[linux.git] / drivers / gpu / drm / drm_auth.c

/*
 * Created: Tue Feb  2 08:37:54 1999 by [email protected]
 *
 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Author Rickard E. (Rik) Faith <[email protected]>
 * Author Gareth Hughes <[email protected]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

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

/**
 * DOC: master and authentication
 *
 * &struct drm_master is used to track groups of clients with open
 * primary/legacy device nodes. For every &struct drm_file which has had at
 * least once successfully became the device master (either through the
 * SET_MASTER IOCTL, or implicitly through opening the primary device node when
 * no one else is the current master that time) there exists one &drm_master.
 * This is noted in &drm_file.is_master. All other clients have just a pointer
 * to the &drm_master they are associated with.
 *
 * In addition only one &drm_master can be the current master for a &drm_device.
 * It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
 * implicitly through closing/openeing the primary device node. See also
 * drm_is_current_master().
 *
 * Clients can authenticate against the current master (if it matches their own)
 * using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
 * this allows controlled access to the device for an entire group of mutually
 * trusted clients.
 */

int drm_getmagic(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
	struct drm_auth *auth = data;
	int ret = 0;

	mutex_lock(&dev->master_mutex);
	if (!file_priv->magic) {
		ret = idr_alloc(&file_priv->master->magic_map, file_priv,
				1, 0, GFP_KERNEL);
		if (ret >= 0)
			file_priv->magic = ret;
	}
	auth->magic = file_priv->magic;
	mutex_unlock(&dev->master_mutex);

	DRM_DEBUG("%u\n", auth->magic);

	return ret < 0 ? ret : 0;
}

int drm_authmagic(struct drm_device *dev, void *data,
		  struct drm_file *file_priv)
{
	struct drm_auth *auth = data;
	struct drm_file *file;

	DRM_DEBUG("%u\n", auth->magic);

	mutex_lock(&dev->master_mutex);
	file = idr_find(&file_priv->master->magic_map, auth->magic);
	if (file) {
		file->authenticated = 1;
		idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
	}
	mutex_unlock(&dev->master_mutex);

	return file ? 0 : -EINVAL;
}

struct drm_master *drm_master_create(struct drm_device *dev)
{
	struct drm_master *master;

	master = kzalloc(sizeof(*master), GFP_KERNEL);
	if (!master)
		return NULL;

	kref_init(&master->refcount);
	spin_lock_init(&master->lock.spinlock);
	init_waitqueue_head(&master->lock.lock_queue);
	idr_init(&master->magic_map);
	master->dev = dev;

	/* initialize the tree of output resource lessees */
	master->lessor = NULL;
	master->lessee_id = 0;
	INIT_LIST_HEAD(&master->lessees);
	INIT_LIST_HEAD(&master->lessee_list);
	idr_init(&master->leases);
	idr_init(&master->lessee_idr);

	return master;
}

static int drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
			  bool new_master)
{
	int ret = 0;

	dev->master = drm_master_get(fpriv->master);
	if (dev->driver->master_set) {
		ret = dev->driver->master_set(dev, fpriv, new_master);
		if (unlikely(ret != 0)) {
			drm_master_put(&dev->master);
		}
	}

	return ret;
}

static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
{
	struct drm_master *old_master;
	int ret;

	lockdep_assert_held_once(&dev->master_mutex);

	WARN_ON(fpriv->is_master);
	old_master = fpriv->master;
	fpriv->master = drm_master_create(dev);
	if (!fpriv->master) {
		fpriv->master = old_master;
		return -ENOMEM;
	}

	if (dev->driver->master_create) {
		ret = dev->driver->master_create(dev, fpriv->master);
		if (ret)
			goto out_err;
	}
	fpriv->is_master = 1;
	fpriv->authenticated = 1;

	ret = drm_set_master(dev, fpriv, true);
	if (ret)
		goto out_err;

	if (old_master)
		drm_master_put(&old_master);

	return 0;

out_err:
	/* drop references and restore old master on failure */
	drm_master_put(&fpriv->master);
	fpriv->master = old_master;
	fpriv->is_master = 0;

