xref: /linux/drivers/gpu/drm/drm_lease.c (revision 0ea5c948cb64bab5bc7a5516774eb8536f05aa0d)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright © 2017 Keith Packard <keithp@keithp.com>
4  */
5 #include <linux/file.h>
6 #include <linux/uaccess.h>
7 
8 #include <drm/drm_auth.h>
9 #include <drm/drm_crtc.h>
10 #include <drm/drm_drv.h>
11 #include <drm/drm_file.h>
12 #include <drm/drm_lease.h>
13 #include <drm/drm_print.h>
14 
15 #include "drm_crtc_internal.h"
16 #include "drm_internal.h"
17 
18 /**
19  * DOC: drm leasing
20  *
21  * DRM leases provide information about whether a DRM master may control a DRM
22  * mode setting object. This enables the creation of multiple DRM masters that
23  * manage subsets of display resources.
24  *
25  * The original DRM master of a device 'owns' the available drm resources. It
26  * may create additional DRM masters and 'lease' resources which it controls
27  * to the new DRM master. This gives the new DRM master control over the
28  * leased resources until the owner revokes the lease, or the new DRM master
29  * is closed. Some helpful terminology:
30  *
31  * - An 'owner' is a &struct drm_master that is not leasing objects from
32  *   another &struct drm_master, and hence 'owns' the objects. The owner can be
33  *   identified as the &struct drm_master for which &drm_master.lessor is NULL.
34  *
35  * - A 'lessor' is a &struct drm_master which is leasing objects to one or more
36  *   other &struct drm_master. Currently, lessees are not allowed to
37  *   create sub-leases, hence the lessor is the same as the owner.
38  *
39  * - A 'lessee' is a &struct drm_master which is leasing objects from some
40  *   other &struct drm_master. Each lessee only leases resources from a single
41  *   lessor recorded in &drm_master.lessor, and holds the set of objects that
42  *   it is leasing in &drm_master.leases.
43  *
44  * - A 'lease' is a contract between the lessor and lessee that identifies
45  *   which resources may be controlled by the lessee. All of the resources
46  *   that are leased must be owned by or leased to the lessor, and lessors are
47  *   not permitted to lease the same object to multiple lessees.
48  *
49  * The set of objects any &struct drm_master 'controls' is limited to the set
50  * of objects it leases (for lessees) or all objects (for owners).
51  *
52  * Objects not controlled by a &struct drm_master cannot be modified through
53  * the various state manipulating ioctls, and any state reported back to user
54  * space will be edited to make them appear idle and/or unusable. For
55  * instance, connectors always report 'disconnected', while encoders
56  * report no possible crtcs or clones.
57  *
58  * Since each lessee may lease objects from a single lessor, display resource
59  * leases form a tree of &struct drm_master. As lessees are currently not
60  * allowed to create sub-leases, the tree depth is limited to 1. All of
61  * these get activated simultaneously when the top level device owner changes
62  * through the SETMASTER or DROPMASTER IOCTL, so &drm_device.master points to
63  * the owner at the top of the lease tree (i.e. the &struct drm_master for which
64  * &drm_master.lessor is NULL). The full list of lessees that are leasing
65  * objects from the owner can be searched via the owner's
66  * &drm_master.lessee_idr.
