root/drivers/gpu/drm/drm_lease.c

DEFINITIONS

1. drm_lease_owner
2. _drm_find_lessee
3. _drm_lease_held_master
4. _drm_has_leased
5. _drm_lease_held
6. drm_lease_held
7. drm_lease_filter_crtcs
8. drm_lease_create
9. drm_lease_destroy
10. _drm_lease_revoke
11. drm_lease_revoke
12. validate_lease
13. fill_object_idr
14. drm_mode_create_lease_ioctl
15. drm_mode_list_lessees_ioctl
16. drm_mode_get_lease_ioctl
17. drm_mode_revoke_lease_ioctl

   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 
  22 static 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  */
  32 struct 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 
  49 static 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  */
  67 static 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  */
  86 static 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  */
 108 bool _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  */
 127 bool 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  */
 150 uint32_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  */
 196 static 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 
 246 out_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  */
 263 void 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  */
 300 static void _drm_lease_revoke(struct drm_master *top)
 301 {
 302         int object;
 303         void *entry;
 304         struct drm_master *master = top;
 305 
 306         lockdep_assert_held(&top->dev->mode_config.idr_mutex);
 307 
 308         /*
 309          * Walk the tree starting at 'top' emptying all leases. Because
 310          * the tree is fully connected, we can do this without recursing
 311          */
 312         for (;;) {
 313                 DRM_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  */
 342 void 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 
 349 static 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 
 381 static 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;
 462 out_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  */
 482 int 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 will take the ownership of leases */
 546         lessee = drm_lease_create(lessor, &leases);
 547 
 548         if (IS_ERR(lessee)) {
 549                 ret = PTR_ERR(lessee);
 550                 idr_destroy(&leases);
 551                 goto out_leases;
 552         }
 553 
 554         /* Clone the lessor file to create a new file for us */
 555         DRM_DEBUG_LEASE("Allocating lease file\n");
 556         lessee_file = file_clone_open(lessor_file);
 557         if (IS_ERR(lessee_file)) {
 558                 ret = PTR_ERR(lessee_file);
 559                 goto out_lessee;
 560         }
 561 
 562         lessee_priv = lessee_file->private_data;
 563         /* Change the file to a master one */
 564         drm_master_put(&lessee_priv->master);
 565         lessee_priv->master = lessee;
 566         lessee_priv->is_master = 1;
 567         lessee_priv->authenticated = 1;
 568 
 569         /* Pass fd back to userspace */
 570         DRM_DEBUG_LEASE("Returning fd %d id %d\n", fd, lessee->lessee_id);
 571         cl->fd = fd;
 572         cl->lessee_id = lessee->lessee_id;
 573 
 574         /* Hook up the fd */
 575         fd_install(fd, lessee_file);
 576 
 577         DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n");
 578         return 0;
 579 
 580 out_lessee:
 581         drm_master_put(&lessee);
 582 
 583 out_leases:
 584         put_unused_fd(fd);
 585 
 586         DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
 587         return ret;
 588 }
 589 
 590 /**
 591  * drm_mode_list_lessees_ioctl - list lessee ids
 592  * @dev: the drm device
 593  * @data: pointer to struct drm_mode_list_lessees
 594  * @lessor_priv: the file being manipulated
 595  *
 596  * Starting from the master associated with the specified file,
 597  * the master with the provided lessee_id is found, and then
 598  * an array of lessee ids associated with leases from that master
 599  * are returned.
 600  */
 601 
 602 int drm_mode_list_lessees_ioctl(struct drm_device *dev,
 603                                void *data, struct drm_file *lessor_priv)
 604 {
 605         struct drm_mode_list_lessees *arg = data;
 606         __u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
 607         __u32 count_lessees = arg->count_lessees;
 608         struct drm_master *lessor = lessor_priv->master, *lessee;
 609         int count;
 610         int ret = 0;
 611 
 612         if (arg->pad)
 613                 return -EINVAL;
 614 
 615         /* Can't lease without MODESET */
 616         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 617                 return -EOPNOTSUPP;
