[mirror_ubuntu-zesty-kernel.git] / drivers / gpu / drm / ttm / ttm_lock.c

/**************************************************************************
 *
 * Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS 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.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#include "ttm/ttm_lock.h"
#include "ttm/ttm_module.h"
#include <linux/atomic.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/module.h>

#define TTM_WRITE_LOCK_PENDING    (1 << 0)
#define TTM_VT_LOCK_PENDING       (1 << 1)
#define TTM_SUSPEND_LOCK_PENDING  (1 << 2)
#define TTM_VT_LOCK               (1 << 3)
#define TTM_SUSPEND_LOCK          (1 << 4)

void ttm_lock_init(struct ttm_lock *lock)
{
	spin_lock_init(&lock->lock);
	init_waitqueue_head(&lock->queue);
	lock->rw = 0;
	lock->flags = 0;
	lock->kill_takers = false;
	lock->signal = SIGKILL;
}
EXPORT_SYMBOL(ttm_lock_init);

void ttm_read_unlock(struct ttm_lock *lock)
{
	spin_lock(&lock->lock);
	if (--lock->rw == 0)
		wake_up_all(&lock->queue);
	spin_unlock(&lock->lock);
}
EXPORT_SYMBOL(ttm_read_unlock);

static bool __ttm_read_lock(struct ttm_lock *lock)
{
	bool locked = false;

	spin_lock(&lock->lock);
	if (unlikely(lock->kill_takers)) {
		send_sig(lock->signal, current, 0);
		spin_unlock(&lock->lock);
		return false;
	}
	if (lock->rw >= 0 && lock->flags == 0) {
		++lock->rw;
		locked = true;
	}
	spin_unlock(&lock->lock);
	return locked;
}

int ttm_read_lock(struct ttm_lock *lock, bool interruptible)
{
	int ret = 0;

	if (interruptible)
		ret = wait_event_interruptible(lock->queue,
					       __ttm_read_lock(lock));
	else
		wait_event(lock->queue, __ttm_read_lock(lock));
	return ret;
}
EXPORT_SYMBOL(ttm_read_lock);

static bool __ttm_read_trylock(struct ttm_lock *lock, bool *locked)
{
	bool block = true;

	*locked = false;

	spin_lock(&lock->lock);
	if (unlikely(lock->kill_takers)) {
		send_sig(lock->signal, current, 0);
		spin_unlock(&lock->lock);
		return false;
	}
	if (lock->rw >= 0 && lock->flags == 0) {
		++lock->rw;
		block = false;
		*locked = true;
	} else if (lock->flags == 0) {
		block = false;
	}
	spin_unlock(&lock->lock);

	return !block;
}

int ttm_read_trylock(struct ttm_lock *lock, bool interruptible)
{
	int ret = 0;
	bool locked;

	if (interruptible)
		ret = wait_event_interruptible
			(lock->queue, __ttm_read_trylock(lock, &locked));
	else
		wait_event(lock->queue, __ttm_read_trylock(lock, &locked));

	if (unlikely(ret != 0)) {
		BUG_ON(locked);
		return ret;
	}

	return (locked) ? 0 : -EBUSY;
}

void ttm_write_unlock(struct ttm_lock *lock)
{
	spin_lock(&lock->lock);
	lock->rw = 0;
	wake_up_all(&lock->queue);
	spin_unlock(&lock->lock);
}
EXPORT_SYMBOL(ttm_write_unlock);

static bool __ttm_write_lock(struct ttm_lock *lock)
{
	bool locked = false;

	spin_lock(&lock->lock);
	if (unlikely(lock->kill_takers)) {
		send_sig(lock->signal, current, 0);
		spin_unlock(&lock->lock);
		return false;
	}
	if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) {
		lock->rw = -1;
		lock->flags &= ~TTM_WRITE_LOCK_PENDING;
		locked = true;
	} else {
		lock->flags |= TTM_WRITE_LOCK_PENDING;
	}
	spin_unlock(&lock->lock);
	return locked;
}

int ttm_write_lock(struct ttm_lock *lock, bool interruptible)
{
	int ret = 0;

	if (interruptible) {
		ret = wait_event_interruptible(lock->queue,
					       __ttm_write_lock(lock));
		if (unlikely(ret != 0)) {
			spin_lock(&lock->lock);
			lock->flags &= ~TTM_WRITE_LOCK_PENDING;
			wake_up_all(&lock->queue);
			spin_unlock(&lock->lock);
		}
	} else
		wait_event(lock->queue, __ttm_read_lock(lock));

	return ret;
}
EXPORT_SYMBOL(ttm_write_lock);

void ttm_write_lock_downgrade(struct ttm_lock *lock)
{
	spin_lock(&lock->lock);
	lock->rw = 1;
	wake_up_all(&lock->queue);
	spin_unlock(&lock->lock);
}

static int __ttm_vt_unlock(struct ttm_lock *lock)
{
	int ret = 0;

	spin_lock(&lock->lock);
	if (unlikely(!(lock->flags & TTM_VT_LOCK)))
		ret = -EINVAL;
	lock->flags &= ~TTM_VT_LOCK;
	wake_up_all(&lock->queue);
	spin_unlock(&lock->lock);

	return ret;
}

static void ttm_vt_lock_remove(struct ttm_base_object **p_base)
{
	struct ttm_base_object *base = *p_base;
	struct ttm_lock *lock = container_of(base, struct ttm_lock, base);
	int ret;

