xref: /linux/drivers/gpu/drm/drm_file.c (revision 55d0969c451159cff86949b38c39171cab962069)
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 #include <linux/vga_switcheroo.h>
42 
43 #include <drm/drm_client.h>
44 #include <drm/drm_drv.h>
45 #include <drm/drm_file.h>
46 #include <drm/drm_gem.h>
47 #include <drm/drm_print.h>
48 
49 #include "drm_crtc_internal.h"
50 #include "drm_internal.h"
51 
52 /* from BKL pushdown */
53 DEFINE_MUTEX(drm_global_mutex);
54 
55 bool drm_dev_needs_global_mutex(struct drm_device *dev)
56 {
57 	/*
58 	 * The deprecated ->load callback must be called after the driver is
59 	 * already registered. This means such drivers rely on the BKL to make
60 	 * sure an open can't proceed until the driver is actually fully set up.
61 	 * Similar hilarity holds for the unload callback.
62 	 */
63 	if (dev->driver->load || dev->driver->unload)
64 		return true;
65 
66 	return false;
67 }
68 
69 /**
70  * DOC: file operations
71  *
72  * Drivers must define the file operations structure that forms the DRM
73  * userspace API entry point, even though most of those operations are
74  * implemented in the DRM core. The resulting &struct file_operations must be
75  * stored in the &drm_driver.fops field. The mandatory functions are drm_open(),
76  * drm_read(), drm_ioctl() and drm_compat_ioctl() if CONFIG_COMPAT is enabled
77  * Note that drm_compat_ioctl will be NULL if CONFIG_COMPAT=n, so there's no
78  * need to sprinkle #ifdef into the code. Drivers which implement private ioctls
79  * that require 32/64 bit compatibility support must provide their own
80  * &file_operations.compat_ioctl handler that processes private ioctls and calls
81  * drm_compat_ioctl() for core ioctls.
82  *
83  * In addition drm_read() and drm_poll() provide support for DRM events. DRM
84  * events are a generic and extensible means to send asynchronous events to
85  * userspace through the file descriptor. They are used to send vblank event and
86  * page flip completions by the KMS API. But drivers can also use it for their
87  * own needs, e.g. to signal completion of rendering.
88  *
89  * For the driver-side event interface see drm_event_reserve_init() and
90  * drm_send_event() as the main starting points.
91  *
92  * The memory mapping implementation will vary depending on how the driver
93  * manages memory. For GEM-based drivers this is drm_gem_mmap().
94  *
95  * No other file operations are supported by the DRM userspace API. Overall the
96  * following is an example &file_operations structure::
97  *
98  *     static const example_drm_fops = {
99  *             .owner = THIS_MODULE,
100  *             .open = drm_open,
101  *             .release = drm_release,
102  *             .unlocked_ioctl = drm_ioctl,
103  *             .compat_ioctl = drm_compat_ioctl, // NULL if CONFIG_COMPAT=n
104  *             .poll = drm_poll,
105  *             .read = drm_read,
106  *             .mmap = drm_gem_mmap,
107  *     };
108  *
109  * For plain GEM based drivers there is the DEFINE_DRM_GEM_FOPS() macro, and for
110  * DMA based drivers there is the DEFINE_DRM_GEM_DMA_FOPS() macro to make this
111  * simpler.
112  *
113  * The driver's &file_operations must be stored in &drm_driver.fops.
114  *
115  * For driver-private IOCTL handling see the more detailed discussion in
116  * :ref:`IOCTL support in the userland interfaces chapter<drm_driver_ioctl>`.
117  */
118 
119 /**
120  * drm_file_alloc - allocate file context
121  * @minor: minor to allocate on
122  *
123  * This allocates a new DRM file context. It is not linked into any context and
124  * can be used by the caller freely. Note that the context keeps a pointer to
125  * @minor, so it must be freed before @minor is.
126  *
127  * RETURNS:
128  * Pointer to newly allocated context, ERR_PTR on failure.
