uaccess.h>
198 
199 #include <drm/drm.h>
200 #include <drm/drm_drv.h>
201 #include <drm/drm_file.h>
202 #include <drm/drm_gem.h>
203 #include <drm/drm_print.h>
204 #include <drm/drm_syncobj.h>
205 #include <drm/drm_utils.h>
206 
207 #include "drm_internal.h"
208 
209 struct syncobj_wait_entry {
210 	struct list_head node;
211 	struct task_struct *task;
212 	struct dma_fence *fence;
213 	struct dma_fence_cb fence_cb;
214 	u64    point;
215 };
216 
217 static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj,
218 				      struct syncobj_wait_entry *wait);
219 
220 struct syncobj_eventfd_entry {
221 	struct list_head node;
222 	struct dma_fence *fence;
223 	struct dma_fence_cb fence_cb;
224 	struct drm_syncobj *syncobj;
225 	struct eventfd_ctx *ev_fd_ctx;
226 	u64 point;
227 	u32 flags;
228 };
229 
230 static void
231 syncobj_eventfd_entry_func(struct drm_syncobj *syncobj,
232 			   struct syncobj_eventfd_entry *entry);
233 
234 /**
235  * drm_syncobj_find - lookup and reference a sync object.
236  * @file_private: drm file private pointer
237  * @handle: sync object handle to lookup.
238  *
239  * Returns a reference to the syncobj pointed to by handle or NULL. The
240  * reference must be released by calling drm_syncobj_put().
241  */
242 struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
243 				     u32 handle)
244 {
245 	struct drm_syncobj *syncobj;
246 
247 	spin_lock(&file_private->syncobj_table_lock);
248 
249 	/* Check if we currently have a reference on the object */
250 	syncobj = idr_find(&file_private->syncobj_idr, handle);
251 	if (syncobj)
252 		drm_syncobj_get(syncobj);
253 
254 	spin_unlock(&file_private->syncobj_table_lock);
255 
256 	return syncobj;
257 }
258 EXPORT_SYMBOL(drm_syncobj_find);
259 
260 static void drm_syncobj_fence_add_wait(struct drm_syncobj *syncobj,
261 				       struct syncobj_wait_entry *wait)
262 {
263 	struct dma_fence *fence;
264 
265 	if (wait->fence)
266 		return;
267 
268 	spin_lock(&syncobj->lock);
269 	/* We've already tried once to get a fence and failed.  Now that we
270 	 * have the lock, try one more time just to be sure we don't add a
271 	 * callback when a fence has already been set.
272 	 */
273 	fence = dma_fence_get(rcu_dereference_protected(syncobj->fence, 1));
274 	if (!fence || dma_fence_chain_find_seqno(&fence, wait->point)) {
275 		dma_fence_put(fence);
276 		list_add_tail(&wait->node, &syncobj->cb_list);
277 	} else if (!fence) {
278 		wait->fence = dma_fence_get_stub();
279 	} else {
280 		wait->fence = fence;
281 	}
282 	spin_unlock(&syncobj->lock);
283 }
284 
285 static void drm_syncobj_remove_wait(struct drm_syncobj *syncobj,
286 				    struct syncobj_wait_entry *wait)
287 {
288 	if (!wait->node.next)
289 		return;
290 
291 	spin_lock(&syncobj->lock);
292 	list_del_init(&wait->node);
293 	spin_unlock(&syncobj->lock);
294 }
295 
296 static void
297 syncobj_eventfd_entry_free(struct syncobj_eventfd_entry *entry)
298 {
299 	eventfd_ctx_put(entry->ev_fd_ctx);
300 	dma_fence_put(entry->fence);
301 	/* This happens either inside the syncobj lock, or after the node has
302 	 * already been removed from the list.
303 	 */
304 	list_del(&entry->node);
305 	kfree(entry);
306 }
307 
308 static void
309 drm_syncobj_add_eventfd(struct drm_syncobj *syncobj,
310 			struct syncobj_eventfd_entry *entry)
311 {
312 	spin_lock(&syncobj->lock);
313 	list_add_tail(&entry->node, &syncobj->ev_fd_list);
314 	syncobj_eventfd_entry_func(syncobj, entry);
315 	spin_unlock(&syncobj->lock);
316 }
317 
318 /**
319  * drm_syncobj_add_point - add new timeline point to the syncobj
320  * @syncobj: sync object to add timeline point do
321  * @chain: chain node to use to add the point
322  * @fence: fence to encapsulate in the chain node
323  * @point: sequence number to use for the point
324  *
325  * Add the chain node as new timeline point to the syncobj.
326  */
327 void drm_syncobj_add_point(struct drm_syncobj *syncobj,
328 			   struct dma_fence_chain *chain,
329 			   struct dma_fence *fence,
330 			   uint64_t point)
331 {
332 	struct syncobj_wait_entry *wait_cur, *wait_tmp;
333 	struct syncobj_eventfd_entry *ev_fd_cur, *ev_fd_tmp;
334 	struct dma_fence *prev;
335 
336 	dma_fence_get(fence);
337 
338 	spin_lock(&syncobj->lock);
339 
340 	prev = drm_syncobj_fence_get(syncobj);
341 	/* You are adding an unorder point to timeline, which could cause payload returned from query_ioctl is 0! */
342 	if (prev && prev->seqno >= point)
343 		DRM_DEBUG("You are adding an unorder point to timeline!\n");
344 	dma_fence_chain_init(chain, prev, fence, point);
345 	rcu_assign_pointer(syncobj->fence, &chain->base);
346 
347 	list_for_each_entry_safe(wait_cur, wait_tmp, &syncobj->cb_list, node)
348 		syncobj_wait_syncobj_func(syncobj, wait_cur);
349 	list_for_each_entry_safe(ev_fd_cur, ev_fd_tmp, &syncobj->ev_fd_list, node)
350 		syncobj_eventfd_entry_func(syncobj, ev_fd_cur);
351 	spin_unlock(&syncobj->lock);
352 
353 	/* Walk the chain once to trigger garbage collection */
354 	dma_fence_chain_for_each(fence, prev);
355 	dma_fence_put(prev);
356 }
357 EXPORT_SYMBOL(drm_syncobj_add_point);
358 
359 /**
360  * drm_syncobj_replace_fence - replace fence in a sync object.
361  * @syncobj: Sync object to replace fence in
362  * @fence: fence to install in sync file.
363  *
364  * This replaces the fence on a sync object.
