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 * Copyright (c) 2013 The FreeBSD Foundation
32 * All rights reserved.
33 *
34 * Portions of this software were developed by Konstantin Belousov
35 * <kib@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
36 */
37
38#include <sys/cdefs.h>
39__FBSDID("$FreeBSD: stable/10/sys/dev/drm2/ttm/ttm_lock.c 247835 2013-03-05 09:49:34Z kib $");
40
41#include <dev/drm2/ttm/ttm_lock.h>
42#include <dev/drm2/ttm/ttm_module.h>
43
44#define TTM_WRITE_LOCK_PENDING (1 << 0)
45#define TTM_VT_LOCK_PENDING (1 << 1)
46#define TTM_SUSPEND_LOCK_PENDING (1 << 2)
47#define TTM_VT_LOCK (1 << 3)
48#define TTM_SUSPEND_LOCK (1 << 4)
49
50void ttm_lock_init(struct ttm_lock *lock)
51{
52 mtx_init(&lock->lock, "ttmlk", NULL, MTX_DEF);
53 lock->rw = 0;
54 lock->flags = 0;
55 lock->kill_takers = false;
56 lock->signal = SIGKILL;
57}
58
59static void
60ttm_lock_send_sig(int signo)
61{
62 struct proc *p;
63
64 p = curproc; /* XXXKIB curthread ? */
65 PROC_LOCK(p);
66 kern_psignal(p, signo);
67 PROC_UNLOCK(p);
68}
69
70void ttm_read_unlock(struct ttm_lock *lock)
71{
72 mtx_lock(&lock->lock);
73 if (--lock->rw == 0)
74 wakeup(lock);
75 mtx_unlock(&lock->lock);
76}
77
78static bool __ttm_read_lock(struct ttm_lock *lock)
79{
80 bool locked = false;
81
82 if (unlikely(lock->kill_takers)) {
83 ttm_lock_send_sig(lock->signal);
84 return false;
85 }
86 if (lock->rw >= 0 && lock->flags == 0) {
87 ++lock->rw;
88 locked = true;
89 }
90 return locked;
91}
92
93int
94ttm_read_lock(struct ttm_lock *lock, bool interruptible)
95{
96 const char *wmsg;
97 int flags, ret;
98
99 ret = 0;
100 if (interruptible) {
101 flags = PCATCH;
102 wmsg = "ttmri";
103 } else {
104 flags = 0;
105 wmsg = "ttmr";
106 }
107 mtx_lock(&lock->lock);
108 while (!__ttm_read_lock(lock)) {
109 ret = msleep(lock, &lock->lock, flags, wmsg, 0);
110 if (ret != 0)
111 break;
112 }
113 return (-ret);
114}
115
116static bool __ttm_read_trylock(struct ttm_lock *lock, bool *locked)
117{
118 bool block = true;
119
120 *locked = false;
121
122 if (unlikely(lock->kill_takers)) {
123 ttm_lock_send_sig(lock->signal);
124 return false;
125 }
126 if (lock->rw >= 0 && lock->flags == 0) {
127 ++lock->rw;
128 block = false;
129 *locked = true;
130 } else if (lock->flags == 0) {
131 block = false;
132 }
133
134 return !block;
135}
136
137int ttm_read_trylock(struct ttm_lock *lock, bool interruptible)
138{
139 const char *wmsg;
140 int flags, ret;
141 bool locked;
142
143 ret = 0;
144 if (interruptible) {
145 flags = PCATCH;
146 wmsg = "ttmrti";
147 } else {
148 flags = 0;
149 wmsg = "ttmrt";
150 }
151 mtx_lock(&lock->lock);
152 while (!__ttm_read_trylock(lock, &locked)) {
153 ret = msleep(lock, &lock->lock, flags, wmsg, 0);
154 if (ret != 0)
155 break;
156 }
157 MPASS(!locked || ret == 0);
158 mtx_unlock(&lock->lock);
159
160 return (locked) ? 0 : -EBUSY;
161}
162
163void ttm_write_unlock(struct ttm_lock *lock)
164{
165 mtx_lock(&lock->lock);
166 lock->rw = 0;
167 wakeup(lock);
168 mtx_unlock(&lock->lock);
169}
170
171static bool __ttm_write_lock(struct ttm_lock *lock)
172{
173 bool locked = false;
174
175 if (unlikely(lock->kill_takers)) {
176 ttm_lock_send_sig(lock->signal);
177 return false;
178 }
179 if (lock->rw == 0 && ((lock->flags & ~TTM_WRITE_LOCK_PENDING) == 0)) {
180 lock->rw = -1;
181 lock->flags &= ~TTM_WRITE_LOCK_PENDING;
182 locked = true;
183 } else {
184 lock->flags |= TTM_WRITE_LOCK_PENDING;
