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  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#include "drm_legacy.h"
 18
 19#define drm_for_each_lessee(lessee, lessor) \
 20	list_for_each_entry((lessee), &(lessor)->lessees, lessee_list)
 21
 22static uint64_t drm_lease_idr_object;
 23
 24/**
 25 * drm_lease_owner - return ancestor owner drm_master
 26 * @master: drm_master somewhere within tree of lessees and lessors
 27 *
 28 * RETURN:
 29 *
 30 * drm_master at the top of the tree (i.e, with lessor NULL
 31 */
 32struct drm_master *drm_lease_owner(struct drm_master *master)
 33{
 34	while (master->lessor != NULL)
 35		master = master->lessor;
 36	return master;
 37}
 38
 39/**
 40 * _drm_find_lessee - find lessee by id (idr_mutex held)
 41 * @master: drm_master of lessor
 42 * @lessee_id: id
 43 *
 44 * RETURN:
 45 *
 46 * drm_master of the lessee if valid, NULL otherwise
 47 */
 48
 49static struct drm_master*
 50_drm_find_lessee(struct drm_master *master, int lessee_id)
 51{
 52	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
 53	return idr_find(&drm_lease_owner(master)->lessee_idr, lessee_id);
 54}
 55
 56/**
 57 * _drm_lease_held_master - check to see if an object is leased (or owned) by master (idr_mutex held)
 58 * @master: the master to check the lease status of
 59 * @id: the id to check
 60 *
 61 * Checks if the specified master holds a lease on the object. Return
 62 * value:
 63 *
 64 *	true		'master' holds a lease on (or owns) the object
 65 *	false		'master' does not hold a lease.
 66 */
 67static int _drm_lease_held_master(struct drm_master *master, int id)
 68{
 69	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
 70	if (master->lessor)
 71		return idr_find(&master->leases, id) != NULL;
 72	return true;
 73}
 74
 75/**
 76 * _drm_has_leased - check to see if an object has been leased (idr_mutex held)
 77 * @master: the master to check the lease status of
 78 * @id: the id to check
 79 *
 80 * Checks if any lessee of 'master' holds a lease on 'id'. Return
 81 * value:
 82 *
 83 *	true		Some lessee holds a lease on the object.
 84 *	false		No lessee has a lease on the object.
 85 */
 86static bool _drm_has_leased(struct drm_master *master, int id)
 87{
 88	struct drm_master *lessee;
 89
 90	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
 91	drm_for_each_lessee(lessee, master)
 92		if (_drm_lease_held_master(lessee, id))
 93			return true;
 94	return false;
 95}
 96
 97/**
 98 * _drm_lease_held - check drm_mode_object lease status (idr_mutex held)
 99 * @file_priv: the master drm_file
100 * @id: the object id
101 *
102 * Checks if the specified master holds a lease on the object. Return
103 * value:
104 *
105 *	true		'master' holds a lease on (or owns) the object
106 *	false		'master' does not hold a lease.
107 */
108bool _drm_lease_held(struct drm_file *file_priv, int id)
109{
110	if (!file_priv || !file_priv->master)
111		return true;
112
113	return _drm_lease_held_master(file_priv->master, id);
114}
115
116/**
117 * drm_lease_held - check drm_mode_object lease status (idr_mutex not held)
118 * @file_priv: the master drm_file
119 * @id: the object id
120 *
121 * Checks if the specified master holds a lease on the object. Return
122 * value:
123 *
124 *	true		'master' holds a lease on (or owns) the object
125 *	false		'master' does not hold a lease.
126 */
127bool drm_lease_held(struct drm_file *file_priv, int id)
128{
129	struct drm_master *master;
130	bool ret;
131
132	if (!file_priv || !file_priv->master || !file_priv->master->lessor)
133		return true;
134
135	master = file_priv->master;
136	mutex_lock(&master->dev->mode_config.idr_mutex);
137	ret = _drm_lease_held_master(master, id);
138	mutex_unlock(&master->dev->mode_config.idr_mutex);
139	return ret;
140}
141
142/**
143 * drm_lease_filter_crtcs - restricted crtc set to leased values (idr_mutex not held)
144 * @file_priv: requestor file
145 * @crtcs_in: bitmask of crtcs to check
146 *
147 * Reconstructs a crtc mask based on the crtcs which are visible
148 * through the specified file.
