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1/**
2 * \file drm_lock.c
3 * IOCTLs for locking
4 *
5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
7 */
8
9/*
10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
11 *
12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
22 *
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
25 * Software.
26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
34 */
35
36#include "drmP.h"
37
38static int drm_notifier(void *priv);
39
40static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
41
42/**
43 * Lock ioctl.
44 *
45 * \param inode device inode.
46 * \param file_priv DRM file private.
47 * \param cmd command.
48 * \param arg user argument, pointing to a drm_lock structure.
49 * \return zero on success or negative number on failure.
50 *
51 * Add the current task to the lock wait queue, and attempt to take to lock.
52 */
53int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
54{
55 DECLARE_WAITQUEUE(entry, current);
56 struct drm_lock *lock = data;
57 struct drm_master *master = file_priv->master;
58 int ret = 0;
59
60 ++file_priv->lock_count;
61
62 if (lock->context == DRM_KERNEL_CONTEXT) {
63 DRM_ERROR("Process %d using kernel context %d\n",
64 task_pid_nr(current), lock->context);
65 return -EINVAL;
66 }
67
68 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
69 lock->context, task_pid_nr(current),
70 master->lock.hw_lock->lock, lock->flags);
71
72 if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
73 if (lock->context < 0)
74 return -EINVAL;
75
76 add_wait_queue(&master->lock.lock_queue, &entry);
77 spin_lock_bh(&master->lock.spinlock);
78 master->lock.user_waiters++;
79 spin_unlock_bh(&master->lock.spinlock);
80
81 for (;;) {
82 __set_current_state(TASK_INTERRUPTIBLE);
83 if (!master->lock.hw_lock) {
84 /* Device has been unregistered */
85 send_sig(SIGTERM, current, 0);
86 ret = -EINTR;
87 break;
88 }
89 if (drm_lock_take(&master->lock, lock->context)) {
90 master->lock.file_priv = file_priv;
91 master->lock.lock_time = jiffies;
92 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
93 break; /* Got lock */
94 }
95
96 /* Contention */
97 mutex_unlock(&drm_global_mutex);
98 schedule();
99 mutex_lock(&drm_global_mutex);
100 if (signal_pending(current)) {
101 ret = -EINTR;
102 break;
103 }
104 }
105 spin_lock_bh(&master->lock.spinlock);
106 master->lock.user_waiters--;
107 spin_unlock_bh(&master->lock.spinlock);
108 __set_current_state(TASK_RUNNING);
109 remove_wait_queue(&master->lock.lock_queue, &entry);
110
111 DRM_DEBUG("%d %s\n", lock->context,
112 ret ? "interrupted" : "has lock");
113 if (ret) return ret;
114
115 /* don't set the block all signals on the master process for now
116 * really probably not the correct answer but lets us debug xkb
117 * xserver for now */
118 if (!file_priv->is_master) {
119 sigemptyset(&dev->sigmask);
120 sigaddset(&dev->sigmask, SIGSTOP);
121 sigaddset(&dev->sigmask, SIGTSTP);
122 sigaddset(&dev->sigmask, SIGTTIN);
123 sigaddset(&dev->sigmask, SIGTTOU);
124 dev->sigdata.context = lock->context;
125 dev->sigdata.lock = master->lock.hw_lock;
126 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
127 }
128
129 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
130 {
131 if (dev->driver->dma_quiescent(dev)) {
132 DRM_DEBUG("%d waiting for DMA quiescent\n",
133 lock->context);
134 return -EBUSY;
135 }
136 }
137
138 return 0;
139}
140
141/**
142 * Unlock ioctl.
143 *
144 * \param inode device inode.
145 * \param file_priv DRM file private.
146 * \param cmd command.
147 * \param arg user argument, pointing to a drm_lock structure.
148 * \return zero on success or negative number on failure.
149 *
150 * Transfer and free the lock.
151 */
152int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
153{
154 struct drm_lock *lock = data;
155 struct drm_master *master = file_priv->master;
156
157 if (lock->context == DRM_KERNEL_CONTEXT) {
158 DRM_ERROR("Process %d using kernel context %d\n",
159 task_pid_nr(current), lock->context);
160 return -EINVAL;
161 }
162
163 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
164
165 if (drm_lock_free(&master->lock, lock->context)) {
166 /* FIXME: Should really bail out here. */
167 }
168
169 unblock_all_signals();
170 return 0;
171}
172
173/**
174 * Take the heavyweight lock.
