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_helper.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_DEBUG_LEASE("lessor %d\n", lessor->lessee_id);
217 
218 	lessee = drm_master_create(lessor->dev);
219 	if (!lessee) {
220 		DRM_DEBUG_LEASE("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_DEBUG_LEASE("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_DEBUG_LEASE("new lessee %d %p, lessor %d %p\n", lessee->lessee_id, lessee, lessor->lessee_id, lessor);
253 
254 	mutex_unlock(&dev->mode_config.idr_mutex);
255 	return lessee;
256 
257 out_lessee:
258 	mutex_unlock(&dev->mode_config.idr_mutex);
259 
260 	drm_master_put(&lessee);
261 
262 	return ERR_PTR(error);
263 }
264 
drm_lease_destroy(struct drm_master * master)265 void drm_lease_destroy(struct drm_master *master)
266 {
267 	struct drm_device *dev = master->dev;
268 
269 	mutex_lock(&dev->mode_config.idr_mutex);
270 
271 	DRM_DEBUG_LEASE("drm_lease_destroy %d\n", master->lessee_id);
272 
273 	/* This master is referenced by all lessees, hence it cannot be destroyed
274 	 * until all of them have been
275 	 */
276 	WARN_ON(!list_empty(&master->lessees));
277 
278 	/* Remove this master from the lessee idr in the owner */
279 	if (master->lessee_id != 0) {
280 		DRM_DEBUG_LEASE("remove master %d from device list of lessees\n", master->lessee_id);
281 		idr_remove(&(drm_lease_owner(master)->lessee_idr), master->lessee_id);
282 	}
283 
284 	/* Remove this master from any lessee list it may be on */
285 	list_del(&master->lessee_list);
286 
287 	mutex_unlock(&dev->mode_config.idr_mutex);
288 
289 	if (master->lessor) {
290 		/* Tell the master to check the lessee list */
291 		drm_sysfs_lease_event(dev);
292 		drm_master_put(&master->lessor);
293 	}
294 
295 	DRM_DEBUG_LEASE("drm_lease_destroy done %d\n", master->lessee_id);
296 }
297 
_drm_lease_revoke(struct drm_master * top)298 static void _drm_lease_revoke(struct drm_master *top)
299 {
300 	int object;
301 	void *entry;
302 	struct drm_master *master = top;
303 
304 	lockdep_assert_held(&top->dev->mode_config.idr_mutex);
305 
306 	/*
307 	 * Walk the tree starting at 'top' emptying all leases. Because
308 	 * the tree is fully connected, we can do this without recursing
309 	 */
310 	for (;;) {
311 		DRM_DEBUG_LEASE("revoke leases for %p %d\n", master, master->lessee_id);
312 
313 		/* Evacuate the lease */
314 		idr_for_each_entry(&master->leases, entry, object)
315 			idr_remove(&master->leases, object);
316 
317 		/* Depth-first list walk */
318 
319 		/* Down */
320 		if (!list_empty(&master->lessees)) {
321 			master = list_first_entry(&master->lessees, struct drm_master, lessee_list);
322 		} else {
323 			/* Up */
324 			while (master != top && master == list_last_entry(&master->lessor->lessees, struct drm_master, lessee_list))
325 				master = master->lessor;
326 
327 			if (master == top)
328 				break;
329 
330 			/* Over */
331 			master = list_next_entry(master, lessee_list);
332 		}
333 	}
334 }
335 
drm_lease_revoke(struct drm_master * top)336 void drm_lease_revoke(struct drm_master *top)
337 {
338 	mutex_lock(&top->dev->mode_config.idr_mutex);
339 	_drm_lease_revoke(top);
340 	mutex_unlock(&top->dev->mode_config.idr_mutex);
341 }
342 
validate_lease(struct drm_device * dev,int object_count,struct drm_mode_object ** objects,bool universal_planes)343 static int validate_lease(struct drm_device *dev,
344 			  int object_count,
345 			  struct drm_mode_object **objects,
346 			  bool universal_planes)
347 {
348 	int o;
349 	int has_crtc = -1;
350 	int has_connector = -1;
351 	int has_plane = -1;
352 
353 	/* we want to confirm that there is at least one crtc, plane
354 	   connector object. */
355 
356 	for (o = 0; o < object_count; o++) {
