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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.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
72static uint64_t drm_lease_idr_object;
73
74struct drm_master *drm_lease_owner(struct drm_master *master)
75{
76 while (master->lessor != NULL)
77 master = master->lessor;
78 return master;
79}
80
81static struct drm_master*
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
88static 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 */
97static 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 */
109bool _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
126bool 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
145out:
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 */
154uint32_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
191out:
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 */
207static 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
258out_lessee:
259 mutex_unlock(&dev->mode_config.idr_mutex);
260
261 drm_master_put(&lessee);
262
263 return ERR_PTR(error);
264}
265
266void 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
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_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
339void 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
346static 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
378static 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;
461out_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 */
476int 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
577out_lessee:
578 drm_master_put(&lessee);
579
580out_leases:
581 put_unused_fd(fd);
582
583out_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
589int 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 */
637int 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 */
695int 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
728fail:
729 mutex_unlock(&dev->mode_config.idr_mutex);
730 drm_master_put(&lessor);
731
732 return ret;
733}
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}