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

/*
 * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
 *
 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Author Rickard E. (Rik) Faith <faith@valinux.com>
 * Author Gareth Hughes <gareth@valinux.com>
 *
 * 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 <linux/slab.h>

#include <drm/drm_auth.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_lease.h>
#include <drm/drm_print.h>

#include "drm_internal.h"
#include "drm_legacy.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);
	drm_master_legacy_init(master);
	idr_init(&master->magic_map);
	master->dev = dev;

	/* initialize the tree of output resource lessees */
	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;
	}

	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;

	drm_legacy_lock_master_cleanup(dev, master);

	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);

	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);

/* Used by drm_client and drm_fb_helper */
bool drm_master_internal_acquire(struct drm_device *dev)
{
	mutex_lock(&dev->master_mutex);
	if (dev->master) {
		mutex_unlock(&dev->master_mutex);
		return false;
	}

	return true;
}
EXPORT_SYMBOL(drm_master_internal_acquire);

/* Used by drm_client and drm_fb_helper */
void drm_master_internal_release(struct drm_device *dev)
{
	mutex_unlock(&dev->master_mutex);
}
EXPORT_SYMBOL(drm_master_internal_release);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
	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 DH	8	* Author Rickard E. (Rik) Faith <faith@valinux.com>
	9	* Author Gareth Hughes <gareth@valinux.com>
	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
0500c04e SR	31	#include <linux/slab.h>
	32
	33	#include <drm/drm_auth.h>
	34	#include <drm/drm_drv.h>
	35	#include <drm/drm_file.h>
	36	#include <drm/drm_lease.h>
	37	#include <drm/drm_print.h>
	38
67d0ec4e	39	#include "drm_internal.h"
6548f4e7	40	#include "drm_legacy.h"
1da177e4	41
1da177e4	42	/**
3b96a0b1	43	* DOC: master and authentication
1da177e4	44	*
ea0dd85a DV	45	* &struct drm_master is used to track groups of clients with open
ea0dd85a DV	46	* primary/legacy device nodes. For every &struct drm_file which has had at
3b96a0b1 DV	47	* least once successfully became the device master (either through the
	48	* SET_MASTER IOCTL, or implicitly through opening the primary device node when
	49	* no one else is the current master that time) there exists one &drm_master.
ef40cbf9 DV	50	* This is noted in &drm_file.is_master. All other clients have just a pointer
ef40cbf9 DV	51	* to the &drm_master they are associated with.
1da177e4	52	*
3b96a0b1 DV	53	* In addition only one &drm_master can be the current master for a &drm_device.
	54	* It can be switched through the DROP_MASTER and SET_MASTER IOCTL, or
	55	* implicitly through closing/openeing the primary device node. See also
	56	* drm_is_current_master().
	57	*
	58	* Clients can authenticate against the current master (if it matches their own)
	59	* using the GETMAGIC and AUTHMAGIC IOCTLs. Together with exchanging masters,
	60	* this allows controlled access to the device for an entire group of mutually
	61	* trusted clients.
1da177e4	62	*/