365  */
366 void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,
367 			       struct dma_fence *fence)
368 {
369 	struct dma_fence *old_fence;
370 	struct syncobj_wait_entry *wait_cur, *wait_tmp;
371 	struct syncobj_eventfd_entry *ev_fd_cur, *ev_fd_tmp;
372 
373 	if (fence)
374 		dma_fence_get(fence);
375 
376 	spin_lock(&syncobj->lock);
377 
378 	old_fence = rcu_dereference_protected(syncobj->fence,
379 					      lockdep_is_held(&syncobj->lock));
380 	rcu_assign_pointer(syncobj->fence, fence);
381 
382 	if (fence != old_fence) {
383 		list_for_each_entry_safe(wait_cur, wait_tmp, &syncobj->cb_list, node)
384 			syncobj_wait_syncobj_func(syncobj, wait_cur);
385 		list_for_each_entry_safe(ev_fd_cur, ev_fd_tmp, &syncobj->ev_fd_list, node)
386 			syncobj_eventfd_entry_func(syncobj, ev_fd_cur);
387 	}
388 
389 	spin_unlock(&syncobj->lock);
390 
391 	dma_fence_put(old_fence);
392 }
393 EXPORT_SYMBOL(drm_syncobj_replace_fence);
394 
395 /**
396  * drm_syncobj_assign_null_handle - assign a stub fence to the sync object
397  * @syncobj: sync object to assign the fence on
398  *
399  * Assign a already signaled stub fence to the sync object.
400  */
401 static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
402 {
403 	struct dma_fence *fence = dma_fence_allocate_private_stub(ktime_get());
404 
405 	if (!fence)
406 		return -ENOMEM;
407 
408 	drm_syncobj_replace_fence(syncobj, fence);
409 	dma_fence_put(fence);
410 	return 0;
411 }
412 
413 /* 5s default for wait submission */
414 #define DRM_SYNCOBJ_WAIT_FOR_SUBMIT_TIMEOUT 5000000000ULL
415 /**
416  * drm_syncobj_find_fence - lookup and reference the fence in a sync object
417  * @file_private: drm file private pointer
418  * @handle: sync object handle to lookup.
419  * @point: timeline point
420  * @flags: DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT or not
421  * @fence: out parameter for the fence
422  *
423  * This is just a convenience function that combines drm_syncobj_find() and
424  * drm_syncobj_fence_get().
425  *
426  * Returns 0 on success or a negative error value on failure. On success @fence
427  * contains a reference to the fence, which must be released by calling
428  * dma_fence_put().
429  */
430 int drm_syncobj_find_fence(struct drm_file *file_private,
431 			   u32 handle, u64 point, u64 flags,
432 			   struct dma_fence **fence)
433 {
434 	struct drm_syncobj *syncobj = drm_syncobj_find(file_private, handle);
435 	struct syncobj_wait_entry wait;
436 	u64 timeout = nsecs_to_jiffies64(DRM_SYNCOBJ_WAIT_FOR_SUBMIT_TIMEOUT);
437 	int ret;
438 
439 	if (!syncobj)
440 		return -ENOENT;
441 
442 	/* Waiting for userspace with locks help is illegal cause that can
443 	 * trivial deadlock with page faults for example. Make lockdep complain
444 	 * about it early on.
445 	 */
446 	if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
447 		might_sleep();
448 		lockdep_assert_none_held_once();
449 	}
450 
451 	*fence = drm_syncobj_fence_get(syncobj);
452 
453 	if (*fence) {
454 		ret = dma_fence_chain_find_seqno(fence, point);
455 		if (!ret) {
456 			/* If the requested seqno is already signaled
457 			 * drm_syncobj_find_fence may return a NULL
458 			 * fence. To make sure the recipient gets
459 			 * signalled, use a new fence instead.
460 			 */
461 			if (!*fence)
462 				*fence = dma_fence_get_stub();
463 
464 			goto out;
465 		}
466 		dma_fence_put(*fence);
467 	} else {
468 		ret = -EINVAL;
469 	}
470 
471 	if (!(flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT))
472 		goto out;
473 
474 	memset(&wait, 0, sizeof(wait));
475 	wait.task = current;
476 	wait.point = point;
477 	drm_syncobj_fence_add_wait(syncobj, &wait);
478 
479 	do {
480 		set_current_state(TASK_INTERRUPTIBLE);
481 		if (wait.fence) {
482 			ret = 0;
483 			break;
484 		}
485                 if (timeout == 0) {
486                         ret = -ETIME;
487                         break;
488                 }
489 
490 		if (signal_pending(current)) {
491 			ret = -ERESTARTSYS;
492 			break;
493 		}
494 
495                 timeout = schedule_timeout(timeout);
496 	} while (1);
497 
498 	__set_current_state(TASK_RUNNING);
499 	*fence = wait.fence;
500 
501 	if (wait.node.next)
502 		drm_syncobj_remove_wait(syncobj, &wait);
503 
504 out:
505 	drm_syncobj_put(syncobj);
506 
507 	return ret;
508 }
509 EXPORT_SYMBOL(drm_syncobj_find_fence);
510 
511 /**
512  * drm_syncobj_free - free a sync object.
513  * @kref: kref to free.
514  *
515  * Only to be called from kref_put in drm_syncobj_put.
516  */
517 void drm_syncobj_free(struct kref *kref)
518 {
519 	struct drm_syncobj *syncobj = container_of(kref,
520 						   struct drm_syncobj,
521 						   refcount);
522 	struct syncobj_eventfd_entry *ev_fd_cur, *ev_fd_tmp;
523 
524 	drm_syncobj_replace_fence(syncobj, NULL);
525 
526 	list_for_each_entry_safe(ev_fd_cur, ev_fd_tmp, &syncobj->ev_fd_list, node)
527 		syncobj_eventfd_entry_free(ev_fd_cur);
528 
529 	kfree(syncobj);
530 }
531 EXPORT_SYMBOL(drm_syncobj_free);
532 
533 /**
534  * drm_syncobj_create - create a new syncobj
535  * @out_syncobj: returned syncobj
536  * @flags: DRM_SYNCOBJ_* flags
537  * @fence: if non-NULL, the syncobj will represent this fence
538  *
539  * This is the first function to create a sync object. After creating, drivers
540  * probably want to make it available to userspace, either through
541  * drm_syncobj_get_handle() or drm_syncobj_get_fd().
542  *
543  * Returns 0 on success or a negative error value on failure.