129  */
130 struct drm_file *drm_file_alloc(struct drm_minor *minor)
131 {
132 	static atomic64_t ident = ATOMIC_INIT(0);
133 	struct drm_device *dev = minor->dev;
134 	struct drm_file *file;
135 	int ret;
136 
137 	file = kzalloc(sizeof(*file), GFP_KERNEL);
138 	if (!file)
139 		return ERR_PTR(-ENOMEM);
140 
141 	/* Get a unique identifier for fdinfo: */
142 	file->client_id = atomic64_inc_return(&ident);
143 	rcu_assign_pointer(file->pid, get_pid(task_tgid(current)));
144 	file->minor = minor;
145 
146 	/* for compatibility root is always authenticated */
147 	file->authenticated = capable(CAP_SYS_ADMIN);
148 
149 	INIT_LIST_HEAD(&file->lhead);
150 	INIT_LIST_HEAD(&file->fbs);
151 	mutex_init(&file->fbs_lock);
152 	INIT_LIST_HEAD(&file->blobs);
153 	INIT_LIST_HEAD(&file->pending_event_list);
154 	INIT_LIST_HEAD(&file->event_list);
155 	init_waitqueue_head(&file->event_wait);
156 	file->event_space = 4096; /* set aside 4k for event buffer */
157 
158 	spin_lock_init(&file->master_lookup_lock);
159 	mutex_init(&file->event_read_lock);
160 
161 	if (drm_core_check_feature(dev, DRIVER_GEM))
162 		drm_gem_open(dev, file);
163 
164 	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
165 		drm_syncobj_open(file);
166 
167 	drm_prime_init_file_private(&file->prime);
168 
169 	if (dev->driver->open) {
170 		ret = dev->driver->open(dev, file);
171 		if (ret < 0)
172 			goto out_prime_destroy;
173 	}
174 
175 	return file;
176 
177 out_prime_destroy:
178 	drm_prime_destroy_file_private(&file->prime);
179 	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
180 		drm_syncobj_release(file);
181 	if (drm_core_check_feature(dev, DRIVER_GEM))
182 		drm_gem_release(dev, file);
183 	put_pid(rcu_access_pointer(file->pid));
184 	kfree(file);
185 
186 	return ERR_PTR(ret);
187 }
188 
189 static void drm_events_release(struct drm_file *file_priv)
190 {
191 	struct drm_device *dev = file_priv->minor->dev;
192 	struct drm_pending_event *e, *et;
193 	unsigned long flags;
194 
195 	spin_lock_irqsave(&dev->event_lock, flags);
196 
197 	/* Unlink pending events */
198 	list_for_each_entry_safe(e, et, &file_priv->pending_event_list,
199 				 pending_link) {
200 		list_del(&e->pending_link);
201 		e->file_priv = NULL;
202 	}
203 
204 	/* Remove unconsumed events */
205 	list_for_each_entry_safe(e, et, &file_priv->event_list, link) {
206 		list_del(&e->link);
207 		kfree(e);
208 	}
209 
210 	spin_unlock_irqrestore(&dev->event_lock, flags);
211 }
212 
213 /**
214  * drm_file_free - free file context
215  * @file: context to free, or NULL
216  *
217  * This destroys and deallocates a DRM file context previously allocated via
218  * drm_file_alloc(). The caller must make sure to unlink it from any contexts
219  * before calling this.
220  *
221  * If NULL is passed, this is a no-op.
222  */
223 void drm_file_free(struct drm_file *file)
224 {
225 	struct drm_device *dev;
226 
227 	if (!file)
228 		return;
229 
230 	dev = file->minor->dev;
231 
232 	drm_dbg_core(dev, "comm=\"%s\", pid=%d, dev=0x%lx, open_count=%d\n",
233 		     current->comm, task_pid_nr(current),
234 		     (long)old_encode_dev(file->minor->kdev->devt),
235 		     atomic_read(&dev->open_count));
236 
237 	drm_events_release(file);
238 
239 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
240 		drm_fb_release(file);
241 		drm_property_destroy_user_blobs(dev, file);
242 	}
243 
244 	if (drm_core_check_feature(dev, DRIVER_SYNCOBJ))
245 		drm_syncobj_release(file);
246 
247 	if (drm_core_check_feature(dev, DRIVER_GEM))
248 		drm_gem_release(dev, file);
249 
250 	if (drm_is_primary_client(file))
251 		drm_master_release(file);
252 
253 	if (dev->driver->postclose)
254 		dev->driver->postclose(dev, file);
255 
256 	drm_prime_destroy_file_private(&file->prime);
257 
258 	WARN_ON(!list_empty(&file->event_list));
259 
260 	put_pid(rcu_access_pointer(file->pid));
261 	kfree(file);
262 }
263 
264 static void drm_close_helper(struct file *filp)
265 {
266 	struct drm_file *file_priv = filp->private_data;
267 	struct drm_device *dev = file_priv->minor->dev;
268 
269 	mutex_lock(&dev->filelist_mutex);
270 	list_del(&file_priv->lhead);
271 	mutex_unlock(&dev->filelist_mutex);
272 
273 	drm_file_free(file_priv);
274 }
275 
276 /*
277  * Check whether DRI will run on this CPU.
