xref: /freebsd/lib/libthr/thread/thr_mutex.c (revision 093fcf1694777dd8b450f4e28c28df63ba825488)
1 /*
2  * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
3  * Copyright (c) 2006 David Xu <davidxu@freebsd.org>.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. All advertising materials mentioning features or use of this software
15  *    must display the following acknowledgement:
16  *	This product includes software developed by John Birrell.
17  * 4. Neither the name of the author nor the names of any co-contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * $FreeBSD$
34  */
35 
36 #include "namespace.h"
37 #include <stdlib.h>
38 #include <errno.h>
39 #include <string.h>
40 #include <sys/param.h>
41 #include <sys/queue.h>
42 #include <pthread.h>
43 #include "un-namespace.h"
44 
45 #include "thr_private.h"
46 
47 #if defined(_PTHREADS_INVARIANTS)
48 #define MUTEX_INIT_LINK(m) 		do {		\
49 	(m)->m_qe.tqe_prev = NULL;			\
50 	(m)->m_qe.tqe_next = NULL;			\
51 } while (0)
52 #define MUTEX_ASSERT_IS_OWNED(m)	do {		\
53 	if ((m)->m_qe.tqe_prev == NULL)			\
54 		PANIC("mutex is not on list");		\
55 } while (0)
56 #define MUTEX_ASSERT_NOT_OWNED(m)	do {		\
57 	if (((m)->m_qe.tqe_prev != NULL) ||		\
58 	    ((m)->m_qe.tqe_next != NULL))		\
59 		PANIC("mutex is on list");		\
60 } while (0)
61 #else
62 #define MUTEX_INIT_LINK(m)
63 #define MUTEX_ASSERT_IS_OWNED(m)
64 #define MUTEX_ASSERT_NOT_OWNED(m)
65 #endif
66 
67 /*
68  * For adaptive mutexes, how many times to spin doing trylock2
69  * before entering the kernel to block
70  */
71 #define MUTEX_ADAPTIVE_SPINS	200
72 
73 /*
74  * Prototypes
75  */
76 int	__pthread_mutex_init(pthread_mutex_t *mutex,
77 		const pthread_mutexattr_t *mutex_attr);
78 int	__pthread_mutex_trylock(pthread_mutex_t *mutex);
79 int	__pthread_mutex_lock(pthread_mutex_t *mutex);
80 int	__pthread_mutex_timedlock(pthread_mutex_t *mutex,
81 		const struct timespec *abstime);
82 int	__pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count);
83 int	_pthread_mutex_getyieldloops_np(pthread_mutex_t *mutex, int *count);
84 
85 static int	mutex_self_trylock(pthread_mutex_t);
86 static int	mutex_self_lock(pthread_mutex_t,
87 				const struct timespec *abstime);
88 static int	mutex_unlock_common(pthread_mutex_t *);
89 
90 __weak_reference(__pthread_mutex_init, pthread_mutex_init);
91 __weak_reference(__pthread_mutex_lock, pthread_mutex_lock);
92 __weak_reference(__pthread_mutex_timedlock, pthread_mutex_timedlock);
93 __weak_reference(__pthread_mutex_trylock, pthread_mutex_trylock);
94 
95 /* Single underscore versions provided for libc internal usage: */
96 /* No difference between libc and application usage of these: */
97 __weak_reference(_pthread_mutex_destroy, pthread_mutex_destroy);
98 __weak_reference(_pthread_mutex_unlock, pthread_mutex_unlock);
99 
100 __weak_reference(_pthread_mutex_getprioceiling, pthread_mutex_getprioceiling);
101 __weak_reference(_pthread_mutex_setprioceiling, pthread_mutex_setprioceiling);
102 
103 __weak_reference(__pthread_mutex_setspinloops_np, pthread_mutex_setspinloops_np);
104 __weak_reference(_pthread_mutex_getspinloops_np, pthread_mutex_getspinloops_np);
105 
106 __weak_reference(__pthread_mutex_setyieldloops_np, pthread_mutex_setyieldloops_np);
107 __weak_reference(_pthread_mutex_getyieldloops_np, pthread_mutex_getyieldloops_np);
108 
109 static int
110 mutex_init(pthread_mutex_t *mutex,
111     const pthread_mutexattr_t *mutex_attr, int private,
112     void *(calloc_cb)(size_t, size_t))
113 {
114 	const struct pthread_mutex_attr *attr;
115 	struct pthread_mutex *pmutex;
116 
117 	if (mutex_attr == NULL) {
