FreeBSD-5.3/lib/libpthread/thread/thr_resume_np.c

/*
 * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by John Birrell.
 * 4. 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: src/lib/libpthread/thread/thr_resume_np.c,v 1.18 2003/07/23 02:11:07 deischen Exp $
 */
#include <errno.h>
#include <pthread.h>
#include "thr_private.h"

static struct kse_mailbox *resume_common(struct pthread *);

__weak_reference(_pthread_resume_np, pthread_resume_np);
__weak_reference(_pthread_resume_all_np, pthread_resume_all_np);


/* Resume a thread: */
int
_pthread_resume_np(pthread_t thread)
{
	struct pthread *curthread = _get_curthread();
	struct kse_mailbox *kmbx;
	int ret;

	/* Add a reference to the thread: */
	if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0)) == 0) {
		/* Lock the threads scheduling queue: */
		THR_SCHED_LOCK(curthread, thread);
		kmbx = resume_common(thread);
		THR_SCHED_UNLOCK(curthread, thread);
		_thr_ref_delete(curthread, thread);
		if (kmbx != NULL)
			kse_wakeup(kmbx);
	}
	return (ret);
}

void
_pthread_resume_all_np(void)
{
	struct pthread *curthread = _get_curthread();
	struct pthread *thread;
	struct kse_mailbox *kmbx;
	kse_critical_t crit;

	/* Take the thread list lock: */
	crit = _kse_critical_enter();
	KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);

	TAILQ_FOREACH(thread, &_thread_list, tle) {
		if (thread != curthread) {
			THR_SCHED_LOCK(curthread, thread);
			kmbx = resume_common(thread);
			THR_SCHED_UNLOCK(curthread, thread);
			if (kmbx != NULL)
				kse_wakeup(kmbx);
		}
	}

	/* Release the thread list lock: */
	KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
	_kse_critical_leave(crit);
}

static struct kse_mailbox *
resume_common(struct pthread *thread)
{
	/* Clear the suspend flag: */
	thread->flags &= ~THR_FLAGS_SUSPENDED;

	/*
	 * If the thread's state is suspended, that means it is
	 * now runnable but not in any scheduling queue.  Set the
	 * state to running and insert it into the run queue.
	 */
	if (thread->state == PS_SUSPENDED)
		return (_thr_setrunnable_unlocked(thread));
	else
		return (NULL);
}