xref: /freebsd/lib/libthr/thread/thr_mutex.c (revision e0f0e66dfeda9df4f104f48bd42d5a28d8ae631e)
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 <pthread_np.h>
44 #include "un-namespace.h"
45 
46 #include "thr_private.h"
47 
48 #if defined(_PTHREADS_INVARIANTS)
49 #define MUTEX_INIT_LINK(m) 		do {		\
50 	(m)->m_qe.tqe_prev = NULL;			\
51 	(m)->m_qe.tqe_next = NULL;			\
52 } while (0)
53 #define MUTEX_ASSERT_IS_OWNED(m)	do {		\
54 	if (__predict_false((m)->m_qe.tqe_prev == NULL))\
55 		PANIC("mutex is not on list");		\
56 } while (0)
57 #define MUTEX_ASSERT_NOT_OWNED(m)	do {		\
58 	if (__predict_false((m)->m_qe.tqe_prev != NULL ||	\
59 	    (m)->m_qe.tqe_next != NULL))	\
60 		PANIC("mutex is on list");		\
61 } while (0)
62 #else
63 #define MUTEX_INIT_LINK(m)
64 #define MUTEX_ASSERT_IS_OWNED(m)
65 #define MUTEX_ASSERT_NOT_OWNED(m)
66 #endif
67 
68 /*
69  * For adaptive mutexes, how many times to spin doing trylock2
70  * before entering the kernel to block
71  */
72 #define MUTEX_ADAPTIVE_SPINS	2000
73 
74 /*
75  * Prototypes
76  */
77 int	__pthread_mutex_init(pthread_mutex_t *mutex,
78 		const pthread_mutexattr_t *mutex_attr);
79 int	__pthread_mutex_trylock(pthread_mutex_t *mutex);
80 int	__pthread_mutex_lock(pthread_mutex_t *mutex);
81 int	__pthread_mutex_timedlock(pthread_mutex_t *mutex,
82 		const struct timespec *abstime);
83 int	_pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
84     		void *(calloc_cb)(size_t, size_t));
85 int	_pthread_mutex_getspinloops_np(pthread_mutex_t *mutex, int *count);
86 int	_pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count);
87 int	__pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count);
88 int	_pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count);
89 int	_pthread_mutex_getyieldloops_np(pthread_mutex_t *mutex, int *count);
90 int	__pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count);
91 
92 static int	mutex_self_trylock(pthread_mutex_t);
93 static int	mutex_self_lock(pthread_mutex_t,
94 				const struct timespec *abstime);
95 static int	mutex_unlock_common(pthread_mutex_t *);
96 static int	mutex_lock_sleep(struct pthread *, pthread_mutex_t,
97 				const struct timespec *);
98 
99 __weak_reference(__pthread_mutex_init, pthread_mutex_init);
100 __strong_reference(__pthread_mutex_init, _pthread_mutex_init);
101 __weak_reference(__pthread_mutex_lock, pthread_mutex_lock);
102 __strong_reference(__pthread_mutex_lock, _pthread_mutex_lock);
103 __weak_reference(__pthread_mutex_timedlock, pthread_mutex_timedlock);
104 __strong_reference(__pthread_mutex_timedlock, _pthread_mutex_timedlock);
105 __weak_reference(__pthread_mutex_trylock, pthread_mutex_trylock);
106 __strong_reference(__pthread_mutex_trylock, _pthread_mutex_trylock);
107 
108 /* Single underscore versions provided for libc internal usage: */
