freebsd-skq/lib/libthr/thread/thr_resume_np.c
davidxu f83ff5dc95 In suspend_common(), don't wait for a thread which is in creation, because
pthread_suspend_all_np() may have already suspended its parent thread.
Add locking code in pthread_suspend_all_np() to only allow one thread
to suspend other threads, this eliminates a deadlock where two or more
threads try to suspend each others.
2012-08-27 03:09:39 +00:00

97 lines
3.0 KiB
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. 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 "namespace.h"
#include <errno.h>
#include <pthread.h>
#include <pthread_np.h>
#include "un-namespace.h"
#include "thr_private.h"
__weak_reference(_pthread_resume_np, pthread_resume_np);
__weak_reference(_pthread_resume_all_np, pthread_resume_all_np);
static void resume_common(struct pthread *thread);
/* Resume a thread: */
int
_pthread_resume_np(pthread_t thread)
{
struct pthread *curthread = _get_curthread();
int ret;
/* Add a reference to the thread: */
if ((ret = _thr_find_thread(curthread, thread, /*include dead*/0)) == 0) {
/* Lock the threads scheduling queue: */
resume_common(thread);
THR_THREAD_UNLOCK(curthread, thread);
}
return (ret);
}
void
_pthread_resume_all_np(void)
{
struct pthread *curthread = _get_curthread();
struct pthread *thread;
int old_nocancel;
old_nocancel = curthread->no_cancel;
curthread->no_cancel = 1;
_thr_suspend_all_lock(curthread);
/* Take the thread list lock: */
THREAD_LIST_RDLOCK(curthread);
TAILQ_FOREACH(thread, &_thread_list, tle) {
if (thread != curthread) {
THR_THREAD_LOCK(curthread, thread);
resume_common(thread);
THR_THREAD_UNLOCK(curthread, thread);
}
}
/* Release the thread list lock: */
THREAD_LIST_UNLOCK(curthread);
_thr_suspend_all_unlock(curthread);
curthread->no_cancel = old_nocancel;
_thr_testcancel(curthread);
}
static void
resume_common(struct pthread *thread)
{
/* Clear the suspend flag: */
thread->flags &= ~THR_FLAGS_NEED_SUSPEND;
thread->cycle++;
_thr_umtx_wake(&thread->cycle, 1, 0);
}