diff --git a/lib/libthr/thread/thr_cond.c b/lib/libthr/thread/thr_cond.c index c1cbd546350e..0eb3dac068ca 100644 --- a/lib/libthr/thread/thr_cond.c +++ b/lib/libthr/thread/thr_cond.c @@ -1,556 +1,557 @@ /*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2005 David Xu * Copyright (c) 2015 The FreeBSD Foundation * All rights reserved. * * Portions of this software were developed by Konstantin Belousov * under sponsorship from the FreeBSD Foundation. * * 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 unmodified, 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. */ #include "namespace.h" #include #include #include #include #include #include "un-namespace.h" #include "thr_private.h" _Static_assert(sizeof(struct pthread_cond) <= THR_PAGE_SIZE_MIN, "pthread_cond too large"); /* * Prototypes */ int __pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec * abstime); static int cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr); static int cond_wait_common(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime, int cancel); static int cond_signal_common(pthread_cond_t *cond); static int cond_broadcast_common(pthread_cond_t *cond); /* * Double underscore versions are cancellation points. Single underscore * versions are not and are provided for libc internal usage (which * shouldn't introduce cancellation points). */ __weak_reference(__thr_cond_wait, pthread_cond_wait); __weak_reference(__thr_cond_wait, __pthread_cond_wait); __weak_reference(_thr_cond_wait, _pthread_cond_wait); __weak_reference(__pthread_cond_timedwait, pthread_cond_timedwait); +__weak_reference(_thr_cond_timedwait, _pthread_cond_timedwait); __weak_reference(_thr_cond_init, pthread_cond_init); __weak_reference(_thr_cond_init, _pthread_cond_init); __weak_reference(_thr_cond_destroy, pthread_cond_destroy); __weak_reference(_thr_cond_destroy, _pthread_cond_destroy); __weak_reference(_thr_cond_signal, pthread_cond_signal); __weak_reference(_thr_cond_signal, _pthread_cond_signal); __weak_reference(_thr_cond_broadcast, pthread_cond_broadcast); __weak_reference(_thr_cond_broadcast, _pthread_cond_broadcast); #define CV_PSHARED(cvp) (((cvp)->kcond.c_flags & USYNC_PROCESS_SHARED) != 0) static void cond_init_body(struct pthread_cond *cvp, const struct pthread_cond_attr *cattr) { if (cattr == NULL) { cvp->kcond.c_clockid = CLOCK_REALTIME; } else { if (cattr->c_pshared) cvp->kcond.c_flags |= USYNC_PROCESS_SHARED; cvp->kcond.c_clockid = cattr->c_clockid; } } static int cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr) { struct pthread_cond *cvp; const struct pthread_cond_attr *cattr; int pshared; cattr = cond_attr != NULL ? *cond_attr : NULL; if (cattr == NULL || cattr->c_pshared == PTHREAD_PROCESS_PRIVATE) { pshared = 0; cvp = calloc(1, sizeof(struct pthread_cond)); if (cvp == NULL) return (ENOMEM); } else { pshared = 1; cvp = __thr_pshared_offpage(cond, 1); if (cvp == NULL) return (EFAULT); } /* * Initialise the condition variable structure: */ cond_init_body(cvp, cattr); *cond = pshared ? THR_PSHARED_PTR : cvp; return (0); } static int init_static(struct pthread *thread, pthread_cond_t *cond) { int ret; THR_LOCK_ACQUIRE(thread, &_cond_static_lock); if (*cond == NULL) ret = cond_init(cond, NULL); else ret = 0; THR_LOCK_RELEASE(thread, &_cond_static_lock); return (ret); } #define CHECK_AND_INIT_COND \ if (*cond == THR_PSHARED_PTR) { \ cvp = __thr_pshared_offpage(cond, 0); \ if (cvp == NULL) \ return (EINVAL); \ } else if (__predict_false((cvp = (*cond)) <= THR_COND_DESTROYED)) { \ if (cvp == THR_COND_INITIALIZER) { \ int ret; \ ret = init_static(_get_curthread(), cond); \ if (ret) \ return (ret); \ } else if (cvp == THR_COND_DESTROYED) { \ return (EINVAL); \ } \ cvp = *cond; \ } int _thr_cond_init(pthread_cond_t * __restrict cond, const pthread_condattr_t * __restrict cond_attr) { *cond = NULL; return (cond_init(cond, cond_attr)); } int _thr_cond_destroy(pthread_cond_t *cond) { struct pthread_cond *cvp; int error; error = 0; if (*cond == THR_PSHARED_PTR) { cvp = __thr_pshared_offpage(cond, 0); if (cvp != NULL) { if (cvp->kcond.c_has_waiters) error = EBUSY; else __thr_pshared_destroy(cond); } if (error == 