	return ret;
}

int drm_setmaster_ioctl(struct drm_device *dev, void *data,
			struct drm_file *file_priv)
{
	int ret = 0;

	mutex_lock(&dev->master_mutex);
	if (drm_is_current_master(file_priv))
		goto out_unlock;

	if (dev->master) {
		ret = -EINVAL;
		goto out_unlock;
	}

	if (!file_priv->master) {
		ret = -EINVAL;
		goto out_unlock;
	}

	if (!file_priv->is_master) {
		ret = drm_new_set_master(dev, file_priv);
		goto out_unlock;
	}

	if (file_priv->master->lessor != NULL) {
		DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id);
		ret = -EINVAL;
		goto out_unlock;
	}

	ret = drm_set_master(dev, file_priv, false);
out_unlock:
	mutex_unlock(&dev->master_mutex);
	return ret;
}

static void drm_drop_master(struct drm_device *dev,
			    struct drm_file *fpriv)
{
	if (dev->driver->master_drop)
		dev->driver->master_drop(dev, fpriv);
	drm_master_put(&dev->master);
}

int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
			 struct drm_file *file_priv)
{
	int ret = -EINVAL;

	mutex_lock(&dev->master_mutex);
	if (!drm_is_current_master(file_priv))
		goto out_unlock;

	if (!dev->master)
		goto out_unlock;

	if (file_priv->master->lessor != NULL) {
		DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id);
		ret = -EINVAL;
		goto out_unlock;
	}

	ret = 0;
	drm_drop_master(dev, file_priv);
out_unlock:
	mutex_unlock(&dev->master_mutex);
	return ret;
}

int drm_master_open(struct drm_file *file_priv)
{
	struct drm_device *dev = file_priv->minor->dev;
	int ret = 0;

	/* if there is no current master make this fd it, but do not create
	 * any master object for render clients */
	mutex_lock(&dev->master_mutex);
	if (!dev->master)
		ret = drm_new_set_master(dev, file_priv);
	else
		file_priv->master = drm_master_get(dev->master);
	mutex_unlock(&dev->master_mutex);

	return ret;
}

void drm_master_release(struct drm_file *file_priv)
{
	struct drm_device *dev = file_priv->minor->dev;
	struct drm_master *master = file_priv->master;

	mutex_lock(&dev->master_mutex);
	if (file_priv->magic)
		idr_remove(&file_priv->master->magic_map, file_priv->magic);

	if (!drm_is_current_master(file_priv))
		goto out;

	if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
		/*
		 * Since the master is disappearing, so is the
		 * possibility to lock.
		 */
		mutex_lock(&dev->struct_mutex);
		if (master->lock.hw_lock) {
			if (dev->sigdata.lock == master->lock.hw_lock)
				dev->sigdata.lock = NULL;
			master->lock.hw_lock = NULL;
			master->lock.file_priv = NULL;
			wake_up_interruptible_all(&master->lock.lock_queue);
		}
		mutex_unlock(&dev->struct_mutex);
	}

	if (dev->master == file_priv->master)
		drm_drop_master(dev, file_priv);
out:
	if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) {
		/* Revoke any leases held by this or lessees, but only if
		 * this is the "real" master
		 */
		drm_lease_revoke(master);
	}

	/* drop the master reference held by the file priv */
	if (file_priv->master)
		drm_master_put(&file_priv->master);
	mutex_unlock(&dev->master_mutex);
}

/**
 * drm_is_current_master - checks whether @priv is the current master
 * @fpriv: DRM file private
 *
 * Checks whether @fpriv is current master on its device. This decides whether a
 * client is allowed to run DRM_MASTER IOCTLs.
 *
 * Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
 * - the current master is assumed to own the non-shareable display hardware.
 */
bool drm_is_current_master(struct drm_file *fpriv)
{
	return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master;
}
EXPORT_SYMBOL(drm_is_current_master);