3b96a0b1	63
c153f45f	64	int drm_getmagic(struct drm_device dev, void data, struct drm_file *file_priv)
1da177e4	65	{
c153f45f	66	struct drm_auth *auth = data;
32e7b94a	67	int ret = 0;
1da177e4	68
d2b34ee6	69	mutex_lock(&dev->master_mutex);
32e7b94a DH	70	if (!file_priv->magic) {
	71	ret = idr_alloc(&file_priv->master->magic_map, file_priv,
	72	1, 0, GFP_KERNEL);
	73	if (ret >= 0)
	74	file_priv->magic = ret;
1da177e4	75	}
32e7b94a	76	auth->magic = file_priv->magic;
d2b34ee6	77	mutex_unlock(&dev->master_mutex);
1da177e4	78
c153f45f EA	79	DRM_DEBUG("%u\n", auth->magic);
c153f45f EA	80
32e7b94a	81	return ret < 0 ? ret : 0;
1da177e4 LT	82	}
1da177e4 LT	83
c153f45f EA	84	int drm_authmagic(struct drm_device dev, void data,
c153f45f EA	85	struct drm_file *file_priv)
1da177e4	86	{
c153f45f	87	struct drm_auth *auth = data;
84b1fd10	88	struct drm_file *file;
1da177e4	89
c153f45f	90	DRM_DEBUG("%u\n", auth->magic);
32e7b94a	91
d2b34ee6	92	mutex_lock(&dev->master_mutex);
32e7b94a DH	93	file = idr_find(&file_priv->master->magic_map, auth->magic);
32e7b94a DH	94	if (file) {
1da177e4	95	file->authenticated = 1;
32e7b94a	96	idr_replace(&file_priv->master->magic_map, NULL, auth->magic);
1da177e4	97	}
d2b34ee6	98	mutex_unlock(&dev->master_mutex);
32e7b94a DH	99
32e7b94a DH	100	return file ? 0 : -EINVAL;
1da177e4	101	}
6548f4e7	102
2ed077e4	103	struct drm_master drm_master_create(struct drm_device dev)
6548f4e7 DV	104	{
	105	struct drm_master *master;
	106
	107	master = kzalloc(sizeof(*master), GFP_KERNEL);
	108	if (!master)
	109	return NULL;
	110
	111	kref_init(&master->refcount);
ee22f763	112	drm_master_legacy_init(master);
6548f4e7 DV	113	idr_init(&master->magic_map);
	114	master->dev = dev;
	115
2ed077e4	116	/* initialize the tree of output resource lessees */
2ed077e4 KP	117	INIT_LIST_HEAD(&master->lessees);
	118	INIT_LIST_HEAD(&master->lessee_list);
	119	idr_init(&master->leases);
	120	idr_init(&master->lessee_idr);
	121
6548f4e7 DV	122	return master;
	123	}
	124
d6ed682e DV	125	static int drm_set_master(struct drm_device dev, struct drm_file fpriv,
	126	bool new_master)
	127	{
	128	int ret = 0;
	129
	130	dev->master = drm_master_get(fpriv->master);
d6ed682e DV	131	if (dev->driver->master_set) {
	132	ret = dev->driver->master_set(dev, fpriv, new_master);
	133	if (unlikely(ret != 0)) {
d6ed682e DV	134	drm_master_put(&dev->master);
	135	}
	136	}
	137
	138	return ret;
	139	}
	140
2cbae7e6	141	static int drm_new_set_master(struct drm_device dev, struct drm_file fpriv)
6548f4e7 DV	142	{
	143	struct drm_master *old_master;
	144	int ret;
	145
	146	lockdep_assert_held_once(&dev->master_mutex);
	147
23a336b3	148	WARN_ON(fpriv->is_master);
6548f4e7	149	old_master = fpriv->master;
d6ed682e DV	150	fpriv->master = drm_master_create(dev);
	151	if (!fpriv->master) {
	152	fpriv->master = old_master;
	153	return -ENOMEM;
	154	}
6548f4e7	155
0aae5920	156	fpriv->is_master = 1;
6548f4e7	157	fpriv->authenticated = 1;
d6ed682e DV	158
	159	ret = drm_set_master(dev, fpriv, true);
	160	if (ret)
	161	goto out_err;
	162
6548f4e7 DV	163	if (old_master)
	164	drm_master_put(&old_master);
	165
	166	return 0;
	167
	168	out_err:
d6ed682e	169	/* drop references and restore old master on failure */