278  *
279  * \return non-zero if the DRI will run on this CPU, or zero otherwise.
280  */
281 static int drm_cpu_valid(void)
282 {
283 #if defined(__sparc__) && !defined(__sparc_v9__)
284 	return 0;		/* No cmpxchg before v9 sparc. */
285 #endif
286 	return 1;
287 }
288 
289 /*
290  * Called whenever a process opens a drm node
291  *
292  * \param filp file pointer.
293  * \param minor acquired minor-object.
294  * \return zero on success or a negative number on failure.
295  *
296  * Creates and initializes a drm_file structure for the file private data in \p
297  * filp and add it into the double linked list in \p dev.
298  */
299 int drm_open_helper(struct file *filp, struct drm_minor *minor)
300 {
301 	struct drm_device *dev = minor->dev;
302 	struct drm_file *priv;
303 	int ret;
304 
305 	if (filp->f_flags & O_EXCL)
306 		return -EBUSY;	/* No exclusive opens */
307 	if (!drm_cpu_valid())
308 		return -EINVAL;
309 	if (dev->switch_power_state != DRM_SWITCH_POWER_ON &&
310 	    dev->switch_power_state != DRM_SWITCH_POWER_DYNAMIC_OFF)
311 		return -EINVAL;
312 	if (WARN_ON_ONCE(!(filp->f_op->fop_flags & FOP_UNSIGNED_OFFSET)))
313 		return -EINVAL;
314 
315 	drm_dbg_core(dev, "comm=\"%s\", pid=%d, minor=%d\n",
316 		     current->comm, task_pid_nr(current), minor->index);
317 
318 	priv = drm_file_alloc(minor);
319 	if (IS_ERR(priv))
320 		return PTR_ERR(priv);
321 
322 	if (drm_is_primary_client(priv)) {
323 		ret = drm_master_open(priv);
324 		if (ret) {
325 			drm_file_free(priv);
326 			return ret;
327 		}
328 	}
329 
330 	filp->private_data = priv;
331 	priv->filp = filp;
332 
333 	mutex_lock(&dev->filelist_mutex);
334 	list_add(&priv->lhead, &dev->filelist);
335 	mutex_unlock(&dev->filelist_mutex);
336 
337 	return 0;
338 }
339 
340 /**
341  * drm_open - open method for DRM file
342  * @inode: device inode
343  * @filp: file pointer.
344  *
345  * This function must be used by drivers as their &file_operations.open method.
346  * It looks up the correct DRM device and instantiates all the per-file
347  * resources for it. It also calls the &drm_driver.open driver callback.
348  *
349  * RETURNS:
350  * 0 on success or negative errno value on failure.
351  */
352 int drm_open(struct inode *inode, struct file *filp)
353 {
354 	struct drm_device *dev;
355 	struct drm_minor *minor;
356 	int retcode;
357 
358 	minor = drm_minor_acquire(&drm_minors_xa, iminor(inode));
359 	if (IS_ERR(minor))
360 		return PTR_ERR(minor);
361 
362 	dev = minor->dev;
363 	if (drm_dev_needs_global_mutex(dev))
364 		mutex_lock(&drm_global_mutex);
365 
366 	atomic_fetch_inc(&dev->open_count);
367 
368 	/* share address_space across all char-devs of a single device */
369 	filp->f_mapping = dev->anon_inode->i_mapping;
370 
371 	retcode = drm_open_helper(filp, minor);
372 	if (retcode)
373 		goto err_undo;
374 
375 	if (drm_dev_needs_global_mutex(dev))
376 		mutex_unlock(&drm_global_mutex);
377 
378 	return 0;
379 
380 err_undo:
381 	atomic_dec(&dev->open_count);
382 	if (drm_dev_needs_global_mutex(dev))
383 		mutex_unlock(&drm_global_mutex);
384 	drm_minor_release(minor);
385 	return retcode;
386 }
387 EXPORT_SYMBOL(drm_open);
388 
389 static void drm_lastclose(struct drm_device *dev)
390 {
391 	drm_client_dev_restore(dev);
392 
393 	if (dev_is_pci(dev->dev))
394 		vga_switcheroo_process_delayed_switch();
395 }
396 
397 /**
398  * drm_release - release method for DRM file
399  * @inode: device inode
400  * @filp: file pointer.