0) *cond = THR_COND_DESTROYED; } else if ((cvp = *cond) == THR_COND_INITIALIZER) { /* nothing */ } else if (cvp == THR_COND_DESTROYED) { error = EINVAL; } else { cvp = *cond; if (cvp->__has_user_waiters || cvp->kcond.c_has_waiters) error = EBUSY; else { *cond = THR_COND_DESTROYED; free(cvp); } } return (error); } /* * Cancellation behavior: * Thread may be canceled at start, if thread is canceled, it means it * did not get a wakeup from pthread_cond_signal(), otherwise, it is * not canceled. * Thread cancellation never cause wakeup from pthread_cond_signal() * to be lost. */ static int cond_wait_kernel(struct pthread_cond *cvp, struct pthread_mutex *mp, const struct timespec *abstime, int cancel) { struct pthread *curthread; int error, error2, recurse, robust; curthread = _get_curthread(); robust = _mutex_enter_robust(curthread, mp); error = _mutex_cv_detach(mp, &recurse); if (error != 0) { if (robust) _mutex_leave_robust(curthread, mp); return (error); } if (cancel) _thr_cancel_enter2(curthread, 0); error = _thr_ucond_wait(&cvp->kcond, &mp->m_lock, abstime, CVWAIT_ABSTIME | CVWAIT_CLOCKID); if (cancel) _thr_cancel_leave(curthread, 0); /* * Note that PP mutex and ROBUST mutex may return * interesting error codes. */ if (error == 0) { error2 = _mutex_cv_lock(mp, recurse, true); } else if (error == EINTR || error == ETIMEDOUT) { error2 = _mutex_cv_lock(mp, recurse, true); /* * Do not do cancellation on EOWNERDEAD there. The * cancellation cleanup handler will use the protected * state and unlock the mutex without making the state * consistent and the state will be unrecoverable. */ if (error2 == 0 && cancel) { if (robust) { _mutex_leave_robust(curthread, mp); robust = false; } _thr_testcancel(curthread); } if (error == EINTR) error = 0; } else { /* We know that it didn't unlock the mutex. */ _mutex_cv_attach(mp, recurse); if (cancel) { if (robust) { _mutex_leave_robust(curthread, mp); robust = false; } _thr_testcancel(curthread); } error2 = 0; } if (robust) _mutex_leave_robust(curthread, mp); return (error2 != 0 ? error2 : error); } /* * Thread waits in userland queue whenever possible, when thread * is signaled or broadcasted, it is removed from the queue, and * is saved in curthread's defer_waiters[] buffer, but won't be * woken up until mutex is unlocked. */ static int cond_wait_user(struct pthread_cond *cvp, struct pthread_mutex *mp, const struct timespec *abstime, int cancel) { struct pthread *curthread; struct sleepqueue *sq; int deferred, error, error2, recurse; curthread = _get_curthread(); if (curthread->wchan != NULL) PANIC("thread %p was already on queue.", curthread); if (cancel) _thr_testcancel(curthread); _sleepq_lock(cvp); /* * set __has_user_waiters before unlocking mutex, this allows * us to check it without locking in pthread_cond_signal(). */ cvp->__has_user_waiters = 1; deferred = 0; (void)_mutex_cv_unlock(mp, &recurse, &deferred); curthread->mutex_obj = mp; _sleepq_add(cvp, curthread); for(;;) { _thr_clear_wake(curthread); _sleepq_unlock(cvp); if (deferred) { deferred = 0; if ((mp->m_lock.m_owner & UMUTEX_CONTESTED) == 0) (void)_umtx_op_err(&mp->m_lock, UMTX_OP_MUTEX_WAKE2, mp->m_lock.m_flags, 0, 0); } if (curthread->nwaiter_defer > 0) { _thr_wake_all(curthread->defer_waiters, curthread->nwaiter_defer); curthread->nwaiter_defer = 0; } if (cancel) _thr_cancel_enter2(curthread, 0); error = _thr_sleep(curthread, cvp->kcond.c_clockid, abstime); if (cancel) _thr_cancel_leave(curthread, 0); _sleepq_lock(cvp); if (curthread->wchan == NULL) { error = 0; break; } else if (cancel && SHOULD_CANCEL(curthread)) { sq = _sleepq_lookup(cvp); cvp->__has_user_waiters = _sleepq_remove(sq, curthread); _sleepq_unlock(cvp); curthread->mutex_obj = NULL; error2 = _mutex_cv_lock(mp, recurse, false); if (!THR_IN_CRITICAL(curthread)) _pthread_exit(PTHREAD_CANCELED); else /* this should not happen */ return (error2); } else if (error == ETIMEDOUT) { sq = _sleepq_lookup(cvp); cvp->__has_user_waiters = _sleepq_remove(sq, curthread); break; } } _sleepq_unlock(cvp); curthread->mutex_obj = NULL; error2 = _mutex_cv_lock(mp, recurse, false); if (error == 0) error = error2; return (error); } static