109 /* No difference between libc and application usage of these: */
110 __weak_reference(_pthread_mutex_destroy, pthread_mutex_destroy);
111 __weak_reference(_pthread_mutex_unlock, pthread_mutex_unlock);
112 
113 __weak_reference(_pthread_mutex_getprioceiling, pthread_mutex_getprioceiling);
114 __weak_reference(_pthread_mutex_setprioceiling, pthread_mutex_setprioceiling);
115 
116 __weak_reference(__pthread_mutex_setspinloops_np, pthread_mutex_setspinloops_np);
117 __strong_reference(__pthread_mutex_setspinloops_np, _pthread_mutex_setspinloops_np);
118 __weak_reference(_pthread_mutex_getspinloops_np, pthread_mutex_getspinloops_np);
119 
120 __weak_reference(__pthread_mutex_setyieldloops_np, pthread_mutex_setyieldloops_np);
121 __strong_reference(__pthread_mutex_setyieldloops_np, _pthread_mutex_setyieldloops_np);
122 __weak_reference(_pthread_mutex_getyieldloops_np, pthread_mutex_getyieldloops_np);
123 __weak_reference(_pthread_mutex_isowned_np, pthread_mutex_isowned_np);
124 
125 static int
126 mutex_init(pthread_mutex_t *mutex,
127     const struct pthread_mutex_attr *mutex_attr,
128     void *(calloc_cb)(size_t, size_t))
129 {
130 	const struct pthread_mutex_attr *attr;
131 	struct pthread_mutex *pmutex;
132 
133 	if (mutex_attr == NULL) {
134 		attr = &_pthread_mutexattr_default;
135 	} else {
136 		attr = mutex_attr;
137 		if (attr->m_type < PTHREAD_MUTEX_ERRORCHECK ||
138 		    attr->m_type >= PTHREAD_MUTEX_TYPE_MAX)
139 			return (EINVAL);
140 		if (attr->m_protocol < PTHREAD_PRIO_NONE ||
141 		    attr->m_protocol > PTHREAD_PRIO_PROTECT)
142 			return (EINVAL);
143 	}
144 	if ((pmutex = (pthread_mutex_t)
145 		calloc_cb(1, sizeof(struct pthread_mutex))) == NULL)
146 		return (ENOMEM);
147 
148 	pmutex->m_type = attr->m_type;
149 	pmutex->m_owner = NULL;
150 	pmutex->m_count = 0;
151 	pmutex->m_refcount = 0;
152 	pmutex->m_spinloops = 0;
153 	pmutex->m_yieldloops = 0;
154 	MUTEX_INIT_LINK(pmutex);
155 	switch(attr->m_protocol) {
156 	case PTHREAD_PRIO_NONE:
157 		pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
158 		pmutex->m_lock.m_flags = 0;
159 		break;
160 	case PTHREAD_PRIO_INHERIT:
161 		pmutex->m_lock.m_owner = UMUTEX_UNOWNED;
162 		pmutex->m_lock.m_flags = UMUTEX_PRIO_INHERIT;
163 		break;
164 	case PTHREAD_PRIO_PROTECT:
165 		pmutex->m_lock.m_owner = UMUTEX_CONTESTED;
166 		pmutex->m_lock.m_flags = UMUTEX_PRIO_PROTECT;
167 		pmutex->m_lock.m_ceilings[0] = attr->m_ceiling;
168 		break;
169 	}
170 
171 	if (pmutex->m_type == PTHREAD_MUTEX_ADAPTIVE_NP) {
172 		pmutex->m_spinloops =
173 		    _thr_spinloops ? _thr_spinloops: MUTEX_ADAPTIVE_SPINS;
174 		pmutex->m_yieldloops = _thr_yieldloops;
175 	}
176 
177 	*mutex = pmutex;
178 	return (0);
179 }
180 
181 static int
182 init_static(struct pthread *thread, pthread_mutex_t *mutex)
183 {
184 	int ret;
