xref: /openbmc/linux/drivers/gpu/drm/drm_file.c (revision 726ccdba)
1 /*
2  * \author Rickard E. (Rik) Faith <faith@valinux.com>
3  * \author Daryll Strauss <daryll@valinux.com>
4  * \author Gareth Hughes <gareth@valinux.com>
5  */
6 
7 /*
8  * Created: Mon Jan  4 08:58:31 1999 by faith@valinux.com
9  *
10  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
11  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
12  * All Rights Reserved.
13  *
14  * Permission is hereby granted, free of charge, to any person obtaining a
15  * copy of this software and associated documentation files (the "Software"),
16  * to deal in the Software without restriction, including without limitation
17  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
18  * and/or sell copies of the Software, and to permit persons to whom the
19  * Software is furnished to do so, subject to the following conditions:
20  *
21  * The above copyright notice and this permission notice (including the next
22  * paragraph) shall be included in all copies or substantial portions of the
23  * Software.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
28  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
29  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
30  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
31  * OTHER DEALINGS IN THE SOFTWARE.
32  */
33 
34 #include <linux/anon_inodes.h>
35 #include <linux/dma-fence.h>
36 #include <linux/file.h>
37 #include <linux/module.h>
38 #include <linux/pci.h>
39 #include <linux/poll.h>
40 #include <linux/slab.h>
41 
42 #include <drm/drm_client.h>
43 #include <drm/drm_drv.h>
44 #include <drm/drm_file.h>
45 #include <drm/drm_print.h>
46 
47 #include "drm_crtc_internal.h"
48 #include "drm_internal.h"
49 #include "drm_legacy.h"
50 
51 /* from BKL pushdown */
52 DEFINE_MUTEX(drm_global_mutex);
53 
54 bool drm_dev_needs_global_mutex(struct drm_device *dev)
55 {
56 	/*
57 	 * Legacy drivers rely on all kinds of BKL locking semantics, don't
58 	 * bother. They also still need BKL locking for their ioctls, so better
59 	 * safe than sorry.
60 	 */
61 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
62 		return true;
63 
64 	/*
65 	 * The deprecated ->load callback must be called after the driver is
66 	 * already registered. This means such drivers rely on the BKL to make
67 	 * sure an open can't proceed until the driver is actually fully set up.
68 	 * Similar hilarity holds for the unload callback.
69 	 */
70 	if (dev->driver->load || dev->driver->unload)
71 		return true;
72 
73 	/*
74 	 * Drivers with the lastclose callback assume that it's synchronized
75 	 * against concurrent opens, which again needs the BKL. The proper fix
76 	 * is to use the drm_client infrastructure with proper locking for each
77 	 * client.
78 	 */
79 	if (dev->driver->lastclose)
80 		return true;
81 
82 	return false;
83 }
84 
85 /**
86  * DOC: file operations
87  *
88  * Drivers must define the file operations structure that forms the DRM
89  * userspace API entry point, even though most of those operations are
90  * implemented in the DRM core. The resulting &struct file_operations must be
91  * stored in the &drm_driver.fops field. The mandatory functions are drm_open(),
92  * drm_read(), drm_ioctl() and drm_compat_ioctl() if CONFIG_COMPAT is enabled
93  * Note that drm_compat_ioctl will be NULL if CONFIG_COMPAT=n, so there's no
94  * need to sprinkle #ifdef into the code. Drivers which implement private ioctls
95  * that require 32/64 bit compatibility support must provide their own
96  * &file_operations.compat_ioctl handler that processes private ioctls and calls
97  * drm_compat_ioctl() for core ioctls.
98  *
99  * In addition drm_read() and drm_poll() provide support for DRM events. DRM
100  * events are a generic and extensible means to send asynchronous events to
101  * userspace through the file descriptor. They are used to send vblank event and
102  * page flip completions by the KMS API. But drivers can also use it for their
103  * own needs, e.g. to signal completion of rendering.
104  *
105  * For the driver-side event interface see drm_event_reserve_init() and
106  * drm_send_event() as the main starting points.
