drm_lease.c 19.8 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
/*
 * Copyright © 2017 Keith Packard <keithp@keithp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#include <drm/drmP.h>
#include "drm_internal.h"
#include "drm_legacy.h"
#include "drm_crtc_internal.h"
#include <drm/drm_lease.h>
#include <drm/drm_auth.h>
#include <drm/drm_crtc_helper.h>

#define drm_for_each_lessee(lessee, lessor) \
	list_for_each_entry((lessee), &(lessor)->lessees, lessee_list)

26 27
static uint64_t drm_lease_idr_object;

28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46
/**
 * drm_lease_owner - return ancestor owner drm_master
 * @master: drm_master somewhere within tree of lessees and lessors
 *
 * RETURN:
 *
 * drm_master at the top of the tree (i.e, with lessor NULL
 */
struct drm_master *drm_lease_owner(struct drm_master *master)
{
	while (master->lessor != NULL)
		master = master->lessor;
	return master;
}
EXPORT_SYMBOL(drm_lease_owner);

/**
 * _drm_find_lessee - find lessee by id (idr_mutex held)
 * @master: drm_master of lessor
47
 * @lessee_id: id
48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
 *
 * RETURN:
 *
 * drm_master of the lessee if valid, NULL otherwise
 */

static struct drm_master*
_drm_find_lessee(struct drm_master *master, int lessee_id)
{
	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
	return idr_find(&drm_lease_owner(master)->lessee_idr, lessee_id);
}

/**
 * _drm_lease_held_master - check to see if an object is leased (or owned) by master (idr_mutex held)
 * @master: the master to check the lease status of
 * @id: the id to check
 *
 * Checks if the specified master holds a lease on the object. Return
 * value:
 *
 *	true		'master' holds a lease on (or owns) the object
 *	false		'master' does not hold a lease.
 */
static int _drm_lease_held_master(struct drm_master *master, int id)
{
	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
	if (master->lessor)
		return idr_find(&master->leases, id) != NULL;
	return true;
}

/**
 * _drm_has_leased - check to see if an object has been leased (idr_mutex held)
 * @master: the master to check the lease status of
 * @id: the id to check
 *
 * Checks if any lessee of 'master' holds a lease on 'id'. Return
 * value:
 *
 *	true		Some lessee holds a lease on the object.
 *	false		No lessee has a lease on the object.
 */
static bool _drm_has_leased(struct drm_master *master, int id)
{
	struct drm_master *lessee;

	lockdep_assert_held(&master->dev->mode_config.idr_mutex);
	drm_for_each_lessee(lessee, master)
		if (_drm_lease_held_master(lessee, id))
			return true;
	return false;
}

/**
 * _drm_lease_held - check drm_mode_object lease status (idr_mutex held)
104
 * @file_priv: the master drm_file
105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123
 * @id: the object id
 *
 * Checks if the specified master holds a lease on the object. Return
 * value:
 *
 *	true		'master' holds a lease on (or owns) the object
 *	false		'master' does not hold a lease.
 */
bool _drm_lease_held(struct drm_file *file_priv, int id)
{
	if (file_priv == NULL || file_priv->master == NULL)
		return true;

	return _drm_lease_held_master(file_priv->master, id);
}
EXPORT_SYMBOL(_drm_lease_held);

/**
 * drm_lease_held - check drm_mode_object lease status (idr_mutex not held)
124
 * @file_priv: the master drm_file
125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151
 * @id: the object id
 *
 * Checks if the specified master holds a lease on the object. Return
 * value:
 *
 *	true		'master' holds a lease on (or owns) the object
 *	false		'master' does not hold a lease.
 */
bool drm_lease_held(struct drm_file *file_priv, int id)
{
	struct drm_master *master;
	bool ret;

	if (file_priv == NULL || file_priv->master == NULL)
		return true;

	master = file_priv->master;
	mutex_lock(&master->dev->mode_config.idr_mutex);
	ret = _drm_lease_held_master(master, id);
	mutex_unlock(&master->dev->mode_config.idr_mutex);
	return ret;
}
EXPORT_SYMBOL(drm_lease_held);