118 		attr = &_pthread_mutexattr_default;
119 	} else {
120 		attr = *mutex_attr;
121 		if (attr->m_type < PTHREAD_MUTEX_ERRORCHECK ||
122 		    attr->m_type >= PTHREAD_MUTEX_TYPE_MAX)
123 			return (EINVAL);
124 		if (attr->m_protocol < PTHREAD_PRIO_NONE ||
125 		    attr->m_protocol > PTHREAD_PRIO_PROTECT)
126 			return (EINVAL);
127 	}
128 	if ((pmutex = (pthread_mutex_t)
129 		calloc_cb(1, sizeof(struct pthread_mutex))) == NULL)
130 		return (ENOMEM);
131 
132 	pmutex->m_type = attr->m_type;
133 	pmutex->m_owner = NULL;
134 	pmutex->m_flags = attr->m_flags | MUTEX_FLAGS_INITED;
135 	if (private)
136 		pmutex->m_flags |= MUTEX_FLAGS_PRIVATE;
137 	pmutex->m_count = 0;
138 	pmutex->m_refcount = 0;
139 	pmutex->m_spinloops = 0;
140 	pmutex->m_yieldloops = 0;
141 	MUTEX_INIT_LINK(pmutex);
142 	switch(attr->m_protocol) {
143 	case PTHREAD_PRIO_INHERIT:
144 		pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
145 		pmutex->m_lock.m_flags = UMUTEX_PRIO_INHERIT;
146 		break;
147 	case PTHREAD_PRIO_PROTECT:
148 		pmutex->m_lock.m_owner = UMUTEX_CONTESTED;
149 		pmutex->m_lock.m_flags = UMUTEX_PRIO_PROTECT;
150 		pmutex->m_lock.m_ceilings[0] = attr->m_ceiling;
151 		break;
152 	case PTHREAD_PRIO_NONE:
153 		pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
154 		pmutex->m_lock.m_flags = 0;
155 	}
156 
157 	if (pmutex->m_type == PTHREAD_MUTEX_ADAPTIVE_NP) {
158 		pmutex->m_spinloops =
159 		    _thr_spinloops ? _thr_spinloops: MUTEX_ADAPTIVE_SPINS;
160 		pmutex->m_yieldloops = _thr_yieldloops;
161 	}
162 
163 	*mutex = pmutex;
164 	return (0);
165 }
166 
167 static int
168 init_static(struct pthread *thread, pthread_mutex_t *mutex)
169 {
170 	int ret;
171 
172 	THR_LOCK_ACQUIRE(thread, &_mutex_static_lock);
173 
174 	if (*mutex == NULL)
175 		ret = mutex_init(mutex, NULL, 0, calloc);
176 	else
177 		ret = 0;
178 
179 	THR_LOCK_RELEASE(thread, &_mutex_static_lock);
180 
181 	return (ret);
182 }
183 
184 static int
185 init_static_private(struct pthread *thread, pthread_mutex_t *mutex)
186 {
187 	int ret;
188 
189 	THR_LOCK_ACQUIRE(thread, &_mutex_static_lock);
190 
191 	if (*mutex == NULL)
192 		ret = mutex_init(mutex, NULL, 1, calloc);
193 	else
194 		ret = 0;
195 
196 	THR_LOCK_RELEASE(thread, &_mutex_static_lock);
197 
198 	return (ret);
199 }
200 
201 static void
202 set_inherited_priority(struct pthread *curthread, struct pthread_mutex *m)
203 {
204 	struct pthread_mutex *m2;
205 
206 	m2 = TAILQ_LAST(&curthread->pp_mutexq, mutex_queue);
207 	if (m2 != NULL)
208 		m->m_lock.m_ceilings[1] = m2->m_lock.m_ceilings[0];
209 	else
210 		m->m_lock.m_ceilings[1] = -1;
211 }
212 
213 int
214 _pthread_mutex_init(pthread_mutex_t *mutex,
215     const pthread_mutexattr_t *mutex_attr)
216 {
217 	return mutex_init(mutex, mutex_attr, 1, calloc);
218 }
219 
220 int
221 __pthread_mutex_init(pthread_mutex_t *mutex,
222     const pthread_mutexattr_t *mutex_attr)
223 {
224 	return mutex_init(mutex, mutex_attr, 0, calloc);
225 }
226 
227 /* This function is used internally by malloc. */
228 int
229 _pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
230     void *(calloc_cb)(size_t, size_t))
231 {
232 	static const struct pthread_mutex_attr attr = {
233 		.m_type = PTHREAD_MUTEX_NORMAL,
234 		.m_protocol = PTHREAD_PRIO_NONE,
235 		.m_ceiling = 0,
236 		.m_flags = 0
237 	};
238 	static const struct pthread_mutex_attr *pattr = &attr;
239 
240 	return mutex_init(mutex, (pthread_mutexattr_t *)&pattr, 0, calloc_cb);
241 }
242 
243 void
244 _mutex_fork(struct pthread *curthread)
245 {
246 	struct pthread_mutex *m;
247 
248 	/*
249 	 * Fix mutex ownership for child process.