/**
 * drm_master_get - reference a master pointer
 * @master: &struct drm_master
 *
 * Increments the reference count of @master and returns a pointer to @master.
 */
struct drm_master *drm_master_get(struct drm_master *master)
{
	kref_get(&master->refcount);
	return master;
}
EXPORT_SYMBOL(drm_master_get);

static void drm_master_destroy(struct kref *kref)
{
	struct drm_master *master = container_of(kref, struct drm_master, refcount);
	struct drm_device *dev = master->dev;

	if (drm_core_check_feature(dev, DRIVER_MODESET))
		drm_lease_destroy(master);

	if (dev->driver->master_destroy)
		dev->driver->master_destroy(dev, master);

	drm_legacy_master_rmmaps(dev, master);

	idr_destroy(&master->magic_map);
	idr_destroy(&master->leases);
	idr_destroy(&master->lessee_idr);

	kfree(master->unique);
	kfree(master);
}

/**
 * drm_master_put - unreference and clear a master pointer
 * @master: pointer to a pointer of &struct drm_master
 *
 * This decrements the &drm_master behind @master and sets it to NULL.
 */
void drm_master_put(struct drm_master **master)
{
	kref_put(&(*master)->refcount, drm_master_destroy);
	*master = NULL;
}
EXPORT_SYMBOL(drm_master_put);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Created: Tue Feb 2 08:37:54 1999 by [email protected]
	3	*
	4	* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
	5	* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
	6	* All Rights Reserved.
	7	*
32e7b94a DR	8	* Author Rickard E. (Rik) Faith <[email protected]>
	9	* Author Gareth Hughes <[email protected]>
	10	*
1da177e4 LT	11	* Permission is hereby granted, free of charge, to any person obtaining a
	12	* copy of this software and associated documentation files (the "Software"),
	13	* to deal in the Software without restriction, including without limitation
	14	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	15	* and/or sell copies of the Software, and to permit persons to whom the
	16	* Software is furnished to do so, subject to the following conditions:
	17	*
	18	* The above copyright notice and this permission notice (including the next
	19	* paragraph) shall be included in all copies or substantial portions of the
	20	* Software.
	21	*
	22	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	23	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	24	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	25	* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	26	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	27	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	28	* OTHER DEALINGS IN THE SOFTWARE.
	29	*/
	30
760285e7	31	#include <drm/drmP.h>
67d0ec4e	32	#include "drm_internal.h"
6548f4e7	33	#include "drm_legacy.h"
2ed077e4	34	#include <drm/drm_lease.h>
1da177e4	35
1da177e4	36	/**
3b96a0b1	37	* DOC: master and authentication
1da177e4	38	*
ea0dd85a SV	39	* &struct drm_master is used to track groups of clients with open
ea0dd85a SV	40	* primary/legacy device nodes. For every &struct drm_file which has had at
3b96a0b1 SV	41	* least once successfully became the device master (either through the
	42	* SET_MASTER IOCTL, or implicitly through opening the primary device node when
	43	* no one else is the current master that time) there exists one &drm_master.
ef40cbf9 SV	44	* This is noted in &drm_file.is_master. All other clients have just a pointer
ef40cbf9 SV	45	* to the &drm_master they are associated with.
1da177e4	46	*