185 
186 	THR_LOCK_ACQUIRE(thread, &_mutex_static_lock);
187 
188 	if (*mutex == THR_MUTEX_INITIALIZER)
189 		ret = mutex_init(mutex, &_pthread_mutexattr_default, calloc);
190 	else if (*mutex == THR_ADAPTIVE_MUTEX_INITIALIZER)
191 		ret = mutex_init(mutex, &_pthread_mutexattr_adaptive_default, calloc);
192 	else
193 		ret = 0;
194 	THR_LOCK_RELEASE(thread, &_mutex_static_lock);
195 
196 	return (ret);
197 }
198 
199 static void
200 set_inherited_priority(struct pthread *curthread, struct pthread_mutex *m)
201 {
202 	struct pthread_mutex *m2;
203 
204 	m2 = TAILQ_LAST(&curthread->pp_mutexq, mutex_queue);
205 	if (m2 != NULL)
206 		m->m_lock.m_ceilings[1] = m2->m_lock.m_ceilings[0];
207 	else
208 		m->m_lock.m_ceilings[1] = -1;
209 }
210 
211 int
212 __pthread_mutex_init(pthread_mutex_t *mutex,
213     const pthread_mutexattr_t *mutex_attr)
214 {
215 	return mutex_init(mutex, mutex_attr ? *mutex_attr : NULL, calloc);
216 }
217 
218 /* This function is used internally by malloc. */
219 int
220 _pthread_mutex_init_calloc_cb(pthread_mutex_t *mutex,
221     void *(calloc_cb)(size_t, size_t))
222 {
223 	static const struct pthread_mutex_attr attr = {
224 		.m_type = PTHREAD_MUTEX_NORMAL,
225 		.m_protocol = PTHREAD_PRIO_NONE,
226 		.m_ceiling = 0
227 	};
228 	int ret;
229 
230 	ret = mutex_init(mutex, &attr, calloc_cb);
231 	if (ret == 0)
232 		(*mutex)->m_private = 1;
233 	return (ret);
234 }
235 
236 void
237 _mutex_fork(struct pthread *curthread)
238 {
239 	struct pthread_mutex *m;
240 
241 	/*
242 	 * Fix mutex ownership for child process.
243 	 * note that process shared mutex should not
244 	 * be inherited because owner is forking thread
245 	 * which is in parent process, they should be
246 	 * removed from the owned mutex list, current,
247 	 * process shared mutex is not supported, so I
248 	 * am not worried.
249 	 */
250 
251 	TAILQ_FOREACH(m, &curthread->mutexq, m_qe)
252 		m->m_lock.m_owner = TID(curthread);
253 	TAILQ_FOREACH(m, &curthread->pp_mutexq, m_qe)
254 		m->m_lock.m_owner = TID(curthread) | UMUTEX_CONTESTED;
255 }
256 
257 int
258 _pthread_mutex_destroy(pthread_mutex_t *mutex)
259 {
260 	struct pthread *curthread = _get_curthread();
261 	pthread_mutex_t m;
262 	uint32_t id;
263 	int ret = 0;
264 
265 	m = *mutex;
266 	if (m < THR_MUTEX_DESTROYED) {
267 		ret = 0;
268 	} else if (m == THR_MUTEX_DESTROYED) {
269 		ret = EINVAL;
270 	} else {
271 		id = TID(curthread);
272 
273 		/*
274 		 * Try to lock the mutex structure, we only need to
275 		 * try once, if failed, the mutex is in used.
276 		 */
277 		ret = _thr_umutex_trylock(&m->m_lock, id);
278 		if (ret)
279 			return (ret);
280 		/*
281 		 * Check mutex other fields to see if this mutex is
282 		 * in use. Mostly for prority mutex types, or there
283 		 * are condition variables referencing it.