67  */
68 
69 #define drm_for_each_lessee(lessee, lessor) \
70 	list_for_each_entry((lessee), &(lessor)->lessees, lessee_list)
71 
72 static uint64_t drm_lease_idr_object;
73 
drm_lease_owner(struct drm_master * master)74 struct drm_master *drm_lease_owner(struct drm_master *master)
75 {
76 	while (master->lessor != NULL)
77 		master = master->lessor;
78 	return master;
79 }
80 
81 static struct drm_master*
_drm_find_lessee(struct drm_master * master,int lessee_id)82 _drm_find_lessee(struct drm_master *master, int lessee_id)
83 {
84 	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
85 	return idr_find(&drm_lease_owner(master)->lessee_idr, lessee_id);
86 }
87 
_drm_lease_held_master(struct drm_master * master,int id)88 static int _drm_lease_held_master(struct drm_master *master, int id)
89 {
90 	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
91 	if (master->lessor)
92 		return idr_find(&master->leases, id) != NULL;
93 	return true;
94 }
95 
96 /* Checks if the given object has been leased to some lessee of drm_master */
_drm_has_leased(struct drm_master * master,int id)97 static bool _drm_has_leased(struct drm_master *master, int id)
98 {
99 	struct drm_master *lessee;
100 
101 	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
102 	drm_for_each_lessee(lessee, master)
103 		if (_drm_lease_held_master(lessee, id))
104 			return true;
105 	return false;
106 }
107 
108 /* Called with idr_mutex held */
_drm_lease_held(struct drm_file * file_priv,int id)109 bool _drm_lease_held(struct drm_file *file_priv, int id)
110 {
111 	bool ret;
112 	struct drm_master *master;
113 
114 	if (!file_priv)
115 		return true;
116 
117 	master = drm_file_get_master(file_priv);
118 	if (!master)
119 		return true;
120 	ret = _drm_lease_held_master(master, id);
121 	drm_master_put(&master);
122 
123 	return ret;
124 }
125 
drm_lease_held(struct drm_file * file_priv,int id)126 bool drm_lease_held(struct drm_file *file_priv, int id)
127 {
128 	struct drm_master *master;
129 	bool ret;
130 
131 	if (!file_priv)
132 		return true;
133 
134 	master = drm_file_get_master(file_priv);
135 	if (!master)
136 		return true;
137 	if (!master->lessor) {
138 		ret = true;
139 		goto out;
140 	}
141 	mutex_lock(&master->dev->mode_config.idr_mutex);
142 	ret = _drm_lease_held_master(master, id);
143 	mutex_unlock(&master->dev->mode_config.idr_mutex);
144 
145 out:
146 	drm_master_put(&master);
147 	return ret;
148 }
149 
150 /*
151  * Given a bitmask of crtcs to check, reconstructs a crtc mask based on the
152  * crtcs which are visible through the specified file.
153  */
drm_lease_filter_crtcs(struct drm_file * file_priv,uint32_t crtcs_in)154 uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in)
155 {
156 	struct drm_master *master;
157 	struct drm_device *dev;
158 	struct drm_crtc *crtc;
159 	int count_in, count_out;
160 	uint32_t crtcs_out = 0;
161 
162 	if (!file_priv)
163 		return crtcs_in;
164 
165 	master = drm_file_get_master(file_priv);
166 	if (!master)
167 		return crtcs_in;
168 	if (!master->lessor) {
169 		crtcs_out = crtcs_in;
170 		goto out;
171 	}
172 	dev = master->dev;
173 
174 	count_in = count_out = 0;
175 	mutex_lock(&master->dev->mode_config.idr_mutex);
176 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
177 		if (_drm_lease_held_master(master, crtc->base.id)) {
178 			uint32_t mask_in = 1ul << count_in;
179 
180 			if ((crtcs_in & mask_in) != 0) {
181 				uint32_t mask_out = 1ul << count_out;
182 
183 				crtcs_out |= mask_out;
184 			}
185 			count_out++;
186 		}
187 		count_in++;
188 	}
189 	mutex_unlock(&master->dev->mode_config.idr_mutex);
190 
191 out:
192 	drm_master_put(&master);
193 	return crtcs_out;
194 }
195 
196 /*
197  * Uses drm_master_create to allocate a new drm_master, then checks to
198  * make sure all of the desired objects can be leased, atomically
199  * leasing them to the new drmmaster.