	*p_base = NULL;
	ret = __ttm_vt_unlock(lock);
	BUG_ON(ret != 0);
}

static bool __ttm_vt_lock(struct ttm_lock *lock)
{
	bool locked = false;

	spin_lock(&lock->lock);
	if (lock->rw == 0) {
		lock->flags &= ~TTM_VT_LOCK_PENDING;
		lock->flags |= TTM_VT_LOCK;
		locked = true;
	} else {
		lock->flags |= TTM_VT_LOCK_PENDING;
	}
	spin_unlock(&lock->lock);
	return locked;
}

int ttm_vt_lock(struct ttm_lock *lock,
		bool interruptible,
		struct ttm_object_file *tfile)
{
	int ret = 0;

	if (interruptible) {
		ret = wait_event_interruptible(lock->queue,
					       __ttm_vt_lock(lock));
		if (unlikely(ret != 0)) {
			spin_lock(&lock->lock);
			lock->flags &= ~TTM_VT_LOCK_PENDING;
			wake_up_all(&lock->queue);
			spin_unlock(&lock->lock);
			return ret;
		}
	} else
		wait_event(lock->queue, __ttm_vt_lock(lock));

	/*
	 * Add a base-object, the destructor of which will
	 * make sure the lock is released if the client dies
	 * while holding it.
	 */

	ret = ttm_base_object_init(tfile, &lock->base, false,
				   ttm_lock_type, &ttm_vt_lock_remove, NULL);
	if (ret)
		(void)__ttm_vt_unlock(lock);
	else
		lock->vt_holder = tfile;

	return ret;
}
EXPORT_SYMBOL(ttm_vt_lock);

int ttm_vt_unlock(struct ttm_lock *lock)
{
	return ttm_ref_object_base_unref(lock->vt_holder,
					 lock->base.hash.key, TTM_REF_USAGE);
}
EXPORT_SYMBOL(ttm_vt_unlock);

void ttm_suspend_unlock(struct ttm_lock *lock)
{
	spin_lock(&lock->lock);
	lock->flags &= ~TTM_SUSPEND_LOCK;
	wake_up_all(&lock->queue);
	spin_unlock(&lock->lock);
}
EXPORT_SYMBOL(ttm_suspend_unlock);

static bool __ttm_suspend_lock(struct ttm_lock *lock)
{
	bool locked = false;

	spin_lock(&lock->lock);
	if (lock->rw == 0) {
		lock->flags &= ~TTM_SUSPEND_LOCK_PENDING;
		lock->flags |= TTM_SUSPEND_LOCK;
		locked = true;
	} else {
		lock->flags |= TTM_SUSPEND_LOCK_PENDING;
	}
	spin_unlock(&lock->lock);
	return locked;
}

