/* * Copyright (c) 1997 John Birrell . * 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 #include #include #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; } }