107  *
108  * The memory mapping implementation will vary depending on how the driver
109  * manages memory. Legacy drivers will use the deprecated drm_legacy_mmap()
110  * function, modern drivers should use one of the provided memory-manager
111  * specific implementations. For GEM-based drivers this is drm_gem_mmap().
112  *
113  * No other file operations are supported by the DRM userspace API. Overall the
114  * following is an example &file_operations structure::
115  *
116  *     static const example_drm_fops = {
117  *             .owner = THIS_MODULE,
118  *             .open = drm_open,
119  *             .release = drm_release,
120  *             .unlocked_ioctl = drm_ioctl,
121  *             .compat_ioctl = drm_compat_ioctl, // NULL if CONFIG_COMPAT=n
122  *             .poll = drm_poll,
123  *             .read = drm_read,
124  *             .llseek = no_llseek,
125  *             .mmap = drm_gem_mmap,
126  *     };
127  *
128  * For plain GEM based drivers there is the DEFINE_DRM_GEM_FOPS() macro, and for
129  * DMA based drivers there is the DEFINE_DRM_GEM_DMA_FOPS() macro to make this
130  * simpler.
131  *
132  * The driver's &file_operations must be stored in &drm_driver.fops.
133  *
134  * For driver-private IOCTL handling see the more detailed discussion in
135  * :ref:`IOCTL support in the userland interfaces chapter<drm_driver_ioctl>`.
136  */
137 
138 /**
139  * drm_file_alloc - allocate file context
140  * @minor: minor to allocate on
141  *
142  * This allocates a new DRM file context. It is not linked into any context and
143  * can be used by the caller freely. Note that the context keeps a pointer to
144  * @minor, so it must be freed before @minor is.
145  *
146  * RETURNS:
147  * Pointer to newly allocated context, ERR_PTR on failure.
148  */
149 struct drm_file *drm_file_alloc(struct drm_minor *minor)
150 {
151 	struct drm_device *dev = minor->dev;
152 	struct drm_file *file;
153 	int ret;
154 
155 	file = kzalloc(sizeof(*file), GFP_KERNEL);
156 	if (!file)
157 		return ERR_PTR(-ENOMEM);
158 
159 	file->pid = get_pid(task_tgid(current));
160 	file->minor = minor;
161 
162 	/* for compatibility root is always authenticated */
163 	file->authenticated = capable(CAP_SYS_ADMIN);
164 
165 	INIT_LIST_HEAD(&file->lhead);
166 	INIT_LIST_HEAD(&file->fbs);
167 	mutex_init(&file->fbs_lock);
168 	INIT_LIST_HEAD(&file->blobs);
169 	INIT_LIST_HEAD(&file->pending_event_list);
170 	INIT_LIST_HEAD(&file->event_list);
171 	init_waitqueue_head(&file->event_wait);
172 	file->event_space = 4096; /* set aside 4k for event buffer */
173 
174 	spin_lock_init(&file->master_lookup_lock);
175 	mutex_init(&file->event_read_lock);
176 
177 	if (drm_core_check_feature(dev, DRIVER_GEM))
178 		drm_gem_open(dev, file);
179 
180 	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
181 		drm_syncobj_open(file);
182 
183 	drm_prime_init_file_private(&file->prime);
184 
185 	if (dev->driver->open) {
186 		ret = dev->driver->open(dev, file);
187 		if (ret < 0)
188 			goto out_prime_destroy;
189 	}
190 
191 	return file;
192 
193 out_prime_destroy:
194 	drm_prime_destroy_file_private(&file->prime);
195 	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
196 		drm_syncobj_release(file);
197 	if (drm_core_check_feature(dev, DRIVER_GEM))
198 		drm_gem_release(dev, file);
199 	put_pid(file->pid);
200 	kfree(file);
201 
202 	return ERR_PTR(ret);
203 }
204 
205 static void drm_events_release(struct drm_file *file_priv)
206 {
207 	struct drm_device *dev = file_priv->minor->dev;
208 	struct drm_pending_event *e, *et;
209 	unsigned long flags;
210 
211 	spin_lock_irqsave(&dev->event_lock, flags);
212 
213 	/* Unlink pending events */
214 	list_for_each_entry_safe(e, et, &file_priv->pending_event_list,
215 				 pending_link) {
216 		list_del(&e->pending_link);
217 		e->file_priv = NULL;
218 	}
219 
220 	/* Remove unconsumed events */
221 	list_for_each_entry_safe(e, et, &file_priv->event_list, link) {
222 		list_del(&e->link);
223 		kfree(e);
224 	}
225 
226 	spin_unlock_irqrestore(&dev->event_lock, flags);
227 }
228 
229 /**
230  * drm_file_free - free file context
231  * @file: context to free, or NULL
232  *
233  * This destroys and deallocates a DRM file context previously allocated via
234  * drm_file_alloc(). The caller must make sure to unlink it from any contexts
235  * before calling this.
