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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
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_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
257out_lessee:
258 mutex_unlock(&dev->mode_config.idr_mutex);
259
260 drm_master_put(&lessee);
261
262 return ERR_PTR(error);
263}
264
265void 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
298static 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
336void 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
343static 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
375static 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;
458out_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 */
473int 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
574out_lessee:
575 drm_master_put(&lessee);
576
577out_leases:
578 put_unused_fd(fd);
579
580out_lessor:
581 drm_master_put(&lessor);
582 DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
583 return ret;
584}
585
586int 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 */
633int 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 */
691int 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
724fail:
725 mutex_unlock(&dev->mode_config.idr_mutex);
726 drm_master_put(&lessor);
727
728 return ret;
729}