401  *
402  * This function must be used by drivers as their &file_operations.release
403  * method. It frees any resources associated with the open file. If this
404  * is the last open file for the DRM device, it also restores the active
405  * in-kernel DRM client.
406  *
407  * RETURNS:
408  * Always succeeds and returns 0.
409  */
410 int drm_release(struct inode *inode, struct file *filp)
411 {
412 	struct drm_file *file_priv = filp->private_data;
413 	struct drm_minor *minor = file_priv->minor;
414 	struct drm_device *dev = minor->dev;
415 
416 	if (drm_dev_needs_global_mutex(dev))
417 		mutex_lock(&drm_global_mutex);
418 
419 	drm_dbg_core(dev, "open_count = %d\n", atomic_read(&dev->open_count));
420 
421 	drm_close_helper(filp);
422 
423 	if (atomic_dec_and_test(&dev->open_count))
424 		drm_lastclose(dev);
425 
426 	if (drm_dev_needs_global_mutex(dev))
427 		mutex_unlock(&drm_global_mutex);
428 
429 	drm_minor_release(minor);
430 
431 	return 0;
432 }
433 EXPORT_SYMBOL(drm_release);
434 
435 void drm_file_update_pid(struct drm_file *filp)
436 {
437 	struct drm_device *dev;
438 	struct pid *pid, *old;
439 
440 	/*
441 	 * Master nodes need to keep the original ownership in order for
442 	 * drm_master_check_perm to keep working correctly. (See comment in
443 	 * drm_auth.c.)
444 	 */
445 	if (filp->was_master)
446 		return;
447 
448 	pid = task_tgid(current);
449 
450 	/*
451 	 * Quick unlocked check since the model is a single handover followed by
452 	 * exclusive repeated use.
453 	 */
454 	if (pid == rcu_access_pointer(filp->pid))
455 		return;
456 
457 	dev = filp->minor->dev;
458 	mutex_lock(&dev->filelist_mutex);
459 	get_pid(pid);
460 	old = rcu_replace_pointer(filp->pid, pid, 1);
461 	mutex_unlock(&dev->filelist_mutex);
462 
463 	synchronize_rcu();
464 	put_pid(old);
465 }
466 
467 /**
468  * drm_release_noglobal - release method for DRM file
469  * @inode: device inode
470  * @filp: file pointer.
471  *
472  * This function may be used by drivers as their &file_operations.release
473  * method. It frees any resources associated with the open file prior to taking
474  * the drm_global_mutex. If this is the last open file for the DRM device, it
475  * then restores the active in-kernel DRM client.
476  *
477  * RETURNS:
478  * Always succeeds and returns 0.
479  */
480 int drm_release_noglobal(struct inode *inode, struct file *filp)
481 {
482 	struct drm_file *file_priv = filp->private_data;
483 	struct drm_minor *minor = file_priv->minor;
484 	struct drm_device *dev = minor->dev;
485 
486 	drm_close_helper(filp);
487 
488 	if (atomic_dec_and_mutex_lock(&dev->open_count, &drm_global_mutex)) {
489 		drm_lastclose(dev);
490 		mutex_unlock(&drm_global_mutex);
491 	}
492 
493 	drm_minor_release(minor);
494 
495 	return 0;
496 }
497 EXPORT_SYMBOL(drm_release_noglobal);
498 
499 /**
500  * drm_read - read method for DRM file
501  * @filp: file pointer
502  * @buffer: userspace destination pointer for the read
503  * @count: count in bytes to read
504  * @offset: offset to read
505  *
506  * This function must be used by drivers as their &file_operations.read
507  * method if they use DRM events for asynchronous signalling to userspace.
508  * Since events are used by the KMS API for vblank and page flip completion this
509  * means all modern display drivers must use it.
510  *
511  * @offset is ignored, DRM events are read like a pipe. Polling support is
512  * provided by drm_poll().
513  *
514  * This function will only ever read a full event. Therefore userspace must
515  * supply a big enough buffer to fit any event to ensure forward progress. Since
516  * the maximum event space is currently 4K it's recommended to just use that for
517  * safety.