544  */
545 int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags,
546 		       struct dma_fence *fence)
547 {
548 	int ret;
549 	struct drm_syncobj *syncobj;
550 
551 	syncobj = kzalloc(sizeof(struct drm_syncobj), GFP_KERNEL);
552 	if (!syncobj)
553 		return -ENOMEM;
554 
555 	kref_init(&syncobj->refcount);
556 	INIT_LIST_HEAD(&syncobj->cb_list);
557 	INIT_LIST_HEAD(&syncobj->ev_fd_list);
558 	spin_lock_init(&syncobj->lock);
559 
560 	if (flags & DRM_SYNCOBJ_CREATE_SIGNALED) {
561 		ret = drm_syncobj_assign_null_handle(syncobj);
562 		if (ret < 0) {
563 			drm_syncobj_put(syncobj);
564 			return ret;
565 		}
566 	}
567 
568 	if (fence)
569 		drm_syncobj_replace_fence(syncobj, fence);
570 
571 	*out_syncobj = syncobj;
572 	return 0;
573 }
574 EXPORT_SYMBOL(drm_syncobj_create);
575 
576 /**
577  * drm_syncobj_get_handle - get a handle from a syncobj
578  * @file_private: drm file private pointer
579  * @syncobj: Sync object to export
580  * @handle: out parameter with the new handle
581  *
582  * Exports a sync object created with drm_syncobj_create() as a handle on
583  * @file_private to userspace.
584  *
585  * Returns 0 on success or a negative error value on failure.
586  */
587 int drm_syncobj_get_handle(struct drm_file *file_private,
588 			   struct drm_syncobj *syncobj, u32 *handle)
589 {
590 	int ret;
591 
592 	/* take a reference to put in the idr */
593 	drm_syncobj_get(syncobj);
594 
595 	idr_preload(GFP_KERNEL);
596 	spin_lock(&file_private->syncobj_table_lock);
597 	ret = idr_alloc(&file_private->syncobj_idr, syncobj, 1, 0, GFP_NOWAIT);
598 	spin_unlock(&file_private->syncobj_table_lock);
599 
600 	idr_preload_end();
601 
602 	if (ret < 0) {
603 		drm_syncobj_put(syncobj);
604 		return ret;
605 	}
606 
607 	*handle = ret;
608 	return 0;
609 }
610 EXPORT_SYMBOL(drm_syncobj_get_handle);
611 
612 static int drm_syncobj_create_as_handle(struct drm_file *file_private,
613 					u32 *handle, uint32_t flags)
614 {
615 	int ret;
616 	struct drm_syncobj *syncobj;
617 
618 	ret = drm_syncobj_create(&syncobj, flags, NULL);
619 	if (ret)
620 		return ret;
621 
622 	ret = drm_syncobj_get_handle(file_private, syncobj, handle);
623 	drm_syncobj_put(syncobj);
624 	return ret;
625 }
626 
627 static int drm_syncobj_destroy(struct drm_file *file_private,
628 			       u32 handle)
629 {
630 	struct drm_syncobj *syncobj;
631 
632 	spin_lock(&file_private->syncobj_table_lock);
633 	syncobj = idr_remove(&file_private->syncobj_idr, handle);
634 	spin_unlock(&file_private->syncobj_table_lock);
635 
636 	if (!syncobj)
637 		return -EINVAL;
638 
639 	drm_syncobj_put(syncobj);
640 	return 0;
641 }
642 
643 static int drm_syncobj_file_release(struct inode *inode, struct file *file)
644 {
645 	struct drm_syncobj *syncobj = file->private_data;
646 
647 	drm_syncobj_put(syncobj);
648 	return 0;
649 }
650 
651 static const struct file_operations drm_syncobj_file_fops = {
652 	.release = drm_syncobj_file_release,
653 };
654 
655 /**
656  * drm_syncobj_get_fd - get a file descriptor from a syncobj
657  * @syncobj: Sync object to export
658  * @p_fd: out parameter with the new file descriptor
659  *
660  * Exports a sync object created with drm_syncobj_create() as a file descriptor.
661  *
662  * Returns 0 on success or a negative error value on failure.
663  */
664 int drm_syncobj_get_fd(struct drm_syncobj *syncobj, int *p_fd)
665 {
666 	struct file *file;
667 	int fd;
668 
669 	fd = get_unused_fd_flags(O_CLOEXEC);
670 	if (fd < 0)
671 		return fd;
672 
673 	file = anon_inode_getfile("syncobj_file",
674 				  &drm_syncobj_file_fops,
675 				  syncobj, 0);
676 	if (IS_ERR(file)) {
677 		put_unused_fd(fd);
678 		return PTR_ERR(file);
679 	}
680 
681 	drm_syncobj_get(syncobj);
682 	fd_install(fd, file);
683 
684 	*p_fd = fd;
685 	return 0;
686 }
687 EXPORT_SYMBOL(drm_syncobj_get_fd);
688 
689 static int drm_syncobj_handle_to_fd(struct drm_file *file_private,
690 				    u32 handle, int *p_fd)
691 {
692 	struct drm_syncobj *syncobj = drm_syncobj_find(file_private, handle);
693 	int ret;
694 
695 	if (!syncobj)
696 		return -EINVAL;
697 
698 	ret = drm_syncobj_get_fd(syncobj, p_fd);
699 	drm_syncobj_put(syncobj);
700 	return ret;
701 }
702 
703 static int drm_syncobj_fd_to_handle(struct drm_file *file_private,
704 				    int fd, u32 *handle)
705 {
706 	struct drm_syncobj *syncobj;
707 	struct fd f = fdget(fd);
708 	int ret;
709 
710 	if (!f.file)
711 		return -EINVAL;
712 
713 	if (f.file->f_op != &drm_syncobj_file_fops) {
714 		fdput(f);
715 		return -EINVAL;
716 	}
717 
718 	/* take a reference to put in the idr */
719 	syncobj = f.file->private_data;
720 	drm_syncobj_get(syncobj);
721 
722 	idr_preload(GFP_KERNEL);
723 	spin_lock(&file_private->syncobj_table_lock);
724 	ret = idr_alloc(&file_private->syncobj_idr, syncobj, 1, 0, GFP_NOWAIT);
725 	spin_unlock(&file_private->syncobj_table_lock);
726 	idr_preload_end();
727 
728 	if (ret > 0) {
729 		*handle = ret;
730 		ret = 0;
731 	} else
732 		drm_syncobj_put(syncobj);
733 
734 	fdput(f);
735 	return ret;
736 }
737 
738 static int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,
739 					      int fd, int handle)
740 {
741 	struct dma_fence *fence = sync_file_get_fence(fd);
742 	struct drm_syncobj *syncobj;
743 
744 	if (!fence)
745 		return -EINVAL;
746 
747 	syncobj = drm_syncobj_find(file_private, handle);
748 	if (!syncobj) {
749 		dma_fence_put(fence);
750 		return -ENOENT;
751 	}
752 
753 	drm_syncobj_replace_fence(syncobj, fence);
754 	dma_fence_put(fence);
755 	drm_syncobj_put(syncobj);
756 	return 0;
757 }
758 
759 static int drm_syncobj_export_sync_file(struct drm_file *file_private,
760 					int handle, int *p_fd)
761 {
762 	int ret;
763 	struct dma_fence *fence;
764 	struct sync_file *sync_file;
765 	int fd = get_unused_fd_flags(O_CLOEXEC);
766 
767 	if (fd < 0)
768 		return fd;
769 
770 	ret = drm_syncobj_find_fence(file_private, handle, 0, 0, &fence);
771 	if (ret)
772 		goto err_put_fd;
773 
774 	sync_file = sync_file_create(fence);
775 
776 	dma_fence_put(fence);
777 
778 	if (!sync_file) {
779 		ret = -EINVAL;
780 		goto err_put_fd;
781 	}
782 
783 	fd_install(fd, sync_file->file);
784 
785 	*p_fd = fd;
786 	return 0;
787 err_put_fd:
788 	put_unused_fd(fd);
789 	return ret;
790 }
791 /**
792  * drm_syncobj_open - initializes syncobj file-private structures at devnode open time
793  * @file_private: drm file-private structure to set up
794  *
795  * Called at device open time, sets up the structure for handling refcounting
796  * of sync objects.