250 	 * note that process shared mutex should not
251 	 * be inherited because owner is forking thread
252 	 * which is in parent process, they should be
253 	 * removed from the owned mutex list, current,
254 	 * process shared mutex is not supported, so I
255 	 * am not worried.
256 	 */
257 
258 	TAILQ_FOREACH(m, &curthread->mutexq, m_qe)
259 		m->m_lock.m_owner = TID(curthread);
260 	TAILQ_FOREACH(m, &curthread->pp_mutexq, m_qe)
261 		m->m_lock.m_owner = TID(curthread) | UMUTEX_CONTESTED;
262 }
263 
264 int
265 _pthread_mutex_destroy(pthread_mutex_t *mutex)
266 {
267 	struct pthread *curthread = _get_curthread();
268 	pthread_mutex_t m;
269 	uint32_t id;
270 	int ret = 0;
271 
272 	if (__predict_false(*mutex == NULL))
273 		ret = EINVAL;
274 	else {
275 		id = TID(curthread);
276 
277 		/*
278 		 * Try to lock the mutex structure, we only need to
279 		 * try once, if failed, the mutex is in used.
280 		 */
281 		ret = _thr_umutex_trylock(&(*mutex)->m_lock, id);
282 		if (ret)
283 			return (ret);
284 		m  = *mutex;
285 		/*
286 		 * Check mutex other fields to see if this mutex is
287 		 * in use. Mostly for prority mutex types, or there
288 		 * are condition variables referencing it.
289 		 */
290 		if (m->m_owner != NULL || m->m_refcount != 0) {
291 			if (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT)
292 				set_inherited_priority(curthread, m);
293 			_thr_umutex_unlock(&m->m_lock, id);
294 			ret = EBUSY;
295 		} else {
296 			/*
297 			 * Save a pointer to the mutex so it can be free'd
298 			 * and set the caller's pointer to NULL.