200  *
201  * 	ERR_PTR(-EACCES)	some other master holds the title to any object
202  * 	ERR_PTR(-ENOENT)	some object is not a valid DRM object for this device
203  * 	ERR_PTR(-EBUSY)		some other lessee holds title to this object
204  *	ERR_PTR(-EEXIST)	same object specified more than once in the provided list
205  *	ERR_PTR(-ENOMEM)	allocation failed
206  */
drm_lease_create(struct drm_master * lessor,struct idr * leases)207 static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr *leases)
208 {
209 	struct drm_device *dev = lessor->dev;
210 	int error;
211 	struct drm_master *lessee;
212 	int object;
213 	int id;
214 	void *entry;
215 
216 	drm_dbg_lease(dev, "lessor %d\n", lessor->lessee_id);
217 
218 	lessee = drm_master_create(lessor->dev);
219 	if (!lessee) {
220 		drm_dbg_lease(dev, "drm_master_create failed\n");
221 		return ERR_PTR(-ENOMEM);
222 	}
223 
224 	mutex_lock(&dev->mode_config.idr_mutex);
225 
226 	idr_for_each_entry(leases, entry, object) {
227 		error = 0;
228 		if (!idr_find(&dev->mode_config.object_idr, object))
229 			error = -ENOENT;
230 		else if (_drm_has_leased(lessor, object))
231 			error = -EBUSY;
232 
233 		if (error != 0) {
234 			drm_dbg_lease(dev, "object %d failed %d\n", object, error);
235 			goto out_lessee;
236 		}
237 	}
238 
239 	/* Insert the new lessee into the tree */
240 	id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL);
241 	if (id < 0) {
242 		error = id;
243 		goto out_lessee;
244 	}
245 
246 	lessee->lessee_id = id;
247 	lessee->lessor = drm_master_get(lessor);
248 	list_add_tail(&lessee->lessee_list, &lessor->lessees);
249 
250 	/* Move the leases over */
251 	lessee->leases = *leases;
252 	drm_dbg_lease(dev, "new lessee %d %p, lessor %d %p\n",
253 		      lessee->lessee_id, lessee, lessor->lessee_id, lessor);
254 
255 	mutex_unlock(&dev->mode_config.idr_mutex);
256 	return lessee;
257 
258 out_lessee:
259 	mutex_unlock(&dev->mode_config.idr_mutex);
260 
261 	drm_master_put(&lessee);
262 
263 	return ERR_PTR(error);
264 }
265 
drm_lease_destroy(struct drm_master * master)266 void drm_lease_destroy(struct drm_master *master)
267 {
268 	struct drm_device *dev = master->dev;
269 
270 	mutex_lock(&dev->mode_config.idr_mutex);
271 
272 	drm_dbg_lease(dev, "drm_lease_destroy %d\n", master->lessee_id);
273 
274 	/* This master is referenced by all lessees, hence it cannot be destroyed
275 	 * until all of them have been
276 	 */
277 	WARN_ON(!list_empty(&master->lessees));
278 
279 	/* Remove this master from the lessee idr in the owner */
280 	if (master->lessee_id != 0) {
281 		drm_dbg_lease(dev, "remove master %d from device list of lessees\n",
282 			      master->lessee_id);
283 		idr_remove(&(drm_lease_owner(master)->lessee_idr), master->lessee_id);
284 	}
285 
286 	/* Remove this master from any lessee list it may be on */
287 	list_del(&master->lessee_list);
288 
289 	mutex_unlock(&dev->mode_config.idr_mutex);
290 
291 	if (master->lessor) {
292 		/* Tell the master to check the lessee list */
293 		drm_sysfs_lease_event(dev);
294 		drm_master_put(&master->lessor);
295 	}
296 
297 	drm_dbg_lease(dev, "drm_lease_destroy done %d\n", master->lessee_id);
298 }
299 
_drm_lease_revoke(struct drm_master * top)300 static void _drm_lease_revoke(struct drm_master *top)
301 {
302 	int object;
303 	void *entry;
304 	struct drm_master *master = top;
305 
306 	lockdep_assert_held(&top->dev->mode_config.idr_mutex);
307 
308 	/*
309 	 * Walk the tree starting at 'top' emptying all leases. Because
310 	 * the tree is fully connected, we can do this without recursing
311 	 */
312 	for (;;) {
313 		drm_dbg_lease(master->dev, "revoke leases for %p %d\n",
314 			      master, master->lessee_id);
315 
316 		/* Evacuate the lease */
317 		idr_for_each_entry(&master->leases, entry, object)