284 		 */
285 		if (m->m_owner != NULL || m->m_refcount != 0) {
286 			if (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT)
287 				set_inherited_priority(curthread, m);
288 			_thr_umutex_unlock(&m->m_lock, id);
289 			ret = EBUSY;
290 		} else {
291 			*mutex = THR_MUTEX_DESTROYED;
292 
293 			if (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT)
294 				set_inherited_priority(curthread, m);
295 			_thr_umutex_unlock(&m->m_lock, id);
296 
297 			MUTEX_ASSERT_NOT_OWNED(m);
298 			free(m);
299 		}
300 	}
301 
302 	return (ret);
303 }
304 
305 #define ENQUEUE_MUTEX(curthread, m)  					\
306 	do {								\
307 		(m)->m_owner = curthread;				\
308 		/* Add to the list of owned mutexes: */			\
309 		MUTEX_ASSERT_NOT_OWNED((m));				\
310 		if (((m)->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)	\
311 			TAILQ_INSERT_TAIL(&curthread->mutexq, (m), m_qe);\
312 		else							\
313 			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, (m), m_qe);\
314 	} while (0)
315 
316 #define CHECK_AND_INIT_MUTEX						\
317 	if (__predict_false((m = *mutex) <= THR_MUTEX_DESTROYED)) {	\
318 		if (m == THR_MUTEX_DESTROYED)				\
319 			return (EINVAL);				\
320 		int ret;						\
321 		ret = init_static(_get_curthread(), mutex);		\
322 		if (ret)						\
323 			return (ret);					\
324 		m = *mutex;						\
325 	}
326 
327 static int
328 mutex_trylock_common(pthread_mutex_t *mutex)
329 {
330 	struct pthread *curthread = _get_curthread();
331 	struct pthread_mutex *m = *mutex;
332 	uint32_t id;
333 	int ret;
334 
335 	id = TID(curthread);
336 	if (m->m_private)
337 		THR_CRITICAL_ENTER(curthread);
338 	ret = _thr_umutex_trylock(&m->m_lock, id);
339 	if (__predict_true(ret == 0)) {
340 		ENQUEUE_MUTEX(curthread, m);
341 	} else if (m->m_owner == curthread) {
342 		ret = mutex_self_trylock(m);
343 	} /* else {} */
344 	if (ret && m->m_private)
345 		THR_CRITICAL_LEAVE(curthread);
346 	return (ret);
347 }
348 
349 int
350 __pthread_mutex_trylock(pthread_mutex_t *mutex)
351 {
352 	struct pthread_mutex *m;
353 
354 	CHECK_AND_INIT_MUTEX
355 
356 	return (mutex_trylock_common(mutex));
357 }
358 
359 static int
360 mutex_lock_sleep(struct pthread *curthread, struct pthread_mutex *m,
361 	const struct timespec *abstime)
362 {
363 	uint32_t	id, owner;
364 	int	count;
365 	int	ret;
366 
367 	if (m->m_owner == curthread)
368 		return mutex_self_lock(m, abstime);
369 
370 	id = TID(curthread);
371 	/*
372 	 * For adaptive mutexes, spin for a bit in the expectation
373 	 * that if the application requests this mutex type then
374 	 * the lock is likely to be released quickly and it is
375 	 * faster than entering the kernel
376 	 */
377 	if (__predict_false(
378 		(m->m_lock.m_flags &
379 		 (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) != 0))
380 			goto sleep_in_kernel;
381 
382 	if (!_thr_is_smp)
383 		goto yield_loop;
384 
385 	count = m->m_spinloops;
386 	while (count--) {
387 		owner = m->m_lock.m_owner;
388 		if ((owner & ~UMUTEX_CONTESTED) == 0) {
389 			if (atomic_cmpset_acq_32(&m->m_lock.m_owner, owner, id|owner)) {
390 				ret = 0;
391 				goto done;
392 			}
393 		}
394 		CPU_SPINWAIT;
395 	}
396 
397 yield_loop:
398 	count = m->m_yieldloops;
399 	while (count--) {
400 		_sched_yield();
401 		owner = m->m_lock.m_owner;
402 		if ((owner & ~UMUTEX_CONTESTED) == 0) {