185 }
186 return locked;
187}
188
189int
190ttm_write_lock(struct ttm_lock *lock, bool interruptible)
191{
192 const char *wmsg;
193 int flags, ret;
194
195 ret = 0;
196 if (interruptible) {
197 flags = PCATCH;
198 wmsg = "ttmwi";
199 } else {
200 flags = 0;
201 wmsg = "ttmw";
202 }
203 mtx_lock(&lock->lock);
204 /* XXXKIB: linux uses __ttm_read_lock for uninterruptible sleeps */
205 while (!__ttm_write_lock(lock)) {
206 ret = msleep(lock, &lock->lock, flags, wmsg, 0);
207 if (interruptible && ret != 0) {
208 lock->flags &= ~TTM_WRITE_LOCK_PENDING;
209 wakeup(lock);
210 break;
211 }
212 }
213 mtx_unlock(&lock->lock);
214
215 return (-ret);
216}
217
218void ttm_write_lock_downgrade(struct ttm_lock *lock)
219{
220 mtx_lock(&lock->lock);
221 lock->rw = 1;
222 wakeup(lock);
223 mtx_unlock(&lock->lock);
224}
225
226static int __ttm_vt_unlock(struct ttm_lock *lock)
227{
228 int ret = 0;
229
230 mtx_lock(&lock->lock);
231 if (unlikely(!(lock->flags & TTM_VT_LOCK)))
232 ret = -EINVAL;
233 lock->flags &= ~TTM_VT_LOCK;
234 wakeup(lock);
235 mtx_unlock(&lock->lock);
236
237 return ret;
238}
239
240static void ttm_vt_lock_remove(struct ttm_base_object **p_base)
241{
242 struct ttm_base_object *base = *p_base;
243 struct ttm_lock *lock = container_of(base, struct ttm_lock, base);
244 int ret;
245
246 *p_base = NULL;
247 ret = __ttm_vt_unlock(lock);
248 MPASS(ret == 0);
249}
250
251static bool __ttm_vt_lock(struct ttm_lock *lock)
252{
253 bool locked = false;
254
255 if (lock->rw == 0) {
256 lock->flags &= ~TTM_VT_LOCK_PENDING;
257 lock->flags |= TTM_VT_LOCK;
258 locked = true;
259 } else {
260 lock->flags |= TTM_VT_LOCK_PENDING;
261 }
262 return locked;
263}
264
265int ttm_vt_lock(struct ttm_lock *lock,
266 bool interruptible,
267 struct ttm_object_file *tfile)
268{
269 const char *wmsg;
270 int flags, ret;
271
272 ret = 0;
273 if (interruptible) {
274 flags = PCATCH;
275 wmsg = "ttmwi";
276 } else {
277 flags = 0;
278 wmsg = "ttmw";
279 }
280 mtx_lock(&lock->lock);
281 while (!__ttm_vt_lock(lock)) {
282 ret = msleep(lock, &lock->lock, flags, wmsg, 0);
283 if (interruptible && ret != 0) {
284 lock->flags &= ~TTM_VT_LOCK_PENDING;
285 wakeup(lock);
286 break;
287 }
288 }
289
290 /*
291 * Add a base-object, the destructor of which will
292 * make sure the lock is released if the client dies
293 * while holding it.
294 */
295
296 ret = ttm_base_object_init(tfile, &lock->base, false,
297 ttm_lock_type, &ttm_vt_lock_remove, NULL);
298 if (ret)
299 (void)__ttm_vt_unlock(lock);
300 else
301 lock->vt_holder = tfile;
302
303 return (-ret);
304}
305
306int ttm_vt_unlock(struct ttm_lock *lock)
307{
308 return ttm_ref_object_base_unref(lock->vt_holder,
309 lock->base.hash.key, TTM_REF_USAGE);
310}
311
312void ttm_suspend_unlock(struct ttm_lock *lock)
313{
314 mtx_lock(&lock->lock);
315 lock->flags &= ~TTM_SUSPEND_LOCK;
316 wakeup(lock);
317 mtx_unlock(&lock->lock);
318}
319
320static bool __ttm_suspend_lock(struct ttm_lock *lock)
321{
322 bool locked = false;
323
324 if (lock->rw == 0) {
325 lock->flags &= ~TTM_SUSPEND_LOCK_PENDING;
326 lock->flags |= TTM_SUSPEND_LOCK;
327 locked = true;
328 } else {
329 lock->flags |= TTM_SUSPEND_LOCK_PENDING;
330 }
331 return locked;
332}
333
334void ttm_suspend_lock(struct ttm_lock *lock)
335{
336 mtx_lock(&lock->lock);
337 while (!__ttm_suspend_lock(lock))
338 msleep(lock, &lock->lock, 0, "ttms", 0);
339 mtx_unlock(&lock->lock);
340}