236  *
237  * If NULL is passed, this is a no-op.
238  */
239 void drm_file_free(struct drm_file *file)
240 {
241 	struct drm_device *dev;
242 
243 	if (!file)
244 		return;
245 
246 	dev = file->minor->dev;
247 
248 	drm_dbg_core(dev, "comm=\"%s\", pid=%d, dev=0x%lx, open_count=%d\n",
249 		     current->comm, task_pid_nr(current),
250 		     (long)old_encode_dev(file->minor->kdev->devt),
251 		     atomic_read(&dev->open_count));
252 
253 #ifdef CONFIG_DRM_LEGACY
254 	if (drm_core_check_feature(dev, DRIVER_LEGACY) &&
255 	    dev->driver->preclose)
256 		dev->driver->preclose(dev, file);
257 #endif
258 
259 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
260 		drm_legacy_lock_release(dev, file->filp);
261 
262 	if (drm_core_check_feature(dev, DRIVER_HAVE_DMA))
263 		drm_legacy_reclaim_buffers(dev, file);
264 
265 	drm_events_release(file);
266 
267 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
268 		drm_fb_release(file);
269 		drm_property_destroy_user_blobs(dev, file);
270 	}
271 
272 	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
273 		drm_syncobj_release(file);
274 
275 	if (drm_core_check_feature(dev, DRIVER_GEM))
276 		drm_gem_release(dev, file);
277 
278 	drm_legacy_ctxbitmap_flush(dev, file);
279 
280 	if (drm_is_primary_client(file))
281 		drm_master_release(file);
282 
283 	if (dev->driver->postclose)
284 		dev->driver->postclose(dev, file);
285 
286 	drm_prime_destroy_file_private(&file->prime);
287 
288 	WARN_ON(!list_empty(&file->event_list));
289 
290 	put_pid(file->pid);
291 	kfree(file);
292 }
293 
294 static void drm_close_helper(struct file *filp)
295 {
296 	struct drm_file *file_priv = filp->private_data;
297 	struct drm_device *dev = file_priv->minor->dev;
298 
299 	mutex_lock(&dev->filelist_mutex);
300 	list_del(&file_priv->lhead);
301 	mutex_unlock(&dev->filelist_mutex);
302 
303 	drm_file_free(file_priv);
304 }
305 
306 /*
307  * Check whether DRI will run on this CPU.
308  *
309  * \return non-zero if the DRI will run on this CPU, or zero otherwise.
310  */
311 static int drm_cpu_valid(void)
312 {
313 #if defined(__sparc__) && !defined(__sparc_v9__)
314 	return 0;		/* No cmpxchg before v9 sparc. */
315 #endif
316 	return 1;
317 }
318 
319 /*
320  * Called whenever a process opens a drm node
321  *
322  * \param filp file pointer.
323  * \param minor acquired minor-object.
324  * \return zero on success or a negative number on failure.
325  *
326  * Creates and initializes a drm_file structure for the file private data in \p
327  * filp and add it into the double linked list in \p dev.