void ttm_suspend_lock(struct ttm_lock *lock)
{
	wait_event(lock->queue, __ttm_suspend_lock(lock));
}
EXPORT_SYMBOL(ttm_suspend_lock);
Commit	Line	Data
4aff1013 TH	1	/**************************************************************************
	2	*
	3	* Copyright (c) 2007-2009 VMware, Inc., Palo Alto, CA., USA
	4	* All Rights Reserved.
	5	*
	6	* Permission is hereby granted, free of charge, to any person obtaining a
	7	* copy of this software and associated documentation files (the
	8	* "Software"), to deal in the Software without restriction, including
	9	* without limitation the rights to use, copy, modify, merge, publish,
	10	* distribute, sub license, and/or sell copies of the Software, and to
	11	* permit persons to whom the Software is furnished to do so, subject to
	12	* the following conditions:
	13	*
	14	* The above copyright notice and this permission notice (including the
	15	* next paragraph) shall be included in all copies or substantial portions
	16	* of the Software.
	17	*
	18	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	19	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	20	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	21	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	22	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	23	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	24	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	25	*
	26	**************************************************************************/
	27	/*
	28	* Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
	29	*/
	30
	31	#include "ttm/ttm_lock.h"
	32	#include "ttm/ttm_module.h"
60063497	33	#include <linux/atomic.h>
4aff1013 TH	34	#include <linux/errno.h>
	35	#include <linux/wait.h>
	36	#include <linux/sched.h>
	37	#include <linux/module.h>
	38
	39	#define TTM_WRITE_LOCK_PENDING (1 << 0)
	40	#define TTM_VT_LOCK_PENDING (1 << 1)
	41	#define TTM_SUSPEND_LOCK_PENDING (1 << 2)
	42	#define TTM_VT_LOCK (1 << 3)
	43	#define TTM_SUSPEND_LOCK (1 << 4)
	44
	45	void ttm_lock_init(struct ttm_lock *lock)
	46	{
	47	spin_lock_init(&lock->lock);
	48	init_waitqueue_head(&lock->queue);
	49	lock->rw = 0;
	50	lock->flags = 0;
	51	lock->kill_takers = false;
	52	lock->signal = SIGKILL;
	53	}
	54	EXPORT_SYMBOL(ttm_lock_init);
	55
	56	void ttm_read_unlock(struct ttm_lock *lock)
	57	{
	58	spin_lock(&lock->lock);
	59	if (--lock->rw == 0)
	60	wake_up_all(&lock->queue);
	61	spin_unlock(&lock->lock);
	62	}
	63	EXPORT_SYMBOL(ttm_read_unlock);
	64
	65	static bool __ttm_read_lock(struct ttm_lock *lock)
	66	{
	67	bool locked = false;
	68
	69	spin_lock(&lock->lock);
	70	if (unlikely(lock->kill_takers)) {
	71	send_sig(lock->signal, current, 0);
	72	spin_unlock(&lock->lock);
	73	return false;
	74	}
	75	if (lock->rw >= 0 && lock->flags == 0) {
	76	++lock->rw;
	77	locked = true;
	78	}
	79	spin_unlock(&lock->lock);
	80	return locked;
	81	}
	82
	83	int ttm_read_lock(struct ttm_lock *lock, bool interruptible)
	84	{
	85	int ret = 0;
	86
	87	if (interruptible)
	88	ret = wait_event_interruptible(lock->queue,
	89	__ttm_read_lock(lock));
	90	else
	91	wait_event(lock->queue, __ttm_read_lock(lock));
	92	return ret;
	93	}
	94	EXPORT_SYMBOL(ttm_read_lock);
	95
	96	static bool __ttm_read_trylock(struct ttm_lock lock, bool locked)
	97	{
98	bool block = true;
99
100	*locked = false;
101
102	spin_lock(&lock->lock);
103	if (unlikely(lock->kill_takers)) {
104	send_sig(lock->signal, current, 0);
105	spin_unlock(&lock->lock);
106	return false;
107	}
108	if (lock->rw >= 0 && lock->flags == 0) {
109	++lock->rw;
110	block = false;
111	*locked = true;
112	} else if (lock->flags == 0) {
113	block = false;
114	}
115	spin_unlock(&lock->lock);
116
117	return !block;
118	}
119
120	int ttm_read_trylock(struct ttm_lock *lock, bool interruptible)
121	{
122	int ret = 0;
123	bool locked;
124
125	if (interruptible)
126	ret = wait_event_interruptible
127	(lock->queue, __ttm_read_trylock(lock, &locked));
128	else
129	wait_event(lock->queue, __ttm_read_trylock(lock, &locked));
130
131	if (unlikely(ret != 0)) {
132	BUG_ON(locked);
133	return ret;
134	}
135
136	return (locked) ? 0 : -EBUSY;
137	}
138
139	void ttm_write_unlock(struct ttm_lock *lock)
140	{
141	spin_lock(&lock->lock);
142	lock->rw = 0;