/**
 * drm_lease_filter_crtcs - restricted crtc set to leased values (idr_mutex not held)
 * @file_priv: requestor file
152
 * @crtcs_in: bitmask of crtcs to check
153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237
 *
 * Reconstructs a crtc mask based on the crtcs which are visible
 * through the specified file.
 */
uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in)
{
	struct drm_master *master;
	struct drm_device *dev;
	struct drm_crtc *crtc;
	int count_in, count_out;
	uint32_t crtcs_out = 0;

	if (file_priv == NULL || file_priv->master == NULL)
		return crtcs_in;

	master = file_priv->master;
	dev = master->dev;

	count_in = count_out = 0;
	mutex_lock(&master->dev->mode_config.idr_mutex);
	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
		if (_drm_lease_held_master(master, crtc->base.id)) {
			uint32_t mask_in = 1ul << count_in;
			if ((crtcs_in & mask_in) != 0) {
				uint32_t mask_out = 1ul << count_out;
				crtcs_out |= mask_out;
			}
			count_out++;
		}
		count_in++;
	}
	mutex_unlock(&master->dev->mode_config.idr_mutex);
	return crtcs_out;
}
EXPORT_SYMBOL(drm_lease_filter_crtcs);

/*
 * drm_lease_create - create a new drm_master with leased objects (idr_mutex not held)
 * @lessor: lease holder (or owner) of objects
 * @leases: objects to lease to the new drm_master
 *
 * Uses drm_master_create to allocate a new drm_master, then checks to
 * make sure all of the desired objects can be leased, atomically
 * leasing them to the new drmmaster.
 *
 * 	ERR_PTR(-EACCESS)	some other master holds the title to any object
 * 	ERR_PTR(-ENOENT)	some object is not a valid DRM object for this device
 * 	ERR_PTR(-EBUSY)		some other lessee holds title to this object
 *	ERR_PTR(-EEXIST)	same object specified more than once in the provided list
 *	ERR_PTR(-ENOMEM)	allocation failed
 */
static struct drm_master *drm_lease_create(struct drm_master *lessor, struct idr *leases)
{
	struct drm_device *dev = lessor->dev;
	int error;
	struct drm_master *lessee;
	int object;
	int id;
	void *entry;

	DRM_DEBUG_LEASE("lessor %d\n", lessor->lessee_id);

	lessee = drm_master_create(lessor->dev);
	if (!lessee) {
		DRM_DEBUG_LEASE("drm_master_create failed\n");
		return ERR_PTR(-ENOMEM);
	}

	mutex_lock(&dev->mode_config.idr_mutex);

	idr_for_each_entry(leases, entry, object) {
		error = 0;
		if (!idr_find(&dev->mode_config.crtc_idr, object))
			error = -ENOENT;
		else if (!_drm_lease_held_master(lessor, object))
			error = -EACCES;
		else if (_drm_has_leased(lessor, object))
			error = -EBUSY;

		if (error != 0) {
			DRM_DEBUG_LEASE("object %d failed %d\n", object, error);
			goto out_lessee;
		}
	}

238 239 240 241 242 243 244 245 246 247 248
	/* Insert the new lessee into the tree */
	id = idr_alloc(&(drm_lease_owner(lessor)->lessee_idr), lessee, 1, 0, GFP_KERNEL);
	if (id < 0) {
		error = id;
		goto out_lessee;
	}

	lessee->lessee_id = id;
	lessee->lessor = drm_master_get(lessor);
	list_add_tail(&lessee->lessee_list, &lessor->lessees);

249 250 251 252 253 254 255 256 257 258
	/* Move the leases over */
	lessee->leases = *leases;
	DRM_DEBUG_LEASE("new lessee %d %p, lessor %d %p\n", lessee->lessee_id, lessee, lessor->lessee_id, lessor);

	mutex_unlock(&dev->mode_config.idr_mutex);
	return lessee;

out_lessee:
	mutex_unlock(&dev->mode_config.idr_mutex);

259 260
	drm_master_put(&lessee);

261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298
	return ERR_PTR(error);
}

/**
 * drm_lease_destroy - a master is going away (idr_mutex not held)
 * @master: the drm_master being destroyed
 *
 * All lessees will have been destroyed as they
 * hold a reference on their lessor. Notify any
 * lessor for this master so that it can check
 * the list of lessees.
 */
void drm_lease_destroy(struct drm_master *master)
{
	struct drm_device *dev = master->dev;

	mutex_lock(&dev->mode_config.idr_mutex);

	DRM_DEBUG_LEASE("drm_lease_destroy %d\n", master->lessee_id);

	/* This master is referenced by all lessees, hence it cannot be destroyed
	 * until all of them have been
	 */
	WARN_ON(!list_empty(&master->lessees));

	/* Remove this master from the lessee idr in the owner */
	if (master->lessee_id != 0) {
		DRM_DEBUG_LEASE("remove master %d from device list of lessees\n", master->lessee_id);
		idr_remove(&(drm_lease_owner(master)->lessee_idr), master->lessee_id);
	}