328  */
329 int drm_open_helper(struct file *filp, struct drm_minor *minor)
330 {
331 	struct drm_device *dev = minor->dev;
332 	struct drm_file *priv;
333 	int ret;
334 
335 	if (filp->f_flags & O_EXCL)
336 		return -EBUSY;	/* No exclusive opens */
337 	if (!drm_cpu_valid())
338 		return -EINVAL;
339 	if (dev->switch_power_state != DRM_SWITCH_POWER_ON &&
340 	    dev->switch_power_state != DRM_SWITCH_POWER_DYNAMIC_OFF)
341 		return -EINVAL;
342 
343 	drm_dbg_core(dev, "comm=\"%s\", pid=%d, minor=%d\n",
344 		     current->comm, task_pid_nr(current), minor->index);
345 
346 	priv = drm_file_alloc(minor);
347 	if (IS_ERR(priv))
348 		return PTR_ERR(priv);
349 
350 	if (drm_is_primary_client(priv)) {
351 		ret = drm_master_open(priv);
352 		if (ret) {
353 			drm_file_free(priv);
354 			return ret;
355 		}
356 	}
357 
358 	filp->private_data = priv;
359 	filp->f_mode |= FMODE_UNSIGNED_OFFSET;
360 	priv->filp = filp;
361 
362 	mutex_lock(&dev->filelist_mutex);
363 	list_add(&priv->lhead, &dev->filelist);
364 	mutex_unlock(&dev->filelist_mutex);
365 
366 #ifdef CONFIG_DRM_LEGACY
367 #ifdef __alpha__
368 	/*
369 	 * Default the hose
370 	 */
371 	if (!dev->hose) {
372 		struct pci_dev *pci_dev;
373 
374 		pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
375 		if (pci_dev) {
376 			dev->hose = pci_dev->sysdata;
377 			pci_dev_put(pci_dev);
378 		}
379 		if (!dev->hose) {
380 			struct pci_bus *b = list_entry(pci_root_buses.next,
381 				struct pci_bus, node);
382 			if (b)
383 				dev->hose = b->sysdata;
384 		}
385 	}
386 #endif
387 #endif
388 
389 	return 0;
390 }
391 
392 /**
393  * drm_open - open method for DRM file
394  * @inode: device inode
395  * @filp: file pointer.
396  *
397  * This function must be used by drivers as their &file_operations.open method.
398  * It looks up the correct DRM device and instantiates all the per-file
399  * resources for it. It also calls the &drm_driver.open driver callback.
400  *
401  * RETURNS:
402  *
403  * 0 on success or negative errno value on failure.
404  */
405 int drm_open(struct inode *inode, struct file *filp)
406 {
407 	struct drm_device *dev;
408 	struct drm_minor *minor;
409 	int retcode;
410 	int need_setup = 0;
411 
412 	minor = drm_minor_acquire(iminor(inode));
413 	if (IS_ERR(minor))
414 		return PTR_ERR(minor);
415 
416 	dev = minor->dev;
417 	if (drm_dev_needs_global_mutex(dev))
418 		mutex_lock(&drm_global_mutex);
419 
420 	if (!atomic_fetch_inc(&dev->open_count))
421 		need_setup = 1;
422 
423 	/* share address_space across all char-devs of a single device */
424 	filp->f_mapping = dev->anon_inode->i_mapping;
425 
426 	retcode = drm_open_helper(filp, minor);
427 	if (retcode)
428 		goto err_undo;
429 	if (need_setup) {
430 		retcode = drm_legacy_setup(dev);
431 		if (retcode) {
432 			drm_close_helper(filp);
433 			goto err_undo;
434 		}
435 	}
436 
437 	if (drm_dev_needs_global_mutex(dev))
438 		mutex_unlock(&drm_global_mutex);
439 
440 	return 0;
441 
442 err_undo:
443 	atomic_dec(&dev->open_count);
444 	if (drm_dev_needs_global_mutex(dev))
445 		mutex_unlock(&drm_global_mutex);
446 	drm_minor_release(minor);
447 	return retcode;
448 }
449 EXPORT_SYMBOL(drm_open);
450 
451 void drm_lastclose(struct drm_device * dev)
452 {
453 	drm_dbg_core(dev, "\n");
454 
455 	if (dev->driver->lastclose)
456 		dev->driver->lastclose(dev);
457 	drm_dbg_core(dev, "driver lastclose completed\n");
458 
459 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
460 		drm_legacy_dev_reinit(dev);
461 
462 	drm_client_dev_restore(dev);
463 }
464 
465 /**
466  * drm_release - release method for DRM file
467  * @inode: device inode
468  * @filp: file pointer.
