FreeBSD/Linux Kernel Cross Reference
sys/sys/simplelock.h

     /*      $NetBSD: simplelock.h,v 1.8 2008/04/28 20:24:11 martin Exp $    */
     
     /*-
      * Copyright (c) 1999, 2000, 2006, 2007 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      * NASA Ames Research Center.
     *
     * This code is derived from software contributed to The NetBSD Foundation
     * by Ross Harvey.
     *
     * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
     */
    
    /*
     * Copyright (c) 1995
     *      The Regents of the University of California.  All rights reserved.
     *
     * This code contains ideas from software contributed to Berkeley by
     * Avadis Tevanian, Jr., Michael Wayne Young, and the Mach Operating
     * System project at Carnegie-Mellon University.
     *
     * 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 University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
     *
     *      @(#)lock.h      8.12 (Berkeley) 5/19/95
     */
    
    #ifndef _SYS_SIMPLELOCK_H_
    #define _SYS_SIMPLELOCK_H_
    
    #if defined(_KERNEL_OPT)
    #include "opt_multiprocessor.h"
    #include "opt_lockdebug.h"
    #endif
    
    #include <machine/types.h>
    #include <machine/lock.h>
    
    /*
     * The simple lock.  Provides a simple spinning mutex.  Note the
     * member which is used in atomic operations must be aligned in
     * order for it to work on the widest range of processor types.
     */
    struct simplelock {
            __cpu_simple_lock_t lock_data;
    #ifdef __CPU_SIMPLE_LOCK_PAD
            /*
             * For binary compatibility where the lock word has been
             * made shorter.
             */
            uint8_t lock_pad[3];
    #endif
    };
    
    #define SIMPLELOCK_INITIALIZER  { .lock_data = __SIMPLELOCK_UNLOCKED }
    
   #ifdef _KERNEL
   
   #if defined(MULTIPROCESSOR) || defined(LOCKDEBUG)
   #define simple_lock_init(alp)   __cpu_simple_lock_init(&(alp)->lock_data)
   #define simple_lock(alp)        __cpu_simple_lock(&(alp)->lock_data)
   #define simple_lock_held(alp)   (__SIMPLELOCK_LOCKED_P(&(alp)->lock_data))
   #define simple_lock_try(alp)    __cpu_simple_lock_try(&(alp)->lock_data)
   #define simple_unlock(alp)      __cpu_simple_unlock(&(alp)->lock_data)
   #else
   #define simple_lock_nothing(alp)        \
   do {                                    \
           (void)alp;                      \
   } while (0);
   #define simple_lock_init(alp)   simple_lock_nothing(alp)
   #define simple_lock(alp)        simple_lock_nothing(alp)
   #define simple_lock_held(alp)   1
   #define simple_lock_try(alp)    1
   #define simple_unlock(alp)      simple_lock_nothing(alp)
   #endif
   
   #endif  /* _KERNEL */
   
   #endif  /* _SYS_SIMPLELOCK_H_ */

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