 618 
 619         DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id);
 620 
 621         mutex_lock(&dev->mode_config.idr_mutex);
 622 
 623         count = 0;
 624         drm_for_each_lessee(lessee, lessor) {
 625                 /* Only list un-revoked leases */
 626                 if (!idr_is_empty(&lessee->leases)) {
 627                         if (count_lessees > count) {
 628                                 DRM_DEBUG_LEASE("Add lessee %d\n", lessee->lessee_id);
 629                                 ret = put_user(lessee->lessee_id, lessee_ids + count);
 630                                 if (ret)
 631                                         break;
 632                         }
 633                         count++;
 634                 }
 635         }
 636 
 637         DRM_DEBUG_LEASE("Lessor leases to %d\n", count);
 638         if (ret == 0)
 639                 arg->count_lessees = count;
 640 
 641         mutex_unlock(&dev->mode_config.idr_mutex);
 642 
 643         return ret;
 644 }
 645 
 646 /**
 647  * drm_mode_get_lease_ioctl - list leased objects
 648  * @dev: the drm device
 649  * @data: pointer to struct drm_mode_get_lease
 650  * @lessee_priv: the file being manipulated
 651  *
 652  * Return the list of leased objects for the specified lessee
 653  */
 654 
 655 int drm_mode_get_lease_ioctl(struct drm_device *dev,
 656                              void *data, struct drm_file *lessee_priv)
 657 {
 658         struct drm_mode_get_lease *arg = data;
 659         __u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
 660         __u32 count_objects = arg->count_objects;
 661         struct drm_master *lessee = lessee_priv->master;
 662         struct idr *object_idr;
 663         int count;
 664         void *entry;
 665         int object;
 666         int ret = 0;
 667 
 668         if (arg->pad)
 669                 return -EINVAL;
 670 
 671         /* Can't lease without MODESET */
 672         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 673                 return -EOPNOTSUPP;
 674 
 675         DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id);
 676 
 677         mutex_lock(&dev->mode_config.idr_mutex);
 678 
 679         if (lessee->lessor == NULL)
 680                 /* owner can use all objects */
 681                 object_idr = &lessee->dev->mode_config.object_idr;
 682         else
 683                 /* lessee can only use allowed object */
 684                 object_idr = &lessee->leases;
 685 
 686         count = 0;
 687         idr_for_each_entry(object_idr, entry, object) {
 688                 if (count_objects > count) {
 689                         DRM_DEBUG_LEASE("adding object %d\n", object);
 690                         ret = put_user(object, object_ids + count);
 691                         if (ret)
 692                                 break;
 693                 }
 694                 count++;
 695         }
 696 
 697         DRM_DEBUG("lease holds %d objects\n", count);
 698         if (ret == 0)
 699                 arg->count_objects = count;
 700 
 701         mutex_unlock(&dev->mode_config.idr_mutex);
 702 
 703         return ret;
 704 }
 705 
 706 /**
 707  * drm_mode_revoke_lease_ioctl - revoke lease
 708  * @dev: the drm device
 709  * @data: pointer to struct drm_mode_revoke_lease
 710  * @lessor_priv: the file being manipulated
 711  *
 712  * This removes all of the objects from the lease without
 713  * actually getting rid of the lease itself; that way all
 714  * references to it still work correctly
 715  */
 716 int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
 717                                 void *data, struct drm_file *lessor_priv)
 718 {
 719         struct drm_mode_revoke_lease *arg = data;
 720         struct drm_master *lessor = lessor_priv->master;
 721         struct drm_master *lessee;
 722         int ret = 0;
 723 
 724         DRM_DEBUG_LEASE("revoke lease for %d\n", arg->lessee_id);
 725 
 726         /* Can't lease without MODESET */
 727         if (!drm_core_check_feature(dev, DRIVER_MODESET))
 728                 return -EOPNOTSUPP;
 729 
 730         mutex_lock(&dev->mode_config.idr_mutex);
 731 
 732         lessee = _drm_find_lessee(lessor, arg->lessee_id);
 733 
 734         /* No such lessee */
 735         if (!lessee) {
 736                 ret = -ENOENT;
 737                 goto fail;
 738         }
 739 
 740         /* Lease is not held by lessor */
 741         if (lessee->lessor != lessor) {
 742                 ret = -EACCES;
 743                 goto fail;
 744         }
 745 
 746         _drm_lease_revoke(lessee);
 747 
 748 fail:
 749         mutex_unlock(&dev->mode_config.idr_mutex);
 750 
 751         return ret;
 752 }