175 *
176 * \param lock lock pointer.
177 * \param context locking context.
178 * \return one if the lock is held, or zero otherwise.
179 *
180 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
181 */
182static
183int drm_lock_take(struct drm_lock_data *lock_data,
184 unsigned int context)
185{
186 unsigned int old, new, prev;
187 volatile unsigned int *lock = &lock_data->hw_lock->lock;
188
189 spin_lock_bh(&lock_data->spinlock);
190 do {
191 old = *lock;
192 if (old & _DRM_LOCK_HELD)
193 new = old | _DRM_LOCK_CONT;
194 else {
195 new = context | _DRM_LOCK_HELD |
196 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
197 _DRM_LOCK_CONT : 0);
198 }
199 prev = cmpxchg(lock, old, new);
200 } while (prev != old);
201 spin_unlock_bh(&lock_data->spinlock);
202
203 if (_DRM_LOCKING_CONTEXT(old) == context) {
204 if (old & _DRM_LOCK_HELD) {
205 if (context != DRM_KERNEL_CONTEXT) {
206 DRM_ERROR("%d holds heavyweight lock\n",
207 context);
208 }
209 return 0;
210 }
211 }
212
213 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
214 /* Have lock */
215 return 1;
216 }
217 return 0;
218}
219
220/**
221 * This takes a lock forcibly and hands it to context. Should ONLY be used
222 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
223 *
224 * \param dev DRM device.
225 * \param lock lock pointer.
226 * \param context locking context.
227 * \return always one.
228 *
229 * Resets the lock file pointer.
230 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
231 */
232static int drm_lock_transfer(struct drm_lock_data *lock_data,
233 unsigned int context)
234{
235 unsigned int old, new, prev;
236 volatile unsigned int *lock = &lock_data->hw_lock->lock;
237
238 lock_data->file_priv = NULL;
239 do {
240 old = *lock;
241 new = context | _DRM_LOCK_HELD;
242 prev = cmpxchg(lock, old, new);
243 } while (prev != old);
244 return 1;
245}
246
247/**
248 * Free lock.
249 *
250 * \param dev DRM device.
251 * \param lock lock.
252 * \param context context.
253 *
254 * Resets the lock file pointer.
255 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
256 * waiting on the lock queue.
257 */
258int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context)
259{
260 unsigned int old, new, prev;
261 volatile unsigned int *lock = &lock_data->hw_lock->lock;
262
263 spin_lock_bh(&lock_data->spinlock);
264 if (lock_data->kernel_waiters != 0) {
265 drm_lock_transfer(lock_data, 0);
266 lock_data->idle_has_lock = 1;
267 spin_unlock_bh(&lock_data->spinlock);
268 return 1;
269 }
270 spin_unlock_bh(&lock_data->spinlock);
271
272 do {
273 old = *lock;
274 new = _DRM_LOCKING_CONTEXT(old);
275 prev = cmpxchg(lock, old, new);
276 } while (prev != old);
277
278 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
279 DRM_ERROR("%d freed heavyweight lock held by %d\n",
280 context, _DRM_LOCKING_CONTEXT(old));
281 return 1;
282 }
283 wake_up_interruptible(&lock_data->lock_queue);
284 return 0;
285}
286
287/**
288 * If we get here, it means that the process has called DRM_IOCTL_LOCK
289 * without calling DRM_IOCTL_UNLOCK.
290 *
291 * If the lock is not held, then let the signal proceed as usual. If the lock
292 * is held, then set the contended flag and keep the signal blocked.
293 *
294 * \param priv pointer to a drm_sigdata structure.
295 * \return one if the signal should be delivered normally, or zero if the
296 * signal should be blocked.