403 			if (atomic_cmpset_acq_32(&m->m_lock.m_owner, owner, id|owner)) {
404 				ret = 0;
405 				goto done;
406 			}
407 		}
408 	}
409 
410 sleep_in_kernel:
411 	if (abstime == NULL) {
412 		ret = __thr_umutex_lock(&m->m_lock, id);
413 	} else if (__predict_false(
414 		   abstime->tv_nsec < 0 ||
415 		   abstime->tv_nsec >= 1000000000)) {
416 		ret = EINVAL;
417 	} else {
418 		ret = __thr_umutex_timedlock(&m->m_lock, id, abstime);
419 	}
420 done:
421 	if (ret == 0)
422 		ENQUEUE_MUTEX(curthread, m);
423 
424 	return (ret);
425 }
426 
427 static inline int
428 mutex_lock_common(struct pthread_mutex *m,
429 	const struct timespec *abstime)
430 {
431 	struct pthread *curthread  = _get_curthread();
432 	int ret;
433 
434 	if (m->m_private)
435 		THR_CRITICAL_ENTER(curthread);
436 	if (_thr_umutex_trylock2(&m->m_lock, TID(curthread)) == 0) {
437 		ENQUEUE_MUTEX(curthread, m);
438 		ret = 0;
439 	} else {
440 		ret = mutex_lock_sleep(curthread, m, abstime);
441 	}
442 	if (ret && m->m_private)
443 		THR_CRITICAL_LEAVE(curthread);
444 	return (ret);
445 }
446 
447 int
448 __pthread_mutex_lock(pthread_mutex_t *mutex)
449 {
450 	struct pthread_mutex	*m;
451 
452 	_thr_check_init();
453 
454 	CHECK_AND_INIT_MUTEX
455 
456 	return (mutex_lock_common(m, NULL));
457 }
458 
459 int
460 __pthread_mutex_timedlock(pthread_mutex_t *mutex, const struct timespec *abstime)
461 {
462 	struct pthread_mutex	*m;
463 
464 	_thr_check_init();
465 
466 	CHECK_AND_INIT_MUTEX
467 
468 	return (mutex_lock_common(m, abstime));
469 }
470 
471 int
472 _pthread_mutex_unlock(pthread_mutex_t *m)
473 {
474 	return (mutex_unlock_common(m));
475 }
476 
477 int
478 _mutex_cv_lock(pthread_mutex_t *mutex, int count)
479 {
480 	struct pthread_mutex	*m;
481 	int	ret;
482 
483 	m = *mutex;
484 	ret = mutex_lock_common(m, NULL);
485 	if (ret == 0) {
486 		m->m_refcount--;
487 		m->m_count += count;
488 	}
489 	return (ret);
490 }
491 
492 static int
493 mutex_self_trylock(struct pthread_mutex *m)
494 {
495 	int	ret;
496 
497 	switch (m->m_type) {
498 	case PTHREAD_MUTEX_ERRORCHECK:
499 	case PTHREAD_MUTEX_NORMAL:
500 		ret = EBUSY;
501 		break;
502 
503 	case PTHREAD_MUTEX_RECURSIVE:
504 		/* Increment the lock count: */
505 		if (m->m_count + 1 > 0) {
506 			m->m_count++;
507 			ret = 0;
508 		} else
509 			ret = EAGAIN;
510 		break;
511 
512 	default:
513 		/* Trap invalid mutex types; */
514 		ret = EINVAL;
515 	}
516 
517 	return (ret);
518 }
519 
520 static int
521 mutex_self_lock(struct pthread_mutex *m, const struct timespec *abstime)
522 {
523 	struct timespec	ts1, ts2;
524 	int	ret;
525 
526 	switch (m->m_type) {
527 	case PTHREAD_MUTEX_ERRORCHECK:
528 	case PTHREAD_MUTEX_ADAPTIVE_NP:
529 		if (abstime) {
530 			if (abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
531 			    abstime->tv_nsec >= 1000000000) {
532 				ret = EINVAL;
533 			} else {
534 				clock_gettime(CLOCK_REALTIME, &ts1);
535 				TIMESPEC_SUB(&ts2, abstime, &ts1);
536 				__sys_nanosleep(&ts2, NULL);
537 				ret = ETIMEDOUT;
538 			}
539 		} else {
540 			/*
541 			 * POSIX specifies that mutexes should return
542 			 * EDEADLK if a recursive lock is detected.
543 			 */
544 			ret = EDEADLK;
545 		}
546 		break;
547 
548 	case PTHREAD_MUTEX_NORMAL:
549 		/*
550 		 * What SS2 define as a 'normal' mutex.  Intentionally
551 		 * deadlock on attempts to get a lock you already own.