318 			idr_remove(&master->leases, object);
319 
320 		/* Depth-first list walk */
321 
322 		/* Down */
323 		if (!list_empty(&master->lessees)) {
324 			master = list_first_entry(&master->lessees, struct drm_master, lessee_list);
325 		} else {
326 			/* Up */
327 			while (master != top && master == list_last_entry(&master->lessor->lessees, struct drm_master, lessee_list))
328 				master = master->lessor;
329 
330 			if (master == top)
331 				break;
332 
333 			/* Over */
334 			master = list_next_entry(master, lessee_list);
335 		}
336 	}
337 }
338 
drm_lease_revoke(struct drm_master * top)339 void drm_lease_revoke(struct drm_master *top)
340 {
341 	mutex_lock(&top->dev->mode_config.idr_mutex);
342 	_drm_lease_revoke(top);
343 	mutex_unlock(&top->dev->mode_config.idr_mutex);
344 }
345 
validate_lease(struct drm_device * dev,int object_count,struct drm_mode_object ** objects,bool universal_planes)346 static int validate_lease(struct drm_device *dev,
347 			  int object_count,
348 			  struct drm_mode_object **objects,
349 			  bool universal_planes)
350 {
351 	int o;
352 	int has_crtc = -1;
353 	int has_connector = -1;
354 	int has_plane = -1;
355 
356 	/* we want to confirm that there is at least one crtc, plane
357 	   connector object. */
358 
359 	for (o = 0; o < object_count; o++) {
360 		if (objects[o]->type == DRM_MODE_OBJECT_CRTC && has_crtc == -1) {
361 			has_crtc = o;
362 		}
363 		if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1)
364 			has_connector = o;
365 
366 		if (universal_planes) {
367 			if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1)
368 				has_plane = o;
369 		}
370 	}
371 	if (has_crtc == -1 || has_connector == -1)
372 		return -EINVAL;
373 	if (universal_planes && has_plane == -1)
374 		return -EINVAL;
375 	return 0;
376 }
377 
fill_object_idr(struct drm_device * dev,struct drm_file * lessor_priv,struct idr * leases,int object_count,u32 * object_ids)378 static int fill_object_idr(struct drm_device *dev,
379 			   struct drm_file *lessor_priv,
380 			   struct idr *leases,
381 			   int object_count,
382 			   u32 *object_ids)
383 {
384 	struct drm_mode_object **objects;
385 	u32 o;
386 	int ret;
387 	bool universal_planes = READ_ONCE(lessor_priv->universal_planes);
388 
389 	objects = kcalloc(object_count, sizeof(struct drm_mode_object *),
390 			  GFP_KERNEL);
391 	if (!objects)
392 		return -ENOMEM;
393 
394 	/* step one - get references to all the mode objects
395 	   and check for validity. */
396 	for (o = 0; o < object_count; o++) {
397 		objects[o] = drm_mode_object_find(dev, lessor_priv,
398 						  object_ids[o],
399 						  DRM_MODE_OBJECT_ANY);
400 		if (!objects[o]) {
401 			ret = -ENOENT;
402 			goto out_free_objects;
403 		}
404 
405 		if (!drm_mode_object_lease_required(objects[o]->type)) {
406 			DRM_DEBUG_KMS("invalid object for lease\n");
407 			ret = -EINVAL;
408 			goto out_free_objects;
409 		}
410 	}
411 
412 	ret = validate_lease(dev, object_count, objects, universal_planes);
413 	if (ret) {
414 		drm_dbg_lease(dev, "lease validation failed\n");
415 		goto out_free_objects;
416 	}
417 
418 	/* add their IDs to the lease request - taking into account
419 	   universal planes */
420 	for (o = 0; o < object_count; o++) {
421 		struct drm_mode_object *obj = objects[o];
422 		u32 object_id = objects[o]->id;
423 
424 		drm_dbg_lease(dev, "Adding object %d to lease\n", object_id);
425 
426 		/*
427 		 * We're using an IDR to hold the set of leased
428 		 * objects, but we don't need to point at the object's
429 		 * data structure from the lease as the main object_idr
430 		 * will be used to actually find that. Instead, all we
431 		 * really want is a 'leased/not-leased' result, for
432 		 * which any non-NULL pointer will work fine.
