From 9724a293f7f7df7e791661a0a5159fe124c80f7d Mon Sep 17 00:00:00 2001 From: obrien Date: Tue, 9 Oct 2007 14:16:39 +0000 Subject: Repo copy libpthreads to libkse. This introduces the WITHOUT_LIBKSE nob, and changes WITHOUT_LIBPTHREADS to mean with neither threading libs. Approved by: re(kensmith) --- lib/libpthread/thread/thr_mutex.c | 1829 ------------------------------------- 1 file changed, 1829 deletions(-) delete mode 100644 lib/libpthread/thread/thr_mutex.c (limited to 'lib/libpthread/thread/thr_mutex.c') diff --git a/lib/libpthread/thread/thr_mutex.c b/lib/libpthread/thread/thr_mutex.c deleted file mode 100644 index 564bc20..0000000 --- a/lib/libpthread/thread/thr_mutex.c +++ /dev/null @@ -1,1829 +0,0 @@ -/* - * Copyright (c) 1995 John Birrell . - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. Neither the name of the author nor the names of any co-contributors - * may be used to endorse or promote products derived from this software - * without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * $FreeBSD$ - */ -#include -#include -#include -#include -#include -#include -#include "thr_private.h" - -#if defined(_PTHREADS_INVARIANTS) -#define MUTEX_INIT_LINK(m) do { \ - (m)->m_qe.tqe_prev = NULL; \ - (m)->m_qe.tqe_next = NULL; \ -} while (0) -#define MUTEX_ASSERT_IS_OWNED(m) do { \ - if ((m)->m_qe.tqe_prev == NULL) \ - PANIC("mutex is not on list"); \ -} while (0) -#define MUTEX_ASSERT_NOT_OWNED(m) do { \ - if (((m)->m_qe.tqe_prev != NULL) || \ - ((m)->m_qe.tqe_next != NULL)) \ - PANIC("mutex is on list"); \ -} while (0) -#define THR_ASSERT_NOT_IN_SYNCQ(thr) do { \ - THR_ASSERT(((thr)->sflags & THR_FLAGS_IN_SYNCQ) == 0, \ - "thread in syncq when it shouldn't be."); \ -} while (0); -#else -#define MUTEX_INIT_LINK(m) -#define MUTEX_ASSERT_IS_OWNED(m) -#define MUTEX_ASSERT_NOT_OWNED(m) -#define THR_ASSERT_NOT_IN_SYNCQ(thr) -#endif - -#define THR_IN_MUTEXQ(thr) (((thr)->sflags & THR_FLAGS_IN_SYNCQ) != 0) -#define MUTEX_DESTROY(m) do { \ - _lock_destroy(&(m)->m_lock); \ - free(m); \ -} while (0) - - -/* - * Prototypes - */ -static struct kse_mailbox *mutex_handoff(struct pthread *, - struct pthread_mutex *); -static inline int mutex_self_trylock(struct pthread *, pthread_mutex_t); -static inline int mutex_self_lock(struct pthread *, pthread_mutex_t); -static int mutex_unlock_common(pthread_mutex_t *, int); -static void mutex_priority_adjust(struct pthread *, pthread_mutex_t); -static void mutex_rescan_owned (struct pthread *, struct pthread *, - struct pthread_mutex *); -static inline pthread_t mutex_queue_deq(pthread_mutex_t); -static inline void mutex_queue_remove(pthread_mutex_t, pthread_t); -static inline void mutex_queue_enq(pthread_mutex_t, pthread_t); -static void mutex_lock_backout(void *arg); - -static struct pthread_mutex_attr static_mutex_attr = - PTHREAD_MUTEXATTR_STATIC_INITIALIZER; -static pthread_mutexattr_t static_mattr = &static_mutex_attr; - -LT10_COMPAT_PRIVATE(__pthread_mutex_init); -LT10_COMPAT_PRIVATE(_pthread_mutex_init); -LT10_COMPAT_DEFAULT(pthread_mutex_init); -LT10_COMPAT_PRIVATE(__pthread_mutex_lock); -LT10_COMPAT_PRIVATE(_pthread_mutex_lock); -LT10_COMPAT_DEFAULT(pthread_mutex_lock); -LT10_COMPAT_PRIVATE(__pthread_mutex_timedlock); -LT10_COMPAT_PRIVATE(_pthread_mutex_timedlock); -LT10_COMPAT_DEFAULT(pthread_mutex_timedlock); -LT10_COMPAT_PRIVATE(__pthread_mutex_trylock); -LT10_COMPAT_PRIVATE(_pthread_mutex_trylock); -LT10_COMPAT_DEFAULT(pthread_mutex_trylock); -LT10_COMPAT_PRIVATE(_pthread_mutex_destroy); -LT10_COMPAT_DEFAULT(pthread_mutex_destroy); -LT10_COMPAT_PRIVATE(_pthread_mutex_unlock); -LT10_COMPAT_DEFAULT(pthread_mutex_unlock); - -/* Single underscore versions provided for libc internal usage: */ -__weak_reference(__pthread_mutex_init, pthread_mutex_init); -__weak_reference(__pthread_mutex_lock, pthread_mutex_lock); -__weak_reference(__pthread_mutex_timedlock, pthread_mutex_timedlock); -__weak_reference(__pthread_mutex_trylock, pthread_mutex_trylock); - -/* No difference between libc and application usage of these: */ -__weak_reference(_pthread_mutex_destroy, pthread_mutex_destroy); -__weak_reference(_pthread_mutex_unlock, pthread_mutex_unlock); - - - -int -__pthread_mutex_init(pthread_mutex_t *mutex, - const pthread_mutexattr_t *mutex_attr) -{ - struct pthread_mutex *pmutex; - enum pthread_mutextype type; - int protocol; - int ceiling; - int flags; - int ret = 0; - - if (mutex == NULL) - ret = EINVAL; - - /* Check if default mutex attributes: */ - else if (mutex_attr == NULL || *mutex_attr == NULL) { - /* Default to a (error checking) POSIX mutex: */ - type = PTHREAD_MUTEX_ERRORCHECK; - protocol = PTHREAD_PRIO_NONE; - ceiling = THR_MAX_PRIORITY; - flags = 0; - } - - /* Check mutex type: */ - else if (((*mutex_attr)->m_type < PTHREAD_MUTEX_ERRORCHECK) || - ((*mutex_attr)->m_type >= PTHREAD_MUTEX_TYPE_MAX)) - /* Return an invalid argument error: */ - ret = EINVAL; - - /* Check mutex protocol: */ - else if (((*mutex_attr)->m_protocol < PTHREAD_PRIO_NONE) || - ((*mutex_attr)->m_protocol > PTHREAD_MUTEX_RECURSIVE)) - /* Return an invalid argument error: */ - ret = EINVAL; - - else { - /* Use the requested mutex type and protocol: */ - type = (*mutex_attr)->m_type; - protocol = (*mutex_attr)->m_protocol; - ceiling = (*mutex_attr)->m_ceiling; - flags = (*mutex_attr)->m_flags; - } - - /* Check no errors so far: */ - if (ret == 0) { - if ((pmutex = (pthread_mutex_t) - malloc(sizeof(struct pthread_mutex))) == NULL) - ret = ENOMEM; - else if (_lock_init(&pmutex->m_lock, LCK_ADAPTIVE, - _thr_lock_wait, _thr_lock_wakeup) != 0) { - free(pmutex); - *mutex = NULL; - ret = ENOMEM; - } else { - /* Set the mutex flags: */ - pmutex->m_flags = flags; - - /* Process according to mutex type: */ - switch (type) { - /* case PTHREAD_MUTEX_DEFAULT: */ - case PTHREAD_MUTEX_ERRORCHECK: - case PTHREAD_MUTEX_NORMAL: - /* Nothing to do here. */ - break; - - /* Single UNIX Spec 2 recursive mutex: */ - case PTHREAD_MUTEX_RECURSIVE: - /* Reset the