143	wake_up_all(&lock->queue);
144	spin_unlock(&lock->lock);
145	}
146	EXPORT_SYMBOL(ttm_write_unlock);
147
148	static bool __ttm_write_lock(struct ttm_lock *lock)
149	{
150	bool locked = false;
151
152	spin_lock(&lock->lock);
153	if (unlikely(lock->kill_takers)) {
154	send_sig(lock->signal, current, 0);
155	spin_unlock(&lock->lock);
156	return false;
157	}
158	if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) {
159	lock->rw = -1;
160	lock->flags &= ~TTM_WRITE_LOCK_PENDING;
161	locked = true;
162	} else {
163	lock->flags \|= TTM_WRITE_LOCK_PENDING;
164	}
165	spin_unlock(&lock->lock);
166	return locked;
167	}
168
169	int ttm_write_lock(struct ttm_lock *lock, bool interruptible)
170	{
171	int ret = 0;
172
173	if (interruptible) {
174	ret = wait_event_interruptible(lock->queue,
175	__ttm_write_lock(lock));
176	if (unlikely(ret != 0)) {
177	spin_lock(&lock->lock);
178	lock->flags &= ~TTM_WRITE_LOCK_PENDING;
179	wake_up_all(&lock->queue);
180	spin_unlock(&lock->lock);
181	}
182	} else
183	wait_event(lock->queue, __ttm_read_lock(lock));
184
185	return ret;
186	}
187	EXPORT_SYMBOL(ttm_write_lock);
188
189	void ttm_write_lock_downgrade(struct ttm_lock *lock)
190	{
191	spin_lock(&lock->lock);
192	lock->rw = 1;
193	wake_up_all(&lock->queue);
194	spin_unlock(&lock->lock);
195	}
196
197	static int __ttm_vt_unlock(struct ttm_lock *lock)
198	{
199	int ret = 0;
200
201	spin_lock(&lock->lock);
202	if (unlikely(!(lock->flags & TTM_VT_LOCK)))
203	ret = -EINVAL;
204	lock->flags &= ~TTM_VT_LOCK;
205	wake_up_all(&lock->queue);
206	spin_unlock(&lock->lock);
4aff1013 TH	207
	208	return ret;
	209	}
	210
	211	static void ttm_vt_lock_remove(struct ttm_base_object **p_base)
	212	{
	213	struct ttm_base_object base = p_base;
	214	struct ttm_lock *lock = container_of(base, struct ttm_lock, base);
	215	int ret;
	216
	217	*p_base = NULL;
	218	ret = __ttm_vt_unlock(lock);
	219	BUG_ON(ret != 0);
	220	}
	221
	222	static bool __ttm_vt_lock(struct ttm_lock *lock)
	223	{
	224	bool locked = false;
	225
	226	spin_lock(&lock->lock);
	227	if (lock->rw == 0) {
	228	lock->flags &= ~TTM_VT_LOCK_PENDING;
	229	lock->flags \|= TTM_VT_LOCK;
	230	locked = true;
	231	} else {
	232	lock->flags \|= TTM_VT_LOCK_PENDING;
	233	}
	234	spin_unlock(&lock->lock);
	235	return locked;
	236	}
	237
	238	int ttm_vt_lock(struct ttm_lock *lock,
	239	bool interruptible,
	240	struct ttm_object_file *tfile)
	241	{
	242	int ret = 0;
	243
	244	if (interruptible) {
	245	ret = wait_event_interruptible(lock->queue,
	246	__ttm_vt_lock(lock));
	247	if (unlikely(ret != 0)) {
	248	spin_lock(&lock->lock);
	249	lock->flags &= ~TTM_VT_LOCK_PENDING;
	250	wake_up_all(&lock->queue);
	251	spin_unlock(&lock->lock);
	252	return ret;
	253	}
	254	} else
	255	wait_event(lock->queue, __ttm_vt_lock(lock));
	256
	257	/*
	258	* Add a base-object, the destructor of which will
	259	* make sure the lock is released if the client dies
	260	* while holding it.
	261	*/
	262
	263	ret = ttm_base_object_init(tfile, &lock->base, false,
	264	ttm_lock_type, &ttm_vt_lock_remove, NULL);
	265	if (ret)
	266	(void)__ttm_vt_unlock(lock);
5be6eff9	267	else
4aff1013	268	lock->vt_holder = tfile;
4aff1013 TH	269
	270	return ret;
	271	}
	272	EXPORT_SYMBOL(ttm_vt_lock);
	273
	274	int ttm_vt_unlock(struct ttm_lock *lock)
	275	{
	276	return ttm_ref_object_base_unref(lock->vt_holder,
	277	lock->base.hash.key, TTM_REF_USAGE);
	278	}
	279	EXPORT_SYMBOL(ttm_vt_unlock);
	280
	281	void ttm_suspend_unlock(struct ttm_lock *lock)
	282	{
	283	spin_lock(&lock->lock);
	284	lock->flags &= ~TTM_SUSPEND_LOCK;
	285	wake_up_all(&lock->queue);
	286	spin_unlock(&lock->lock);
	287	}
e99e1e78	288	EXPORT_SYMBOL(ttm_suspend_unlock);
4aff1013 TH	289
	290	static bool __ttm_suspend_lock(struct ttm_lock *lock)
	291	{
	292	bool locked = false;
	293
	294	spin_lock(&lock->lock);
	295	if (lock->rw == 0) {
	296	lock->flags &= ~TTM_SUSPEND_LOCK_PENDING;
	297	lock->flags \|= TTM_SUSPEND_LOCK;
	298	locked = true;
	299	} else {
	300	lock->flags \|= TTM_SUSPEND_LOCK_PENDING;
	301	}
	302	spin_unlock(&lock->lock);
	303	return locked;
	304	}
	305
	306	void ttm_suspend_lock(struct ttm_lock *lock)
	307	{
	308	wait_event(lock->queue, __ttm_suspend_lock(lock));
	309	}
e99e1e78	310	EXPORT_SYMBOL(ttm_suspend_lock);