149 */
150uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in)
151{
152	struct drm_master *master;
153	struct drm_device *dev;
154	struct drm_crtc *crtc;
155	int count_in, count_out;
156	uint32_t crtcs_out = 0;
157
158	if (!file_priv || !file_priv->master || !file_priv->master->lessor)
159		return crtcs_in;
160
161	master = file_priv->master;
162	dev = master->dev;
163
164	count_in = count_out = 0;
165	mutex_lock(&master->dev->mode_config.idr_mutex);
166	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
167		if (_drm_lease_held_master(master, crtc->base.id)) {
168			uint32_t mask_in = 1ul << count_in;
169			if ((crtcs_in & mask_in) != 0) {
170				uint32_t mask_out = 1ul << count_out;
171				crtcs_out |= mask_out;
172			}
173			count_out++;
174		}
175		count_in++;
176	}
177	mutex_unlock(&master->dev->mode_config.idr_mutex);
178	return crtcs_out;
179}
180
181/*
182 * drm_lease_create - create a new drm_master with leased objects (idr_mutex not held)
183 * @lessor: lease holder (or owner) of objects
184 * @leases: objects to lease to the new drm_master
185 *
186 * Uses drm_master_create to allocate a new drm_master, then checks to
187 * make sure all of the desired objects can be leased, atomically
188 * leasing them to the new drmmaster.
189 *
190 * 	ERR_PTR(-EACCES)	some other master holds the title to any object
191 * 	ERR_PTR(-ENOENT)	some object is not a valid DRM object for this device
192 * 	ERR_PTR(-EBUSY)		some other lessee holds title to this object
193 *	ERR_PTR(-EEXIST)	same object specified more than once in the provided list
194 *	ERR_PTR(-ENOMEM)	allocation failed
195 */
196static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr *leases)
197{
198	struct drm_device *dev = lessor->dev;
199	int error;
200	struct drm_master *lessee;
201	int object;
202	int id;
203	void *entry;
204
205	DRM_DEBUG_LEASE("lessor %d\n", lessor->lessee_id);
206
207	lessee = drm_master_create(lessor->dev);
208	if (!lessee) {
209		DRM_DEBUG_LEASE("drm_master_create failed\n");
210		return ERR_PTR(-ENOMEM);
211	}
212
213	mutex_lock(&dev->mode_config.idr_mutex);
214
215	idr_for_each_entry(leases, entry, object) {
216		error = 0;
217		if (!idr_find(&dev->mode_config.object_idr, object))
218			error = -ENOENT;
219		else if (_drm_has_leased(lessor, object))
220			error = -EBUSY;
221
222		if (error != 0) {
223			DRM_DEBUG_LEASE("object %d failed %d\n", object, error);
224			goto out_lessee;
225		}
226	}
227
228	/* Insert the new lessee into the tree */
229	id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL);
230	if (id < 0) {
231		error = id;
232		goto out_lessee;
233	}
234
235	lessee->lessee_id = id;
236	lessee->lessor = drm_master_get(lessor);
237	list_add_tail(&lessee->lessee_list, &lessor->lessees);
238
239	/* Move the leases over */
240	lessee->leases = *leases;
241	DRM_DEBUG_LEASE("new lessee %d %p, lessor %d %p\n", lessee->lessee_id, lessee, lessor->lessee_id, lessor);
242
243	mutex_unlock(&dev->mode_config.idr_mutex);
244	return lessee;
245
246out_lessee:
247	mutex_unlock(&dev->mode_config.idr_mutex);
248
249	drm_master_put(&lessee);
250
251	return ERR_PTR(error);
252}
253
254/**
255 * drm_lease_destroy - a master is going away (idr_mutex not held)
256 * @master: the drm_master being destroyed
257 *
258 * All lessees will have been destroyed as they
259 * hold a reference on their lessor. Notify any
260 * lessor for this master so that it can check
261 * the list of lessees.