	/* Remove this master from any lessee list it may be on */
	list_del(&master->lessee_list);

	mutex_unlock(&dev->mode_config.idr_mutex);

	if (master->lessor) {
		/* Tell the master to check the lessee list */
D
Daniel Vetter 已提交
299
		drm_sysfs_lease_event(dev);
300 301 302 303 304 305 306 307
		drm_master_put(&master->lessor);
	}

	DRM_DEBUG_LEASE("drm_lease_destroy done %d\n", master->lessee_id);
}

/**
 * _drm_lease_revoke - revoke access to all leased objects (idr_mutex held)
308
 * @top: the master losing its lease
309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
 */
static void _drm_lease_revoke(struct drm_master *top)
{
	int object;
	void *entry;
	struct drm_master *master = top;

	lockdep_assert_held(&top->dev->mode_config.idr_mutex);

	/*
	 * Walk the tree starting at 'top' emptying all leases. Because
	 * the tree is fully connected, we can do this without recursing
	 */
	for (;;) {
		DRM_DEBUG_LEASE("revoke leases for %p %d\n", master, master->lessee_id);

		/* Evacuate the lease */
		idr_for_each_entry(&master->leases, entry, object)
			idr_remove(&master->leases, object);

		/* Depth-first list walk */

		/* Down */
		if (!list_empty(&master->lessees)) {
			master = list_first_entry(&master->lessees, struct drm_master, lessee_list);
		} else {
			/* Up */
			while (master != top && master == list_last_entry(&master->lessor->lessees, struct drm_master, lessee_list))
				master = master->lessor;

			if (master == top)
				break;

			/* Over */
343
			master = list_next_entry(master, lessee_list);
344 345 346 347 348 349 350 351 352 353 354 355 356 357
		}
	}
}

/**
 * drm_lease_revoke - revoke access to all leased objects (idr_mutex not held)
 * @top: the master losing its lease
 */
void drm_lease_revoke(struct drm_master *top)
{
	mutex_lock(&top->dev->mode_config.idr_mutex);
	_drm_lease_revoke(top);
	mutex_unlock(&top->dev->mode_config.idr_mutex);
}
358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484

static int validate_lease(struct drm_device *dev,
			  struct drm_file *lessor_priv,
			  int object_count,
			  struct drm_mode_object **objects)
{
	int o;
	int has_crtc = -1;
	int has_connector = -1;
	int has_plane = -1;

	/* we want to confirm that there is at least one crtc, plane
	   connector object. */

	for (o = 0; o < object_count; o++) {
		if (objects[o]->type == DRM_MODE_OBJECT_CRTC && has_crtc == -1) {
			has_crtc = o;
		}
		if (objects[o]->type == DRM_MODE_OBJECT_CONNECTOR && has_connector == -1)
			has_connector = o;

		if (lessor_priv->universal_planes) {
			if (objects[o]->type == DRM_MODE_OBJECT_PLANE && has_plane == -1)
				has_plane = o;
		}
	}
	if (has_crtc == -1 || has_connector == -1)
		return -EINVAL;
	if (lessor_priv->universal_planes && has_plane == -1)
		return -EINVAL;
	return 0;
}

static int fill_object_idr(struct drm_device *dev,
			   struct drm_file *lessor_priv,
			   struct idr *leases,
			   int object_count,
			   u32 *object_ids)
{
	struct drm_mode_object **objects;
	u32 o;
	int ret;
	objects = kcalloc(object_count, sizeof(struct drm_mode_object *),
			  GFP_KERNEL);
	if (!objects)
		return -ENOMEM;

	/* step one - get references to all the mode objects
	   and check for validity. */
	for (o = 0; o < object_count; o++) {
		if ((int) object_ids[o] < 0) {
			ret = -EINVAL;
			goto out_free_objects;
		}

		objects[o] = drm_mode_object_find(dev, lessor_priv,
						  object_ids[o],
						  DRM_MODE_OBJECT_ANY);
		if (!objects[o]) {
			ret = -ENOENT;
			goto out_free_objects;
		}

		if (!drm_mode_object_lease_required(objects[o]->type)) {
			ret = -EINVAL;
			goto out_free_objects;
		}
	}

	ret = validate_lease(dev, lessor_priv, object_count, objects);
	if (ret)
		goto out_free_objects;

	/* add their IDs to the lease request - taking into account
	   universal planes */
	for (o = 0; o < object_count; o++) {
		struct drm_mode_object *obj = objects[o];
		u32 object_id = objects[o]->id;
		DRM_DEBUG_LEASE("Adding object %d to lease\n", object_id);