433 		 */
434 		ret = idr_alloc(leases, &drm_lease_idr_object , object_id, object_id + 1, GFP_KERNEL);
435 		if (ret < 0) {
436 			drm_dbg_lease(dev, "Object %d cannot be inserted into leases (%d)\n",
437 				      object_id, ret);
438 			goto out_free_objects;
439 		}
440 		if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {
441 			struct drm_crtc *crtc = obj_to_crtc(obj);
442 
443 			ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL);
444 			if (ret < 0) {
445 				drm_dbg_lease(dev, "Object primary plane %d cannot be inserted into leases (%d)\n",
446 					      object_id, ret);
447 				goto out_free_objects;
448 			}
449 			if (crtc->cursor) {
450 				ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);
451 				if (ret < 0) {
452 					drm_dbg_lease(dev, "Object cursor plane %d cannot be inserted into leases (%d)\n",
453 						      object_id, ret);
454 					goto out_free_objects;
455 				}
456 			}
457 		}
458 	}
459 
460 	ret = 0;
461 out_free_objects:
462 	for (o = 0; o < object_count; o++) {
463 		if (objects[o])
464 			drm_mode_object_put(objects[o]);
465 	}
466 	kfree(objects);
467 	return ret;
468 }
469 
470 /*
471  * The master associated with the specified file will have a lease
472  * created containing the objects specified in the ioctl structure.
473  * A file descriptor will be allocated for that and returned to the
474  * application.
475  */
drm_mode_create_lease_ioctl(struct drm_device * dev,void * data,struct drm_file * lessor_priv)476 int drm_mode_create_lease_ioctl(struct drm_device *dev,
477 				void *data, struct drm_file *lessor_priv)
478 {
479 	struct drm_mode_create_lease *cl = data;
480 	size_t object_count;
481 	int ret = 0;
482 	struct idr leases;
483 	struct drm_master *lessor;
484 	struct drm_master *lessee = NULL;
485 	struct file *lessee_file = NULL;
486 	struct file *lessor_file = lessor_priv->filp;
487 	struct drm_file *lessee_priv;
488 	int fd = -1;
489 	uint32_t *object_ids;
490 
491 	/* Can't lease without MODESET */
492 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
493 		return -EOPNOTSUPP;
494 
495 	if (cl->flags && (cl->flags & ~(O_CLOEXEC | O_NONBLOCK))) {
496 		drm_dbg_lease(dev, "invalid flags\n");
497 		return -EINVAL;
498 	}
499 
500 	lessor = drm_file_get_master(lessor_priv);
501 	/* Do not allow sub-leases */
502 	if (lessor->lessor) {
503 		drm_dbg_lease(dev, "recursive leasing not allowed\n");
504 		ret = -EINVAL;
505 		goto out_lessor;
506 	}
507 
508 	object_count = cl->object_count;
509 
510 	/* Handle leased objects, if any */
511 	idr_init(&leases);
512 	if (object_count != 0) {
513 		object_ids = memdup_array_user(u64_to_user_ptr(cl->object_ids),
514 					       object_count, sizeof(__u32));
515 		if (IS_ERR(object_ids)) {
516 			ret = PTR_ERR(object_ids);
517 			idr_destroy(&leases);
518 			goto out_lessor;
519 		}
520 
521 		/* fill and validate the object idr */
522 		ret = fill_object_idr(dev, lessor_priv, &leases,
523 				      object_count, object_ids);
524 		kfree(object_ids);
525 		if (ret) {