262 */
263void drm_lease_destroy(struct drm_master *master)
264{
265	struct drm_device *dev = master->dev;
266
267	mutex_lock(&dev->mode_config.idr_mutex);
268
269	DRM_DEBUG_LEASE("drm_lease_destroy %d\n", master->lessee_id);
270
271	/* This master is referenced by all lessees, hence it cannot be destroyed
272	 * until all of them have been
273	 */
274	WARN_ON(!list_empty(&master->lessees));
275
276	/* Remove this master from the lessee idr in the owner */
277	if (master->lessee_id != 0) {
278		DRM_DEBUG_LEASE("remove master %d from device list of lessees\n", master->lessee_id);
279		idr_remove(&(drm_lease_owner(master)->lessee_idr), master->lessee_id);
280	}
281
282	/* Remove this master from any lessee list it may be on */
283	list_del(&master->lessee_list);
284
285	mutex_unlock(&dev->mode_config.idr_mutex);
286
287	if (master->lessor) {
288		/* Tell the master to check the lessee list */
289		drm_sysfs_lease_event(dev);
290		drm_master_put(&master->lessor);
291	}
292
293	DRM_DEBUG_LEASE("drm_lease_destroy done %d\n", master->lessee_id);
294}
295
296/**
297 * _drm_lease_revoke - revoke access to all leased objects (idr_mutex held)
298 * @top: the master losing its lease
299 */
300static 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_DEBUG_LEASE("revoke leases for %p %d\n", master, master->lessee_id);
314
315		/* Evacuate the lease */
316		idr_for_each_entry(&master->leases, entry, object)
317			idr_remove(&master->leases, object);
318
319		/* Depth-first list walk */
320
321		/* Down */
322		if (!list_empty(&master->lessees)) {
323			master = list_first_entry(&master->lessees, struct drm_master, lessee_list);
324		} else {
325			/* Up */
326			while (master != top && master == list_last_entry(&master->lessor->lessees, struct drm_master, lessee_list))
327				master = master->lessor;
328
329			if (master == top)
330				break;
331
332			/* Over */
333			master = list_next_entry(master, lessee_list);
334		}
335	}
336}
337
338/**
339 * drm_lease_revoke - revoke access to all leased objects (idr_mutex not held)
340 * @top: the master losing its lease
341 */
342void drm_lease_revoke(struct drm_master *top)
343{
344	mutex_lock(&top->dev->mode_config.idr_mutex);
345	_drm_lease_revoke(top);
346	mutex_unlock(&top->dev->mode_config.idr_mutex);
347}
348
349static int validate_lease(struct drm_device *dev,
350			  int object_count,
351			  struct drm_mode_object **objects,
352			  bool universal_planes)
353{
354	int o;
355	int has_crtc = -1;
356	int has_connector = -1;
357	int has_plane = -1;
358
359	/* we want to confirm that there is at least one crtc, plane
360	   connector object. */
361
362	for (o = 0; o < object_count; o++) {
363		if (objects[o]->type == DRM_MODE_OBJECT_CRTC && has_crtc == -1) {
364			has_crtc = o;
365		}
366		if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1)
367			has_connector = o;
368
369		if (universal_planes) {
370			if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1)
371				has_plane = o;
372		}
373	}
374	if (has_crtc == -1 || has_connector == -1)
375		return -EINVAL;
376	if (universal_planes && has_plane == -1)
377		return -EINVAL;
378	return 0;
379}
380
381static int fill_object_idr(struct drm_device *dev,