797  */
798 void
799 drm_syncobj_open(struct drm_file *file_private)
800 {
801 	idr_init_base(&file_private->syncobj_idr, 1);
802 	spin_lock_init(&file_private->syncobj_table_lock);
803 }
804 
805 static int
806 drm_syncobj_release_handle(int id, void *ptr, void *data)
807 {
808 	struct drm_syncobj *syncobj = ptr;
809 
810 	drm_syncobj_put(syncobj);
811 	return 0;
812 }
813 
814 /**
815  * drm_syncobj_release - release file-private sync object resources
816  * @file_private: drm file-private structure to clean up
817  *
818  * Called at close time when the filp is going away.
819  *
820  * Releases any remaining references on objects by this filp.
821  */
822 void
823 drm_syncobj_release(struct drm_file *file_private)
824 {
825 	idr_for_each(&file_private->syncobj_idr,
826 		     &drm_syncobj_release_handle, file_private);
827 	idr_destroy(&file_private->syncobj_idr);
828 }
829 
830 int
831 drm_syncobj_create_ioctl(struct drm_device *dev, void *data,
832 			 struct drm_file *file_private)
833 {
834 	struct drm_syncobj_create *args = data;
835 
836 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
837 		return -EOPNOTSUPP;
838 
839 	/* no valid flags yet */
840 	if (args->flags & ~DRM_SYNCOBJ_CREATE_SIGNALED)
841 		return -EINVAL;
842 
843 	return drm_syncobj_create_as_handle(file_private,
844 					    &args->handle, args->flags);
845 }
846 
847 int
848 drm_syncobj_destroy_ioctl(struct drm_device *dev, void *data,
849 			  struct drm_file *file_private)
850 {
851 	struct drm_syncobj_destroy *args = data;
852 
853 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
854 		return -EOPNOTSUPP;
855 
856 	/* make sure padding is empty */
857 	if (args->pad)
858 		return -EINVAL;
859 	return drm_syncobj_destroy(file_private, args->handle);
860 }
861 
862 int
863 drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
864 				   struct drm_file *file_private)
865 {
866 	struct drm_syncobj_handle *args = data;
867 
868 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
869 		return -EOPNOTSUPP;
870 
871 	if (args->pad)
872 		return -EINVAL;
873 
874 	if (args->flags != 0 &&
875 	    args->flags != DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE)
876 		return -EINVAL;
877 
878 	if (args->flags & DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE)
879 		return drm_syncobj_export_sync_file(file_private, args->handle,
880 						    &args->fd);
881 
882 	return drm_syncobj_handle_to_fd(file_private, args->handle,
883 					&args->fd);
884 }
885 
886 int
887 drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
888 				   struct drm_file *file_private)
889 {
890 	struct drm_syncobj_handle *args = data;
891 
892 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
893 		return -EOPNOTSUPP;
894 
895 	if (args->pad)
896 		return -EINVAL;
897 
898 	if (args->flags != 0 &&
899 	    args->flags != DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE)
900 		return -EINVAL;
901 
902 	if (args->flags & DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE)
903 		return drm_syncobj_import_sync_file_fence(file_private,
904 							  args->fd,
905 							  args->handle);
906 
907 	return drm_syncobj_fd_to_handle(file_private, args->fd,
908 					&args->handle);
909 }
910 
911 static int drm_syncobj_transfer_to_timeline(struct drm_file *file_private,
912 					    struct drm_syncobj_transfer *args)
913 {
914 	struct drm_syncobj *timeline_syncobj = NULL;
915 	struct dma_fence *fence, *tmp;
916 	struct dma_fence_chain *chain;
917 	int ret;
918 
919 	timeline_syncobj = drm_syncobj_find(file_private, args->dst_handle);
920 	if (!timeline_syncobj) {
921 		return -ENOENT;
922 	}
923 	ret = drm_syncobj_find_fence(file_private, args->src_handle,
924 				     args->src_point, args->flags,
925 				     &tmp);
926 	if (ret)
927 		goto err_put_timeline;
928 
929 	fence = dma_fence_unwrap_merge(tmp);
930 	dma_fence_put(tmp);
931 	if (!fence) {
932 		ret = -ENOMEM;
933 		goto err_put_timeline;
934 	}
935 
936 	chain = dma_fence_chain_alloc();
937 	if (!chain) {
938 		ret = -ENOMEM;
939 		goto err_free_fence;
940 	}
941 
942 	drm_syncobj_add_point(timeline_syncobj, chain, fence, args->dst_point);
943 err_free_fence:
944 	dma_fence_put(fence);
945 err_put_timeline:
946 	drm_syncobj_put(timeline_syncobj);
947 
948 	return ret;
949 }
950 
951 static int
952 drm_syncobj_transfer_to_binary(struct drm_file *file_private,
953 			       struct drm_syncobj_transfer *args)
954 {
955 	struct drm_syncobj *binary_syncobj = NULL;
956 	struct dma_fence *fence;
957 	int ret;
958 
959 	binary_syncobj = drm_syncobj_find(file_private, args->dst_handle);