469  *
470  * This function must be used by drivers as their &file_operations.release
471  * method. It frees any resources associated with the open file, and calls the
472  * &drm_driver.postclose driver callback. If this is the last open file for the
473  * DRM device also proceeds to call the &drm_driver.lastclose driver callback.
474  *
475  * RETURNS:
476  *
477  * Always succeeds and returns 0.
478  */
479 int drm_release(struct inode *inode, struct file *filp)
480 {
481 	struct drm_file *file_priv = filp->private_data;
482 	struct drm_minor *minor = file_priv->minor;
483 	struct drm_device *dev = minor->dev;
484 
485 	if (drm_dev_needs_global_mutex(dev))
486 		mutex_lock(&drm_global_mutex);
487 
488 	drm_dbg_core(dev, "open_count = %d\n", atomic_read(&dev->open_count));
489 
490 	drm_close_helper(filp);
491 
492 	if (atomic_dec_and_test(&dev->open_count))
493 		drm_lastclose(dev);
494 
495 	if (drm_dev_needs_global_mutex(dev))
496 		mutex_unlock(&drm_global_mutex);
497 
498 	drm_minor_release(minor);
499 
500 	return 0;
501 }
502 EXPORT_SYMBOL(drm_release);
503 
504 /**
505  * drm_release_noglobal - release method for DRM file
506  * @inode: device inode
507  * @filp: file pointer.
508  *
509  * This function may be used by drivers as their &file_operations.release
510  * method. It frees any resources associated with the open file prior to taking
511  * the drm_global_mutex, which then calls the &drm_driver.postclose driver
512  * callback. If this is the last open file for the DRM device also proceeds to
513  * call the &drm_driver.lastclose driver callback.
514  *
515  * RETURNS:
516  *
517  * Always succeeds and returns 0.
518  */
519 int drm_release_noglobal(struct inode *inode, struct file *filp)
520 {
521 	struct drm_file *file_priv = filp->private_data;
522 	struct drm_minor *minor = file_priv->minor;
523 	struct drm_device *dev = minor->dev;
524 
525 	drm_close_helper(filp);
526 
527 	if (atomic_dec_and_mutex_lock(&dev->open_count, &drm_global_mutex)) {
528 		drm_lastclose(dev);
529 		mutex_unlock(&drm_global_mutex);
530 	}
531 
532 	drm_minor_release(minor);
533 
534 	return 0;
535 }
536 EXPORT_SYMBOL(drm_release_noglobal);
537 
538 /**
539  * drm_read - read method for DRM file
540  * @filp: file pointer
541  * @buffer: userspace destination pointer for the read
542  * @count: count in bytes to read
543  * @offset: offset to read
544  *
545  * This function must be used by drivers as their &file_operations.read
546  * method if they use DRM events for asynchronous signalling to userspace.
547  * Since events are used by the KMS API for vblank and page flip completion this
548  * means all modern display drivers must use it.
549  *
550  * @offset is ignored, DRM events are read like a pipe. Polling support is
551  * provided by drm_poll().
552  *
553  * This function will only ever read a full event. Therefore userspace must
554  * supply a big enough buffer to fit any event to ensure forward progress. Since
555  * the maximum event space is currently 4K it's recommended to just use that for
556  * safety.
557  *
558  * RETURNS:
559  *
560  * Number of bytes read (always aligned to full events, and can be 0) or a
561  * negative error code on failure.