382			   struct drm_file *lessor_priv,
383			   struct idr *leases,
384			   int object_count,
385			   u32 *object_ids)
386{
387	struct drm_mode_object **objects;
388	u32 o;
389	int ret;
390	bool universal_planes = READ_ONCE(lessor_priv->universal_planes);
391
392	objects = kcalloc(object_count, sizeof(struct drm_mode_object *),
393			  GFP_KERNEL);
394	if (!objects)
395		return -ENOMEM;
396
397	/* step one - get references to all the mode objects
398	   and check for validity. */
399	for (o = 0; o < object_count; o++) {
400		objects[o] = drm_mode_object_find(dev, lessor_priv,
401						  object_ids[o],
402						  DRM_MODE_OBJECT_ANY);
403		if (!objects[o]) {
404			ret = -ENOENT;
405			goto out_free_objects;
406		}
407
408		if (!drm_mode_object_lease_required(objects[o]->type)) {
409			DRM_DEBUG_KMS("invalid object for lease\n");
410			ret = -EINVAL;
411			goto out_free_objects;
412		}
413	}
414
415	ret = validate_lease(dev, object_count, objects, universal_planes);
416	if (ret) {
417		DRM_DEBUG_LEASE("lease validation failed\n");
418		goto out_free_objects;
419	}
420
421	/* add their IDs to the lease request - taking into account
422	   universal planes */
423	for (o = 0; o < object_count; o++) {
424		struct drm_mode_object *obj = objects[o];
425		u32 object_id = objects[o]->id;
426		DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id);
427
428		/*
429		 * We're using an IDR to hold the set of leased
430		 * objects, but we don't need to point at the object's
431		 * data structure from the lease as the main object_idr
432		 * will be used to actually find that. Instead, all we
433		 * really want is a 'leased/not-leased' result, for
434		 * which any non-NULL pointer will work fine.
435		 */
436		ret = idr_alloc(leases, &drm_lease_idr_object , object_id, object_id + 1, GFP_KERNEL);
437		if (ret < 0) {
438			DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
439					object_id, ret);
440			goto out_free_objects;
441		}
442		if (obj->type == DRM_MODE_OBJECT_CRTC && !universal_planes) {
443			struct drm_crtc *crtc = obj_to_crtc(obj);
444			ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL);
445			if (ret < 0) {
446				DRM_DEBUG_LEASE("Object primary plane %d cannot be inserted into leases (%d)\n",
447						object_id, ret);
448				goto out_free_objects;
449			}
450			if (crtc->cursor) {
451				ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);
452				if (ret < 0) {
453					DRM_DEBUG_LEASE("Object cursor plane %d cannot be inserted into leases (%d)\n",
454							object_id, ret);
455					goto out_free_objects;
456				}
457			}
458		}
459	}
460
461	ret = 0;
462out_free_objects:
463	for (o = 0; o < object_count; o++) {
464		if (objects[o])
465			drm_mode_object_put(objects[o]);
466	}
467	kfree(objects);
468	return ret;
469}
470
471/**
472 * drm_mode_create_lease_ioctl - create a new lease
473 * @dev: the drm device
474 * @data: pointer to struct drm_mode_create_lease
475 * @lessor_priv: the file being manipulated
476 *
477 * The master associated with the specified file will have a lease
478 * created containing the objects specified in the ioctl structure.
479 * A file descriptor will be allocated for that and returned to the
480 * application.