299 			 */
300 			*mutex = NULL;
301 
302 			if (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT)
303 				set_inherited_priority(curthread, m);
304 			_thr_umutex_unlock(&m->m_lock, id);
305 
306 			MUTEX_ASSERT_NOT_OWNED(m);
307 			free(m);
308 		}
309 	}
310 
311 	return (ret);
312 }
313 
314 
315 #define ENQUEUE_MUTEX(curthread, m)  					\
316 	do {								\
317 		(m)->m_owner = curthread;				\
318 		/* Add to the list of owned mutexes: */			\
319 		MUTEX_ASSERT_NOT_OWNED((m));				\
320 		if (((m)->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)	\
321 			TAILQ_INSERT_TAIL(&curthread->mutexq, (m), m_qe);\
322 		else							\
323 			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, (m), m_qe);\
324 	} while (0)
325 
326 static int
327 mutex_trylock_common(struct pthread *curthread, pthread_mutex_t *mutex)
328 {
329 	struct pthread_mutex *m;
330 	uint32_t id;
331 	int ret;
332 
333 	id = TID(curthread);
334 	m = *mutex;
335 	ret = _thr_umutex_trylock(&m->m_lock, id);
336 	if (ret == 0) {
337 		ENQUEUE_MUTEX(curthread, m);
338 	} else if (m->m_owner == curthread) {
339 		ret = mutex_self_trylock(m);
340 	} /* else {} */
341 
342 	return (ret);
343 }
344 
345 int
346 __pthread_mutex_trylock(pthread_mutex_t *mutex)
347 {
348 	struct pthread *curthread = _get_curthread();
349 	int ret;
350 
351 	/*
352 	 * If the mutex is statically initialized, perform the dynamic
353 	 * initialization:
354 	 */
355 	if (__predict_false(*mutex == NULL)) {
356 		ret = init_static(curthread, mutex);
357 		if (__predict_false(ret))
358 			return (ret);
359 	}
360 	return (mutex_trylock_common(curthread, mutex));
361 }
362 
363 int
364 _pthread_mutex_trylock(pthread_mutex_t *mutex)
365 {
366 	struct pthread	*curthread = _get_curthread();
367 	int	ret;
368 
369 	/*
370 	 * If the mutex is statically initialized, perform the dynamic
371 	 * initialization marking the mutex private (delete safe):
372 	 */
373 	if (__predict_false(*mutex == NULL)) {
374 		ret = init_static_private(curthread, mutex);
375 		if (__predict_false(ret))
376 			return (ret);
377 	}
378 	return (mutex_trylock_common(curthread, mutex));
379 }
380 
381 static int
382 mutex_lock_common(struct pthread *curthread, pthread_mutex_t *mutex,
383 	const struct timespec * abstime)
384 {
385 	struct  timespec ts, ts2;
386 	struct	pthread_mutex *m;
387 	uint32_t	id;
388 	int	ret;
389 	int	count;
390 
391 	id = TID(curthread);
392 	m = *mutex;
393 	ret = _thr_umutex_trylock2(&m->m_lock, id);
394 	if (ret == 0) {
395 		ENQUEUE_MUTEX(curthread, m);
396 	} else if (m->m_owner == curthread) {
397 		ret = mutex_self_lock(m, abstime);
398 	} else {
399 		/*
400 		 * For adaptive mutexes, spin for a bit in the expectation
401 		 * that if the application requests this mutex type then
402 		 * the lock is likely to be released quickly and it is
403 		 * faster than entering the kernel
404 		 */
405 		if (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT)
406 			goto sleep_in_kernel;
407 
408 		if (!_thr_is_smp)
409 			goto yield_loop;
410 
411 		count = m->m_spinloops;
412 		while (count--) {
413 			if (m->m_lock.m_owner == UMUTEX_UNOWNED) {
414 				ret = _thr_umutex_trylock2(&m->m_lock, id);
415 				if (ret == 0)
416 					goto done;
417 			}
418 			CPU_SPINWAIT;
419 		}
420 
421 yield_loop:
422 		count = m->m_yieldloops;
423 		while (count--) {
424 			_sched_yield();
425 			ret = _thr_umutex_trylock2(&m->m_lock, id);
426 			if (ret == 0)
427 				goto done;
428 		}
429 
430 sleep_in_kernel:
431 		if (abstime == NULL) {
432 			ret = __thr_umutex_lock(&m->m_lock);
433 		} else if (__predict_false(
434 			   abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
435 			   abstime->tv_nsec >= 1000000000)) {
436 			ret = EINVAL;
437 		} else {
438 			clock_gettime(CLOCK_REALTIME, &ts);
439 			TIMESPEC_SUB(&ts2, abstime, &ts);
440 			ret = __thr_umutex_timedlock(&m->m_lock, &ts2);
441 			/*
442 			 * Timed out wait is not restarted if
443 			 * it was interrupted, not worth to do it.