960 	if (!binary_syncobj)
961 		return -ENOENT;
962 	ret = drm_syncobj_find_fence(file_private, args->src_handle,
963 				     args->src_point, args->flags, &fence);
964 	if (ret)
965 		goto err;
966 	drm_syncobj_replace_fence(binary_syncobj, fence);
967 	dma_fence_put(fence);
968 err:
969 	drm_syncobj_put(binary_syncobj);
970 
971 	return ret;
972 }
973 int
974 drm_syncobj_transfer_ioctl(struct drm_device *dev, void *data,
975 			   struct drm_file *file_private)
976 {
977 	struct drm_syncobj_transfer *args = data;
978 	int ret;
979 
980 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
981 		return -EOPNOTSUPP;
982 
983 	if (args->pad)
984 		return -EINVAL;
985 
986 	if (args->dst_point)
987 		ret = drm_syncobj_transfer_to_timeline(file_private, args);
988 	else
989 		ret = drm_syncobj_transfer_to_binary(file_private, args);
990 
991 	return ret;
992 }
993 
994 static void syncobj_wait_fence_func(struct dma_fence *fence,
995 				    struct dma_fence_cb *cb)
996 {
997 	struct syncobj_wait_entry *wait =
998 		container_of(cb, struct syncobj_wait_entry, fence_cb);
999 
1000 	wake_up_process(wait->task);
1001 }
1002 
1003 static void syncobj_wait_syncobj_func(struct drm_syncobj *syncobj,
1004 				      struct syncobj_wait_entry *wait)
1005 {
1006 	struct dma_fence *fence;
1007 
1008 	/* This happens inside the syncobj lock */
1009 	fence = rcu_dereference_protected(syncobj->fence,
1010 					  lockdep_is_held(&syncobj->lock));
1011 	dma_fence_get(fence);
1012 	if (!fence || dma_fence_chain_find_seqno(&fence, wait->point)) {
1013 		dma_fence_put(fence);
1014 		return;
1015 	} else if (!fence) {
1016 		wait->fence = dma_fence_get_stub();
1017 	} else {
1018 		wait->fence = fence;
1019 	}
1020 
1021 	wake_up_process(wait->task);
1022 	list_del_init(&wait->node);
1023 }
1024 
1025 static signed long drm_syncobj_array_wait_timeout(struct drm_syncobj **syncobjs,
1026 						  void __user *user_points,
1027 						  uint32_t count,
1028 						  uint32_t flags,
1029 						  signed long timeout,
1030 						  uint32_t *idx)
1031 {
1032 	struct syncobj_wait_entry *entries;
1033 	struct dma_fence *fence;
1034 	uint64_t *points;
1035 	uint32_t signaled_count, i;
1036 
1037 	if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT)
1038 		lockdep_assert_none_held_once();
1039 
1040 	points = kmalloc_array(count, sizeof(*points), GFP_KERNEL);
1041 	if (points == NULL)
1042 		return -ENOMEM;
1043 
1044 	if (!user_points) {
1045 		memset(points, 0, count * sizeof(uint64_t));
1046 
1047 	} else if (copy_from_user(points, user_points,
1048 				  sizeof(uint64_t) * count)) {
1049 		timeout = -EFAULT;
1050 		goto err_free_points;
1051 	}
1052 
1053 	entries = kcalloc(count, sizeof(*entries), GFP_KERNEL);
1054 	if (!entries) {
1055 		timeout = -ENOMEM;
1056 		goto err_free_points;
1057 	}
1058 	/* Walk the list of sync objects and initialize entries.  We do
1059 	 * this up-front so that we can properly return -EINVAL if there is
1060 	 * a syncobj with a missing fence and then never have the chance of
1061 	 * returning -EINVAL again.
1062 	 */
1063 	signaled_count = 0;
1064 	for (i = 0; i < count; ++i) {
1065 		struct dma_fence *fence;
1066 
1067 		entries[i].task = current;
1068 		entries[i].point = points[i];
1069 		fence = drm_syncobj_fence_get(syncobjs[i]);
1070 		if (!fence || dma_fence_chain_find_seqno(&fence, points[i])) {
1071 			dma_fence_put(fence);
1072 			if (flags & (DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT |
1073 				     DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE)) {
1074 				continue;
1075 			} else {
1076 				timeout = -EINVAL;
1077 				goto cleanup_entries;
1078 			}
1079 		}
1080 
1081 		if (fence)
1082 			entries[i].fence = fence;
1083 		else
1084 			entries[i].fence = dma_fence_get_stub();
1085 
1086 		if ((flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) ||
1087 		    dma_fence_is_signaled(entries[i].fence)) {
1088 			if (signaled_count == 0 && idx)
1089 				*idx = i;
1090 			signaled_count++;
1091 		}
1092 	}
1093 
1094 	if (signaled_count == count ||
1095 	    (signaled_count > 0 &&
1096 	     !(flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL)))
1097 		goto cleanup_entries;
1098 
1099 	/* There's a very annoying laxness in the dma_fence API here, in
1100 	 * that backends are not required to automatically report when a
1101 	 * fence is signaled prior to fence->ops->enable_signaling() being
1102 	 * called.  So here if we fail to match signaled_count, we need to
1103 	 * fallthough and try a 0 timeout wait!