481 */
482int drm_mode_create_lease_ioctl(struct drm_device *dev,
483				void *data, struct drm_file *lessor_priv)
484{
485	struct drm_mode_create_lease *cl = data;
486	size_t object_count;
487	int ret = 0;
488	struct idr leases;
489	struct drm_master *lessor = lessor_priv->master;
490	struct drm_master *lessee = NULL;
491	struct file *lessee_file = NULL;
492	struct file *lessor_file = lessor_priv->filp;
493	struct drm_file *lessee_priv;
494	int fd = -1;
495	uint32_t *object_ids;
496
497	/* Can't lease without MODESET */
498	if (!drm_core_check_feature(dev, DRIVER_MODESET))
499		return -EOPNOTSUPP;
500
501	/* Do not allow sub-leases */
502	if (lessor->lessor) {
503		DRM_DEBUG_LEASE("recursive leasing not allowed\n");
504		return -EINVAL;
505	}
506
507	/* need some objects */
508	if (cl->object_count == 0) {
509		DRM_DEBUG_LEASE("no objects in lease\n");
510		return -EINVAL;
511	}
512
513	if (cl->flags && (cl->flags & ~(O_CLOEXEC | O_NONBLOCK))) {
514		DRM_DEBUG_LEASE("invalid flags\n");
515		return -EINVAL;
516	}
517
518	object_count = cl->object_count;
519
520	object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
521			array_size(object_count, sizeof(__u32)));
522	if (IS_ERR(object_ids))
523		return PTR_ERR(object_ids);
524
525	idr_init(&leases);
526
527	/* fill and validate the object idr */
528	ret = fill_object_idr(dev, lessor_priv, &leases,
529			      object_count, object_ids);
530	kfree(object_ids);
531	if (ret) {
532		DRM_DEBUG_LEASE("lease object lookup failed: %i\n", ret);
533		idr_destroy(&leases);
534		return ret;
535	}
536
537	/* Allocate a file descriptor for the lease */
538	fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));
539	if (fd < 0) {
540		idr_destroy(&leases);
541		return fd;
542	}
543
544	DRM_DEBUG_LEASE("Creating lease\n");
545	lessee = drm_lease_create(lessor, &leases);
546
547	if (IS_ERR(lessee)) {
548		ret = PTR_ERR(lessee);
549		goto out_leases;
550	}
551
552	/* Clone the lessor file to create a new file for us */
553	DRM_DEBUG_LEASE("Allocating lease file\n");
554	lessee_file = file_clone_open(lessor_file);
555	if (IS_ERR(lessee_file)) {
556		ret = PTR_ERR(lessee_file);
557		goto out_lessee;
558	}
559
560	lessee_priv = lessee_file->private_data;
561	/* Change the file to a master one */
562	drm_master_put(&lessee_priv->master);
563	lessee_priv->master = lessee;
564	lessee_priv->is_master = 1;
565	lessee_priv->authenticated = 1;
566
567	/* Pass fd back to userspace */
568	DRM_DEBUG_LEASE("Returning fd %d id %d\n", fd, lessee->lessee_id);
569	cl->fd = fd;
570	cl->lessee_id = lessee->lessee_id;
571
572	/* Hook up the fd */
573	fd_install(fd, lessee_file);
574
575	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n");
576	return 0;
577
578out_lessee:
579	drm_master_put(&lessee);
580
581out_leases:
582	put_unused_fd(fd);
583	idr_destroy(&leases);
584
585	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
586	return ret;
587}
588
589/**
590 * drm_mode_list_lessees_ioctl - list lessee ids
591 * @dev: the drm device
592 * @data: pointer to struct drm_mode_list_lessees
593 * @lessor_priv: the file being manipulated
594 *
595 * Starting from the master associated with the specified file,
596 * the master with the provided lessee_id is found, and then
597 * an array of lessee ids associated with leases from that master
598 * are returned.