444 			 */
445 			if (ret == EINTR)
446 				ret = ETIMEDOUT;
447 		}
448 done:
449 		if (ret == 0)
450 			ENQUEUE_MUTEX(curthread, m);
451 	}
452 	return (ret);
453 }
454 
455 int
456 __pthread_mutex_lock(pthread_mutex_t *m)
457 {
458 	struct pthread *curthread;
459 	int	ret;
460 
461 	_thr_check_init();
462 
463 	curthread = _get_curthread();
464 
465 	/*
466 	 * If the mutex is statically initialized, perform the dynamic
467 	 * initialization:
468 	 */
469 	if (__predict_false(*m == NULL)) {
470 		ret = init_static(curthread, m);
471 		if (__predict_false(ret))
472 			return (ret);
473 	}
474 	return (mutex_lock_common(curthread, m, NULL));
475 }
476 
477 int
478 _pthread_mutex_lock(pthread_mutex_t *m)
479 {
480 	struct pthread *curthread;
481 	int	ret;
482 
483 	_thr_check_init();
484 
485 	curthread = _get_curthread();
486 
487 	/*
488 	 * If the mutex is statically initialized, perform the dynamic
489 	 * initialization marking it private (delete safe):
490 	 */
491 	if (__predict_false(*m == NULL)) {
492 		ret = init_static_private(curthread, m);
493 		if (__predict_false(ret))
494 			return (ret);
495 	}
496 	return (mutex_lock_common(curthread, m, NULL));
497 }
498 
499 int
500 __pthread_mutex_timedlock(pthread_mutex_t *m, const struct timespec *abstime)
501 {
502 	struct pthread *curthread;
503 	int	ret;
504 
505 	_thr_check_init();
506 
507 	curthread = _get_curthread();
508 
509 	/*
510 	 * If the mutex is statically initialized, perform the dynamic
511 	 * initialization:
512 	 */
513 	if (__predict_false(*m == NULL)) {
514 		ret = init_static(curthread, m);
515 		if (__predict_false(ret))
516 			return (ret);
517 	}
518 	return (mutex_lock_common(curthread, m, abstime));
519 }
520 
521 int
522 _pthread_mutex_timedlock(pthread_mutex_t *m, const struct timespec *abstime)
523 {
524 	struct pthread	*curthread;
525 	int	ret;
526 
527 	_thr_check_init();
528 
529 	curthread = _get_curthread();
530 
531 	/*
532 	 * If the mutex is statically initialized, perform the dynamic
533 	 * initialization marking it private (delete safe):
534 	 */
535 	if (__predict_false(*m == NULL)) {
536 		ret = init_static_private(curthread, m);
537 		if (__predict_false(ret))
538 			return (ret);
539 	}
540 	return (mutex_lock_common(curthread, m, abstime));
541 }
542 
543 int
544 _pthread_mutex_unlock(pthread_mutex_t *m)
545 {
546 	return (mutex_unlock_common(m));
547 }
548 
549 int
550 _mutex_cv_lock(pthread_mutex_t *m, int count)
551 {
552 	int	ret;
553 
554 	ret = mutex_lock_common(_get_curthread(), m, NULL);
555 	if (ret == 0) {
556 		(*m)->m_refcount--;
557 		(*m)->m_count += count;
558 	}
559 	return (ret);
560 }
561 
562 static int
563 mutex_self_trylock(pthread_mutex_t m)
564 {
565 	int	ret;
566 
567 	switch (m->m_type) {
568 	case PTHREAD_MUTEX_ERRORCHECK:
569 	case PTHREAD_MUTEX_NORMAL:
570 		ret = EBUSY;
571 		break;
572 
573 	case PTHREAD_MUTEX_RECURSIVE:
574 		/* Increment the lock count: */
575 		if (m->m_count + 1 > 0) {
576 			m->m_count++;
577 			ret = 0;
578 		} else
579 			ret = EAGAIN;
580 		break;
581 
582 	default:
583 		/* Trap invalid mutex types; */
584 		ret = EINVAL;
585 	}
586 
587 	return (ret);
588 }
589 
590 static int
591 mutex_self_lock(pthread_mutex_t m, const struct timespec *abstime)
592 {
593 	struct timespec	ts1, ts2;
594 	int	ret;
595 
596 	switch (m->m_type) {
597 	case PTHREAD_MUTEX_ERRORCHECK:
598 	case PTHREAD_MUTEX_ADAPTIVE_NP:
599 		if (abstime) {
600 			clock_gettime(CLOCK_REALTIME, &ts1);
601 			TIMESPEC_SUB(&ts2, abstime, &ts1);
602 			__sys_nanosleep(&ts2, NULL);
603 			ret = ETIMEDOUT;
604 		} else {
605 			/*
606 			 * POSIX specifies that mutexes should return
607 			 * EDEADLK if a recursive lock is detected.
