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/*
* Copyright (c) 1997 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.
*
* $FreeBSD$
*
*/
#include <sys/types.h>
#include <machine/atomic.h>
#include <libc_private.h>
#include "spinlock.h"
#include "thr_private.h"
#define MAX_SPINLOCKS 5
struct spinlock_extra {
spinlock_t *owner;
pthread_mutex_t lock;
};
static void init_spinlock(spinlock_t *lck);
static pthread_mutex_t spinlock_static_lock;
static struct spinlock_extra extra[MAX_SPINLOCKS];
static int spinlock_count = 0;
static int initialized = 0;
/*
* These are for compatability only. Spinlocks of this type
* are deprecated.
*/
void
_spinunlock(spinlock_t *lck)
{
struct spinlock_extra *extra;
extra = (struct spinlock_extra *)lck->fname;
pthread_mutex_unlock(&extra->lock);
}
/*
* Lock a location for the running thread. Yield to allow other
* threads to run if this thread is blocked because the lock is
* not available. Note that this function does not sleep. It
* assumes that the lock will be available very soon.
*/
void
_spinlock(spinlock_t *lck)
{
struct spinlock_extra *extra;
if (!__isthreaded)
PANIC("Spinlock called when not threaded.");
if (!initialized)
PANIC("Spinlocks not initialized.");
/*
* Try to grab the lock and loop if another thread grabs
* it before we do.
*/
if (lck->fname == NULL)
init_spinlock(lck);
extra = (struct spinlock_extra *)lck->fname;
pthread_mutex_lock(&extra->lock);
}
/*
* Lock a location for the running thread. Yield to allow other
* threads to run if this thread is blocked because the lock is
* not available. Note that this function does not sleep. It
* assumes that the lock will be available very soon.
*
* This function checks if the running thread has already locked the
* location, warns if this occurs and creates a thread dump before
* returning.
*/
void
_spinlock_debug(spinlock_t *lck, char *fname, int lineno)
{
_spinlock(lck);
}
static void
init_spinlock(spinlock_t *lck)
{
pthread_mutex_lock(&spinlock_static_lock);
if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) {
lck->fname = (char *)&extra[spinlock_count];
extra[spinlock_count].owner = lck;
spinlock_count++;
}
pthread_mutex_unlock(&spinlock_static_lock);
if (lck->fname == NULL)
PANIC("Exceeded max spinlocks");
}
void
_thr_spinlock_init(void)
{
int i;
if (initialized != 0) {
_thr_mutex_reinit(&spinlock_static_lock);
for (i = 0; i < spinlock_count; i++)
_thr_mutex_reinit(&extra[i].lock);
} else {
if (pthread_mutex_init(&spinlock_static_lock, NULL))
PANIC("Cannot initialize spinlock_static_lock");
for (i = 0; i < MAX_SPINLOCKS; i++) {
if (pthread_mutex_init(&extra[i].lock, NULL))
PANIC("Cannot initialize spinlock extra");
}
initialized = 1;
}
}
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