mutex count: */ - pmutex->m_count = 0; - break; - - /* Trap invalid mutex types: */ - default: - /* Return an invalid argument error: */ - ret = EINVAL; - break; - } - if (ret == 0) { - /* Initialise the rest of the mutex: */ - TAILQ_INIT(&pmutex->m_queue); - pmutex->m_flags |= MUTEX_FLAGS_INITED; - pmutex->m_owner = NULL; - pmutex->m_type = type; - pmutex->m_protocol = protocol; - pmutex->m_refcount = 0; - if (protocol == PTHREAD_PRIO_PROTECT) - pmutex->m_prio = ceiling; - else - pmutex->m_prio = -1; - pmutex->m_saved_prio = 0; - MUTEX_INIT_LINK(pmutex); - *mutex = pmutex; - } else { - /* Free the mutex lock structure: */ - MUTEX_DESTROY(pmutex); - *mutex = NULL; - } - } - } - /* Return the completion status: */ - return (ret); -} - -int -_pthread_mutex_init(pthread_mutex_t *mutex, - const pthread_mutexattr_t *mutex_attr) -{ - struct pthread_mutex_attr mattr, *mattrp; - - if ((mutex_attr == NULL) || (*mutex_attr == NULL)) - return (__pthread_mutex_init(mutex, &static_mattr)); - else { - mattr = **mutex_attr; - mattr.m_flags |= MUTEX_FLAGS_PRIVATE; - mattrp = &mattr; - return (__pthread_mutex_init(mutex, &mattrp)); - } -} - -void -_thr_mutex_reinit(pthread_mutex_t *mutex) -{ - _lock_reinit(&(*mutex)->m_lock, LCK_ADAPTIVE, - _thr_lock_wait, _thr_lock_wakeup); - TAILQ_INIT(&(*mutex)->m_queue); - (*mutex)->m_owner = NULL; - (*mutex)->m_count = 0; - (*mutex)->m_refcount = 0; - (*mutex)->m_prio = 0; - (*mutex)->m_saved_prio = 0; -} - -int -_pthread_mutex_destroy(pthread_mutex_t *mutex) -{ - struct pthread *curthread = _get_curthread(); - pthread_mutex_t m; - int ret = 0; - - if (mutex == NULL || *mutex == NULL) - ret = EINVAL; - else { - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &(*mutex)->m_lock); - - /* - * Check to see if this mutex is in use: - */ - if (((*mutex)->m_owner != NULL) || - (!TAILQ_EMPTY(&(*mutex)->m_queue)) || - ((*mutex)->m_refcount != 0)) { - ret = EBUSY; - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*mutex)->m_lock); - } else { - /* - * Save a pointer to the mutex so it can be free'd - * and set the caller's pointer to NULL: - */ - m = *mutex; - *mutex = NULL; - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &m->m_lock); - - /* - * Free the memory allocated for the mutex - * structure: - */ - MUTEX_ASSERT_NOT_OWNED(m); - MUTEX_DESTROY(m); - } - } - - /* Return the completion status: */ - return (ret); -} - -static int -init_static(struct pthread *thread, pthread_mutex_t *mutex) -{ - int ret; - - THR_LOCK_ACQUIRE(thread, &_mutex_static_lock); - - if (*mutex == NULL) - ret = pthread_mutex_init(mutex, NULL); - else - ret = 0; - - THR_LOCK_RELEASE(thread, &_mutex_static_lock); - - return (ret); -} - -static int -init_static_private(struct pthread *thread, pthread_mutex_t *mutex) -{ - int ret; - - THR_LOCK_ACQUIRE(thread, &_mutex_static_lock); - - if (*mutex == NULL) - ret = pthread_mutex_init(mutex, &static_mattr); - else - ret = 0; - - THR_LOCK_RELEASE(thread, &_mutex_static_lock); - - return (ret); -} - -static int -mutex_trylock_common(struct pthread *curthread, pthread_mutex_t *mutex) -{ - int private; - int ret = 0; - - THR_ASSERT((mutex != NULL) && (*mutex != NULL), - "Uninitialized mutex in pthread_mutex_trylock_basic"); - - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &(*mutex)->m_lock); - private = (*mutex)->m_flags & MUTEX_FLAGS_PRIVATE; - - /* - * If the mutex was statically allocated, properly - * initialize the tail queue. - */ - if (((*mutex)->m_flags & MUTEX_FLAGS_INITED) == 0) { - TAILQ_INIT(&(*mutex)->m_queue); - MUTEX_INIT_LINK(*mutex); - (*mutex)->m_flags |= MUTEX_FLAGS_INITED; - } - - /* Process according to mutex type: */ - switch ((*mutex)->m_protocol) { - /* Default POSIX mutex: */ - case PTHREAD_PRIO_NONE: - /* Check if this mutex is not locked: */ - if ((*mutex)->m_owner == NULL) { - /* Lock the mutex for the running thread: */ - (*mutex)->m_owner = curthread; - - /* Add to the list of owned mutexes: */ - MUTEX_ASSERT_NOT_OWNED(*mutex); - TAILQ_INSERT_TAIL(&curthread->mutexq, - (*mutex), m_qe); - } else if ((*mutex)->m_owner == curthread) - ret = mutex_self_trylock(curthread, *mutex); - else - /* Return a busy error: */ - ret = EBUSY; - break; - - /* POSIX priority inheritence mutex: */ - case PTHREAD_PRIO_INHERIT: - /* Check if this mutex is not locked: */ - if ((*mutex)->m_owner == NULL) { - /* Lock the mutex for the running thread: */ - (*mutex)->m_owner = curthread; - - THR_SCHED_LOCK(curthread, curthread); - /* Track number of priority mutexes owned: */ - curthread->priority_mutex_count++; - - /* - * The mutex takes on the attributes of the - * running thread when there are no waiters. - */ - (*mutex)->m_prio = curthread->active_priority; - (*mutex)->m_saved_prio = - curthread->inherited_priority; - curthread->inherited_priority = (*mutex)->m_prio; - THR_SCHED_UNLOCK(curthread, curthread); - - /* Add to the list of owned mutexes: */ - MUTEX_ASSERT_NOT_OWNED(*mutex); - TAILQ_INSERT_TAIL(&curthread->mutexq, - (*mutex), m_qe); - } else if ((*mutex)->m_owner == curthread) - ret = mutex_self_trylock(curthread, *mutex); - else - /* Return a busy error: */ - ret = EBUSY; - break; - - /* POSIX priority protection mutex: */ - case PTHREAD_PRIO_PROTECT: - /* Check for a priority ceiling violation: */ - if (curthread->active_priority > (*mutex)->m_prio) - ret = EINVAL; - - /* Check if this mutex is not locked: */ - else if ((*mutex)->m_owner == NULL) { - /* Lock the mutex for the running thread: */ - (*mutex)->m_owner = curthread; - - THR_SCHED_LOCK(curthread, curthread); - /* Track number of priority mutexes owned: */ - curthread->priority_mutex_count++; - - /* - * The running thread inherits the ceiling - * priority of the mutex and executes at that - * priority. - */ - curthread->active_priority = (*mutex)->m_prio; - (*mutex)->m_saved_prio = - curthread->inherited_priority; - curthread->inherited_priority = - (*mutex)->m_prio; - THR_SCHED_UNLOCK(curthread, curthread); - /* Add to the list of owned