526 			drm_dbg_lease(dev, "lease object lookup failed: %i\n", ret);
527 			idr_destroy(&leases);
528 			goto out_lessor;
529 		}
530 	}
531 
532 	/* Allocate a file descriptor for the lease */
533 	fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));
534 	if (fd < 0) {
535 		idr_destroy(&leases);
536 		ret = fd;
537 		goto out_lessor;
538 	}
539 
540 	drm_dbg_lease(dev, "Creating lease\n");
541 	/* lessee will take the ownership of leases */
542 	lessee = drm_lease_create(lessor, &leases);
543 
544 	if (IS_ERR(lessee)) {
545 		ret = PTR_ERR(lessee);
546 		idr_destroy(&leases);
547 		goto out_leases;
548 	}
549 
550 	/* Clone the lessor file to create a new file for us */
551 	drm_dbg_lease(dev, "Allocating lease file\n");
552 	lessee_file = file_clone_open(lessor_file);
553 	if (IS_ERR(lessee_file)) {
554 		ret = PTR_ERR(lessee_file);
555 		goto out_lessee;
556 	}
557 
558 	lessee_priv = lessee_file->private_data;
559 	/* Change the file to a master one */
560 	drm_master_put(&lessee_priv->master);
561 	lessee_priv->master = lessee;
562 	lessee_priv->is_master = 1;
563 	lessee_priv->authenticated = 1;
564 
565 	/* Pass fd back to userspace */
566 	drm_dbg_lease(dev, "Returning fd %d id %d\n", fd, lessee->lessee_id);
567 	cl->fd = fd;
568 	cl->lessee_id = lessee->lessee_id;
569 
570 	/* Hook up the fd */
571 	fd_install(fd, lessee_file);
572 
573 	drm_master_put(&lessor);
574 	drm_dbg_lease(dev, "drm_mode_create_lease_ioctl succeeded\n");
575 	return 0;
576 
577 out_lessee:
578 	drm_master_put(&lessee);
579 
580 out_leases:
581 	put_unused_fd(fd);
582 
583 out_lessor:
584 	drm_master_put(&lessor);
585 	drm_dbg_lease(dev, "drm_mode_create_lease_ioctl failed: %d\n", ret);
586 	return ret;
587 }
588 
drm_mode_list_lessees_ioctl(struct drm_device * dev,void * data,struct drm_file * lessor_priv)589 int drm_mode_list_lessees_ioctl(struct drm_device *dev,
590 			       void *data, struct drm_file *lessor_priv)
591 {
592 	struct drm_mode_list_lessees *arg = data;
593 	__u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
594 	__u32 count_lessees = arg->count_lessees;
595 	struct drm_master *lessor, *lessee;
596 	int count;
597 	int ret = 0;
598 
599 	if (arg->pad)
600 		return -EINVAL;
601 
602 	/* Can't lease without MODESET */
603 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
604 		return -EOPNOTSUPP;
605 
606 	lessor = drm_file_get_master(lessor_priv);
607 	drm_dbg_lease(dev, "List lessees for %d\n", lessor->lessee_id);
608 
609 	mutex_lock(&dev->mode_config.idr_mutex);
610 
611 	count = 0;
612 	drm_for_each_lessee(lessee, lessor) {
613 		/* Only list un-revoked leases */
614 		if (!idr_is_empty(&lessee->leases)) {
615 			if (count_lessees > count) {
616 				drm_dbg_lease(dev, "Add lessee %d\n",
617 					      lessee->lessee_id);
618 				ret = put_user(lessee->lessee_id, lessee_ids + count);
619 				if (ret)
620 					break;
621 			}
622 			count++;
623 		}
624 	}
625 
626 	drm_dbg_lease(dev, "Lessor leases to %d\n", count);
627 	if (ret == 0)
628 		arg->count_lessees = count;