297 */
298static int drm_notifier(void *priv)
299{
300 struct drm_sigdata *s = (struct drm_sigdata *) priv;
301 unsigned int old, new, prev;
302
303 /* Allow signal delivery if lock isn't held */
304 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
305 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
306 return 1;
307
308 /* Otherwise, set flag to force call to
309 drmUnlock */
310 do {
311 old = s->lock->lock;
312 new = old | _DRM_LOCK_CONT;
313 prev = cmpxchg(&s->lock->lock, old, new);
314 } while (prev != old);
315 return 0;
316}
317
318/**
319 * This function returns immediately and takes the hw lock
320 * with the kernel context if it is free, otherwise it gets the highest priority when and if
321 * it is eventually released.
322 *
323 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
324 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
325 * a deadlock, which is why the "idlelock" was invented).
326 *
327 * This should be sufficient to wait for GPU idle without
328 * having to worry about starvation.
329 */
330
331void drm_idlelock_take(struct drm_lock_data *lock_data)
332{
333 int ret = 0;
334
335 spin_lock_bh(&lock_data->spinlock);
336 lock_data->kernel_waiters++;
337 if (!lock_data->idle_has_lock) {
338
339 spin_unlock_bh(&lock_data->spinlock);
340 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
341 spin_lock_bh(&lock_data->spinlock);
342
343 if (ret == 1)
344 lock_data->idle_has_lock = 1;
345 }
346 spin_unlock_bh(&lock_data->spinlock);
347}
348
349void drm_idlelock_release(struct drm_lock_data *lock_data)
350{
351 unsigned int old, prev;
352 volatile unsigned int *lock = &lock_data->hw_lock->lock;
353
354 spin_lock_bh(&lock_data->spinlock);
355 if (--lock_data->kernel_waiters == 0) {
356 if (lock_data->idle_has_lock) {
357 do {
358 old = *lock;
359 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
360 } while (prev != old);
361 wake_up_interruptible(&lock_data->lock_queue);
362 lock_data->idle_has_lock = 0;
363 }
364 }
365 spin_unlock_bh(&lock_data->spinlock);
366}
367
368int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
369{
370 struct drm_master *master = file_priv->master;
371 return (file_priv->lock_count && master->lock.hw_lock &&
372 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
373 master->lock.file_priv == file_priv);
374}
1/**
2 * \file drm_lock.c
3 * IOCTLs for locking
4 *
5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
7 */
8
9/*
10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
11 *
12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a
17 * copy of this software and associated documentation files (the "Software"),
18 * to deal in the Software without restriction, including without limitation
19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
20 * and/or sell copies of the Software, and to permit persons to whom the
21 * Software is furnished to do so, subject to the following conditions:
22 *
23 * The above copyright notice and this permission notice (including the next
24 * paragraph) shall be included in all copies or substantial portions of the
25 * Software.
26 *
27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
33 * OTHER DEALINGS IN THE SOFTWARE.
34 */
35
36#include <linux/export.h>
37#include <linux/sched/signal.h>
38
39#include <drm/drmP.h>
40#include "drm_legacy.h"
41#include "drm_internal.h"
42
43static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
44
45/**
46 * Take the heavyweight lock.
47 *
48 * \param lock lock pointer.
49 * \param context locking context.
50 * \return one if the lock is held, or zero otherwise.
51 *
52 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
53 */
54static
55int drm_lock_take(struct drm_lock_data *lock_data,
56 unsigned int context)
57{
58 unsigned int old, new, prev;
59 volatile unsigned int *lock = &lock_data->hw_lock->lock;
60
61 spin_lock_bh(&lock_data->spinlock);
62 do {
63 old = *lock;
64 if (old & _DRM_LOCK_HELD)
65 new = old | _DRM_LOCK_CONT;
66 else {
67 new = context | _DRM_LOCK_HELD |
68 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
69 _DRM_LOCK_CONT : 0);
70 }
71 prev = cmpxchg(lock, old, new);
72 } while (prev != old);
73 spin_unlock_bh(&lock_data->spinlock);
74
75 if (_DRM_LOCKING_CONTEXT(old) == context) {
76 if (old & _DRM_LOCK_HELD) {
77 if (context != DRM_KERNEL_CONTEXT) {
78 DRM_ERROR("%d holds heavyweight lock\n",
79 context);
80 }
81 return 0;
82 }
83 }
84
85 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
86 /* Have lock */
87 return 1;
88 }
89 return 0;
90}
91
92/**
93 * This takes a lock forcibly and hands it to context. Should ONLY be used
94 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
95 *
96 * \param dev DRM device.
