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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 <linux/export.h>
37#include <linux/sched/signal.h>
38
39#include <drm/drm.h>
40#include <drm/drm_drv.h>
41#include <drm/drm_file.h>
42#include <drm/drm_print.h>
43
44#include "drm_internal.h"
45#include "drm_legacy.h"
46
47static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
48
49/**
50 * Take the heavyweight lock.
51 *
52 * \param lock lock pointer.
53 * \param context locking context.
54 * \return one if the lock is held, or zero otherwise.
55 *
56 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
57 */
58static
59int drm_lock_take(struct drm_lock_data *lock_data,
60 unsigned int context)
61{
62 unsigned int old, new, prev;
63 volatile unsigned int *lock = &lock_data->hw_lock->lock;
64
65 spin_lock_bh(&lock_data->spinlock);
66 do {
67 old = *lock;
68 if (old & _DRM_LOCK_HELD)
69 new = old | _DRM_LOCK_CONT;
70 else {
71 new = context | _DRM_LOCK_HELD |
72 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
73 _DRM_LOCK_CONT : 0);
74 }
75 prev = cmpxchg(lock, old, new);
76 } while (prev != old);
77 spin_unlock_bh(&lock_data->spinlock);
78
79 if (_DRM_LOCKING_CONTEXT(old) == context) {
80 if (old & _DRM_LOCK_HELD) {
81 if (context != DRM_KERNEL_CONTEXT) {
82 DRM_ERROR("%d holds heavyweight lock\n",
83 context);
84 }
85 return 0;
86 }
87 }
88
89 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
90 /* Have lock */
91 return 1;
92 }
93 return 0;
94}
95
96/**
97 * This takes a lock forcibly and hands it to context. Should ONLY be used
98 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
99 *
100 * \param dev DRM device.
101 * \param lock lock pointer.
102 * \param context locking context.
103 * \return always one.
104 *
105 * Resets the lock file pointer.
106 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
107 */
108static int drm_lock_transfer(struct drm_lock_data *lock_data,
109 unsigned int context)
110{
111 unsigned int old, new, prev;
112 volatile unsigned int *lock = &lock_data->hw_lock->lock;
113
114 lock_data->file_priv = NULL;
115 do {
116 old = *lock;
117 new = context | _DRM_LOCK_HELD;
118 prev = cmpxchg(lock, old, new);
119 } while (prev != old);
120 return 1;
121}
122
123static int drm_legacy_lock_free(struct drm_lock_data *lock_data,
124 unsigned int context)
125{
126 unsigned int old, new, prev;
127 volatile unsigned int *lock = &lock_data->hw_lock->lock;
128
129 spin_lock_bh(&lock_data->spinlock);
130 if (lock_data->kernel_waiters != 0) {
131 drm_lock_transfer(lock_data, 0);
132 lock_data->idle_has_lock = 1;
133 spin_unlock_bh(&lock_data->spinlock);
134 return 1;
135 }
136 spin_unlock_bh(&lock_data->spinlock);
137
138 do {
139 old = *lock;
140 new = _DRM_LOCKING_CONTEXT(old);
141 prev = cmpxchg(lock, old, new);
142 } while (prev != old);
143
144 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
145 DRM_ERROR("%d freed heavyweight lock held by %d\n",
146 context, _DRM_LOCKING_CONTEXT(old));
147 return 1;
148 }
149 wake_up_interruptible(&lock_data->lock_queue);
150 return 0;
151}
152
153/**
154 * Lock ioctl.
155 *
156 * \param inode device inode.
157 * \param file_priv DRM file private.
158 * \param cmd command.
159 * \param arg user argument, pointing to a drm_lock structure.
160 * \return zero on success or negative number on failure.
161 *
162 * Add the current task to the lock wait queue, and attempt to take to lock.
163 */
164int drm_legacy_lock(struct drm_device *dev, void *data,
165 struct drm_file *file_priv)
166{
167 DECLARE_WAITQUEUE(entry, current);
168 struct drm_lock *lock = data;
169 struct drm_master *master = file_priv->master;
170 int ret = 0;
171
172 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
173 return -EOPNOTSUPP;
174
175 ++file_priv->lock_count;
176
177 if (lock->context == DRM_KERNEL_CONTEXT) {
178 DRM_ERROR("Process %d using kernel context %d\n",
179 task_pid_nr(current), lock->context);
180 return -EINVAL;
181 }
182
183 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
184 lock->context, task_pid_nr(current),
185 master->lock.hw_lock ? master->lock.hw_lock->lock : -1,
186 lock->flags);
187
188 add_wait_queue(&master->lock.lock_queue, &entry);
189 spin_lock_bh(&master->lock.spinlock);
190 master->lock.user_waiters++;
191 spin_unlock_bh(&master->lock.spinlock);
192
193 for (;;) {
194 __set_current_state(TASK_INTERRUPTIBLE);
195 if (!master->lock.hw_lock) {
196 /* Device has been unregistered */
197 send_sig(SIGTERM, current, 0);
198 ret = -EINTR;
199 break;
200 }
201 if (drm_lock_take(&master->lock, lock->context)) {
202 master->lock.file_priv = file_priv;
203 master->lock.lock_time = jiffies;
204 break; /* Got lock */
205 }
206
207 /* Contention */
208 mutex_unlock(&drm_global_mutex);
209 schedule();
210 mutex_lock(&drm_global_mutex);
211 if (signal_pending(current)) {
212 ret = -EINTR;
213 break;
214 }
215 }
216 spin_lock_bh(&master->lock.spinlock);
217 master->lock.user_waiters--;
218 spin_unlock_bh(&master->lock.spinlock);
219 __set_current_state(TASK_RUNNING);
220 remove_wait_queue(&master->lock.lock_queue, &entry);
221
222 DRM_DEBUG("%d %s\n", lock->context,
223 ret ? "interrupted" : "has lock");
224 if (ret) return ret;
225
226 /* don't set the block all signals on the master process for now
227 * really probably not the correct answer but lets us debug xkb
228 * xserver for now */
229 if (!drm_is_current_master(file_priv)) {
230 dev->sigdata.context = lock->context;
231 dev->sigdata.lock = master->lock.hw_lock;
232 }
233
234 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
235 {
236 if (dev->driver->dma_quiescent(dev)) {
237 DRM_DEBUG("%d waiting for DMA quiescent\n",
238 lock->context);
239 return -EBUSY;
240 }
241 }
242
243 return 0;
244}
245
246/**
247 * Unlock ioctl.