562  */
563 ssize_t drm_read(struct file *filp, char __user *buffer,
564 		 size_t count, loff_t *offset)
565 {
566 	struct drm_file *file_priv = filp->private_data;
567 	struct drm_device *dev = file_priv->minor->dev;
568 	ssize_t ret;
569 
570 	ret = mutex_lock_interruptible(&file_priv->event_read_lock);
571 	if (ret)
572 		return ret;
573 
574 	for (;;) {
575 		struct drm_pending_event *e = NULL;
576 
577 		spin_lock_irq(&dev->event_lock);
578 		if (!list_empty(&file_priv->event_list)) {
579 			e = list_first_entry(&file_priv->event_list,
580 					struct drm_pending_event, link);
581 			file_priv->event_space += e->event->length;
582 			list_del(&e->link);
583 		}
584 		spin_unlock_irq(&dev->event_lock);
585 
586 		if (e == NULL) {
587 			if (ret)
588 				break;
589 
590 			if (filp->f_flags & O_NONBLOCK) {
591 				ret = -EAGAIN;
592 				break;
593 			}
594 
595 			mutex_unlock(&file_priv->event_read_lock);
596 			ret = wait_event_interruptible(file_priv->event_wait,
597 						       !list_empty(&file_priv->event_list));
598 			if (ret >= 0)
599 				ret = mutex_lock_interruptible(&file_priv->event_read_lock);
600 			if (ret)
601 				return ret;
602 		} else {
603 			unsigned length = e->event->length;
604 
605 			if (length > count - ret) {
606 put_back_event:
607 				spin_lock_irq(&dev->event_lock);
608 				file_priv->event_space -= length;
609 				list_add(&e->link, &file_priv->event_list);
610 				spin_unlock_irq(&dev->event_lock);
611 				wake_up_interruptible_poll(&file_priv->event_wait,
612 					EPOLLIN | EPOLLRDNORM);
613 				break;
614 			}
615 
616 			if (copy_to_user(buffer + ret, e->event, length)) {
617 				if (ret == 0)
618 					ret = -EFAULT;
619 				goto put_back_event;
620 			}
621 
622 			ret += length;
623 			kfree(e);
624 		}
625 	}
626 	mutex_unlock(&file_priv->event_read_lock);
627 
628 	return ret;
629 }
630 EXPORT_SYMBOL(drm_read);
631 
632 /**
633  * drm_poll - poll method for DRM file
634  * @filp: file pointer
635  * @wait: poll waiter table
636  *
637  * This function must be used by drivers as their &file_operations.read method
638  * if they use DRM events for asynchronous signalling to userspace.  Since
639  * events are used by the KMS API for vblank and page flip completion this means
640  * all modern display drivers must use it.
641  *
642  * See also drm_read().
643  *
644  * RETURNS:
645  *
646  * Mask of POLL flags indicating the current status of the file.
647  */
648 __poll_t drm_poll(struct file *filp, struct poll_table_struct *wait)
649 {
650 	struct drm_file *file_priv = filp->private_data;
651 	__poll_t mask = 0;
652 
653 	poll_wait(filp, &file_priv->event_wait, wait);
654 
655 	if (!list_empty(&file_priv->event_list))
656 		mask |= EPOLLIN | EPOLLRDNORM;
657 
658 	return mask;
659 }
660 EXPORT_SYMBOL(drm_poll);
661 
662 /**
663  * drm_event_reserve_init_locked - init a DRM event and reserve space for it
664  * @dev: DRM device
665  * @file_priv: DRM file private data
666  * @p: tracking structure for the pending event
667  * @e: actual event data to deliver to userspace
668  *
669  * This function prepares the passed in event for eventual delivery. If the event
670  * doesn't get delivered (because the IOCTL fails later on, before queuing up
671  * anything) then the even must be cancelled and freed using
672  * drm_event_cancel_free(). Successfully initialized events should be sent out
673  * using drm_send_event() or drm_send_event_locked() to signal completion of the
674  * asynchronous event to userspace.
675  *
676  * If callers embedded @p into a larger structure it must be allocated with
677  * kmalloc and @p must be the first member element.
678  *
679  * This is the locked version of drm_event_reserve_init() for callers which
680  * already hold &drm_device.event_lock.
681  *
682  * RETURNS:
683  *
684  * 0 on success or a negative error code on failure.