97 * \param lock lock pointer.
98 * \param context locking context.
99 * \return always one.
100 *
101 * Resets the lock file pointer.
102 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
103 */
104static int drm_lock_transfer(struct drm_lock_data *lock_data,
105 unsigned int context)
106{
107 unsigned int old, new, prev;
108 volatile unsigned int *lock = &lock_data->hw_lock->lock;
109
110 lock_data->file_priv = NULL;
111 do {
112 old = *lock;
113 new = context | _DRM_LOCK_HELD;
114 prev = cmpxchg(lock, old, new);
115 } while (prev != old);
116 return 1;
117}
118
119static int drm_legacy_lock_free(struct drm_lock_data *lock_data,
120 unsigned int context)
121{
122 unsigned int old, new, prev;
123 volatile unsigned int *lock = &lock_data->hw_lock->lock;
124
125 spin_lock_bh(&lock_data->spinlock);
126 if (lock_data->kernel_waiters != 0) {
127 drm_lock_transfer(lock_data, 0);
128 lock_data->idle_has_lock = 1;
129 spin_unlock_bh(&lock_data->spinlock);
130 return 1;
131 }
132 spin_unlock_bh(&lock_data->spinlock);
133
134 do {
135 old = *lock;
136 new = _DRM_LOCKING_CONTEXT(old);
137 prev = cmpxchg(lock, old, new);
138 } while (prev != old);
139
140 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
141 DRM_ERROR("%d freed heavyweight lock held by %d\n",
142 context, _DRM_LOCKING_CONTEXT(old));
143 return 1;
144 }
145 wake_up_interruptible(&lock_data->lock_queue);
146 return 0;
147}
148
149/**
150 * Lock ioctl.
151 *
152 * \param inode device inode.
153 * \param file_priv DRM file private.
154 * \param cmd command.
155 * \param arg user argument, pointing to a drm_lock structure.
156 * \return zero on success or negative number on failure.
157 *
158 * Add the current task to the lock wait queue, and attempt to take to lock.
159 */
160int drm_legacy_lock(struct drm_device *dev, void *data,
161 struct drm_file *file_priv)
162{
163 DECLARE_WAITQUEUE(entry, current);
164 struct drm_lock *lock = data;
165 struct drm_master *master = file_priv->master;
166 int ret = 0;
167
168 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
169 return -EINVAL;
170
171 ++file_priv->lock_count;
172
173 if (lock->context == DRM_KERNEL_CONTEXT) {
174 DRM_ERROR("Process %d using kernel context %d\n",
175 task_pid_nr(current), lock->context);
176 return -EINVAL;
177 }
178
179 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
180 lock->context, task_pid_nr(current),
181 master->lock.hw_lock ? master->lock.hw_lock->lock : -1,
182 lock->flags);
183
184 add_wait_queue(&master->lock.lock_queue, &entry);
185 spin_lock_bh(&master->lock.spinlock);
186 master->lock.user_waiters++;
187 spin_unlock_bh(&master->lock.spinlock);
188
189 for (;;) {
190 __set_current_state(TASK_INTERRUPTIBLE);
191 if (!master->lock.hw_lock) {
192 /* Device has been unregistered */
193 send_sig(SIGTERM, current, 0);
194 ret = -EINTR;
195 break;
196 }
197 if (drm_lock_take(&master->lock, lock->context)) {
198 master->lock.file_priv = file_priv;
199 master->lock.lock_time = jiffies;
200 break; /* Got lock */
201 }
202
203 /* Contention */
204 mutex_unlock(&drm_global_mutex);
205 schedule();
206 mutex_lock(&drm_global_mutex);
207 if (signal_pending(current)) {
208 ret = -EINTR;
209 break;
210 }
211 }
212 spin_lock_bh(&master->lock.spinlock);
213 master->lock.user_waiters--;
214 spin_unlock_bh(&master->lock.spinlock);
215 __set_current_state(TASK_RUNNING);
216 remove_wait_queue(&master->lock.lock_queue, &entry);
217
218 DRM_DEBUG("%d %s\n", lock->context,
219 ret ? "interrupted" : "has lock");
220 if (ret) return ret;
221
222 /* don't set the block all signals on the master process for now
223 * really probably not the correct answer but lets us debug xkb
224 * xserver for now */
225 if (!drm_is_current_master(file_priv)) {
226 dev->sigdata.context = lock->context;
227 dev->sigdata.lock = master->lock.hw_lock;
228 }
229
230 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
231 {
232 if (dev->driver->dma_quiescent(dev)) {
233 DRM_DEBUG("%d waiting for DMA quiescent\n",
234 lock->context);
235 return -EBUSY;
236 }
237 }
238
239 return 0;
240}
241
242/**
243 * Unlock ioctl.