552 		 */
553 		ret = 0;
554 		if (abstime) {
555 			if (abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
556 			    abstime->tv_nsec >= 1000000000) {
557 				ret = EINVAL;
558 			} else {
559 				clock_gettime(CLOCK_REALTIME, &ts1);
560 				TIMESPEC_SUB(&ts2, abstime, &ts1);
561 				__sys_nanosleep(&ts2, NULL);
562 				ret = ETIMEDOUT;
563 			}
564 		} else {
565 			ts1.tv_sec = 30;
566 			ts1.tv_nsec = 0;
567 			for (;;)
568 				__sys_nanosleep(&ts1, NULL);
569 		}
570 		break;
571 
572 	case PTHREAD_MUTEX_RECURSIVE:
573 		/* Increment the lock count: */
574 		if (m->m_count + 1 > 0) {
575 			m->m_count++;
576 			ret = 0;
577 		} else
578 			ret = EAGAIN;
579 		break;
580 
581 	default:
582 		/* Trap invalid mutex types; */
583 		ret = EINVAL;
584 	}
585 
586 	return (ret);
587 }
588 
589 static int
590 mutex_unlock_common(pthread_mutex_t *mutex)
591 {
592 	struct pthread *curthread = _get_curthread();
593 	struct pthread_mutex *m;
594 	uint32_t id;
595 
596 	m = *mutex;
597 	if (__predict_false(m <= THR_MUTEX_DESTROYED)) {
598 		if (m == THR_MUTEX_DESTROYED)
599 			return (EINVAL);
600 		return (EPERM);
601 	}
602 
603 	/*
604 	 * Check if the running thread is not the owner of the mutex.
605 	 */
606 	if (__predict_false(m->m_owner != curthread))
607 		return (EPERM);
608 
609 	id = TID(curthread);
610 	if (__predict_false(
611 		m->m_type == PTHREAD_MUTEX_RECURSIVE &&
612 		m->m_count > 0)) {
613 		m->m_count--;
614 	} else {
615 		m->m_owner = NULL;
616 		/* Remove the mutex from the threads queue. */
617 		MUTEX_ASSERT_IS_OWNED(m);
618 		if (__predict_true((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0))
619 			TAILQ_REMOVE(&curthread->mutexq, m, m_qe);
620 		else {
621 			TAILQ_REMOVE(&curthread->pp_mutexq, m, m_qe);
622 			set_inherited_priority(curthread, m);
623 		}
624 		MUTEX_INIT_LINK(m);
625 		_thr_umutex_unlock(&m->m_lock, id);
626 	}
627 	if (m->m_private)
628 		THR_CRITICAL_LEAVE(curthread);
629 	return (0);
630 }
631 
632 int
633 _mutex_cv_unlock(pthread_mutex_t *mutex, int *count)
634 {
635 	struct pthread *curthread = _get_curthread();
636 	struct pthread_mutex *m;
637 
638 	m = *mutex;
639 	if (__predict_false(m <= THR_MUTEX_DESTROYED)) {
640 		if (m == THR_MUTEX_DESTROYED)
641 			return (EINVAL);
642 		return (EPERM);
643 	}
644 
645 	/*
646 	 * Check if the running thread is not the owner of the mutex.
647 	 */
648 	if (__predict_false(m->m_owner != curthread))
649 		return (EPERM);
650 
651 	/*
652 	 * Clear the count in case this is a recursive mutex.