6548f4e7 DV	170	drm_master_put(&fpriv->master);
6548f4e7 DV	171	fpriv->master = old_master;
23a336b3	172	fpriv->is_master = 0;
6548f4e7 DV	173
	174	return ret;
	175	}
	176
	177	int drm_setmaster_ioctl(struct drm_device dev, void data,
	178	struct drm_file *file_priv)
	179	{
	180	int ret = 0;
	181
	182	mutex_lock(&dev->master_mutex);
b3ac9f25	183	if (drm_is_current_master(file_priv))
6548f4e7 DV	184	goto out_unlock;
6548f4e7 DV	185
95c081c1	186	if (dev->master) {
6548f4e7 DV	187	ret = -EINVAL;
	188	goto out_unlock;
	189	}
	190
	191	if (!file_priv->master) {
	192	ret = -EINVAL;
	193	goto out_unlock;
	194	}
	195
0aae5920	196	if (!file_priv->is_master) {
6548f4e7 DV	197	ret = drm_new_set_master(dev, file_priv);
	198	goto out_unlock;
	199	}
	200
2ed077e4 KP	201	if (file_priv->master->lessor != NULL) {
	202	DRM_DEBUG_LEASE("Attempt to set lessee %d as master\n", file_priv->master->lessee_id);
	203	ret = -EINVAL;
	204	goto out_unlock;
	205	}
	206
d6ed682e	207	ret = drm_set_master(dev, file_priv, false);
6548f4e7 DV	208	out_unlock:
	209	mutex_unlock(&dev->master_mutex);
	210	return ret;
	211	}
	212
d6ed682e DV	213	static void drm_drop_master(struct drm_device *dev,
	214	struct drm_file *fpriv)
	215	{
	216	if (dev->driver->master_drop)
	217	dev->driver->master_drop(dev, fpriv);
	218	drm_master_put(&dev->master);
d6ed682e DV	219	}
d6ed682e DV	220
6548f4e7 DV	221	int drm_dropmaster_ioctl(struct drm_device dev, void data,
	222	struct drm_file *file_priv)
	223	{
	224	int ret = -EINVAL;
	225
	226	mutex_lock(&dev->master_mutex);
b3ac9f25	227	if (!drm_is_current_master(file_priv))
6548f4e7 DV	228	goto out_unlock;
6548f4e7 DV	229
95c081c1	230	if (!dev->master)
6548f4e7 DV	231	goto out_unlock;
6548f4e7 DV	232
761e05a7 KP	233	if (file_priv->master->lessor != NULL) {
	234	DRM_DEBUG_LEASE("Attempt to drop lessee %d as master\n", file_priv->master->lessee_id);
	235	ret = -EINVAL;
	236	goto out_unlock;
	237	}
	238
6548f4e7	239	ret = 0;
d6ed682e	240	drm_drop_master(dev, file_priv);
6548f4e7 DV	241	out_unlock:
	242	mutex_unlock(&dev->master_mutex);
	243	return ret;
	244	}
	245
2cbae7e6 DV	246	int drm_master_open(struct drm_file *file_priv)
	247	{
	248	struct drm_device *dev = file_priv->minor->dev;
	249	int ret = 0;
	250
	251	/* if there is no current master make this fd it, but do not create
	252	* any master object for render clients */
	253	mutex_lock(&dev->master_mutex);
95c081c1	254	if (!dev->master)
2cbae7e6 DV	255	ret = drm_new_set_master(dev, file_priv);
2cbae7e6 DV	256	else
95c081c1	257	file_priv->master = drm_master_get(dev->master);
2cbae7e6 DV	258	mutex_unlock(&dev->master_mutex);
	259
	260	return ret;
	261	}
	262
14d71ebd DV	263	void drm_master_release(struct drm_file *file_priv)
	264	{
	265	struct drm_device *dev = file_priv->minor->dev;
0de4cc99	266	struct drm_master *master = file_priv->master;
14d71ebd	267
d2b34ee6	268	mutex_lock(&dev->master_mutex);
a77316bf DV	269	if (file_priv->magic)
a77316bf DV	270	idr_remove(&file_priv->master->magic_map, file_priv->magic);
a77316bf	271
b3ac9f25	272	if (!drm_is_current_master(file_priv))
0de4cc99	273	goto out;
14d71ebd	274
058ca50c	275	drm_legacy_lock_master_cleanup(dev, master);
14d71ebd	276
d6ed682e DV	277	if (dev->master == file_priv->master)