3b96a0b1 SV	47	* In addition only one &drm_master can be the current master for a &drm_device.
	48	* It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
	49	* implicitly through closing/openeing the primary device node. See also
	50	* drm_is_current_master().
	51	*
	52	* Clients can authenticate against the current master (if it matches their own)
	53	* using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
	54	* this allows controlled access to the device for an entire group of mutually
	55	* trusted clients.
1da177e4	56	*/
3b96a0b1	57
c153f45f	58	int drm_getmagic(struct drm_device dev, void data, struct drm_file *file_priv)
1da177e4	59	{
c153f45f	60	struct drm_auth *auth = data;
32e7b94a	61	int ret = 0;
1da177e4	62
d2b34ee6	63	mutex_lock(&dev->master_mutex);
32e7b94a DR	64	if (!file_priv->magic) {
	65	ret = idr_alloc(&file_priv->master->magic_map, file_priv,
	66	1, 0, GFP_KERNEL);
	67	if (ret >= 0)
	68	file_priv->magic = ret;
1da177e4	69	}
32e7b94a	70	auth->magic = file_priv->magic;
d2b34ee6	71	mutex_unlock(&dev->master_mutex);
1da177e4	72
c153f45f EA	73	DRM_DEBUG("%u\n", auth->magic);
c153f45f EA	74
32e7b94a	75	return ret < 0 ? ret : 0;
1da177e4 LT	76	}
1da177e4 LT	77
c153f45f EA	78	int drm_authmagic(struct drm_device dev, void data,
c153f45f EA	79	struct drm_file *file_priv)
1da177e4	80	{
c153f45f	81	struct drm_auth *auth = data;
84b1fd10	82	struct drm_file *file;
1da177e4	83
c153f45f	84	DRM_DEBUG("%u\n", auth->magic);
32e7b94a	85
d2b34ee6	86	mutex_lock(&dev->master_mutex);
32e7b94a DR	87	file = idr_find(&file_priv->master->magic_map, auth->magic);
32e7b94a DR	88	if (file) {
1da177e4	89	file->authenticated = 1;
32e7b94a	90	idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
1da177e4	91	}
d2b34ee6	92	mutex_unlock(&dev->master_mutex);
32e7b94a DR	93
32e7b94a DR	94	return file ? 0 : -EINVAL;
1da177e4	95	}
6548f4e7	96
2ed077e4	97	struct drm_master drm_master_create(struct drm_device dev)
6548f4e7 SV	98	{
	99	struct drm_master *master;
	100
	101	master = kzalloc(sizeof(*master), GFP_KERNEL);
	102	if (!master)
	103	return NULL;
	104
	105	kref_init(&master->refcount);
	106	spin_lock_init(&master->lock.spinlock);
	107	init_waitqueue_head(&master->lock.lock_queue);
	108	idr_init(&master->magic_map);
	109	master->dev = dev;
	110
2ed077e4 KP	111	/* initialize the tree of output resource lessees */
	112	master->lessor = NULL;
	113	master->lessee_id = 0;
	114	INIT_LIST_HEAD(&master->lessees);
	115	INIT_LIST_HEAD(&master->lessee_list);
	116	idr_init(&master->leases);
	117	idr_init(&master->lessee_idr);
	118
6548f4e7 SV	119	return master;
	120	}
	121
d6ed682e SV	122	static int drm_set_master(struct drm_device dev, struct drm_file fpriv,
	123	bool new_master)
	124	{
	125	int ret = 0;
	126
	127	dev->master = drm_master_get(fpriv->master);
d6ed682e SV	128	if (dev->driver->master_set) {
	129	ret = dev->driver->master_set(dev, fpriv, new_master);
	130	if (unlikely(ret != 0)) {
d6ed682e SV	131	drm_master_put(&dev->master);
	132	}
	133	}
	134
	135	return ret;
	136	}
	137
2cbae7e6	138	static int drm_new_set_master(struct drm_device dev, struct drm_file fpriv)
6548f4e7 SV	139	{
	140	struct drm_master *old_master;
	141	int ret;
	142
	143	lockdep_assert_held_once(&dev->master_mutex);
	144
23a336b3	145	WARN_ON(fpriv->is_master);
6548f4e7	146	old_master = fpriv->master;
d6ed682e SV	147	fpriv->master = drm_master_create(dev);
	148	if (!fpriv->master) {
	149	fpriv->master = old_master;