1104 	 */
1105 
1106 	if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT) {
1107 		for (i = 0; i < count; ++i)
1108 			drm_syncobj_fence_add_wait(syncobjs[i], &entries[i]);
1109 	}
1110 
1111 	do {
1112 		set_current_state(TASK_INTERRUPTIBLE);
1113 
1114 		signaled_count = 0;
1115 		for (i = 0; i < count; ++i) {
1116 			fence = entries[i].fence;
1117 			if (!fence)
1118 				continue;
1119 
1120 			if ((flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) ||
1121 			    dma_fence_is_signaled(fence) ||
1122 			    (!entries[i].fence_cb.func &&
1123 			     dma_fence_add_callback(fence,
1124 						    &entries[i].fence_cb,
1125 						    syncobj_wait_fence_func))) {
1126 				/* The fence has been signaled */
1127 				if (flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL) {
1128 					signaled_count++;
1129 				} else {
1130 					if (idx)
1131 						*idx = i;
1132 					goto done_waiting;
1133 				}
1134 			}
1135 		}
1136 
1137 		if (signaled_count == count)
1138 			goto done_waiting;
1139 
1140 		if (timeout == 0) {
1141 			timeout = -ETIME;
1142 			goto done_waiting;
1143 		}
1144 
1145 		if (signal_pending(current)) {
1146 			timeout = -ERESTARTSYS;
1147 			goto done_waiting;
1148 		}
1149 
1150 		timeout = schedule_timeout(timeout);
1151 	} while (1);
1152 
1153 done_waiting:
1154 	__set_current_state(TASK_RUNNING);
1155 
1156 cleanup_entries:
1157 	for (i = 0; i < count; ++i) {
1158 		drm_syncobj_remove_wait(syncobjs[i], &entries[i]);
1159 		if (entries[i].fence_cb.func)
1160 			dma_fence_remove_callback(entries[i].fence,
1161 						  &entries[i].fence_cb);
1162 		dma_fence_put(entries[i].fence);
1163 	}
1164 	kfree(entries);
1165 
1166 err_free_points:
1167 	kfree(points);
1168 
1169 	return timeout;
1170 }
1171 
1172 /**
1173  * drm_timeout_abs_to_jiffies - calculate jiffies timeout from absolute value
1174  *
1175  * @timeout_nsec: timeout nsec component in ns, 0 for poll
1176  *
1177  * Calculate the timeout in jiffies from an absolute time in sec/nsec.
1178  */
1179 signed long drm_timeout_abs_to_jiffies(int64_t timeout_nsec)
1180 {
1181 	ktime_t abs_timeout, now;
1182 	u64 timeout_ns, timeout_jiffies64;
1183 
1184 	/* make 0 timeout means poll - absolute 0 doesn't seem valid */
1185 	if (timeout_nsec == 0)
1186 		return 0;
1187 
1188 	abs_timeout = ns_to_ktime(timeout_nsec);
1189 	now = ktime_get();
1190 
1191 	if (!ktime_after(abs_timeout, now))
1192 		return 0;
1193 
1194 	timeout_ns = ktime_to_ns(ktime_sub(abs_timeout, now));
1195 
1196 	timeout_jiffies64 = nsecs_to_jiffies64(timeout_ns);
1197 	/*  clamp timeout to avoid infinite timeout */
1198 	if (timeout_jiffies64 >= MAX_SCHEDULE_TIMEOUT - 1)
1199 		return MAX_SCHEDULE_TIMEOUT - 1;
1200 
1201 	return timeout_jiffies64 + 1;
1202 }
1203 EXPORT_SYMBOL(drm_timeout_abs_to_jiffies);
1204 
1205 static int drm_syncobj_array_wait(struct drm_device *dev,
1206 				  struct drm_file *file_private,
1207 				  struct drm_syncobj_wait *wait,
1208 				  struct drm_syncobj_timeline_wait *timeline_wait,
1209 				  struct drm_syncobj **syncobjs, bool timeline)
1210 {
1211 	signed long timeout = 0;
1212 	uint32_t first = ~0;
1213 
1214 	if (!timeline) {
1215 		timeout = drm_timeout_abs_to_jiffies(wait->timeout_nsec);
1216 		timeout = drm_syncobj_array_wait_timeout(syncobjs,
1217 							 NULL,
1218 							 wait->count_handles,
1219 							 wait->flags,
1220 							 timeout, &first);
1221 		if (timeout < 0)
1222 			return timeout;
1223 		wait->first_signaled = first;
1224 	} else {
1225 		timeout = drm_timeout_abs_to_jiffies(timeline_wait->timeout_nsec);
1226 		timeout = drm_syncobj_array_wait_timeout(syncobjs,
1227 							 u64_to_user_ptr(timeline_wait->points),
1228 							 timeline_wait->count_handles,
1229 							 timeline_wait->flags,
1230 							 timeout, &first);
1231 		if (timeout < 0)
1232 			return timeout;
1233 		timeline_wait->first_signaled = first;
1234 	}
1235 	return 0;
1236 }
1237 
1238 static int drm_syncobj_array_find(struct drm_file *file_private,
1239 				  void __user *user_handles,
1240 				  uint32_t count_handles,
1241 				  struct drm_syncobj ***syncobjs_out)
1242 {
1243 	uint32_t i, *handles;
1244 	struct drm_syncobj **syncobjs;
1245 	int ret;
1246 
1247 	handles = kmalloc_array(count_handles, sizeof(*handles), GFP_KERNEL);
1248 	if (handles == NULL)
1249 		return -ENOMEM;
1250 
1251 	if (copy_from_user(handles, user_handles,
1252 			   sizeof(uint32_t) * count_handles)) {
1253 		ret = -EFAULT;
1254 		goto err_free_handles;
1255 	}
1256 
1257 	syncobjs = kmalloc_array(count_handles, sizeof(*syncobjs), GFP_KERNEL);
1258 	if (syncobjs == NULL) {
1259 		ret = -ENOMEM;
1260 		goto err_free_handles;
1261 	}
1262 
1263 	for (i = 0; i < count_handles; i++) {
1264 		syncobjs[i] = drm_syncobj_find(file_private, handles[i]);
1265 		if (!syncobjs[i]) {
1266 			ret = -ENOENT;
1267 			goto err_put_syncobjs;
1268 		}
1269 	}
1270 
1271 	kfree(handles);
1272 	*syncobjs_out = syncobjs;
1273 	return 0;
1274 
1275 err_put_syncobjs:
1276 	while (i-- > 0)
1277 		drm_syncobj_put(syncobjs[i]);
1278 	kfree(syncobjs);
1279 err_free_handles:
1280 	kfree(handles);
1281 
1282 	return ret;
1283 }
1284 
1285 static void drm_syncobj_array_free(struct drm_syncobj **syncobjs,
1286 				   uint32_t count)