599 */
600
601int drm_mode_list_lessees_ioctl(struct drm_device *dev,
602			       void *data, struct drm_file *lessor_priv)
603{
604	struct drm_mode_list_lessees *arg = data;
605	__u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
606	__u32 count_lessees = arg->count_lessees;
607	struct drm_master *lessor = lessor_priv->master, *lessee;
608	int count;
609	int ret = 0;
610
611	if (arg->pad)
612		return -EINVAL;
613
614	/* Can't lease without MODESET */
615	if (!drm_core_check_feature(dev, DRIVER_MODESET))
616		return -EOPNOTSUPP;
617
618	DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id);
619
620	mutex_lock(&dev->mode_config.idr_mutex);
621
622	count = 0;
623	drm_for_each_lessee(lessee, lessor) {
624		/* Only list un-revoked leases */
625		if (!idr_is_empty(&lessee->leases)) {
626			if (count_lessees > count) {
627				DRM_DEBUG_LEASE("Add lessee %d\n", lessee->lessee_id);
628				ret = put_user(lessee->lessee_id, lessee_ids + count);
629				if (ret)
630					break;
631			}
632			count++;
633		}
634	}
635
636	DRM_DEBUG_LEASE("Lessor leases to %d\n", count);
637	if (ret == 0)
638		arg->count_lessees = count;
639
640	mutex_unlock(&dev->mode_config.idr_mutex);
641
642	return ret;
643}
644
645/**
646 * drm_mode_get_lease_ioctl - list leased objects
647 * @dev: the drm device
648 * @data: pointer to struct drm_mode_get_lease
649 * @lessee_priv: the file being manipulated
650 *
651 * Return the list of leased objects for the specified lessee
652 */
653
654int drm_mode_get_lease_ioctl(struct drm_device *dev,
655			     void *data, struct drm_file *lessee_priv)
656{
657	struct drm_mode_get_lease *arg = data;
658	__u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
659	__u32 count_objects = arg->count_objects;
660	struct drm_master *lessee = lessee_priv->master;
661	struct idr *object_idr;
662	int count;
663	void *entry;
664	int object;
665	int ret = 0;
666
667	if (arg->pad)
668		return -EINVAL;
669
670	/* Can't lease without MODESET */
671	if (!drm_core_check_feature(dev, DRIVER_MODESET))
672		return -EOPNOTSUPP;
673
674	DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id);
675
676	mutex_lock(&dev->mode_config.idr_mutex);
677
678	if (lessee->lessor == NULL)
679		/* owner can use all objects */
680		object_idr = &lessee->dev->mode_config.object_idr;
681	else
682		/* lessee can only use allowed object */
683		object_idr = &lessee->leases;
684
685	count = 0;
686	idr_for_each_entry(object_idr, entry, object) {
687		if (count_objects > count) {
688			DRM_DEBUG_LEASE("adding object %d\n", object);
689			ret = put_user(object, object_ids + count);
690			if (ret)
691				break;
692		}
693		count++;
694	}
695
696	DRM_DEBUG("lease holds %d objects\n", count);
697	if (ret == 0)
698		arg->count_objects = count;
699
700	mutex_unlock(&dev->mode_config.idr_mutex);
701
702	return ret;
703}
704
705/**
706 * drm_mode_revoke_lease_ioctl - revoke lease
707 * @dev: the drm device
708 * @data: pointer to struct drm_mode_revoke_lease
709 * @lessor_priv: the file being manipulated
710 *
711 * This removes all of the objects from the lease without
712 * actually getting rid of the lease itself; that way all
713 * references to it still work correctly
714 */
715int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
716				void *data, struct drm_file *lessor_priv)
717{
718	struct drm_mode_revoke_lease *arg = data;
719	struct drm_master *lessor = lessor_priv->master;
720	struct drm_master *lessee;
721	int ret = 0;
722
723	DRM_DEBUG_LEASE("revoke lease for %d\n", arg->lessee_id);
724
725	/* Can't lease without MODESET */
726	if (!drm_core_check_feature(dev, DRIVER_MODESET))
727		return -EOPNOTSUPP;
728
729	mutex_lock(&dev->mode_config.idr_mutex);
730
731	lessee = _drm_find_lessee(lessor, arg->lessee_id);
732
733	/* No such lessee */
734	if (!lessee) {
735		ret = -ENOENT;
736		goto fail;
737	}
738
739	/* Lease is not held by lessor */
740	if (lessee->lessor != lessor) {
741		ret = -EACCES;
742		goto fail;
743	}
744
745	_drm_lease_revoke(lessee);
746
747fail:
748	mutex_unlock(&dev->mode_config.idr_mutex);
749
750	return ret;
751}