	150	return -ENOMEM;
	151	}
6548f4e7 SV	152
	153	if (dev->driver->master_create) {
	154	ret = dev->driver->master_create(dev, fpriv->master);
	155	if (ret)
	156	goto out_err;
	157	}
0aae5920	158	fpriv->is_master = 1;
6548f4e7	159	fpriv->authenticated = 1;
d6ed682e SV	160
	161	ret = drm_set_master(dev, fpriv, true);
	162	if (ret)
	163	goto out_err;
	164
6548f4e7 SV	165	if (old_master)
	166	drm_master_put(&old_master);
	167
	168	return 0;
	169
	170	out_err:
d6ed682e	171	/* drop references and restore old master on failure */
6548f4e7 SV	172	drm_master_put(&fpriv->master);
6548f4e7 SV	173	fpriv->master = old_master;
23a336b3	174	fpriv->is_master = 0;
6548f4e7 SV	175
	176	return ret;
	177	}
	178
	179	int drm_setmaster_ioctl(struct drm_device dev, void data,
	180	struct drm_file *file_priv)
	181	{
	182	int ret = 0;
	183
	184	mutex_lock(&dev->master_mutex);
b3ac9f25	185	if (drm_is_current_master(file_priv))
6548f4e7 SV	186	goto out_unlock;
6548f4e7 SV	187
95c081c1	188	if (dev->master) {
6548f4e7 SV	189	ret = -EINVAL;
	190	goto out_unlock;
	191	}
	192
	193	if (!file_priv->master) {
	194	ret = -EINVAL;
	195	goto out_unlock;
	196	}
	197
0aae5920	198	if (!file_priv->is_master) {
6548f4e7 SV	199	ret = drm_new_set_master(dev, file_priv);
	200	goto out_unlock;
	201	}
	202
2ed077e4 KP	203	if (file_priv->master->lessor != NULL) {
	204	DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id);
	205	ret = -EINVAL;
	206	goto out_unlock;
	207	}
	208
d6ed682e	209	ret = drm_set_master(dev, file_priv, false);
6548f4e7 SV	210	out_unlock:
	211	mutex_unlock(&dev->master_mutex);
	212	return ret;
	213	}
	214
d6ed682e SV	215	static void drm_drop_master(struct drm_device *dev,
	216	struct drm_file *fpriv)
	217	{
	218	if (dev->driver->master_drop)
	219	dev->driver->master_drop(dev, fpriv);
	220	drm_master_put(&dev->master);
d6ed682e SV	221	}
d6ed682e SV	222
6548f4e7 SV	223	int drm_dropmaster_ioctl(struct drm_device dev, void data,
	224	struct drm_file *file_priv)
	225	{
	226	int ret = -EINVAL;
	227
	228	mutex_lock(&dev->master_mutex);
b3ac9f25	229	if (!drm_is_current_master(file_priv))
6548f4e7 SV	230	goto out_unlock;
6548f4e7 SV	231
95c081c1	232	if (!dev->master)
6548f4e7 SV	233	goto out_unlock;
6548f4e7 SV	234
761e05a7 KP	235	if (file_priv->master->lessor != NULL) {
	236	DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id);
	237	ret = -EINVAL;
	238	goto out_unlock;
	239	}
	240
6548f4e7	241	ret = 0;
d6ed682e	242	drm_drop_master(dev, file_priv);
6548f4e7 SV	243	out_unlock:
	244	mutex_unlock(&dev->master_mutex);
	245	return ret;
	246	}
	247
2cbae7e6 SV	248	int drm_master_open(struct drm_file *file_priv)
	249	{
	250	struct drm_device *dev = file_priv->minor->dev;
	251	int ret = 0;
	252
	253	/* if there is no current master make this fd it, but do not create
	254	* any master object for render clients */
	255	mutex_lock(&dev->master_mutex);
95c081c1	256	if (!dev->master)
2cbae7e6 SV	257	ret = drm_new_set_master(dev, file_priv);
2cbae7e6 SV	258	else
95c081c1	259	file_priv->master = drm_master_get(dev->master);
2cbae7e6 SV	260	mutex_unlock(&dev->master_mutex);
	261
	262	return ret;
	263	}
	264
14d71ebd SV	265	void drm_master_release(struct drm_file *file_priv)
	266	{
	267	struct drm_device *dev = file_priv->minor->dev;
0de4cc99	268	struct drm_master *master = file_priv->master;
14d71ebd	269
d2b34ee6	270	mutex_lock(&dev->master_mutex);
a77316bf SV	271	if (file_priv->magic)