685  */
686 int drm_event_reserve_init_locked(struct drm_device *dev,
687 				  struct drm_file *file_priv,
688 				  struct drm_pending_event *p,
689 				  struct drm_event *e)
690 {
691 	if (file_priv->event_space < e->length)
692 		return -ENOMEM;
693 
694 	file_priv->event_space -= e->length;
695 
696 	p->event = e;
697 	list_add(&p->pending_link, &file_priv->pending_event_list);
698 	p->file_priv = file_priv;
699 
700 	return 0;
701 }
702 EXPORT_SYMBOL(drm_event_reserve_init_locked);
703 
704 /**
705  * drm_event_reserve_init - init a DRM event and reserve space for it
706  * @dev: DRM device
707  * @file_priv: DRM file private data
708  * @p: tracking structure for the pending event
709  * @e: actual event data to deliver to userspace
710  *
711  * This function prepares the passed in event for eventual delivery. If the event
712  * doesn't get delivered (because the IOCTL fails later on, before queuing up
713  * anything) then the even must be cancelled and freed using
714  * drm_event_cancel_free(). Successfully initialized events should be sent out
715  * using drm_send_event() or drm_send_event_locked() to signal completion of the
716  * asynchronous event to userspace.
717  *
718  * If callers embedded @p into a larger structure it must be allocated with
719  * kmalloc and @p must be the first member element.
720  *
721  * Callers which already hold &drm_device.event_lock should use
722  * drm_event_reserve_init_locked() instead.
723  *
724  * RETURNS:
725  *
726  * 0 on success or a negative error code on failure.
727  */
728 int drm_event_reserve_init(struct drm_device *dev,
729 			   struct drm_file *file_priv,
730 			   struct drm_pending_event *p,
731 			   struct drm_event *e)
732 {
733 	unsigned long flags;
734 	int ret;
735 
736 	spin_lock_irqsave(&dev->event_lock, flags);
737 	ret = drm_event_reserve_init_locked(dev, file_priv, p, e);
738 	spin_unlock_irqrestore(&dev->event_lock, flags);
739 
740 	return ret;
741 }
742 EXPORT_SYMBOL(drm_event_reserve_init);
743 
744 /**
745  * drm_event_cancel_free - free a DRM event and release its space
746  * @dev: DRM device
747  * @p: tracking structure for the pending event
748  *
749  * This function frees the event @p initialized with drm_event_reserve_init()
750  * and releases any allocated space. It is used to cancel an event when the
751  * nonblocking operation could not be submitted and needed to be aborted.
752  */
753 void drm_event_cancel_free(struct drm_device *dev,
754 			   struct drm_pending_event *p)
755 {
756 	unsigned long flags;
757 
758 	spin_lock_irqsave(&dev->event_lock, flags);
759 	if (p->file_priv) {
760 		p->file_priv->event_space += p->event->length;
761 		list_del(&p->pending_link);
762 	}
763 	spin_unlock_irqrestore(&dev->event_lock, flags);
764 
765 	if (p->fence)
766 		dma_fence_put(p->fence);
767 
768 	kfree(p);
769 }
770 EXPORT_SYMBOL(drm_event_cancel_free);
771 
772 static void drm_send_event_helper(struct drm_device *dev,
773 			   struct drm_pending_event *e, ktime_t timestamp)
774 {
775 	assert_spin_locked(&dev->event_lock);
776 
777 	if (e->completion) {
778 		complete_all(e->completion);
779 		e->completion_release(e->completion);
780 		e->completion = NULL;
781 	}
782 
783 	if (e->fence) {
784 		if (timestamp)
785 			dma_fence_signal_timestamp(e->fence, timestamp);
786 		else
787 			dma_fence_signal(e->fence);
788 		dma_fence_put(e->fence);
789 	}
790 
791 	if (!e->file_priv) {
792 		kfree(e);
793 		return;
794 	}
795 
796 	list_del(&e->pending_link);
797 	list_add_tail(&e->link,
798 		      &e->file_priv->event_list);
799 	wake_up_interruptible_poll(&e->file_priv->event_wait,
800 		EPOLLIN | EPOLLRDNORM);
801 }
802 
803 /**
804  * drm_send_event_timestamp_locked - send DRM event to file descriptor
805  * @dev: DRM device
806  * @e: DRM event to deliver
807  * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
808  * time domain
809  *
810  * This function sends the event @e, initialized with drm_event_reserve_init(),
811  * to its associated userspace DRM file. Callers must already hold
812  * &drm_device.event_lock.
