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/drivers/gpu/drm/ttm/ttm_lock.c

https://gitlab.com/TeamTators/hp-kernel-tenderloin
C | 310 lines | 236 code | 40 blank | 34 comment | 38 complexity | db7736255178afbabdc029ee34bccc15 MD5 | raw file
  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"
 33#include <asm/atomic.h>
 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
 45void 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}
 54EXPORT_SYMBOL(ttm_lock_init);
 55
 56void 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}
 63EXPORT_SYMBOL(ttm_read_unlock);
 64
 65static 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
 83int 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}
 94EXPORT_SYMBOL(ttm_read_lock);
 95
 96static 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
120int 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
139void 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}
146EXPORT_SYMBOL(ttm_write_unlock);
147
148static 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
169int 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}
187EXPORT_SYMBOL(ttm_write_lock);
188
189void 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
197static 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);
207
208	return ret;
209}
210
211static 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
222static 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
238int 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);
267	else
268		lock->vt_holder = tfile;
269
270	return ret;
271}
272EXPORT_SYMBOL(ttm_vt_lock);
273
274int 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}
279EXPORT_SYMBOL(ttm_vt_unlock);
280
281void 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}
288EXPORT_SYMBOL(ttm_suspend_unlock);
289
290static 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
306void ttm_suspend_lock(struct ttm_lock *lock)
307{
308	wait_event(lock->queue, __ttm_suspend_lock(lock));
309}
310EXPORT_SYMBOL(ttm_suspend_lock);