244 *
245 * \param inode device inode.
246 * \param file_priv DRM file private.
247 * \param cmd command.
248 * \param arg user argument, pointing to a drm_lock structure.
249 * \return zero on success or negative number on failure.
250 *
251 * Transfer and free the lock.
252 */
253int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
254{
255 struct drm_lock *lock = data;
256 struct drm_master *master = file_priv->master;
257
258 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
259 return -EINVAL;
260
261 if (lock->context == DRM_KERNEL_CONTEXT) {
262 DRM_ERROR("Process %d using kernel context %d\n",
263 task_pid_nr(current), lock->context);
264 return -EINVAL;
265 }
266
267 if (drm_legacy_lock_free(&master->lock, lock->context)) {
268 /* FIXME: Should really bail out here. */
269 }
270
271 return 0;
272}
273
274/**
275 * This function returns immediately and takes the hw lock
276 * with the kernel context if it is free, otherwise it gets the highest priority when and if
277 * it is eventually released.
278 *
279 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
280 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
281 * a deadlock, which is why the "idlelock" was invented).
282 *
283 * This should be sufficient to wait for GPU idle without
284 * having to worry about starvation.
285 */
286
287void drm_legacy_idlelock_take(struct drm_lock_data *lock_data)
288{
289 int ret;
290
291 spin_lock_bh(&lock_data->spinlock);
292 lock_data->kernel_waiters++;
293 if (!lock_data->idle_has_lock) {
294
295 spin_unlock_bh(&lock_data->spinlock);
296 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
297 spin_lock_bh(&lock_data->spinlock);
298
299 if (ret == 1)
300 lock_data->idle_has_lock = 1;
301 }
302 spin_unlock_bh(&lock_data->spinlock);
303}
304EXPORT_SYMBOL(drm_legacy_idlelock_take);
305
306void drm_legacy_idlelock_release(struct drm_lock_data *lock_data)
307{
308 unsigned int old, prev;
309 volatile unsigned int *lock = &lock_data->hw_lock->lock;
310
311 spin_lock_bh(&lock_data->spinlock);
312 if (--lock_data->kernel_waiters == 0) {
313 if (lock_data->idle_has_lock) {
314 do {
315 old = *lock;
316 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
317 } while (prev != old);
318 wake_up_interruptible(&lock_data->lock_queue);
319 lock_data->idle_has_lock = 0;
320 }
321 }
322 spin_unlock_bh(&lock_data->spinlock);
323}
324EXPORT_SYMBOL(drm_legacy_idlelock_release);
325
326static int drm_legacy_i_have_hw_lock(struct drm_device *dev,
327 struct drm_file *file_priv)
328{
329 struct drm_master *master = file_priv->master;
330 return (file_priv->lock_count && master->lock.hw_lock &&
331 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
332 master->lock.file_priv == file_priv);
333}
334
335void drm_legacy_lock_release(struct drm_device *dev, struct file *filp)
336{
337 struct drm_file *file_priv = filp->private_data;
338
339 /* if the master has gone away we can't do anything with the lock */
340 if (!dev->master)
341 return;
342
343 if (drm_legacy_i_have_hw_lock(dev, file_priv)) {
344 DRM_DEBUG("File %p released, freeing lock for context %d\n",
345 filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
346 drm_legacy_lock_free(&file_priv->master->lock,
347 _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
348 }
349}