mutexes: */ - MUTEX_ASSERT_NOT_OWNED(*mutex); - TAILQ_INSERT_TAIL(&curthread->mutexq, - (*mutex), m_qe); - } else if ((*mutex)->m_owner == curthread) - ret = mutex_self_trylock(curthread, *mutex); - else - /* Return a busy error: */ - ret = EBUSY; - break; - - /* Trap invalid mutex types: */ - default: - /* Return an invalid argument error: */ - ret = EINVAL; - break; - } - - if (ret == 0 && private) - THR_CRITICAL_ENTER(curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*mutex)->m_lock); - - /* Return the completion status: */ - return (ret); -} - -int -__pthread_mutex_trylock(pthread_mutex_t *mutex) -{ - struct pthread *curthread = _get_curthread(); - int ret = 0; - - if (mutex == NULL) - ret = EINVAL; - - /* - * If the mutex is statically initialized, perform the dynamic - * initialization: - */ - else if ((*mutex != NULL) || - ((ret = init_static(curthread, mutex)) == 0)) - ret = mutex_trylock_common(curthread, mutex); - - return (ret); -} - -int -_pthread_mutex_trylock(pthread_mutex_t *mutex) -{ - struct pthread *curthread = _get_curthread(); - int ret = 0; - - if (mutex == NULL) - ret = EINVAL; - - /* - * If the mutex is statically initialized, perform the dynamic - * initialization marking the mutex private (delete safe): - */ - else if ((*mutex != NULL) || - ((ret = init_static_private(curthread, mutex)) == 0)) - ret = mutex_trylock_common(curthread, mutex); - - return (ret); -} - -static int -mutex_lock_common(struct pthread *curthread, pthread_mutex_t *m, - const struct timespec * abstime) -{ - int private; - int ret = 0; - - THR_ASSERT((m != NULL) && (*m != NULL), - "Uninitialized mutex in pthread_mutex_trylock_basic"); - - if (abstime != NULL && (abstime->tv_sec < 0 || abstime->tv_nsec < 0 || - abstime->tv_nsec >= 1000000000)) - return (EINVAL); - - /* Reset the interrupted flag: */ - curthread->interrupted = 0; - curthread->timeout = 0; - curthread->wakeup_time.tv_sec = -1; - - private = (*m)->m_flags & MUTEX_FLAGS_PRIVATE; - - /* - * Enter a loop waiting to become the mutex owner. We need a - * loop in case the waiting thread is interrupted by a signal - * to execute a signal handler. It is not (currently) possible - * to remain in the waiting queue while running a handler. - * Instead, the thread is interrupted and backed out of the - * waiting queue prior to executing the signal handler. - */ - do { - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - - /* - * If the mutex was statically allocated, properly - * initialize the tail queue. - */ - if (((*m)->m_flags & MUTEX_FLAGS_INITED) == 0) { - TAILQ_INIT(&(*m)->m_queue); - (*m)->m_flags |= MUTEX_FLAGS_INITED; - MUTEX_INIT_LINK(*m); - } - - /* Process according to mutex type: */ - switch ((*m)->m_protocol) { - /* Default POSIX mutex: */ - case PTHREAD_PRIO_NONE: - if ((*m)->m_owner == NULL) { - /* Lock the mutex for this thread: */ - (*m)->m_owner = curthread; - - /* Add to the list of owned mutexes: */ - MUTEX_ASSERT_NOT_OWNED(*m); - TAILQ_INSERT_TAIL(&curthread->mutexq, - (*m), m_qe); - if (private) - THR_CRITICAL_ENTER(curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } else if ((*m)->m_owner == curthread) { - ret = mutex_self_lock(curthread, *m); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } else { - /* - * Join the queue of threads waiting to lock - * the mutex and save a pointer to the mutex. - */ - mutex_queue_enq(*m, curthread); - curthread->data.mutex = *m; - curthread->sigbackout = mutex_lock_backout; - /* - * This thread is active and is in a critical - * region (holding the mutex lock); we should - * be able to safely set the state. - */ - THR_SCHED_LOCK(curthread, curthread); - /* Set the wakeup time: */ - if (abstime) { - curthread->wakeup_time.tv_sec = - abstime->tv_sec; - curthread->wakeup_time.tv_nsec = - abstime->tv_nsec; - } - - THR_SET_STATE(curthread, PS_MUTEX_WAIT); - THR_SCHED_UNLOCK(curthread, curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - - /* Schedule the next thread: */ - _thr_sched_switch(curthread); - - if (THR_IN_MUTEXQ(curthread)) { - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - mutex_queue_remove(*m, curthread); - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } - /* - * Only clear these after assuring the - * thread is dequeued. - */ - curthread->data.mutex = NULL; - curthread->sigbackout = NULL; - } - break; - - /* POSIX priority inheritence mutex: */ - case PTHREAD_PRIO_INHERIT: - /* Check if this mutex is not locked: */ - if ((*m)->m_owner == NULL) { - /* Lock the mutex for this thread: */ - (*m)->m_owner = curthread; - - THR_SCHED_LOCK(curthread, curthread); - /* Track number of priority mutexes owned: */ - curthread->priority_mutex_count++; - - /* - * The mutex takes on attributes of the - * running thread when there are no waiters. - * Make sure the thread's scheduling lock is - * held while priorities are adjusted. - */ - (*m)->m_prio = curthread->active_priority; - (*m)->m_saved_prio = - curthread->inherited_priority; - curthread->inherited_priority = (*m)->m_prio; - THR_SCHED_UNLOCK(curthread, curthread); - - /* Add to the list of owned mutexes: */ - MUTEX_ASSERT_NOT_OWNED(*m); - TAILQ_INSERT_TAIL(&curthread->mutexq, - (*m), m_qe); - if (private) - THR_CRITICAL_ENTER(curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } else if ((*m)->m_owner == curthread) { - ret = mutex_self_lock(curthread, *m); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } else { - /* - * Join the queue of threads waiting to lock - * the mutex and save a pointer to the mutex. - */ - mutex_queue_enq(*m, curthread); - curthread->data.mutex = *m; - curthread->sigbackout = mutex_lock_backout; - - /* - * This thread is active and is in a critical - * region (holding the mutex lock); we should - * be able to safely set the state. - */ - if (curthread->active_priority > (*m)->m_prio) - /* Adjust priorities: */ - mutex_priority_adjust(curthread, *m); - - THR_SCHED_LOCK(curthread, curthread); - /* Set the wakeup time: */ - if (abstime) { - curthread->wakeup_time.tv_sec = - abstime->tv_sec; - curthread->wakeup_time.tv_nsec = - abstime->tv_nsec; - } - THR_SET_STATE(curthread, PS_MUTEX_WAIT); - THR_SCHED_UNLOCK(curthread, curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - - /* Schedule the next thread: */ - _thr_sched_switch(curthread); - - if (THR_IN_MUTEXQ(curthread)) { - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - mutex_queue_remove(*m, curthread); - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } - /* - * Only clear these after assuring the - * thread is dequeued. - */ - curthread->data.mutex = NULL; - curthread->sigbackout = NULL; - } - break; - - /* POSIX priority protection mutex: */ - case PTHREAD_PRIO_PROTECT: - /* Check for a priority ceiling violation: */ - if (curthread->active_priority > (*m)->m_prio) { - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - ret = EINVAL; - } - /* Check if this mutex is not locked: */ - else if ((*m)->m_owner == NULL) { - /* - * Lock the mutex for the running - * thread: - */ - (*m)->m_owner = curthread; - - THR_SCHED_LOCK(curthread, curthread); - /* Track number of priority mutexes owned: */ - curthread->priority_mutex_count++; - - /* - * The running thread inherits the ceiling - * priority of the mutex and executes at that - * priority. Make sure the thread's - * scheduling lock is held while priorities - * are adjusted. - */ - curthread->active_priority = (*m)->m_prio; - (*m)->m_saved_prio = - curthread->inherited_priority; - curthread->inherited_priority = (*m)->m_prio; - THR_SCHED_UNLOCK(curthread, curthread); - - /* Add to the list of owned mutexes: */ - MUTEX_ASSERT_NOT_OWNED(*m); - TAILQ_INSERT_TAIL(&curthread->mutexq, - (*m), m_qe); - if (private) - THR_CRITICAL_ENTER(curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } else if ((*m)->m_owner == curthread) { - ret = mutex_self_lock(curthread, *m); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } else { - /* - * Join the queue of threads waiting to lock - * the mutex and save a pointer to the mutex. - */ - mutex_queue_enq(*m, curthread); - curthread->data.mutex = *m; - curthread->sigbackout = mutex_lock_backout; - - /* Clear any previous error: */ - curthread->error = 0; - - /* - * This thread is active and is in a critical - * region (holding the mutex lock); we should - * be able to safely set the state. - */ - - THR_SCHED_LOCK(curthread, curthread); - /* Set the wakeup time: */ - if (abstime) { - curthread->wakeup_time.tv_sec = - abstime->tv_sec; - curthread->wakeup_time.tv_nsec = - abstime->tv_nsec; - } - THR_SET_STATE(curthread, PS_MUTEX_WAIT); - THR_SCHED_UNLOCK(curthread, curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - - /* Schedule the next thread: */ - _thr_sched_switch(curthread); - - if (THR_IN_MUTEXQ(curthread)) { - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - mutex_queue_remove(*m, curthread); - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } - /* - * Only clear these after assuring the - * thread is dequeued. - */ - curthread->data.mutex = NULL; - curthread->sigbackout = NULL; - - /* - * The threads priority may have changed while - * waiting for the mutex causing a ceiling - * violation. - */ - ret = curthread->error; - curthread->error = 0; - } - break; - - /* Trap invalid mutex types: */ - default: - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - - /* Return an invalid argument error: */ - ret = EINVAL; - break; - } - - } while (((*m)->m_owner != curthread) && (ret == 0) && - (curthread->interrupted == 0) && (curthread->timeout == 0)); - - if (ret == 0 && (*m)->m_owner != curthread && curthread->timeout) - ret = ETIMEDOUT; - - /* - * Check to see if this thread was interrupted and - * is still in the mutex queue of waiting threads: - */ - if (curthread->interrupted != 0) { - /* Remove this thread from the mutex queue. */ - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - if (THR_IN_SYNCQ(curthread)) - mutex_queue_remove(*m, curthread); - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - - /* Check for asynchronous cancellation. */ - if (curthread->continuation != NULL) - curthread->continuation((void *) curthread); - } - - /* Return the completion status: */ - return (ret); -} - -int -__pthread_mutex_lock(pthread_mutex_t *m) -{ - struct pthread *curthread; - int ret = 0; - - if (_thr_initial == NULL) - _libpthread_init(NULL); - - curthread = _get_curthread(); - if (m == NULL) - ret = EINVAL; - - /* - * If the mutex is statically initialized, perform the dynamic - * initialization: - */ - else if ((*m != NULL) || ((ret = init_static(curthread, m)) == 0)) - ret = mutex_lock_common(curthread, m, NULL); - - return (ret); -} - -__strong_reference(__pthread_mutex_lock, _thr_mutex_lock); - -int -_pthread_mutex_lock(pthread_mutex_t *m) -{ - struct pthread *curthread; - int ret = 0; - - if (_thr_initial == NULL) - _libpthread_init(NULL); - curthread = _get_curthread(); - - if (m == NULL) - ret = EINVAL; - - /* - * If the mutex is statically initialized, perform the dynamic - * initialization marking it private (delete safe): - */ - else if ((*m != NULL) || - ((ret = init_static_private(curthread, m)) == 0)) - ret = mutex_lock_common(curthread, m, NULL); - - return (ret); -} - -int -__pthread_mutex_timedlock(pthread_mutex_t *m, - const struct timespec *abs_timeout) -{ - struct pthread *curthread; - int ret = 0; - - if (_thr_initial == NULL) - _libpthread_init(NULL); - - curthread = _get_curthread(); - if (m == NULL) - ret = EINVAL; - - /* - * If the mutex is statically initialized, perform the dynamic - * initialization: - */ - else if ((*m != NULL) || ((ret = init_static(curthread, m)) == 0)) - ret = mutex_lock_common(curthread, m, abs_timeout); - - return (ret); -} - -int -_pthread_mutex_timedlock(pthread_mutex_t *m, - const struct timespec *abs_timeout) -{ - struct pthread *curthread; - int ret = 0; - - if (_thr_initial == NULL) - _libpthread_init(NULL); - curthread = _get_curthread(); - - if (m == NULL) - ret = EINVAL; - - /* - * If the mutex is statically initialized, perform the dynamic - * initialization marking it private (delete safe): - */ - else if ((*m != NULL) || - ((ret = init_static_private(curthread, m)) == 0)) - ret = mutex_lock_common(curthread, m, abs_timeout); - - return (ret); -} - -int -_pthread_mutex_unlock(pthread_mutex_t *m) -{ - return (mutex_unlock_common(m, /* add reference */ 0)); -} - -__strong_reference(_pthread_mutex_unlock, _thr_mutex_unlock); - -int -_mutex_cv_unlock(pthread_mutex_t *m) -{ - return (mutex_unlock_common(m, /* add reference */ 1)); -} - -int -_mutex_cv_lock(pthread_mutex_t *m) -{ - struct pthread *curthread; - int ret; - - curthread = _get_curthread(); - if ((ret = _pthread_mutex_lock(m)) == 0) { - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - (*m)->m_refcount--; - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - } - return (ret); -} - -static inline int -mutex_self_trylock(struct pthread *curthread, pthread_mutex_t m) -{ - int ret = 0; - - switch (m->m_type) { - /* case PTHREAD_MUTEX_DEFAULT: */ - case PTHREAD_MUTEX_ERRORCHECK: - case PTHREAD_MUTEX_NORMAL: - ret = EBUSY; - break; - - case PTHREAD_MUTEX_RECURSIVE: - /* Increment the lock count: */ - m->m_count++; - break; - - default: - /* Trap invalid mutex types; */ - ret = EINVAL; - } - - return (ret); -} - -static inline int -mutex_self_lock(struct pthread *curthread, pthread_mutex_t m) -{ - int ret = 0; - - /* - * Don't allow evil recursive mutexes for private use - * in libc and libpthread. - */ - if (m->m_flags & MUTEX_FLAGS_PRIVATE) - PANIC("Recurse on a private mutex."); - - switch (m->m_type) { - /* case PTHREAD_MUTEX_DEFAULT: */ - case PTHREAD_MUTEX_ERRORCHECK: - /* - * POSIX specifies that mutexes should return EDEADLK if a - * recursive lock is detected. - */ - ret = EDEADLK; - break; - - case PTHREAD_MUTEX_NORMAL: - /* - * What SS2 define as a 'normal' mutex. Intentionally - * deadlock on attempts to get a lock you already own. - */ - - THR_SCHED_LOCK(curthread, curthread); - THR_SET_STATE(curthread, PS_DEADLOCK); - THR_SCHED_UNLOCK(curthread, curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &m->m_lock); - - /* Schedule the next thread: */ - _thr_sched_switch(curthread); - break; - - case PTHREAD_MUTEX_RECURSIVE: - /* Increment the lock count: */ - m->m_count++; - break; - - default: - /* Trap invalid mutex types; */ - ret = EINVAL; - } - - return (ret); -} - -static int -mutex_unlock_common(pthread_mutex_t *m, int add_reference) -{ - struct pthread *curthread = _get_curthread(); - struct kse_mailbox *kmbx = NULL; - int ret = 0; - - if (m == NULL || *m == NULL) - ret = EINVAL; - else { - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &(*m)->m_lock); - - /* Process according to mutex type: */ - switch ((*m)->m_protocol) { - /* Default POSIX mutex: */ - case PTHREAD_PRIO_NONE: - /* - * Check if the running thread is not the owner of the - * mutex: - */ - if ((*m)->m_owner != curthread) - ret = EPERM; - else if (((*m)->m_type == PTHREAD_MUTEX_RECURSIVE) && - ((*m)->m_count > 0)) - /* Decrement the count: */ - (*m)->m_count--; - else { - /* - * Clear the count in case this is a recursive - * mutex. - */ - (*m)->m_count = 0; - - /* Remove the mutex from the threads queue. */ - MUTEX_ASSERT_IS_OWNED(*m); - TAILQ_REMOVE(&(*m)->m_owner->mutexq, - (*m), m_qe); - MUTEX_INIT_LINK(*m); - - /* - * Hand off the mutex to the next waiting - * thread: - */ - kmbx = mutex_handoff(curthread, *m); - } - break; - - /* POSIX priority inheritence mutex: */ - case PTHREAD_PRIO_INHERIT: - /* - * Check if the running thread is not the owner of the - * mutex: - */ - if ((*m)->m_owner != curthread) - ret = EPERM; - else if (((*m)->m_type == PTHREAD_MUTEX_RECURSIVE) && - ((*m)->m_count > 0)) - /* Decrement the count: */ - (*m)->m_count--; - else { - /* - * Clear the count in case this is recursive - * mutex. - */ - (*m)->m_count = 0; - - /* - * Restore the threads inherited priority and - * recompute the active priority (being careful - * not to override changes in the threads base - * priority subsequent to locking the mutex). - */ - THR_SCHED_LOCK(curthread, curthread); - curthread->inherited_priority = - (*m)->m_saved_prio; - curthread->active_priority = - MAX(curthread->inherited_priority, - curthread->base_priority); - - /* - * This thread now owns one less priority mutex. - */ - curthread->priority_mutex_count--; - THR_SCHED_UNLOCK(curthread, curthread); - - /* Remove the mutex from the threads queue. */ - MUTEX_ASSERT_IS_OWNED(*m); - TAILQ_REMOVE(&(*m)->m_owner->mutexq, - (*m), m_qe); - MUTEX_INIT_LINK(*m); - - /* - * Hand off the mutex to the next waiting - * thread: - */ - kmbx = mutex_handoff(curthread, *m); - } - break; - - /* POSIX priority ceiling mutex: */ - case PTHREAD_PRIO_PROTECT: - /* - * Check if the running thread is not the owner of the - * mutex: - */ - if ((*m)->m_owner != curthread) - ret = EPERM; - else if (((*m)->m_type == PTHREAD_MUTEX_RECURSIVE) && - ((*m)->m_count > 0)) - /* Decrement the count: */ - (*m)->m_count--; - else { - /* - * Clear the count in case this is a recursive - * mutex. - */ - (*m)->m_count = 0; - - /* - * Restore the threads inherited priority and - * recompute the active priority (being careful - * not to override changes in the threads base - * priority subsequent to locking the mutex). - */ - THR_SCHED_LOCK(curthread, curthread); - curthread->inherited_priority = - (*m)->m_saved_prio; - curthread->active_priority = - MAX(curthread->inherited_priority, - curthread->base_priority); - - /* - * This thread now owns one less priority mutex. - */ - curthread->priority_mutex_count--; - THR_SCHED_UNLOCK(curthread, curthread); - - /* Remove the mutex from the threads queue. */ - MUTEX_ASSERT_IS_OWNED(*m); - TAILQ_REMOVE(&(*m)->m_owner->mutexq, - (*m), m_qe); - MUTEX_INIT_LINK(*m); - - /* - * Hand off the mutex to the next waiting - * thread: - */ - kmbx = mutex_handoff(curthread, *m); - } - break; - - /* Trap