608 			 */
609 			ret = EDEADLK;
610 		}
611 		break;
612 
613 	case PTHREAD_MUTEX_NORMAL:
614 		/*
615 		 * What SS2 define as a 'normal' mutex.  Intentionally
616 		 * deadlock on attempts to get a lock you already own.
617 		 */
618 		ret = 0;
619 		if (abstime) {
620 			clock_gettime(CLOCK_REALTIME, &ts1);
621 			TIMESPEC_SUB(&ts2, abstime, &ts1);
622 			__sys_nanosleep(&ts2, NULL);
623 			ret = ETIMEDOUT;
624 		} else {
625 			ts1.tv_sec = 30;
626 			ts1.tv_nsec = 0;
627 			for (;;)
628 				__sys_nanosleep(&ts1, NULL);
629 		}
630 		break;
631 
632 	case PTHREAD_MUTEX_RECURSIVE:
633 		/* Increment the lock count: */
634 		if (m->m_count + 1 > 0) {
635 			m->m_count++;
636 			ret = 0;
637 		} else
638 			ret = EAGAIN;
639 		break;
640 
641 	default:
642 		/* Trap invalid mutex types; */
643 		ret = EINVAL;
644 	}
645 
646 	return (ret);
647 }
648 
649 static int
650 mutex_unlock_common(pthread_mutex_t *mutex)
651 {
652 	struct pthread *curthread = _get_curthread();
653 	struct pthread_mutex *m;
654 	uint32_t id;
655 
656 	if (__predict_false((m = *mutex) == NULL))
657 		return (EINVAL);
658 
659 	/*
660 	 * Check if the running thread is not the owner of the mutex.
661 	 */
662 	if (__predict_false(m->m_owner != curthread))
663 		return (EPERM);
664 
665 	id = TID(curthread);
666 	if (__predict_false(
667 		m->m_type == PTHREAD_MUTEX_RECURSIVE &&
668 		m->m_count > 0)) {
669 		m->m_count--;
670 	} else {
671 		m->m_owner = NULL;
672 		/* Remove the mutex from the threads queue. */
673 		MUTEX_ASSERT_IS_OWNED(m);
674 		if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
675 			TAILQ_REMOVE(&curthread->mutexq, m, m_qe);
676 		else {
677 			TAILQ_REMOVE(&curthread->pp_mutexq, m, m_qe);
678 			set_inherited_priority(curthread, m);
679 		}
680 		MUTEX_INIT_LINK(m);
681 		_thr_umutex_unlock(&m->m_lock, id);
682 	}
683 	return (0);
684 }
685 
686 int
687 _mutex_cv_unlock(pthread_mutex_t *mutex, int *count)
688 {
689 	struct pthread *curthread = _get_curthread();
690 	struct pthread_mutex *m;
691 
692 	if (__predict_false((m = *mutex) == NULL))
693 		return (EINVAL);
694 
695 	/*
696 	 * Check if the running thread is not the owner of the mutex.
697 	 */
698 	if (__predict_false(m->m_owner != curthread))
699 		return (EPERM);
700 
701 	/*
702 	 * Clear the count in case this is a recursive mutex.