653 	 */
654 	*count = m->m_count;
655 	m->m_refcount++;
656 	m->m_count = 0;
657 	m->m_owner = NULL;
658 	/* Remove the mutex from the threads queue. */
659 	MUTEX_ASSERT_IS_OWNED(m);
660 	if (__predict_true((m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0))
661 		TAILQ_REMOVE(&curthread->mutexq, m, m_qe);
662 	else {
663 		TAILQ_REMOVE(&curthread->pp_mutexq, m, m_qe);
664 		set_inherited_priority(curthread, m);
665 	}
666 	MUTEX_INIT_LINK(m);
667 	_thr_umutex_unlock(&m->m_lock, TID(curthread));
668 
669 	if (m->m_private)
670 		THR_CRITICAL_LEAVE(curthread);
671 	return (0);
672 }
673 
674 int
675 _pthread_mutex_getprioceiling(pthread_mutex_t *mutex,
676 			      int *prioceiling)
677 {
678 	struct pthread_mutex *m;
679 	int ret;
680 
681 	m = *mutex;
682 	if ((m <= THR_MUTEX_DESTROYED) ||
683 	    (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
684 		ret = EINVAL;
685 	else {
686 		*prioceiling = m->m_lock.m_ceilings[0];
687 		ret = 0;
688 	}
689 
690 	return (ret);
691 }
692 
693 int
694 _pthread_mutex_setprioceiling(pthread_mutex_t *mutex,
695 			      int ceiling, int *old_ceiling)
696 {
697 	struct pthread *curthread = _get_curthread();
698 	struct pthread_mutex *m, *m1, *m2;
699 	int ret;
700 
701 	m = *mutex;
702 	if ((m <= THR_MUTEX_DESTROYED) ||
703 	    (m->m_lock.m_flags & UMUTEX_PRIO_PROTECT) == 0)
704 		return (EINVAL);
705 
706 	ret = __thr_umutex_set_ceiling(&m->m_lock, ceiling, old_ceiling);
707 	if (ret != 0)
708 		return (ret);
709 
710 	if (m->m_owner == curthread) {
711 		MUTEX_ASSERT_IS_OWNED(m);
712 		m1 = TAILQ_PREV(m, mutex_queue, m_qe);
713 		m2 = TAILQ_NEXT(m, m_qe);
714 		if ((m1 != NULL && m1->m_lock.m_ceilings[0] > (u_int)ceiling) ||
715 		    (m2 != NULL && m2->m_lock.m_ceilings[0] < (u_int)ceiling)) {
716 			TAILQ_REMOVE(&curthread->pp_mutexq, m, m_qe);
717 			TAILQ_FOREACH(m2, &curthread->pp_mutexq, m_qe) {
718 				if (m2->m_lock.m_ceilings[0] > (u_int)ceiling) {
719 					TAILQ_INSERT_BEFORE(m2, m, m_qe);
720 					return (0);
721 				}
722 			}
723 			TAILQ_INSERT_TAIL(&curthread->pp_mutexq, m, m_qe);
724 		}
725 	}
726 	return (0);
727 }
728 
729 int
730 _pthread_mutex_getspinloops_np(pthread_mutex_t *mutex, int *count)
731 {
732 	struct pthread_mutex	*m;
733 
734 	CHECK_AND_INIT_MUTEX
735 
736 	*count = m->m_spinloops;
737 	return (0);
738 }
739 
740 int
741 __pthread_mutex_setspinloops_np(pthread_mutex_t *mutex, int count)
742 {
743 	struct pthread_mutex	*m;
744 
745 	CHECK_AND_INIT_MUTEX
746 
747 	m->m_spinloops = count;
748 	return (0);
749 }
750 
751 int
752 _pthread_mutex_getyieldloops_np(pthread_mutex_t *mutex, int *count)
753 {
754 	struct pthread_mutex	*m;
755 
756 	CHECK_AND_INIT_MUTEX
757 
758 	*count = m->m_yieldloops;
759 	return (0);
760 }
761 
762 int
763 __pthread_mutex_setyieldloops_np(pthread_mutex_t *mutex, int count)
764 {
765 	struct pthread_mutex	*m;
766 
767 	CHECK_AND_INIT_MUTEX
768 
769 	m->m_yieldloops = count;
770 	return (0);
771 }
772 
773 int
774 _pthread_mutex_isowned_np(pthread_mutex_t *mutex)
775 {
776 	struct pthread_mutex	*m;
777 
778 	m = *mutex;
779 	if (m <= THR_MUTEX_DESTROYED)
780 		return (0);
781 	return (m->m_owner == _get_curthread());
782 }
783