518  *
519  * RETURNS:
520  * Number of bytes read (always aligned to full events, and can be 0) or a
521  * negative error code on failure.
522  */
523 ssize_t drm_read(struct file *filp, char __user *buffer,
524 		 size_t count, loff_t *offset)
525 {
526 	struct drm_file *file_priv = filp->private_data;
527 	struct drm_device *dev = file_priv->minor->dev;
528 	ssize_t ret;
529 
530 	ret = mutex_lock_interruptible(&file_priv->event_read_lock);
531 	if (ret)
532 		return ret;
533 
534 	for (;;) {
535 		struct drm_pending_event *e = NULL;
536 
537 		spin_lock_irq(&dev->event_lock);
538 		if (!list_empty(&file_priv->event_list)) {
539 			e = list_first_entry(&file_priv->event_list,
540 					struct drm_pending_event, link);
541 			file_priv->event_space += e->event->length;
542 			list_del(&e->link);
543 		}
544 		spin_unlock_irq(&dev->event_lock);
545 
546 		if (e == NULL) {
547 			if (ret)
548 				break;
549 
550 			if (filp->f_flags & O_NONBLOCK) {
551 				ret = -EAGAIN;
552 				break;
553 			}
554 
555 			mutex_unlock(&file_priv->event_read_lock);
556 			ret = wait_event_interruptible(file_priv->event_wait,
557 						       !list_empty(&file_priv->event_list));
558 			if (ret >= 0)
559 				ret = mutex_lock_interruptible(&file_priv->event_read_lock);
560 			if (ret)
561 				return ret;
562 		} else {
563 			unsigned length = e->event->length;
564 
565 			if (length > count - ret) {
566 put_back_event:
567 				spin_lock_irq(&dev->event_lock);
568 				file_priv->event_space -= length;
569 				list_add(&e->link, &file_priv->event_list);
570 				spin_unlock_irq(&dev->event_lock);
571 				wake_up_interruptible_poll(&file_priv->event_wait,
572 					EPOLLIN | EPOLLRDNORM);
573 				break;
574 			}
575 
576 			if (copy_to_user(buffer + ret, e->event, length)) {
577 				if (ret == 0)
578 					ret = -EFAULT;
579 				goto put_back_event;
580 			}
581 
582 			ret += length;
583 			kfree(e);
584 		}
585 	}
586 	mutex_unlock(&file_priv->event_read_lock);
587 
588 	return ret;
589 }
590 EXPORT_SYMBOL(drm_read);
591 
592 /**
593  * drm_poll - poll method for DRM file
594  * @filp: file pointer
595  * @wait: poll waiter table
596  *
597  * This function must be used by drivers as their &file_operations.read method
598  * if they use DRM events for asynchronous signalling to userspace.  Since
599  * events are used by the KMS API for vblank and page flip completion this means
600  * all modern display drivers must use it.
601  *
602  * See also drm_read().
603  *
604  * RETURNS:
605  * Mask of POLL flags indicating the current status of the file.
606  */
607 __poll_t drm_poll(struct file *filp, struct poll_table_struct *wait)
608 {
609 	struct drm_file *file_priv = filp->private_data;
610 	__poll_t mask = 0;
611 
612 	poll_wait(filp, &file_priv->event_wait, wait);
613 
614 	if (!list_empty(&file_priv->event_list))
615 		mask |= EPOLLIN | EPOLLRDNORM;
616 
617 	return mask;
618 }
619 EXPORT_SYMBOL(drm_poll);
620 
621 /**
622  * drm_event_reserve_init_locked - init a DRM event and reserve space for it
623  * @dev: DRM device
624  * @file_priv: DRM file private data
625  * @p: tracking structure for the pending event
626  * @e: actual event data to deliver to userspace
627  *
628  * This function prepares the passed in event for eventual delivery. If the event
629  * doesn't get delivered (because the IOCTL fails later on, before queuing up
630  * anything) then the even must be cancelled and freed using
631  * drm_event_cancel_free(). Successfully initialized events should be sent out
632  * using drm_send_event() or drm_send_event_locked() to signal completion of the
633  * asynchronous event to userspace.
634  *
635  * If callers embedded @p into a larger structure it must be allocated with
636  * kmalloc and @p must be the first member element.
637  *
638  * This is the locked version of drm_event_reserve_init() for callers which
639  * already hold &drm_device.event_lock.