invalid mutex types: */ - default: - /* Return an invalid argument error: */ - ret = EINVAL; - break; - } - - if ((ret == 0) && (add_reference != 0)) - /* Increment the reference count: */ - (*m)->m_refcount++; - - /* Leave the critical region if this is a private mutex. */ - if ((ret == 0) && ((*m)->m_flags & MUTEX_FLAGS_PRIVATE)) - THR_CRITICAL_LEAVE(curthread); - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &(*m)->m_lock); - - if (kmbx != NULL) - kse_wakeup(kmbx); - } - - /* Return the completion status: */ - return (ret); -} - - -/* - * This function is called when a change in base priority occurs for - * a thread that is holding or waiting for a priority protection or - * inheritence mutex. A change in a threads base priority can effect - * changes to active priorities of other threads and to the ordering - * of mutex locking by waiting threads. - * - * This must be called without the target thread's scheduling lock held. - */ -void -_mutex_notify_priochange(struct pthread *curthread, struct pthread *pthread, - int propagate_prio) -{ - struct pthread_mutex *m; - - /* Adjust the priorites of any owned priority mutexes: */ - if (pthread->priority_mutex_count > 0) { - /* - * Rescan the mutexes owned by this thread and correct - * their priorities to account for this threads change - * in priority. This has the side effect of changing - * the threads active priority. - * - * Be sure to lock the first mutex in the list of owned - * mutexes. This acts as a barrier against another - * simultaneous call to change the threads priority - * and from the owning thread releasing the mutex. - */ - m = TAILQ_FIRST(&pthread->mutexq); - if (m != NULL) { - THR_LOCK_ACQUIRE(curthread, &m->m_lock); - /* - * Make sure the thread still owns the lock. - */ - if (m == TAILQ_FIRST(&pthread->mutexq)) - mutex_rescan_owned(curthread, pthread, - /* rescan all owned */ NULL); - THR_LOCK_RELEASE(curthread, &m->m_lock); - } - } - - /* - * If this thread is waiting on a priority inheritence mutex, - * check for priority adjustments. A change in priority can - * also cause a ceiling violation(*) for a thread waiting on - * a priority protection mutex; we don't perform the check here - * as it is done in pthread_mutex_unlock. - * - * (*) It should be noted that a priority change to a thread - * _after_ taking and owning a priority ceiling mutex - * does not affect ownership of that mutex; the ceiling - * priority is only checked before mutex ownership occurs. - */ - if (propagate_prio != 0) { - /* - * Lock the thread's scheduling queue. This is a bit - * convoluted; the "in synchronization queue flag" can - * only be cleared with both the thread's scheduling and - * mutex locks held. The thread's pointer to the wanted - * mutex is guaranteed to be valid during this time. - */ - THR_SCHED_LOCK(curthread, pthread); - - if (((pthread->sflags & THR_FLAGS_IN_SYNCQ) == 0) || - ((m = pthread->data.mutex) == NULL)) - THR_SCHED_UNLOCK(curthread, pthread); - else { - /* - * This thread is currently waiting on a mutex; unlock - * the scheduling queue lock and lock the mutex. We - * can't hold both at the same time because the locking - * order could cause a deadlock. - */ - THR_SCHED_UNLOCK(curthread, pthread); - THR_LOCK_ACQUIRE(curthread, &m->m_lock); - - /* - * Check to make sure this thread is still in the - * same state (the lock above can yield the CPU to - * another thread or the thread may be running on - * another CPU). - */ - if (((pthread->sflags & THR_FLAGS_IN_SYNCQ) != 0) && - (pthread->data.mutex == m)) { - /* - * Remove and reinsert this thread into - * the list of waiting threads to preserve - * decreasing priority order. - */ - mutex_queue_remove(m, pthread); - mutex_queue_enq(m, pthread); - - if (m->m_protocol == PTHREAD_PRIO_INHERIT) - /* Adjust priorities: */ - mutex_priority_adjust(curthread, m); - } - - /* Unlock the mutex structure: */ - THR_LOCK_RELEASE(curthread, &m->m_lock); - } - } -} - -/* - * Called when a new thread is added to the mutex waiting queue or - * when a threads priority changes that is already in the mutex - * waiting queue. - * - * This must be called with the mutex locked by the current thread. - */ -static void -mutex_priority_adjust(struct pthread *curthread, pthread_mutex_t mutex) -{ - pthread_mutex_t m = mutex; - struct pthread *pthread_next, *pthread = mutex->m_owner; - int done, temp_prio; - - /* - * Calculate the mutex priority as the maximum of the highest - * active priority of any waiting threads and the owning threads - * active priority(*). - * - * (*) Because the owning threads current active priority may - * reflect priority inherited from this mutex (and the mutex - * priority may have changed) we must recalculate the active - * priority based on the threads saved inherited priority - * and its base priority. - */ - pthread_next = TAILQ_FIRST(&m->m_queue); /* should never be NULL */ - temp_prio = MAX(pthread_next->active_priority, - MAX(m->m_saved_prio, pthread->base_priority)); - - /* See if this mutex really needs adjusting: */ - if (temp_prio == m->m_prio) - /* No need to propagate the priority: */ - return; - - /* Set new priority of the mutex: */ - m->m_prio = temp_prio; - - /* - * Don't unlock the mutex passed in as an argument. It is - * expected to be locked and unlocked by the caller. - */ - done = 1; - do { - /* - * Save the threads priority before rescanning the - * owned mutexes: - */ - temp_prio = pthread->active_priority; - - /* - * Fix the priorities for all mutexes held by the owning - * thread since taking this mutex. This also has a - * potential side-effect of changing the threads priority. - * - * At this point the mutex is locked by the current thread. - * The owning thread can't release the mutex until it is - * unlocked, so we should be able to safely walk its list - * of owned mutexes. - */ - mutex_rescan_owned(curthread, pthread, m); - - /* - * If this isn't the first time through the loop, - * the current