int cond_wait_common(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime, int cancel) { struct pthread *curthread = _get_curthread(); struct pthread_cond *cvp; struct pthread_mutex *mp; int error; CHECK_AND_INIT_COND if (*mutex == THR_PSHARED_PTR) { mp = __thr_pshared_offpage(mutex, 0); if (mp == NULL) return (EINVAL); } else { mp = *mutex; } if ((error = _mutex_owned(curthread, mp)) != 0) return (error); if (curthread->attr.sched_policy != SCHED_OTHER || (mp->m_lock.m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT | USYNC_PROCESS_SHARED)) != 0 || CV_PSHARED(cvp)) return (cond_wait_kernel(cvp, mp, abstime, cancel)); else return (cond_wait_user(cvp, mp, abstime, cancel)); } int _thr_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) { return (cond_wait_common(cond, mutex, NULL, 0)); } int __thr_cond_wait(pthread_cond_t * __restrict cond, pthread_mutex_t * __restrict mutex) { return (cond_wait_common(cond, mutex, NULL, 1)); } int _thr_cond_timedwait(pthread_cond_t * __restrict cond, pthread_mutex_t * __restrict mutex, const struct timespec * __restrict abstime) { if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) return (EINVAL); return (cond_wait_common(cond, mutex, abstime, 0)); } int __pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, const struct timespec *abstime) { if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) return (EINVAL); return (cond_wait_common(cond, mutex, abstime, 1)); } static int cond_signal_common(pthread_cond_t *cond) { struct pthread *curthread = _get_curthread(); struct pthread *td; struct pthread_cond *cvp; struct pthread_mutex *mp; struct sleepqueue *sq; int *waddr; int pshared; /* * If the condition variable is statically initialized, perform dynamic * initialization. */ CHECK_AND_INIT_COND pshared = CV_PSHARED(cvp); _thr_ucond_signal(&cvp->kcond); if (pshared || cvp->__has_user_waiters == 0) return (0); curthread = _get_curthread(); waddr = NULL; _sleepq_lock(cvp); sq = _sleepq_lookup(cvp); if (sq == NULL) { _sleepq_unlock(cvp); return (0); } td = _sleepq_first(sq); mp = td->mutex_obj; cvp->__has_user_waiters = _sleepq_remove(sq, td); if (PMUTEX_OWNER_ID(mp) == TID(curthread)) { if (curthread->nwaiter_defer >= MAX_DEFER_WAITERS) { _thr_wake_all(curthread->defer_waiters, curthread->nwaiter_defer); curthread->nwaiter_defer = 0; } curthread->defer_waiters[curthread->nwaiter_defer++] = &td->wake_addr->value; mp->m_flags |= PMUTEX_FLAG_DEFERRED; } else { waddr = &td->wake_addr->value; } _sleepq_unlock(cvp); if (waddr != NULL) _thr_set_wake(waddr); return (0); } struct broadcast_arg { struct pthread *curthread; unsigned int *waddrs[MAX_DEFER_WAITERS]; int count; }; static void drop_cb(struct pthread *td, void *arg) { struct broadcast_arg *ba = arg; struct pthread_mutex *mp; struct pthread *curthread = ba->curthread; mp = td->mutex_obj; if (PMUTEX_OWNER_ID(mp) == TID(curthread)) { if (curthread->nwaiter_defer >= MAX_DEFER_WAITERS) { _thr_wake_all(curthread->defer_waiters, curthread->nwaiter_defer); curthread->nwaiter_defer = 0; } curthread->defer_waiters[curthread->nwaiter_defer++] = &td->wake_addr->value; mp->m_flags |= PMUTEX_FLAG_DEFERRED; } else { if (ba->count >= MAX_DEFER_WAITERS) { _thr_wake_all(ba->waddrs, ba->count); ba->count = 0; } ba->waddrs[ba->count++] = &td->wake_addr->value; } } static int cond_broadcast_common(pthread_cond_t *cond) { int pshared; struct pthread_cond *cvp; struct sleepqueue *sq; struct broadcast_arg ba; /* * If the condition variable is statically initialized, perform dynamic * initialization. */ CHECK_AND_INIT_COND pshared = CV_PSHARED(cvp); _thr_ucond_broadcast(&cvp->kcond); if (pshared || cvp->__has_user_waiters == 0) return (0); ba.curthread = _get_curthread(); ba.count = 0; _sleepq_lock(cvp); sq = _sleepq_lookup(cvp); if (sq == NULL) { _sleepq_unlock(cvp); return (0); } _sleepq_drop(sq, drop_cb, &ba); cvp->__has_user_waiters = 0; _sleepq_unlock(cvp); if (ba.count > 0) _thr_wake_all(ba.waddrs, ba.count); return (0); } int _thr_cond_signal(pthread_cond_t * cond) { return (cond_signal_common(cond)); } int _thr_cond_broadcast(pthread_cond_t * cond) { return (cond_broadcast_common(cond)); }