640  *
641  * RETURNS:
642  * 0 on success or a negative error code on failure.
643  */
644 int drm_event_reserve_init_locked(struct drm_device *dev,
645 				  struct drm_file *file_priv,
646 				  struct drm_pending_event *p,
647 				  struct drm_event *e)
648 {
649 	if (file_priv->event_space < e->length)
650 		return -ENOMEM;
651 
652 	file_priv->event_space -= e->length;
653 
654 	p->event = e;
655 	list_add(&p->pending_link, &file_priv->pending_event_list);
656 	p->file_priv = file_priv;
657 
658 	return 0;
659 }
660 EXPORT_SYMBOL(drm_event_reserve_init_locked);
661 
662 /**
663  * drm_event_reserve_init - 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  * Callers which already hold &drm_device.event_lock should use
680  * drm_event_reserve_init_locked() instead.
681  *
682  * RETURNS:
683  * 0 on success or a negative error code on failure.
684  */
685 int drm_event_reserve_init(struct drm_device *dev,
686 			   struct drm_file *file_priv,
687 			   struct drm_pending_event *p,
688 			   struct drm_event *e)
689 {
690 	unsigned long flags;
691 	int ret;
692 
693 	spin_lock_irqsave(&dev->event_lock, flags);
694 	ret = drm_event_reserve_init_locked(dev, file_priv, p, e);
695 	spin_unlock_irqrestore(&dev->event_lock, flags);
696 
697 	return ret;
698 }
699 EXPORT_SYMBOL(drm_event_reserve_init);
700 
701 /**
702  * drm_event_cancel_free - free a DRM event and release its space
703  * @dev: DRM device
704  * @p: tracking structure for the pending event
705  *
706  * This function frees the event @p initialized with drm_event_reserve_init()
707  * and releases any allocated space. It is used to cancel an event when the
708  * nonblocking operation could not be submitted and needed to be aborted.
709  */
710 void drm_event_cancel_free(struct drm_device *dev,
711 			   struct drm_pending_event *p)
712 {
713 	unsigned long flags;
714 
715 	spin_lock_irqsave(&dev->event_lock, flags);
716 	if (p->file_priv) {
717 		p->file_priv->event_space += p->event->length;
718 		list_del(&p->pending_link);
719 	}
720 	spin_unlock_irqrestore(&dev->event_lock, flags);
721 
722 	if (p->fence)
723 		dma_fence_put(p->fence);
724 
725 	kfree(p);
726 }
727 EXPORT_SYMBOL(drm_event_cancel_free);
728 
729 static void drm_send_event_helper(struct drm_device *dev,
730 			   struct drm_pending_event *e, ktime_t timestamp)
731 {
732 	assert_spin_locked(&dev->event_lock);
733 
734 	if (e->completion) {
735 		complete_all(e->completion);
736 		e->completion_release(e->completion);
737 		e->completion = NULL;
738 	}
739 
740 	if (e->fence) {
741 		if (timestamp)
742 			dma_fence_signal_timestamp(e->fence, timestamp);
743 		else
744 			dma_fence_signal(e->fence);
745 		dma_fence_put(e->fence);
746 	}
747 
748 	if (!e->file_priv) {
749 		kfree(e);
750 		return;
751 	}
752 
753 	list_del(&e->pending_link);
754 	list_add_tail(&e->link,
755 		      &e->file_priv->event_list);
756 	wake_up_interruptible_poll(&e->file_priv->event_wait,
757 		EPOLLIN | EPOLLRDNORM);
758 }
759 
760 /**
761  * drm_send_event_timestamp_locked - send DRM event to file descriptor
762  * @dev: DRM device
763  * @e: DRM event to deliver
764  * @timestamp: timestamp to set for the fence event in kernel's CLOCK_MONOTONIC
765  * time domain
766  *
767  * This function sends the event @e, initialized with drm_event_reserve_init(),
768  * to its associated userspace DRM file. Callers must already hold
769  * &drm_device.event_lock.
770  *
771  * Note that the core will take care of unlinking and disarming events when the
772  * corresponding DRM file is closed. Drivers need not worry about whether the
773  * DRM file for this event still exists and can call this function upon
774  * completion of the asynchronous work unconditionally.