357 		if (objects[o]->type == DRM_MODE_OBJECT_CRTC && has_crtc == -1) {
358 			has_crtc = o;
359 		}
360 		if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1)
361 			has_connector = o;
362 
363 		if (universal_planes) {
364 			if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1)
365 				has_plane = o;
366 		}
367 	}
368 	if (has_crtc == -1 || has_connector == -1)
369 		return -EINVAL;
370 	if (universal_planes && has_plane == -1)
371 		return -EINVAL;
372 	return 0;
373 }
374 
fill_object_idr(struct drm_device * dev,struct drm_file * lessor_priv,struct idr * leases,int object_count,u32 * object_ids)375 static int fill_object_idr(struct drm_device *dev,
376 			   struct drm_file *lessor_priv,
377 			   struct idr *leases,
378 			   int object_count,
379 			   u32 *object_ids)
380 {
381 	struct drm_mode_object **objects;
382 	u32 o;
383 	int ret;
384 	bool universal_planes = READ_ONCE(lessor_priv->universal_planes);
385 
386 	objects = kcalloc(object_count, sizeof(struct drm_mode_object *),
387 			  GFP_KERNEL);
388 	if (!objects)
389 		return -ENOMEM;
390 
391 	/* step one - get references to all the mode objects
392 	   and check for validity. */
393 	for (o = 0; o < object_count; o++) {
394 		objects[o] = drm_mode_object_find(dev, lessor_priv,
395 						  object_ids[o],
396 						  DRM_MODE_OBJECT_ANY);
397 		if (!objects[o]) {
398 			ret = -ENOENT;
399 			goto out_free_objects;
400 		}
401 
402 		if (!drm_mode_object_lease_required(objects[o]->type)) {
403 			DRM_DEBUG_KMS("invalid object for lease\n");
404 			ret = -EINVAL;
405 			goto out_free_objects;
406 		}
407 	}
408 
409 	ret = validate_lease(dev, object_count, objects, universal_planes);
410 	if (ret) {
411 		DRM_DEBUG_LEASE("lease validation failed\n");
412 		goto out_free_objects;
413 	}
414 
415 	/* add their IDs to the lease request - taking into account
416 	   universal planes */
417 	for (o = 0; o < object_count; o++) {
418 		struct drm_mode_object *obj = objects[o];
419 		u32 object_id = objects[o]->id;
420 
421 		DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id);
422 
423 		/*
424 		 * We're using an IDR to hold the set of leased
425 		 * objects, but we don't need to point at the object's
426 		 * data structure from the lease as the main object_idr
427 		 * will be used to actually find that. Instead, all we
428 		 * really want is a 'leased/not-leased' result, for
429 		 * which any non-NULL pointer will work fine.
430 		 */
431 		ret = idr_alloc(leases, &drm_lease_idr_object , object_id, object_id + 1, GFP_KERNEL);
432 		if (ret < 0) {
433 			DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
434 					object_id, ret);
435 			goto out_free_objects;
436 		}
437 		if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {
438 			struct drm_crtc *crtc = obj_to_crtc(obj);
439 
440 			ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL);
441 			if (ret < 0) {
442 				DRM_DEBUG_LEASE("Object primary plane %d cannot be inserted into leases (%d)\n",
443 						object_id, ret);
444 				goto out_free_objects;
445 			}
446 			if (crtc->cursor) {
447 				ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);
448 				if (ret < 0) {
449 					DRM_DEBUG_LEASE("Object cursor plane %d cannot be inserted into leases (%d)\n",
450 							object_id, ret);
451 					goto out_free_objects;
452 				}
453 			}
454 		}
455 	}
456 
457 	ret = 0;
458 out_free_objects:
459 	for (o = 0; o < object_count; o++) {
460 		if (objects[o])
461 			drm_mode_object_put(objects[o]);
462 	}
463 	kfree(objects);
464 	return ret;
465 }
466 
467 /*
468  * The master associated with the specified file will have a lease
469  * created containing the objects specified in the ioctl structure.
470  * A file descriptor will be allocated for that and returned to the
471  * application.