1287 {
1288 	uint32_t i;
1289 
1290 	for (i = 0; i < count; i++)
1291 		drm_syncobj_put(syncobjs[i]);
1292 	kfree(syncobjs);
1293 }
1294 
1295 int
1296 drm_syncobj_wait_ioctl(struct drm_device *dev, void *data,
1297 		       struct drm_file *file_private)
1298 {
1299 	struct drm_syncobj_wait *args = data;
1300 	struct drm_syncobj **syncobjs;
1301 	int ret = 0;
1302 
1303 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
1304 		return -EOPNOTSUPP;
1305 
1306 	if (args->flags & ~(DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL |
1307 			    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT))
1308 		return -EINVAL;
1309 
1310 	if (args->count_handles == 0)
1311 		return -EINVAL;
1312 
1313 	ret = drm_syncobj_array_find(file_private,
1314 				     u64_to_user_ptr(args->handles),
1315 				     args->count_handles,
1316 				     &syncobjs);
1317 	if (ret < 0)
1318 		return ret;
1319 
1320 	ret = drm_syncobj_array_wait(dev, file_private,
1321 				     args, NULL, syncobjs, false);
1322 
1323 	drm_syncobj_array_free(syncobjs, args->count_handles);
1324 
1325 	return ret;
1326 }
1327 
1328 int
1329 drm_syncobj_timeline_wait_ioctl(struct drm_device *dev, void *data,
1330 				struct drm_file *file_private)
1331 {
1332 	struct drm_syncobj_timeline_wait *args = data;
1333 	struct drm_syncobj **syncobjs;
1334 	int ret = 0;
1335 
1336 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
1337 		return -EOPNOTSUPP;
1338 
1339 	if (args->flags & ~(DRM_SYNCOBJ_WAIT_FLAGS_WAIT_ALL |
1340 			    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT |
1341 			    DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE))
1342 		return -EINVAL;
1343 
1344 	if (args->count_handles == 0)
1345 		return -EINVAL;
1346 
1347 	ret = drm_syncobj_array_find(file_private,
1348 				     u64_to_user_ptr(args->handles),
1349 				     args->count_handles,
1350 				     &syncobjs);
1351 	if (ret < 0)
1352 		return ret;
1353 
1354 	ret = drm_syncobj_array_wait(dev, file_private,
1355 				     NULL, args, syncobjs, true);
1356 
1357 	drm_syncobj_array_free(syncobjs, args->count_handles);
1358 
1359 	return ret;
1360 }
1361 
1362 static void syncobj_eventfd_entry_fence_func(struct dma_fence *fence,
1363 					     struct dma_fence_cb *cb)
1364 {
1365 	struct syncobj_eventfd_entry *entry =
1366 		container_of(cb, struct syncobj_eventfd_entry, fence_cb);
1367 
1368 	eventfd_signal(entry->ev_fd_ctx, 1);
1369 	syncobj_eventfd_entry_free(entry);
1370 }
1371 
1372 static void
1373 syncobj_eventfd_entry_func(struct drm_syncobj *syncobj,
1374 			   struct syncobj_eventfd_entry *entry)
1375 {
1376 	int ret;
1377 	struct dma_fence *fence;
1378 
1379 	/* This happens inside the syncobj lock */
1380 	fence = dma_fence_get(rcu_dereference_protected(syncobj->fence, 1));
1381 	ret = dma_fence_chain_find_seqno(&fence, entry->point);
1382 	if (ret != 0 || !fence) {
1383 		dma_fence_put(fence);
1384 		return;
1385 	}
1386 
1387 	list_del_init(&entry->node);
1388 	entry->fence = fence;
1389 
1390 	if (entry->flags & DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE) {
1391 		eventfd_signal(entry->ev_fd_ctx, 1);
1392 		syncobj_eventfd_entry_free(entry);
1393 	} else {
1394 		ret = dma_fence_add_callback(fence, &entry->fence_cb,
1395 					     syncobj_eventfd_entry_fence_func);
1396 		if (ret == -ENOENT) {
1397 			eventfd_signal(entry->ev_fd_ctx, 1);
1398 			syncobj_eventfd_entry_free(entry);
1399 		}
1400 	}
1401 }
1402 
1403 int
1404 drm_syncobj_eventfd_ioctl(struct drm_device *dev, void *data,
1405 			  struct drm_file *file_private)
1406 {
1407 	struct drm_syncobj_eventfd *args = data;
1408 	struct drm_syncobj *syncobj;
1409 	struct eventfd_ctx *ev_fd_ctx;
1410 	struct syncobj_eventfd_entry *entry;
1411 
1412 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
1413 		return -EOPNOTSUPP;
1414 
1415 	if (args->flags & ~DRM_SYNCOBJ_WAIT_FLAGS_WAIT_AVAILABLE)
1416 		return -EINVAL;
1417 
1418 	if (args->pad)
1419 		return -EINVAL;
1420 
1421 	syncobj = drm_syncobj_find(file_private, args->handle);
1422 	if (!syncobj)
1423 		return -ENOENT;
1424 
1425 	ev_fd_ctx = eventfd_ctx_fdget(args->fd);
1426 	if (IS_ERR(ev_fd_ctx))
1427 		return PTR_ERR(ev_fd_ctx);
1428 
1429 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
1430 	if (!entry) {
1431 		eventfd_ctx_put(ev_fd_ctx);
1432 		return -ENOMEM;
1433 	}
1434 	entry->syncobj = syncobj;
1435 	entry->ev_fd_ctx = ev_fd_ctx;
1436 	entry->point = args->point;
1437 	entry->flags = args->flags;
1438 
1439 	drm_syncobj_add_eventfd(syncobj, entry);
1440 	drm_syncobj_put(syncobj);
1441 
1442 	return 0;
1443 }
1444 
1445 int
1446 drm_syncobj_reset_ioctl(struct drm_device *dev, void *data,
1447 			struct drm_file *file_private)
1448 {
1449 	struct drm_syncobj_array *args = data;
1450 	struct drm_syncobj **syncobjs;
1451 	uint32_t i;
1452 	int ret;
1453 
1454 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
1455 		return -EOPNOTSUPP;
1456 
1457 	if (args->pad != 0)
1458 		return -EINVAL;
1459 
1460 	if (args->count_handles == 0)
1461 		return -EINVAL;
1462 
1463 	ret = drm_syncobj_array_find(file_private,
1464 				     u64_to_user_ptr(args->handles),
1465 				     args->count_handles,
1466 				     &syncobjs);
1467 	if (ret < 0)
1468 		return ret;
1469 