775  */
776 void drm_send_event_timestamp_locked(struct drm_device *dev,
777 				     struct drm_pending_event *e, ktime_t timestamp)
778 {
779 	drm_send_event_helper(dev, e, timestamp);
780 }
781 EXPORT_SYMBOL(drm_send_event_timestamp_locked);
782 
783 /**
784  * drm_send_event_locked - send DRM event to file descriptor
785  * @dev: DRM device
786  * @e: DRM event to deliver
787  *
788  * This function sends the event @e, initialized with drm_event_reserve_init(),
789  * to its associated userspace DRM file. Callers must already hold
790  * &drm_device.event_lock, see drm_send_event() for the unlocked version.
791  *
792  * Note that the core will take care of unlinking and disarming events when the
793  * corresponding DRM file is closed. Drivers need not worry about whether the
794  * DRM file for this event still exists and can call this function upon
795  * completion of the asynchronous work unconditionally.
796  */
797 void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e)
798 {
799 	drm_send_event_helper(dev, e, 0);
800 }
801 EXPORT_SYMBOL(drm_send_event_locked);
802 
803 /**
804  * drm_send_event - send DRM event to file descriptor
805  * @dev: DRM device
806  * @e: DRM event to deliver
807  *
808  * This function sends the event @e, initialized with drm_event_reserve_init(),
809  * to its associated userspace DRM file. This function acquires
810  * &drm_device.event_lock, see drm_send_event_locked() for callers which already
811  * hold this lock.
812  *
813  * Note that the core will take care of unlinking and disarming events when the
814  * corresponding DRM file is closed. Drivers need not worry about whether the
815  * DRM file for this event still exists and can call this function upon
816  * completion of the asynchronous work unconditionally.
817  */
818 void drm_send_event(struct drm_device *dev, struct drm_pending_event *e)
819 {
820 	unsigned long irqflags;
821 
822 	spin_lock_irqsave(&dev->event_lock, irqflags);
823 	drm_send_event_helper(dev, e, 0);
824 	spin_unlock_irqrestore(&dev->event_lock, irqflags);
825 }
826 EXPORT_SYMBOL(drm_send_event);
827 
828 static void print_size(struct drm_printer *p, const char *stat,
829 		       const char *region, u64 sz)
830 {
831 	const char *units[] = {"", " KiB", " MiB"};
832 	unsigned u;
833 
834 	for (u = 0; u < ARRAY_SIZE(units) - 1; u++) {
835 		if (sz == 0 || !IS_ALIGNED(sz, SZ_1K))
836 			break;
837 		sz = div_u64(sz, SZ_1K);
838 	}
839 
840 	drm_printf(p, "drm-%s-%s:\t%llu%s\n", stat, region, sz, units[u]);
841 }
842 
843 /**
844  * drm_print_memory_stats - A helper to print memory stats
845  * @p: The printer to print output to
846  * @stats: The collected memory stats
847  * @supported_status: Bitmask of optional stats which are available
848  * @region: The memory region
849  *
850  */
851 void drm_print_memory_stats(struct drm_printer *p,
852 			    const struct drm_memory_stats *stats,
853 			    enum drm_gem_object_status supported_status,
854 			    const char *region)
855 {
856 	print_size(p, "total", region, stats->private + stats->shared);
857 	print_size(p, "shared", region, stats->shared);
858 	print_size(p, "active", region, stats->active);
859 
860 	if (supported_status & DRM_GEM_OBJECT_RESIDENT)
861 		print_size(p, "resident", region, stats->resident);
862 
863 	if (supported_status & DRM_GEM_OBJECT_PURGEABLE)
864 		print_size(p, "purgeable", region, stats->purgeable);
865 }
866 EXPORT_SYMBOL(drm_print_memory_stats);
867 
868 /**
869  * drm_show_memory_stats - Helper to collect and show standard fdinfo memory stats
870  * @p: the printer to print output to
871  * @file: the DRM file
872  *
873  * Helper to iterate over GEM objects with a handle allocated in the specified
874  * file.
875  */
876 void drm_show_memory_stats(struct drm_printer *p, struct drm_file *file)
877 {
878 	struct drm_gem_object *obj;
879 	struct drm_memory_stats status = {};
880 	enum drm_gem_object_status supported_status = 0;
881 	int id;
882 
883 	spin_lock(&file->table_lock);
884 	idr_for_each_entry (&file->object_idr, obj, id) {
885 		enum drm_gem_object_status s = 0;
886 		size_t add_size = (obj->funcs && obj->funcs->rss) ?