472  */
drm_mode_create_lease_ioctl(struct drm_device * dev,void * data,struct drm_file * lessor_priv)473 int drm_mode_create_lease_ioctl(struct drm_device *dev,
474 				void *data, struct drm_file *lessor_priv)
475 {
476 	struct drm_mode_create_lease *cl = data;
477 	size_t object_count;
478 	int ret = 0;
479 	struct idr leases;
480 	struct drm_master *lessor;
481 	struct drm_master *lessee = NULL;
482 	struct file *lessee_file = NULL;
483 	struct file *lessor_file = lessor_priv->filp;
484 	struct drm_file *lessee_priv;
485 	int fd = -1;
486 	uint32_t *object_ids;
487 
488 	/* Can't lease without MODESET */
489 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
490 		return -EOPNOTSUPP;
491 
492 	if (cl->flags && (cl->flags & ~(O_CLOEXEC | O_NONBLOCK))) {
493 		DRM_DEBUG_LEASE("invalid flags\n");
494 		return -EINVAL;
495 	}
496 
497 	lessor = drm_file_get_master(lessor_priv);
498 	/* Do not allow sub-leases */
499 	if (lessor->lessor) {
500 		DRM_DEBUG_LEASE("recursive leasing not allowed\n");
501 		ret = -EINVAL;
502 		goto out_lessor;
503 	}
504 
505 	object_count = cl->object_count;
506 
507 	/* Handle leased objects, if any */
508 	idr_init(&leases);
509 	if (object_count != 0) {
510 		object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
511 					 array_size(object_count, sizeof(__u32)));
512 		if (IS_ERR(object_ids)) {
513 			ret = PTR_ERR(object_ids);
514 			idr_destroy(&leases);
515 			goto out_lessor;
516 		}
517 
518 		/* fill and validate the object idr */
519 		ret = fill_object_idr(dev, lessor_priv, &leases,
520 				      object_count, object_ids);
521 		kfree(object_ids);
522 		if (ret) {
523 			DRM_DEBUG_LEASE("lease object lookup failed: %i\n", ret);
524 			idr_destroy(&leases);
525 			goto out_lessor;
526 		}
527 	}
528 
529 	/* Allocate a file descriptor for the lease */
530 	fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));
531 	if (fd < 0) {
532 		idr_destroy(&leases);
533 		ret = fd;
534 		goto out_lessor;
535 	}
536 
537 	DRM_DEBUG_LEASE("Creating lease\n");
538 	/* lessee will take the ownership of leases */
539 	lessee = drm_lease_create(lessor, &leases);
540 
541 	if (IS_ERR(lessee)) {
542 		ret = PTR_ERR(lessee);
543 		idr_destroy(&leases);
544 		goto out_leases;
545 	}
546 
547 	/* Clone the lessor file to create a new file for us */
548 	DRM_DEBUG_LEASE("Allocating lease file\n");
549 	lessee_file = file_clone_open(lessor_file);
550 	if (IS_ERR(lessee_file)) {
551 		ret = PTR_ERR(lessee_file);
552 		goto out_lessee;
553 	}
554 
555 	lessee_priv = lessee_file->private_data;
556 	/* Change the file to a master one */
557 	drm_master_put(&lessee_priv->master);
558 	lessee_priv->master = lessee;
559 	lessee_priv->is_master = 1;
560 	lessee_priv->authenticated = 1;
561 
562 	/* Pass fd back to userspace */
563 	DRM_DEBUG_LEASE("Returning fd %d id %d\n", fd, lessee->lessee_id);
564 	cl->fd = fd;
565 	cl->lessee_id = lessee->lessee_id;
566 
567 	/* Hook up the fd */
568 	fd_install(fd, lessee_file);
569 
570 	drm_master_put(&lessor);
571 	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n");
572 	return 0;
573 
574 out_lessee:
575 	drm_master_put(&lessee);
576 
577 out_leases:
578 	put_unused_fd(fd);
579 
580 out_lessor:
581 	drm_master_put(&lessor);
582 	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
583 	return ret;
584 }
585 
drm_mode_list_lessees_ioctl(struct drm_device * dev,void * data,struct drm_file * lessor_priv)586 int drm_mode_list_lessees_ioctl(struct drm_device *dev,
587 			       void *data, struct drm_file *lessor_priv)
588 {
589 	struct drm_mode_list_lessees *arg = data;
590 	__u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
591 	__u32 count_lessees = arg->count_lessees;
592 	struct drm_master *lessor, *lessee;
593 	int count;