248 *
249 * \param inode device inode.
250 * \param file_priv DRM file private.
251 * \param cmd command.
252 * \param arg user argument, pointing to a drm_lock structure.
253 * \return zero on success or negative number on failure.
254 *
255 * Transfer and free the lock.
256 */
257int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
258{
259 struct drm_lock *lock = data;
260 struct drm_master *master = file_priv->master;
261
262 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
263 return -EOPNOTSUPP;
264
265 if (lock->context == DRM_KERNEL_CONTEXT) {
266 DRM_ERROR("Process %d using kernel context %d\n",
267 task_pid_nr(current), lock->context);
268 return -EINVAL;
269 }
270
271 if (drm_legacy_lock_free(&master->lock, lock->context)) {
272 /* FIXME: Should really bail out here. */
273 }
274
275 return 0;
276}
277
278/**
279 * This function returns immediately and takes the hw lock
280 * with the kernel context if it is free, otherwise it gets the highest priority when and if
281 * it is eventually released.
282 *
283 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
284 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
285 * a deadlock, which is why the "idlelock" was invented).
286 *
287 * This should be sufficient to wait for GPU idle without
288 * having to worry about starvation.
289 */
290
291void drm_legacy_idlelock_take(struct drm_lock_data *lock_data)
292{
293 int ret;
294
295 spin_lock_bh(&lock_data->spinlock);
296 lock_data->kernel_waiters++;
297 if (!lock_data->idle_has_lock) {
298
299 spin_unlock_bh(&lock_data->spinlock);
300 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
301 spin_lock_bh(&lock_data->spinlock);
302
303 if (ret == 1)
304 lock_data->idle_has_lock = 1;
305 }
306 spin_unlock_bh(&lock_data->spinlock);
307}
308EXPORT_SYMBOL(drm_legacy_idlelock_take);
309
310void drm_legacy_idlelock_release(struct drm_lock_data *lock_data)
311{
312 unsigned int old, prev;
313 volatile unsigned int *lock = &lock_data->hw_lock->lock;
314
315 spin_lock_bh(&lock_data->spinlock);
316 if (--lock_data->kernel_waiters == 0) {
317 if (lock_data->idle_has_lock) {
318 do {
319 old = *lock;
320 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
321 } while (prev != old);
322 wake_up_interruptible(&lock_data->lock_queue);
323 lock_data->idle_has_lock = 0;
324 }
325 }
326 spin_unlock_bh(&lock_data->spinlock);
327}
328EXPORT_SYMBOL(drm_legacy_idlelock_release);
329
330static int drm_legacy_i_have_hw_lock(struct drm_device *dev,
331 struct drm_file *file_priv)
332{
333 struct drm_master *master = file_priv->master;
334 return (file_priv->lock_count && master->lock.hw_lock &&
335 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
336 master->lock.file_priv == file_priv);
337}
338
339void drm_legacy_lock_release(struct drm_device *dev, struct file *filp)
340{
341 struct drm_file *file_priv = filp->private_data;
342
343 /* if the master has gone away we can't do anything with the lock */
344 if (!dev->master)
345 return;
346
347 if (drm_legacy_i_have_hw_lock(dev, file_priv)) {
348 DRM_DEBUG("File %p released, freeing lock for context %d\n",
349 filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
350 drm_legacy_lock_free(&file_priv->master->lock,
351 _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
352 }
353}
354
355void drm_legacy_lock_master_cleanup(struct drm_device *dev, struct drm_master *master)
356{
357 if (!drm_core_check_feature(dev, DRIVER_LEGACY))
358 return;
359
360 /*
361 * Since the master is disappearing, so is the
362 * possibility to lock.
363 */ mutex_lock(&dev->struct_mutex);
364 if (master->lock.hw_lock) {
365 if (dev->sigdata.lock == master->lock.hw_lock)
366 dev->sigdata.lock = NULL;
367 master->lock.hw_lock = NULL;
368 master->lock.file_priv = NULL;
369 wake_up_interruptible_all(&master->lock.lock_queue);
370 }
371 mutex_unlock(&dev->struct_mutex);
372}
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}