887 			obj->funcs->rss(obj) : obj->size;
888 
889 		if (obj->funcs && obj->funcs->status) {
890 			s = obj->funcs->status(obj);
891 			supported_status = DRM_GEM_OBJECT_RESIDENT |
892 					DRM_GEM_OBJECT_PURGEABLE;
893 		}
894 
895 		if (drm_gem_object_is_shared_for_memory_stats(obj)) {
896 			status.shared += obj->size;
897 		} else {
898 			status.private += obj->size;
899 		}
900 
901 		if (s & DRM_GEM_OBJECT_RESIDENT) {
902 			status.resident += add_size;
903 		} else {
904 			/* If already purged or not yet backed by pages, don't
905 			 * count it as purgeable:
906 			 */
907 			s &= ~DRM_GEM_OBJECT_PURGEABLE;
908 		}
909 
910 		if (!dma_resv_test_signaled(obj->resv, dma_resv_usage_rw(true))) {
911 			status.active += add_size;
912 
913 			/* If still active, don't count as purgeable: */
914 			s &= ~DRM_GEM_OBJECT_PURGEABLE;
915 		}
916 
917 		if (s & DRM_GEM_OBJECT_PURGEABLE)
918 			status.purgeable += add_size;
919 	}
920 	spin_unlock(&file->table_lock);
921 
922 	drm_print_memory_stats(p, &status, supported_status, "memory");
923 }
924 EXPORT_SYMBOL(drm_show_memory_stats);
925 
926 /**
927  * drm_show_fdinfo - helper for drm file fops
928  * @m: output stream
929  * @f: the device file instance
930  *
931  * Helper to implement fdinfo, for userspace to query usage stats, etc, of a
932  * process using the GPU.  See also &drm_driver.show_fdinfo.
933  *
934  * For text output format description please see Documentation/gpu/drm-usage-stats.rst
935  */
936 void drm_show_fdinfo(struct seq_file *m, struct file *f)
937 {
938 	struct drm_file *file = f->private_data;
939 	struct drm_device *dev = file->minor->dev;
940 	struct drm_printer p = drm_seq_file_printer(m);
941 
942 	drm_printf(&p, "drm-driver:\t%s\n", dev->driver->name);
943 	drm_printf(&p, "drm-client-id:\t%llu\n", file->client_id);
944 
945 	if (dev_is_pci(dev->dev)) {
946 		struct pci_dev *pdev = to_pci_dev(dev->dev);
947 
948 		drm_printf(&p, "drm-pdev:\t%04x:%02x:%02x.%d\n",
949 			   pci_domain_nr(pdev->bus), pdev->bus->number,
950 			   PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn));
951 	}
952 
953 	if (dev->driver->show_fdinfo)
954 		dev->driver->show_fdinfo(&p, file);
955 }
956 EXPORT_SYMBOL(drm_show_fdinfo);
957 
958 /**
959  * mock_drm_getfile - Create a new struct file for the drm device
960  * @minor: drm minor to wrap (e.g. #drm_device.primary)
961  * @flags: file creation mode (O_RDWR etc)
962  *
963  * This create a new struct file that wraps a DRM file context around a
964  * DRM minor. This mimicks userspace opening e.g. /dev/dri/card0, but without
965  * invoking userspace. The struct file may be operated on using its f_op
966  * (the drm_device.driver.fops) to mimick userspace operations, or be supplied
967  * to userspace facing functions as an internal/anonymous client.
968  *
969  * RETURNS:
970  * Pointer to newly created struct file, ERR_PTR on failure.
971  */
972 struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags)
973 {
974 	struct drm_device *dev = minor->dev;
975 	struct drm_file *priv;
976 	struct file *file;
977 
978 	priv = drm_file_alloc(minor);
979 	if (IS_ERR(priv))
980 		return ERR_CAST(priv);
981 
982 	file = anon_inode_getfile("drm", dev->driver->fops, priv, flags);
983 	if (IS_ERR(file)) {
984 		drm_file_free(priv);
985 		return file;
986 	}
987 
988 	/* Everyone shares a single global address space */
989 	file->f_mapping = dev->anon_inode->i_mapping;
990 
991 	drm_dev_get(dev);
992 	priv->filp = file;
993 
994 	return file;
995 }
996 EXPORT_SYMBOL_FOR_TESTS_ONLY(mock_drm_getfile);
997