594 	int ret = 0;
595 
596 	if (arg->pad)
597 		return -EINVAL;
598 
599 	/* Can't lease without MODESET */
600 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
601 		return -EOPNOTSUPP;
602 
603 	lessor = drm_file_get_master(lessor_priv);
604 	DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id);
605 
606 	mutex_lock(&dev->mode_config.idr_mutex);
607 
608 	count = 0;
609 	drm_for_each_lessee(lessee, lessor) {
610 		/* Only list un-revoked leases */
611 		if (!idr_is_empty(&lessee->leases)) {
612 			if (count_lessees > count) {
613 				DRM_DEBUG_LEASE("Add lessee %d\n", lessee->lessee_id);
614 				ret = put_user(lessee->lessee_id, lessee_ids + count);
615 				if (ret)
616 					break;
617 			}
618 			count++;
619 		}
620 	}
621 
622 	DRM_DEBUG_LEASE("Lessor leases to %d\n", count);
623 	if (ret == 0)
624 		arg->count_lessees = count;
625 
626 	mutex_unlock(&dev->mode_config.idr_mutex);
627 	drm_master_put(&lessor);
628 
629 	return ret;
630 }
631 
632 /* 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)633 int drm_mode_get_lease_ioctl(struct drm_device *dev,
634 			     void *data, struct drm_file *lessee_priv)
635 {
636 	struct drm_mode_get_lease *arg = data;
637 	__u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
638 	__u32 count_objects = arg->count_objects;
639 	struct drm_master *lessee;
640 	struct idr *object_idr;
641 	int count;
642 	void *entry;
643 	int object;
644 	int ret = 0;
645 
646 	if (arg->pad)
647 		return -EINVAL;
648 
649 	/* Can't lease without MODESET */
650 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
651 		return -EOPNOTSUPP;
652 
653 	lessee = drm_file_get_master(lessee_priv);
654 	DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id);
655 
656 	mutex_lock(&dev->mode_config.idr_mutex);
657 
658 	if (lessee->lessor == NULL)
659 		/* owner can use all objects */
660 		object_idr = &lessee->dev->mode_config.object_idr;
661 	else
662 		/* lessee can only use allowed object */
663 		object_idr = &lessee->leases;
664 
665 	count = 0;
666 	idr_for_each_entry(object_idr, entry, object) {
667 		if (count_objects > count) {
668 			DRM_DEBUG_LEASE("adding object %d\n", object);
669 			ret = put_user(object, object_ids + count);
670 			if (ret)
671 				break;
672 		}
673 		count++;
674 	}
675 
676 	DRM_DEBUG("lease holds %d objects\n", count);
677 	if (ret == 0)
678 		arg->count_objects = count;
679 
680 	mutex_unlock(&dev->mode_config.idr_mutex);
681 	drm_master_put(&lessee);
682 
683 	return ret;
684 }
685 
686 /*
687  * This removes all of the objects from the lease without
688  * actually getting rid of the lease itself; that way all
689  * references to it still work correctly
690  */
drm_mode_revoke_lease_ioctl(struct drm_device * dev,void * data,struct drm_file * lessor_priv)691 int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
692 				void *data, struct drm_file *lessor_priv)
693 {
694 	struct drm_mode_revoke_lease *arg = data;
695 	struct drm_master *lessor;
696 	struct drm_master *lessee;
697 	int ret = 0;
698 
699 	DRM_DEBUG_LEASE("revoke lease for %d\n", arg->lessee_id);
700 
701 	/* Can't lease without MODESET */
702 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
703 		return -EOPNOTSUPP;
704 
705 	lessor = drm_file_get_master(lessor_priv);
706 	mutex_lock(&dev->mode_config.idr_mutex);
707 
708 	lessee = _drm_find_lessee(lessor, arg->lessee_id);
709 
710 	/* No such lessee */
711 	if (!lessee) {
712 		ret = -ENOENT;
713 		goto fail;
714 	}
715 
716 	/* Lease is not held by lessor */
717 	if (lessee->lessor != lessor) {
718 		ret = -EACCES;
719 		goto fail;
720 	}
721 
722 	_drm_lease_revoke(lessee);
723 
724 fail:
725 	mutex_unlock(&dev->mode_config.idr_mutex);
726 	drm_master_put(&lessor);
727 
728 	return ret;
729 }
730