		/*
		 * We're using an IDR to hold the set of leased
		 * objects, but we don't need to point at the object's
		 * data structure from the lease as the main crtc_idr
		 * will be used to actually find that. Instead, all we
		 * really want is a 'leased/not-leased' result, for
		 * which any non-NULL pointer will work fine.
		 */
		ret = idr_alloc(leases, &drm_lease_idr_object , object_id, object_id + 1, GFP_KERNEL);
		if (ret < 0) {
			DRM_DEBUG_LEASE("Object %d cannot be inserted into leases (%d)\n",
					object_id, ret);
			goto out_free_objects;
		}
		if (obj->type == DRM_MODE_OBJECT_CRTC && !lessor_priv->universal_planes) {
			struct drm_crtc *crtc = obj_to_crtc(obj);
			ret = idr_alloc(leases, &drm_lease_idr_object, crtc->primary->base.id, crtc->primary->base.id + 1, GFP_KERNEL);
			if (ret < 0) {
				DRM_DEBUG_LEASE("Object primary plane %d cannot be inserted into leases (%d)\n",
						object_id, ret);
				goto out_free_objects;
			}
			if (crtc->cursor) {
				ret = idr_alloc(leases, &drm_lease_idr_object, crtc->cursor->base.id, crtc->cursor->base.id + 1, GFP_KERNEL);
				if (ret < 0) {
					DRM_DEBUG_LEASE("Object cursor plane %d cannot be inserted into leases (%d)\n",
							object_id, ret);
					goto out_free_objects;
				}
			}
		}
	}

	ret = 0;
out_free_objects:
	for (o = 0; o < object_count; o++) {
		if (objects[o])
			drm_mode_object_put(objects[o]);
	}
	kfree(objects);
	return ret;
}

/**
 * drm_mode_create_lease_ioctl - create a new lease
 * @dev: the drm device
 * @data: pointer to struct drm_mode_create_lease
485
 * @lessor_priv: the file being manipulated
486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523
 *
 * The master associated with the specified file will have a lease
 * created containing the objects specified in the ioctl structure.
 * A file descriptor will be allocated for that and returned to the
 * application.
 */
int drm_mode_create_lease_ioctl(struct drm_device *dev,
				void *data, struct drm_file *lessor_priv)
{
	struct drm_mode_create_lease *cl = data;
	size_t object_count;
	int ret = 0;
	struct idr leases;
	struct drm_master *lessor = lessor_priv->master;
	struct drm_master *lessee = NULL;
	struct file *lessee_file = NULL;
	struct file *lessor_file = lessor_priv->filp;
	struct drm_file *lessee_priv;
	int fd = -1;
	uint32_t *object_ids;

	/* Can't lease without MODESET */
	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -EINVAL;

	/* Do not allow sub-leases */
	if (lessor->lessor)
		return -EINVAL;

	/* need some objects */
	if (cl->object_count == 0)
		return -EINVAL;

	if (cl->flags && (cl->flags & ~(O_CLOEXEC | O_NONBLOCK)))
		return -EINVAL;

	object_count = cl->object_count;

524 525
	object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
			array_size(object_count, sizeof(__u32)));
526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556
	if (IS_ERR(object_ids))
		return PTR_ERR(object_ids);

	idr_init(&leases);

	/* fill and validate the object idr */
	ret = fill_object_idr(dev, lessor_priv, &leases,
			      object_count, object_ids);
	kfree(object_ids);
	if (ret) {
		idr_destroy(&leases);
		return ret;
	}

	/* Allocate a file descriptor for the lease */
	fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));
	if (fd < 0) {
		idr_destroy(&leases);
		return fd;
	}

	DRM_DEBUG_LEASE("Creating lease\n");
	lessee = drm_lease_create(lessor, &leases);

	if (IS_ERR(lessee)) {
		ret = PTR_ERR(lessee);
		goto out_leases;
	}

	/* Clone the lessor file to create a new file for us */
	DRM_DEBUG_LEASE("Allocating lease file\n");
557
	lessee_file = file_clone_open(lessor_file);
558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574
	if (IS_ERR(lessee_file)) {
		ret = PTR_ERR(lessee_file);
		goto out_lessee;
	}

	lessee_priv = lessee_file->private_data;
	/* Change the file to a master one */
	drm_master_put(&lessee_priv->master);
	lessee_priv->master = lessee;
	lessee_priv->is_master = 1;
	lessee_priv->authenticated = 1;

	/* Pass fd back to userspace */
	DRM_DEBUG_LEASE("Returning fd %d id %d\n", fd, lessee->lessee_id);
	cl->fd = fd;
	cl->lessee_id = lessee->lessee_id;

575 576 577
	/* Hook up the fd */
	fd_install(fd, lessee_file);