d6ed682e DV	278	drm_drop_master(dev, file_priv);
0de4cc99	279	out:
2ed077e4 KP	280	if (drm_core_check_feature(dev, DRIVER_MODESET) && file_priv->is_master) {
	281	/* Revoke any leases held by this or lessees, but only if
	282	* this is the "real" master
	283	*/
	284	drm_lease_revoke(master);
	285	}
	286
14d71ebd DV	287	/* drop the master reference held by the file priv */
	288	if (file_priv->master)
	289	drm_master_put(&file_priv->master);
14d71ebd DV	290	mutex_unlock(&dev->master_mutex);
	291	}
	292
3b96a0b1 DV	293	/**
	294	* drm_is_current_master - checks whether @priv is the current master
	295	* @fpriv: DRM file private
	296	*
	297	* Checks whether @fpriv is current master on its device. This decides whether a
	298	* client is allowed to run DRM_MASTER IOCTLs.
	299	*
	300	* Most of the modern IOCTL which require DRM_MASTER are for kernel modesetting
	301	* - the current master is assumed to own the non-shareable display hardware.
	302	*/
b3ac9f25 DV	303	bool drm_is_current_master(struct drm_file *fpriv)
b3ac9f25 DV	304	{
7de440db	305	return fpriv->is_master && drm_lease_owner(fpriv->master) == fpriv->minor->dev->master;
b3ac9f25 DV	306	}
	307	EXPORT_SYMBOL(drm_is_current_master);
	308
3b96a0b1 DV	309	/**
3b96a0b1 DV	310	* drm_master_get - reference a master pointer
ea0dd85a	311	* @master: &struct drm_master
3b96a0b1 DV	312	*
	313	* Increments the reference count of @master and returns a pointer to @master.
	314	*/
6548f4e7 DV	315	struct drm_master drm_master_get(struct drm_master master)
	316	{
	317	kref_get(&master->refcount);
	318	return master;
	319	}
	320	EXPORT_SYMBOL(drm_master_get);
	321
	322	static void drm_master_destroy(struct kref *kref)
	323	{
	324	struct drm_master *master = container_of(kref, struct drm_master, refcount);
	325	struct drm_device *dev = master->dev;
	326
2ed077e4 KP	327	if (drm_core_check_feature(dev, DRIVER_MODESET))
	328	drm_lease_destroy(master);
	329
6548f4e7 DV	330	drm_legacy_master_rmmaps(dev, master);
	331
	332	idr_destroy(&master->magic_map);
2ed077e4 KP	333	idr_destroy(&master->leases);
	334	idr_destroy(&master->lessee_idr);
	335
6548f4e7 DV	336	kfree(master->unique);
	337	kfree(master);
	338	}
	339
3b96a0b1 DV	340	/**
3b96a0b1 DV	341	* drm_master_put - unreference and clear a master pointer
ea0dd85a	342	* @master: pointer to a pointer of &struct drm_master
3b96a0b1 DV	343	*
	344	* This decrements the &drm_master behind @master and sets it to NULL.
	345	*/
6548f4e7 DV	346	void drm_master_put(struct drm_master **master)
	347	{
	348	kref_put(&(*master)->refcount, drm_master_destroy);
	349	*master = NULL;
	350	}
	351	EXPORT_SYMBOL(drm_master_put);
03a9606e NT	352
	353	/* Used by drm_client and drm_fb_helper */
	354	bool drm_master_internal_acquire(struct drm_device *dev)
	355	{
	356	mutex_lock(&dev->master_mutex);
	357	if (dev->master) {
	358	mutex_unlock(&dev->master_mutex);
	359	return false;
	360	}
	361
	362	return true;
	363	}
	364	EXPORT_SYMBOL(drm_master_internal_acquire);
	365
	366	/* Used by drm_client and drm_fb_helper */
	367	void drm_master_internal_release(struct drm_device *dev)
	368	{
	369	mutex_unlock(&dev->master_mutex);
	370	}
	371	EXPORT_SYMBOL(drm_master_internal_release);