a77316bf SV	272	idr_remove(&file_priv->master->magic_map, file_priv->magic);
a77316bf	273
b3ac9f25	274	if (!drm_is_current_master(file_priv))
0de4cc99	275	goto out;
14d71ebd	276
fa538645	277	if (drm_core_check_feature(dev, DRIVER_LEGACY)) {
14d71ebd SV	278	/*
	279	* Since the master is disappearing, so is the
	280	* possibility to lock.
	281	*/
	282	mutex_lock(&dev->struct_mutex);
	283	if (master->lock.hw_lock) {
	284	if (dev->sigdata.lock == master->lock.hw_lock)
	285	dev->sigdata.lock = NULL;
	286	master->lock.hw_lock = NULL;
	287	master->lock.file_priv = NULL;
	288	wake_up_interruptible_all(&master->lock.lock_queue);
	289	}
	290	mutex_unlock(&dev->struct_mutex);
14d71ebd SV	291	}
14d71ebd SV	292
d6ed682e SV	293	if (dev->master == file_priv->master)
d6ed682e SV	294	drm_drop_master(dev, file_priv);
0de4cc99	295	out:
2ed077e4 KP	296	if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) {
	297	/* Revoke any leases held by this or lessees, but only if
	298	* this is the "real" master
	299	*/
	300	drm_lease_revoke(master);
	301	}
	302
14d71ebd SV	303	/* drop the master reference held by the file priv */
	304	if (file_priv->master)
	305	drm_master_put(&file_priv->master);
14d71ebd SV	306	mutex_unlock(&dev->master_mutex);
	307	}
	308
3b96a0b1 SV	309	/**
	310	* drm_is_current_master - checks whether @priv is the current master
	311	* @fpriv: DRM file private
	312	*
	313	* Checks whether @fpriv is current master on its device. This decides whether a
	314	* client is allowed to run DRM_MASTER IOCTLs.
	315	*
	316	* Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
	317	* - the current master is assumed to own the non-shareable display hardware.
	318	*/
b3ac9f25 SV	319	bool drm_is_current_master(struct drm_file *fpriv)
b3ac9f25 SV	320	{
7de440db	321	return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master;
b3ac9f25 SV	322	}
	323	EXPORT_SYMBOL(drm_is_current_master);
	324
3b96a0b1 SV	325	/**
3b96a0b1 SV	326	* drm_master_get - reference a master pointer
ea0dd85a	327	* @master: &struct drm_master
3b96a0b1 SV	328	*
	329	* Increments the reference count of @master and returns a pointer to @master.
	330	*/
6548f4e7 SV	331	struct drm_master drm_master_get(struct drm_master master)
	332	{
	333	kref_get(&master->refcount);
	334	return master;
	335	}
	336	EXPORT_SYMBOL(drm_master_get);
	337
	338	static void drm_master_destroy(struct kref *kref)
	339	{
	340	struct drm_master *master = container_of(kref, struct drm_master, refcount);
	341	struct drm_device *dev = master->dev;
	342
2ed077e4 KP	343	if (drm_core_check_feature(dev, DRIVER_MODESET))
	344	drm_lease_destroy(master);
	345
6548f4e7 SV	346	if (dev->driver->master_destroy)
	347	dev->driver->master_destroy(dev, master);
	348
	349	drm_legacy_master_rmmaps(dev, master);
	350
	351	idr_destroy(&master->magic_map);
2ed077e4 KP	352	idr_destroy(&master->leases);
	353	idr_destroy(&master->lessee_idr);
	354
6548f4e7 SV	355	kfree(master->unique);
	356	kfree(master);
	357	}
	358
3b96a0b1 SV	359	/**
3b96a0b1 SV	360	* drm_master_put - unreference and clear a master pointer
ea0dd85a	361	* @master: pointer to a pointer of &struct drm_master
3b96a0b1 SV	362	*
	363	* This decrements the &drm_master behind @master and sets it to NULL.
	364	*/
6548f4e7 SV	365	void drm_master_put(struct drm_master **master)
	366	{
	367	kref_put(&(*master)->refcount, drm_master_destroy);
	368	*master = NULL;
	369	}
	370	EXPORT_SYMBOL(drm_master_put);