1470 	for (i = 0; i < args->count_handles; i++)
1471 		drm_syncobj_replace_fence(syncobjs[i], NULL);
1472 
1473 	drm_syncobj_array_free(syncobjs, args->count_handles);
1474 
1475 	return 0;
1476 }
1477 
1478 int
1479 drm_syncobj_signal_ioctl(struct drm_device *dev, void *data,
1480 			 struct drm_file *file_private)
1481 {
1482 	struct drm_syncobj_array *args = data;
1483 	struct drm_syncobj **syncobjs;
1484 	uint32_t i;
1485 	int ret;
1486 
1487 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
1488 		return -EOPNOTSUPP;
1489 
1490 	if (args->pad != 0)
1491 		return -EINVAL;
1492 
1493 	if (args->count_handles == 0)
1494 		return -EINVAL;
1495 
1496 	ret = drm_syncobj_array_find(file_private,
1497 				     u64_to_user_ptr(args->handles),
1498 				     args->count_handles,
1499 				     &syncobjs);
1500 	if (ret < 0)
1501 		return ret;
1502 
1503 	for (i = 0; i < args->count_handles; i++) {
1504 		ret = drm_syncobj_assign_null_handle(syncobjs[i]);
1505 		if (ret < 0)
1506 			break;
1507 	}
1508 
1509 	drm_syncobj_array_free(syncobjs, args->count_handles);
1510 
1511 	return ret;
1512 }
1513 
1514 int
1515 drm_syncobj_timeline_signal_ioctl(struct drm_device *dev, void *data,
1516 				  struct drm_file *file_private)
1517 {
1518 	struct drm_syncobj_timeline_array *args = data;
1519 	struct drm_syncobj **syncobjs;
1520 	struct dma_fence_chain **chains;
1521 	uint64_t *points;
1522 	uint32_t i, j;
1523 	int ret;
1524 
1525 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
1526 		return -EOPNOTSUPP;
1527 
1528 	if (args->flags != 0)
1529 		return -EINVAL;
1530 
1531 	if (args->count_handles == 0)
1532 		return -EINVAL;
1533 
1534 	ret = drm_syncobj_array_find(file_private,
1535 				     u64_to_user_ptr(args->handles),
1536 				     args->count_handles,
1537 				     &syncobjs);
1538 	if (ret < 0)
1539 		return ret;
1540 
1541 	points = kmalloc_array(args->count_handles, sizeof(*points),
1542 			       GFP_KERNEL);
1543 	if (!points) {
1544 		ret = -ENOMEM;
1545 		goto out;
1546 	}
1547 	if (!u64_to_user_ptr(args->points)) {
1548 		memset(points, 0, args->count_handles * sizeof(uint64_t));
1549 	} else if (copy_from_user(points, u64_to_user_ptr(args->points),
1550 				  sizeof(uint64_t) * args->count_handles)) {
1551 		ret = -EFAULT;
1552 		goto err_points;
1553 	}
1554 
1555 	chains = kmalloc_array(args->count_handles, sizeof(void *), GFP_KERNEL);
1556 	if (!chains) {
1557 		ret = -ENOMEM;
1558 		goto err_points;
1559 	}
1560 	for (i = 0; i < args->count_handles; i++) {
1561 		chains[i] = dma_fence_chain_alloc();
1562 		if (!chains[i]) {
1563 			for (j = 0; j < i; j++)
1564 				dma_fence_chain_free(chains[j]);
1565 			ret = -ENOMEM;
1566 			goto err_chains;
1567 		}
1568 	}
1569 
1570 	for (i = 0; i < args->count_handles; i++) {
1571 		struct dma_fence *fence = dma_fence_get_stub();
1572 
1573 		drm_syncobj_add_point(syncobjs[i], chains[i],
1574 				      fence, points[i]);
1575 		dma_fence_put(fence);
1576 	}
1577 err_chains:
1578 	kfree(chains);
1579 err_points:
1580 	kfree(points);
1581 out:
1582 	drm_syncobj_array_free(syncobjs, args->count_handles);
1583 
1584 	return ret;
1585 }
1586 
1587 int drm_syncobj_query_ioctl(struct drm_device *dev, void *data,
1588 			    struct drm_file *file_private)
1589 {
1590 	struct drm_syncobj_timeline_array *args = data;
1591 	struct drm_syncobj **syncobjs;
1592 	uint64_t __user *points = u64_to_user_ptr(args->points);
1593 	uint32_t i;
1594 	int ret;
1595 
1596 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
1597 		return -EOPNOTSUPP;
1598 
1599 	if (args->flags & ~DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED)
1600 		return -EINVAL;
1601 
1602 	if (args->count_handles == 0)
1603 		return -EINVAL;
1604 
1605 	ret = drm_syncobj_array_find(file_private,
1606 				     u64_to_user_ptr(args->handles),
1607 				     args->count_handles,
1608 				     &syncobjs);
1609 	if (ret < 0)
1610 		return ret;
1611 
1612 	for (i = 0; i < args->count_handles; i++) {
1613 		struct dma_fence_chain *chain;
1614 		struct dma_fence *fence;
1615 		uint64_t point;
1616 
1617 		fence = drm_syncobj_fence_get(syncobjs[i]);
1618 		chain = to_dma_fence_chain(fence);
1619 		if (chain) {
1620 			struct dma_fence *iter, *last_signaled =
1621 				dma_fence_get(fence);
1622 
1623 			if (args->flags &
1624 			    DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED) {
1625 				point = fence->seqno;
1626 			} else {
1627 				dma_fence_chain_for_each(iter, fence) {
1628 					if (iter->context != fence->context) {
1629 						dma_fence_put(iter);
1630 						/* It is most likely that timeline has
1631 						* unorder points. */
1632 						break;
1633 					}
1634 					dma_fence_put(last_signaled);
1635 					last_signaled = dma_fence_get(iter);
1636 				}
1637 				point = dma_fence_is_signaled(last_signaled) ?
1638 					last_signaled->seqno :
1639 					to_dma_fence_chain(last_signaled)->prev_seqno;
1640 			}
1641 			dma_fence_put(last_signaled);
1642 		} else {
1643 			point = 0;
1644 		}
1645 		dma_fence_put(fence);
1646 		ret = copy_to_user(&points[i], &point, sizeof(uint64_t));
1647 		ret = ret ? -EFAULT : 0;
1648 		if (ret)
1649 			break;
1650 	}
1651 	drm_syncobj_array_free(syncobjs, args->count_handles);
1652 
1653 	return ret;
1654 }
1655