629 
630 	mutex_unlock(&dev->mode_config.idr_mutex);
631 	drm_master_put(&lessor);
632 
633 	return ret;
634 }
635 
636 /* Return the list of leased objects for the specified lessee */
drm_mode_get_lease_ioctl(struct drm_device * dev,void * data,struct drm_file * lessee_priv)637 int drm_mode_get_lease_ioctl(struct drm_device *dev,
638 			     void *data, struct drm_file *lessee_priv)
639 {
640 	struct drm_mode_get_lease *arg = data;
641 	__u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
642 	__u32 count_objects = arg->count_objects;
643 	struct drm_master *lessee;
644 	struct idr *object_idr;
645 	int count;
646 	void *entry;
647 	int object;
648 	int ret = 0;
649 
650 	if (arg->pad)
651 		return -EINVAL;
652 
653 	/* Can't lease without MODESET */
654 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
655 		return -EOPNOTSUPP;
656 
657 	lessee = drm_file_get_master(lessee_priv);
658 	drm_dbg_lease(dev, "get lease for %d\n", lessee->lessee_id);
659 
660 	mutex_lock(&dev->mode_config.idr_mutex);
661 
662 	if (lessee->lessor == NULL)
663 		/* owner can use all objects */
664 		object_idr = &lessee->dev->mode_config.object_idr;
665 	else
666 		/* lessee can only use allowed object */
667 		object_idr = &lessee->leases;
668 
669 	count = 0;
670 	idr_for_each_entry(object_idr, entry, object) {
671 		if (count_objects > count) {
672 			drm_dbg_lease(dev, "adding object %d\n", object);
673 			ret = put_user(object, object_ids + count);
674 			if (ret)
675 				break;
676 		}
677 		count++;
678 	}
679 
680 	DRM_DEBUG("lease holds %d objects\n", count);
681 	if (ret == 0)
682 		arg->count_objects = count;
683 
684 	mutex_unlock(&dev->mode_config.idr_mutex);
685 	drm_master_put(&lessee);
686 
687 	return ret;
688 }
689 
690 /*
691  * This removes all of the objects from the lease without
692  * actually getting rid of the lease itself; that way all
693  * references to it still work correctly
694  */
drm_mode_revoke_lease_ioctl(struct drm_device * dev,void * data,struct drm_file * lessor_priv)695 int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
696 				void *data, struct drm_file *lessor_priv)
697 {
698 	struct drm_mode_revoke_lease *arg = data;
699 	struct drm_master *lessor;
700 	struct drm_master *lessee;
701 	int ret = 0;
702 
703 	drm_dbg_lease(dev, "revoke lease for %d\n", arg->lessee_id);
704 
705 	/* Can't lease without MODESET */
706 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
707 		return -EOPNOTSUPP;
708 
709 	lessor = drm_file_get_master(lessor_priv);
710 	mutex_lock(&dev->mode_config.idr_mutex);
711 
712 	lessee = _drm_find_lessee(lessor, arg->lessee_id);
713 
714 	/* No such lessee */
715 	if (!lessee) {
716 		ret = -ENOENT;
717 		goto fail;
718 	}
719 
720 	/* Lease is not held by lessor */
721 	if (lessee->lessor != lessor) {
722 		ret = -EACCES;
723 		goto fail;
724 	}
725 
726 	_drm_lease_revoke(lessee);
727 
728 fail:
729 	mutex_unlock(&dev->mode_config.idr_mutex);
730 	drm_master_put(&lessor);
731 
732 	return ret;
733 }
734