813  *
814  * Note that the core will take care of unlinking and disarming events when the
815  * corresponding DRM file is closed. Drivers need not worry about whether the
816  * DRM file for this event still exists and can call this function upon
817  * completion of the asynchronous work unconditionally.
818  */
819 void drm_send_event_timestamp_locked(struct drm_device *dev,
820 				     struct drm_pending_event *e, ktime_t timestamp)
821 {
822 	drm_send_event_helper(dev, e, timestamp);
823 }
824 EXPORT_SYMBOL(drm_send_event_timestamp_locked);
825 
826 /**
827  * drm_send_event_locked - send DRM event to file descriptor
828  * @dev: DRM device
829  * @e: DRM event to deliver
830  *
831  * This function sends the event @e, initialized with drm_event_reserve_init(),
832  * to its associated userspace DRM file. Callers must already hold
833  * &drm_device.event_lock, see drm_send_event() for the unlocked version.
834  *
835  * Note that the core will take care of unlinking and disarming events when the
836  * corresponding DRM file is closed. Drivers need not worry about whether the
837  * DRM file for this event still exists and can call this function upon
838  * completion of the asynchronous work unconditionally.
839  */
840 void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
841 {
842 	drm_send_event_helper(dev, e, 0);
843 }
844 EXPORT_SYMBOL(drm_send_event_locked);
845 
846 /**
847  * drm_send_event - send DRM event to file descriptor
848  * @dev: DRM device
849  * @e: DRM event to deliver
850  *
851  * This function sends the event @e, initialized with drm_event_reserve_init(),
852  * to its associated userspace DRM file. This function acquires
853  * &drm_device.event_lock, see drm_send_event_locked() for callers which already
854  * hold this lock.
855  *
856  * Note that the core will take care of unlinking and disarming events when the
857  * corresponding DRM file is closed. Drivers need not worry about whether the
858  * DRM file for this event still exists and can call this function upon
859  * completion of the asynchronous work unconditionally.
860  */
861 void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
862 {
863 	unsigned long irqflags;
864 
865 	spin_lock_irqsave(&dev->event_lock, irqflags);
866 	drm_send_event_helper(dev, e, 0);
867 	spin_unlock_irqrestore(&dev->event_lock, irqflags);
868 }
869 EXPORT_SYMBOL(drm_send_event);
870 
871 /**
872  * mock_drm_getfile - Create a new struct file for the drm device
873  * @minor: drm minor to wrap (e.g. #drm_device.primary)
874  * @flags: file creation mode (O_RDWR etc)
875  *
876  * This create a new struct file that wraps a DRM file context around a
877  * DRM minor. This mimicks userspace opening e.g. /dev/dri/card0, but without
878  * invoking userspace. The struct file may be operated on using its f_op
879  * (the drm_device.driver.fops) to mimick userspace operations, or be supplied
880  * to userspace facing functions as an internal/anonymous client.
881  *
882  * RETURNS:
883  * Pointer to newly created struct file, ERR_PTR on failure.
884  */
885 struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags)
886 {
887 	struct drm_device *dev = minor->dev;
888 	struct drm_file *priv;
889 	struct file *file;
890 
891 	priv = drm_file_alloc(minor);
892 	if (IS_ERR(priv))
893 		return ERR_CAST(priv);
894 
895 	file = anon_inode_getfile("drm", dev->driver->fops, priv, flags);
896 	if (IS_ERR(file)) {
897 		drm_file_free(priv);
898 		return file;
899 	}
900 
901 	/* Everyone shares a single global address space */
902 	file->f_mapping = dev->anon_inode->i_mapping;
903 
904 	drm_dev_get(dev);
905 	priv->filp = file;
906 
907 	return file;
908 }
909 EXPORT_SYMBOL_FOR_TESTS_ONLY(mock_drm_getfile);
910