703 	 */
704 	*count = m->m_count;
705 	m->m_refcount++;
706 	m->m_count = 0;
707 	m->m_owner = NULL;
708 	/* Remove the mutex from the threads queue. */
709 	MUTEX_ASSERT_IS_OWNED(m);
710 	if ((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
711 		TAILQ_REMOVE(&curthread->mutexq, m, m_qe);
712 	else {
713 		TAILQ_REMOVE(&curthread->pp_mutexq, m, m_qe);
714 		set_inherited_priority(curthread, m);
715 	}
716 	MUTEX_INIT_LINK(m);
717 	_thr_umutex_unlock(&m->m_lock, TID(curthread));
718 	return (0);
719 }
720 
721 void
722 _mutex_unlock_private(pthread_t pthread)
723 {
724 	struct pthread_mutex	*m, *m_next;
725 
726 	TAILQ_FOREACH_SAFE(m, &pthread->mutexq, m_qe, m_next) {
727 		if ((m->m_flags & MUTEX_FLAGS_PRIVATE) != 0)
728 			_pthread_mutex_unlock(&m);
729 	}
730 }
731 
732 int
733 _pthread_mutex_getprioceiling(pthread_mutex_t *mutex,
734 			      int *prioceiling)
735 {
736 	int ret;
737 
738 	if (*mutex == NULL)
739 		ret = EINVAL;
740 	else if (((*mutex)->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
741 		ret = EINVAL;
742 	else {
743 		*prioceiling = (*mutex)->m_lock.m_ceilings[0];
744 		ret = 0;
745 	}
746 
747 	return(ret);
748 }
749 
750 int
751 _pthread_mutex_setprioceiling(pthread_mutex_t *mutex,
752 			      int ceiling, int *old_ceiling)
753 {
754 	struct pthread *curthread = _get_curthread();
755 	struct pthread_mutex *m, *m1, *m2;
756 	int ret;
757 
758 	m = *mutex;
759 	if (m == NULL || (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
760 		return (EINVAL);
761 
762 	ret = __thr_umutex_set_ceiling(&m->m_lock, ceiling, old_ceiling);
763 	if (ret != 0)
764 		return (ret);
765 
766 	if (m->m_owner == curthread) {
767 		MUTEX_ASSERT_IS_OWNED(m);
768 		m1 = TAILQ_PREV(m, mutex_queue, m_qe);
769 		m2 = TAILQ_NEXT(m, m_qe);
770 		if ((m1 != NULL && m1->m_lock.m_ceilings[0] > (u_int)ceiling) ||
771 		    (m2 != NULL && m2->m_lock.m_ceilings[0] < (u_int)ceiling)) {
772 			TAILQ_REMOVE(&curthread->pp_mutexq, m, m_qe);
773 			TAILQ_FOREACH(m2, &curthread->pp_mutexq, m_qe) {
774 				if (m2->m_lock.m_ceilings[0] > (u_int)ceiling) {
775 					TAILQ_INSERT_BEFORE(m2, m, m_qe);
776 					return (0);
777 				}
778 			}
779 			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, m, m_qe);
780 		}
781 	}
782 	return (0);
783 }
784 
785 int
786 _pthread_mutex_getspinloops_np(pthread_mutex_t *mutex, int *count)
787 {
788 	if (*mutex == NULL)
789 		return (0);
790 	return (*mutex)->m_spinloops;
791 }
792 
793 int
794 _pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count)
795 {
796 	struct pthread *curthread = _get_curthread();
797 	int ret;
798 
799 	if (__predict_false(*mutex == NULL)) {
800 		ret = init_static_private(curthread, mutex);
801 		if (__predict_false(ret))
802 			return (ret);
803 	}
804 	(*mutex)->m_spinloops = count;
805 	return (0);
806 }
807 
808 int
809 __pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count)
810 {
811 	struct pthread *curthread = _get_curthread();
812 	int ret;
813 
814 	if (__predict_false(*mutex == NULL)) {
815 		ret = init_static(curthread, mutex);
816 		if (__predict_false(ret))
817 			return (ret);
818 	}
819 	(*mutex)->m_spinloops = count;
820 	return (0);
821 }
822 
823 int
824 _pthread_mutex_getyieldloops_np(pthread_mutex_t *mutex, int *count)
825 {
826 	if (*mutex == NULL)
827 		return (0);
828 	return (*mutex)->m_yieldloops;
829 }
830 
831 int
832 _pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count)
833 {
834 	struct pthread *curthread = _get_curthread();
835 	int ret;
836 
837 	if (__predict_false(*mutex == NULL)) {
838 		ret = init_static_private(curthread, mutex);
839 		if (__predict_false(ret))
840 			return (ret);
841 	}
842 	(*mutex)->m_yieldloops = count;
843 	return (0);
844 }
845 
846 int
847 __pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count)
848 {
849 	struct pthread *curthread = _get_curthread();
850 	int ret;
851 
852 	if (__predict_false(*mutex == NULL)) {
853 		ret = init_static(curthread, mutex);
854 		if (__predict_false(ret))
855 			return (ret);
856 	}
857 	(*mutex)->m_yieldloops = count;
858 	return (0);
859 }
860