mutex needs to be unlocked. - */ - if (done == 0) - THR_LOCK_RELEASE(curthread, &m->m_lock); - - /* Assume we're done unless told otherwise: */ - done = 1; - - /* - * If the thread is currently waiting on a mutex, check - * to see if the threads new priority has affected the - * priority of the mutex. - */ - if ((temp_prio != pthread->active_priority) && - ((pthread->sflags & THR_FLAGS_IN_SYNCQ) != 0) && - ((m = pthread->data.mutex) != NULL) && - (m->m_protocol == PTHREAD_PRIO_INHERIT)) { - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &m->m_lock); - - /* - * Make sure the thread is still waiting on the - * mutex: - */ - if (((pthread->sflags & THR_FLAGS_IN_SYNCQ) != 0) && - (m == pthread->data.mutex)) { - /* - * The priority for this thread has changed. - * Remove and reinsert this thread into the - * list of waiting threads to preserve - * decreasing priority order. - */ - mutex_queue_remove(m, pthread); - mutex_queue_enq(m, pthread); - - /* - * Grab the waiting thread with highest - * priority: - */ - pthread_next = TAILQ_FIRST(&m->m_queue); - - /* - * Calculate the mutex priority as the maximum - * of the highest active priority of any - * waiting threads and the owning threads - * active priority. - */ - temp_prio = MAX(pthread_next->active_priority, - MAX(m->m_saved_prio, - m->m_owner->base_priority)); - - if (temp_prio != m->m_prio) { - /* - * The priority needs to be propagated - * to the mutex this thread is waiting - * on and up to the owner of that mutex. - */ - m->m_prio = temp_prio; - pthread = m->m_owner; - - /* We're not done yet: */ - done = 0; - } - } - /* Only release the mutex if we're done: */ - if (done != 0) - THR_LOCK_RELEASE(curthread, &m->m_lock); - } - } while (done == 0); -} - -static void -mutex_rescan_owned(struct pthread *curthread, struct pthread *pthread, - struct pthread_mutex *mutex) -{ - struct pthread_mutex *m; - struct pthread *pthread_next; - int active_prio, inherited_prio; - - /* - * Start walking the mutexes the thread has taken since - * taking this mutex. - */ - if (mutex == NULL) { - /* - * A null mutex means start at the beginning of the owned - * mutex list. - */ - m = TAILQ_FIRST(&pthread->mutexq); - - /* There is no inherited priority yet. */ - inherited_prio = 0; - } else { - /* - * The caller wants to start after a specific mutex. It - * is assumed that this mutex is a priority inheritence - * mutex and that its priority has been correctly - * calculated. - */ - m = TAILQ_NEXT(mutex, m_qe); - - /* Start inheriting priority from the specified mutex. */ - inherited_prio = mutex->m_prio; - } - active_prio = MAX(inherited_prio, pthread->base_priority); - - for (; m != NULL; m = TAILQ_NEXT(m, m_qe)) { - /* - * We only want to deal with priority inheritence - * mutexes. This might be optimized by only placing - * priority inheritence mutexes into the owned mutex - * list, but it may prove to be useful having all - * owned mutexes in this list. Consider a thread - * exiting while holding mutexes... - */ - if (m->m_protocol == PTHREAD_PRIO_INHERIT) { - /* - * Fix the owners saved (inherited) priority to - * reflect the priority of the previous mutex. - */ - m->m_saved_prio = inherited_prio; - - if ((pthread_next = TAILQ_FIRST(&m->m_queue)) != NULL) - /* Recalculate the priority of the mutex: */ - m->m_prio = MAX(active_prio, - pthread_next->active_priority); - else - m->m_prio = active_prio; - - /* Recalculate new inherited and active priorities: */ - inherited_prio = m->m_prio; - active_prio = MAX(m->m_prio, pthread->base_priority); - } - } - - /* - * Fix the threads inherited priority and recalculate its - * active priority. - */ - pthread->inherited_priority = inherited_prio; - active_prio = MAX(inherited_prio, pthread->base_priority); - - if (active_prio != pthread->active_priority) { - /* Lock the thread's scheduling queue: */ - THR_SCHED_LOCK(curthread, pthread); - - if ((pthread->flags & THR_FLAGS_IN_RUNQ) == 0) { - /* - * This thread is not in a run queue. Just set - * its active priority. - */ - pthread->active_priority = active_prio; - } - else { - /* - * This thread is in a run queue. Remove it from - * the queue before changing its priority: - */ - THR_RUNQ_REMOVE(pthread); - - /* - * POSIX states that if the priority is being - * lowered, the thread must be inserted at the - * head of the queue for its priority if it owns - * any priority protection or inheritence mutexes. - */ - if ((active_prio < pthread->active_priority) && - (pthread->priority_mutex_count > 0)) { - /* Set the new active priority. */ - pthread->active_priority = active_prio; - - THR_RUNQ_INSERT_HEAD(pthread); - } else { - /* Set the new active priority. */ - pthread->active_priority = active_prio; - - THR_RUNQ_INSERT_TAIL(pthread); - } - } - THR_SCHED_UNLOCK(curthread, pthread); - } -} - -void -_mutex_unlock_private(pthread_t pthread) -{ - struct pthread_mutex *m, *m_next; - - for (m = TAILQ_FIRST(&pthread->mutexq); m != NULL; m = m_next) { - m_next = TAILQ_NEXT(m, m_qe); - if ((m->m_flags & MUTEX_FLAGS_PRIVATE) != 0) - pthread_mutex_unlock(&m); - } -} - -/* - * This is called by the current thread when it wants to back out of a - * mutex_lock in order to run a signal handler. - */ -static void -mutex_lock_backout(void *arg) -{ - struct pthread *curthread = (struct pthread *)arg; - struct pthread_mutex *m; - - if ((curthread->sflags & THR_FLAGS_IN_SYNCQ) != 0) { - /* - * Any other thread may clear the "in sync queue flag", - * but only the current thread can clear the pointer - * to the mutex. So if the flag is set, we can - * guarantee that the pointer to the mutex is valid. - * The only problem may be if the mutex is destroyed - * out from under us, but that should be considered - * an application bug. - */ - m = curthread->data.mutex; - - /* Lock the mutex structure: */ - THR_LOCK_ACQUIRE(curthread, &m->m_lock); - - - /* - * Check to make sure this thread doesn't already own - * the mutex. Since mutexes are unlocked with direct - * handoffs, it is possible the previous owner gave it - * to us after we checked the sync queue flag and before - * we locked the mutex structure. - */ - if (m->m_owner == curthread) { - THR_LOCK_RELEASE(curthread, &m->m_lock); - mutex_unlock_common(&m, /* add_reference */ 0); - } else { - /* - * Remove ourselves from the mutex queue and - * clear the pointer to the mutex. We may no - * longer be in the mutex queue, but the removal - * function will DTRT. - */ - mutex_queue_remove(m, curthread); - curthread->data.mutex = NULL; - THR_LOCK_RELEASE(curthread, &m->m_lock); - } - } - /* No need to call this again. */ - curthread->sigbackout = NULL; -} - -/* - * Dequeue a waiting thread from the head of a mutex queue in descending - * priority order. - * - * In order to properly dequeue a thread from the mutex queue and - * make it runnable without the possibility of errant wakeups, it - * is necessary to lock the thread's scheduling queue while also - * holding the mutex lock. - */ -static struct kse_mailbox * -mutex_handoff(struct pthread *curthread, struct pthread_mutex *mutex) -{ - struct kse_mailbox *kmbx = NULL; - struct pthread *pthread; - - /* Keep dequeueing until we find a valid thread: */ - mutex->m_owner = NULL; - pthread = TAILQ_FIRST(&mutex->m_queue); - while (pthread != NULL) { - /* Take the thread's scheduling lock: */ - THR_SCHED_LOCK(curthread, pthread); - - /* Remove the thread from the mutex queue: */ - TAILQ_REMOVE(&mutex->m_queue, pthread, sqe); - pthread->sflags &= ~THR_FLAGS_IN_SYNCQ; - - /* - * Only exit the loop if the thread hasn't been - * cancelled. - */ - switch (mutex->m_protocol) { - case PTHREAD_PRIO_NONE: - /* - * Assign the new owner and add the mutex to the - * thread's list of owned mutexes. - */ - mutex->m_owner = pthread; - TAILQ_INSERT_TAIL(&pthread->mutexq, mutex, m_qe); - break; - - case PTHREAD_PRIO_INHERIT: - /* - * Assign the new owner and add the mutex to the - * thread's list of owned mutexes. - */ - mutex->m_owner = pthread; - TAILQ_INSERT_TAIL(&pthread->mutexq, mutex, m_qe); - - /* Track number of priority mutexes owned: */ - pthread->priority_mutex_count++; - - /* - * Set the priority of the mutex. Since our waiting - * threads are in descending priority order, the - * priority of the mutex becomes the active priority - * of the thread we just dequeued. - */ - mutex->m_prio = pthread->active_priority; - - /* Save the owning threads inherited priority: */ - mutex->m_saved_prio = pthread->inherited_priority; - - /* - * The owning threads inherited priority now becomes - * his active priority (the priority of the mutex). - */ - pthread->inherited_priority = mutex->m_prio; - break; - - case PTHREAD_PRIO_PROTECT: - if (pthread->active_priority > mutex->m_prio) { - /* - * Either the mutex ceiling priority has - * been lowered and/or this threads priority - * has been raised subsequent to the thread - * being queued on the waiting list. - */ - pthread->error = EINVAL; - } - else { - /* - * Assign the new owner and add the mutex - * to the thread's list of owned mutexes. - */ - mutex->m_owner = pthread; - TAILQ_INSERT_TAIL(&pthread->mutexq, - mutex, m_qe); - - /* Track number of priority mutexes owned: */ - pthread->priority_mutex_count++; - - /* - * Save the owning threads inherited - * priority: - */ - mutex->m_saved_prio = - pthread->inherited_priority; - - /* - * The owning thread inherits the ceiling - * priority of the mutex and executes at - * that priority: - */ - pthread->inherited_priority = mutex->m_prio; - pthread->active_priority = mutex->m_prio; - - } - break; - } - - /* Make the thread runnable and unlock the scheduling queue: */ - kmbx = _thr_setrunnable_unlocked(pthread); - - /* Add a preemption point. */ - if ((curthread->kseg == pthread->kseg) && - (pthread->active_priority > curthread->active_priority)) - curthread->critical_yield = 1; - - if (mutex->m_owner == pthread) { - /* We're done; a valid owner was found. */ - if (mutex->m_flags & MUTEX_FLAGS_PRIVATE) - THR_CRITICAL_ENTER(pthread); - THR_SCHED_UNLOCK(curthread, pthread); - break; - } - THR_SCHED_UNLOCK(curthread, pthread); - /* Get the next thread from the waiting queue: */ - pthread = TAILQ_NEXT(pthread, sqe); - } - - if ((pthread == NULL) && (mutex->m_protocol == PTHREAD_PRIO_INHERIT)) - /* This mutex has no priority: */ - mutex->m_prio = 0; - return (kmbx); -} - -/* - * Dequeue a waiting thread from the head of a mutex queue in descending - * priority order. - */ -static inline pthread_t -mutex_queue_deq(struct pthread_mutex *mutex) -{ - pthread_t pthread; - - while ((pthread = TAILQ_FIRST(&mutex->m_queue)) != NULL) { - TAILQ_REMOVE(&mutex->m_queue, pthread, sqe); - pthread->sflags &= ~THR_FLAGS_IN_SYNCQ; - - /* - * Only exit the loop if the thread hasn't been - * cancelled. - */ - if (pthread->interrupted == 0) - break; - } - - return (pthread); -} - -/* - * Remove a waiting thread from a mutex queue in descending priority order. - */ -static inline void -mutex_queue_remove(pthread_mutex_t mutex, pthread_t pthread) -{ - if ((pthread->sflags & THR_FLAGS_IN_SYNCQ) != 0) { - TAILQ_REMOVE(&mutex->m_queue, pthread, sqe); - pthread->sflags &= ~THR_FLAGS_IN_SYNCQ; - } -} - -/* - * Enqueue a waiting thread to a queue in descending priority order. - */ -static inline void -mutex_queue_enq(pthread_mutex_t mutex, pthread_t pthread) -{ - pthread_t tid = TAILQ_LAST(&mutex->m_queue, mutex_head); - - THR_ASSERT_NOT_IN_SYNCQ(pthread); - /* - * For the common case of all threads having equal priority, - * we perform a quick check against the priority of the thread - * at the tail of the queue. - */ - if ((tid == NULL) || (pthread->active_priority <= tid->active_priority)) - TAILQ_INSERT_TAIL(&mutex->m_queue, pthread, sqe); - else { - tid = TAILQ_FIRST(&mutex->m_queue); - while (pthread->active_priority <= tid->active_priority) - tid = TAILQ_NEXT(tid, sqe); - TAILQ_INSERT_BEFORE(tid, pthread, sqe); - } - pthread->sflags |= THR_FLAGS_IN_SYNCQ; -} -- cgit v1.1