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145 lines
4.3 KiB
C
145 lines
4.3 KiB
C
/*
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* Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*
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*/
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#include <sys/types.h>
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#include <machine/atomic.h>
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#include <libc_private.h>
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#include "spinlock.h"
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#include "thr_private.h"
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#define MAX_SPINLOCKS 5
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struct spinlock_extra {
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spinlock_t *owner;
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pthread_mutex_t lock;
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};
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static void init_spinlock(spinlock_t *lck);
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static pthread_mutex_t spinlock_static_lock;
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static struct spinlock_extra extra[MAX_SPINLOCKS];
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static int spinlock_count = 0;
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static int initialized = 0;
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/*
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* These are for compatability only. Spinlocks of this type
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* are deprecated.
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*/
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void
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_spinunlock(spinlock_t *lck)
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{
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struct spinlock_extra *extra;
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extra = (struct spinlock_extra *)lck->fname;
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pthread_mutex_unlock(&extra->lock);
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}
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/*
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* Lock a location for the running thread. Yield to allow other
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* threads to run if this thread is blocked because the lock is
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* not available. Note that this function does not sleep. It
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* assumes that the lock will be available very soon.
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*/
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void
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_spinlock(spinlock_t *lck)
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{
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struct spinlock_extra *extra;
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if (!__isthreaded)
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PANIC("Spinlock called when not threaded.");
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if (!initialized)
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PANIC("Spinlocks not initialized.");
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/*
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* Try to grab the lock and loop if another thread grabs
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* it before we do.
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*/
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if (lck->fname == NULL)
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init_spinlock(lck);
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extra = (struct spinlock_extra *)lck->fname;
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pthread_mutex_lock(&extra->lock);
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}
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/*
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* Lock a location for the running thread. Yield to allow other
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* threads to run if this thread is blocked because the lock is
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* not available. Note that this function does not sleep. It
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* assumes that the lock will be available very soon.
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*
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* This function checks if the running thread has already locked the
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* location, warns if this occurs and creates a thread dump before
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* returning.
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*/
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void
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_spinlock_debug(spinlock_t *lck, char *fname, int lineno)
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{
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_spinlock(lck);
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}
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static void
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init_spinlock(spinlock_t *lck)
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{
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pthread_mutex_lock(&spinlock_static_lock);
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if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) {
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lck->fname = (char *)&extra[spinlock_count];
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extra[spinlock_count].owner = lck;
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spinlock_count++;
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}
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pthread_mutex_unlock(&spinlock_static_lock);
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if (lck->fname == NULL)
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PANIC("Exceeded max spinlocks");
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}
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void
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_thr_spinlock_init(void)
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{
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int i;
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if (initialized != 0) {
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_thr_mutex_reinit(&spinlock_static_lock);
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for (i = 0; i < spinlock_count; i++)
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_thr_mutex_reinit(&extra[i].lock);
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} else {
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if (pthread_mutex_init(&spinlock_static_lock, NULL))
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PANIC("Cannot initialize spinlock_static_lock");
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for (i = 0; i < MAX_SPINLOCKS; i++) {
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if (pthread_mutex_init(&extra[i].lock, NULL))
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PANIC("Cannot initialize spinlock extra");
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}
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initialized = 1;
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}
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}
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