578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651
	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n");
	return 0;

out_lessee:
	drm_master_put(&lessee);

out_leases:
	put_unused_fd(fd);
	idr_destroy(&leases);

	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
	return ret;
}

/**
 * drm_mode_list_lessees_ioctl - list lessee ids
 * @dev: the drm device
 * @data: pointer to struct drm_mode_list_lessees
 * @lessor_priv: the file being manipulated
 *
 * Starting from the master associated with the specified file,
 * the master with the provided lessee_id is found, and then
 * an array of lessee ids associated with leases from that master
 * are returned.
 */

int drm_mode_list_lessees_ioctl(struct drm_device *dev,
			       void *data, struct drm_file *lessor_priv)
{
	struct drm_mode_list_lessees *arg = data;
	__u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
	__u32 count_lessees = arg->count_lessees;
	struct drm_master *lessor = lessor_priv->master, *lessee;
	int count;
	int ret = 0;

	if (arg->pad)
		return -EINVAL;

	/* Can't lease without MODESET */
	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -EINVAL;

	DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id);

	mutex_lock(&dev->mode_config.idr_mutex);

	count = 0;
	drm_for_each_lessee(lessee, lessor) {
		/* Only list un-revoked leases */
		if (!idr_is_empty(&lessee->leases)) {
			if (count_lessees > count) {
				DRM_DEBUG_LEASE("Add lessee %d\n", lessee->lessee_id);
				ret = put_user(lessee->lessee_id, lessee_ids + count);
				if (ret)
					break;
			}
			count++;
		}
	}

	DRM_DEBUG_LEASE("Lessor leases to %d\n", count);
	if (ret == 0)
		arg->count_lessees = count;

	mutex_unlock(&dev->mode_config.idr_mutex);

	return ret;
}

/**
 * drm_mode_get_lease_ioctl - list leased objects
 * @dev: the drm device
 * @data: pointer to struct drm_mode_get_lease
652
 * @lessee_priv: the file being manipulated
653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711
 *
 * Return the list of leased objects for the specified lessee
 */

int drm_mode_get_lease_ioctl(struct drm_device *dev,
			     void *data, struct drm_file *lessee_priv)
{
	struct drm_mode_get_lease *arg = data;
	__u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
	__u32 count_objects = arg->count_objects;
	struct drm_master *lessee = lessee_priv->master;
	struct idr *object_idr;
	int count;
	void *entry;
	int object;
	int ret = 0;

	if (arg->pad)
		return -EINVAL;

	/* Can't lease without MODESET */
	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -EINVAL;

	DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id);

	mutex_lock(&dev->mode_config.idr_mutex);

	if (lessee->lessor == NULL)
		/* owner can use all objects */
		object_idr = &lessee->dev->mode_config.crtc_idr;
	else
		/* lessee can only use allowed object */
		object_idr = &lessee->leases;

	count = 0;
	idr_for_each_entry(object_idr, entry, object) {
		if (count_objects > count) {
			DRM_DEBUG_LEASE("adding object %d\n", object);
			ret = put_user(object, object_ids + count);
			if (ret)
				break;
		}
		count++;
	}

	DRM_DEBUG("lease holds %d objects\n", count);
	if (ret == 0)
		arg->count_objects = count;

	mutex_unlock(&dev->mode_config.idr_mutex);

	return ret;
}

/**
 * drm_mode_revoke_lease_ioctl - revoke lease
 * @dev: the drm device
 * @data: pointer to struct drm_mode_revoke_lease
712
 * @lessor_priv: the file being manipulated
713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754
 *
 * This removes all of the objects from the lease without
 * actually getting rid of the lease itself; that way all
 * references to it still work correctly
 */
int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
				void *data, struct drm_file *lessor_priv)
{
	struct drm_mode_revoke_lease *arg = data;
	struct drm_master *lessor = lessor_priv->master;
	struct drm_master *lessee;
	int ret = 0;

	DRM_DEBUG_LEASE("revoke lease for %d\n", arg->lessee_id);

	/* Can't lease without MODESET */
	if (!drm_core_check_feature(dev, DRIVER_MODESET))
		return -EINVAL;

	mutex_lock(&dev->mode_config.idr_mutex);

	lessee = _drm_find_lessee(lessor, arg->lessee_id);

	/* No such lessee */
	if (!lessee) {
		ret = -ENOENT;
		goto fail;
	}

	/* Lease is not held by lessor */
	if (lessee->lessor != lessor) {
		ret = -EACCES;
		goto fail;
	}

	_drm_lease_revoke(lessee);

fail:
	mutex_unlock(&dev->mode_config.idr_mutex);

	return ret;
}