FreeBSD/Linux Kernel Cross Reference
sys/bsd/sys/lock.h

     /*
      * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_LICENSE_HEADER_START@
      * 
      * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
     * Version 2.0 (the 'License'). You may not use this file except in
     * compliance with the License. Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this
     * file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     * Please see the License for the specific language governing rights and
     * limitations under the License.
     * 
     * @APPLE_LICENSE_HEADER_END@
     */
    /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
    /* 
     * 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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. 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_LOCK_H_
    #define _SYS_LOCK_H_
    
    #include <sys/appleapiopts.h>
    
    #ifdef KERNEL
    #ifdef __APPLE_API_UNSTABLE
    #include <kern/simple_lock.h>
    #include <kern/simple_lock_types.h>
    
    #if defined(simple_lock_init)
    #undef simple_lock_init
    #endif
    #define simple_lock_init(l)     usimple_lock_init((l),0)
    
    #if defined(simple_lock)
    #undef simple_lock
    #endif
    #define simple_lock(l)         ((void) 1)
    
    #if defined(simple_unlock)
    #undef simple_unlock
    #endif
    #define simple_unlock(l)        ((void) 1)
    
    #if defined(simple_lock_try)
    #undef simple_lock_try
    #endif
    #define simple_lock_try(l)      1
    
    #if defined(thread_sleep_simple_lock)
    #undef thread_sleep_simple_lock
    #endif
    #define thread_sleep_simple_lock(l, e, i) thread_sleep_funnel((e), (i))
    
   #endif /* __APPLE_API_UNSTABLE */
   #else /* KERNEL */
   
   #ifndef _MACHINE_SIMPLE_LOCK_DATA_
   #define _MACHINE_SIMPLE_LOCK_DATA_
   
   #include <mach/boolean.h>
   
   struct slock{
           volatile unsigned int lock_data[10];
   };
   typedef struct slock    simple_lock_data_t;
   typedef struct slock    *simple_lock_t;
   #define decl_simple_lock_data(class,name) \
   class   simple_lock_data_t      name;
   
   #endif  /* _MACHINE_SIMPLE_LOCK_DATA_ */
   
   #endif /* KERNEL */
   
   #ifdef __APPLE_API_UNSTABLE
   /*
    * The general lock structure.  Provides for multiple shared locks,
    * upgrading from shared to exclusive, and sleeping until the lock
    * can be gained. The simple locks are defined in <machine/param.h>.
    */
   struct lock__bsd__ {
           simple_lock_data_t
                   lk_interlock;           /* lock on remaining fields */
           u_int   lk_flags;               /* see below */
           int     lk_sharecount;          /* # of accepted shared locks */
           int     lk_waitcount;           /* # of processes sleeping for lock */
           short   lk_exclusivecount;      /* # of recursive exclusive locks */
           short   lk_prio;                /* priority at which to sleep */
           char    *lk_wmesg;              /* resource sleeping (for tsleep) */
           int     lk_timo;                /* maximum sleep time (for tsleep) */
           pid_t   lk_lockholder;          /* pid of exclusive lock holder */
           void    *lk_lockthread;         /* thread which acquired excl lock */
   };
   /*
    * Lock request types:
    *   LK_SHARED - get one of many possible shared locks. If a process
    *      holding an exclusive lock requests a shared lock, the exclusive
    *      lock(s) will be downgraded to shared locks.
    *   LK_EXCLUSIVE - stop further shared locks, when they are cleared,
    *      grant a pending upgrade if it exists, then grant an exclusive
    *      lock. Only one exclusive lock may exist at a time, except that
    *      a process holding an exclusive lock may get additional exclusive
    *      locks if it explicitly sets the LK_CANRECURSE flag in the lock
    *      request, or if the LK_CANRECUSE flag was set when the lock was
    *      initialized.
    *   LK_UPGRADE - the process must hold a shared lock that it wants to
    *      have upgraded to an exclusive lock. Other processes may get
    *      exclusive access to the resource between the time that the upgrade
    *      is requested and the time that it is granted.
    *   LK_EXCLUPGRADE - the process must hold a shared lock that it wants to
    *      have upgraded to an exclusive lock. If the request succeeds, no
    *      other processes will have gotten exclusive access to the resource
    *      between the time that the upgrade is requested and the time that
    *      it is granted. However, if another process has already requested
    *      an upgrade, the request will fail (see error returns below).
    *   LK_DOWNGRADE - the process must hold an exclusive lock that it wants
    *      to have downgraded to a shared lock. If the process holds multiple
    *      (recursive) exclusive locks, they will all be downgraded to shared
    *      locks.
    *   LK_RELEASE - release one instance of a lock.
    *   LK_DRAIN - wait for all activity on the lock to end, then mark it
    *      decommissioned. This feature is used before freeing a lock that
    *      is part of a piece of memory that is about to be freed.
    *
    * These are flags that are passed to the lockmgr routine.
    */
   #define LK_TYPE_MASK    0x0000000f      /* type of lock sought */
   #define LK_SHARED       0x00000001      /* shared lock */
   #define LK_EXCLUSIVE    0x00000002      /* exclusive lock */
   #define LK_UPGRADE      0x00000003      /* shared-to-exclusive upgrade */
   #define LK_EXCLUPGRADE  0x00000004      /* first shared-to-exclusive upgrade */
   #define LK_DOWNGRADE    0x00000005      /* exclusive-to-shared downgrade */
   #define LK_RELEASE      0x00000006      /* release any type of lock */
   #define LK_DRAIN        0x00000007      /* wait for all lock activity to end */
   /*
    * External lock flags.
    *
    * The first three flags may be set in lock_init to set their mode permanently,
    * or passed in as arguments to the lock manager. The LK_REENABLE flag may be
    * set only at the release of a lock obtained by drain.
    */
   #define LK_EXTFLG_MASK  0x00000070      /* mask of external flags */
   #define LK_NOWAIT       0x00000010      /* do not sleep to await lock */
   #define LK_SLEEPFAIL    0x00000020      /* sleep, then return failure */
   #define LK_CANRECURSE   0x00000040      /* allow recursive exclusive lock */
   #define LK_REENABLE     0x00000080      /* lock is be reenabled after drain */
   /*
    * Internal lock flags.
    *
    * These flags are used internally to the lock manager.
    */
   #define LK_WANT_UPGRADE 0x00000100      /* waiting for share-to-excl upgrade */
   #define LK_WANT_EXCL    0x00000200      /* exclusive lock sought */
   #define LK_HAVE_EXCL    0x00000400      /* exclusive lock obtained */
   #define LK_WAITDRAIN    0x00000800      /* process waiting for lock to drain */
   #define LK_DRAINING     0x00004000      /* lock is being drained */
   #define LK_DRAINED      0x00008000      /* lock has been decommissioned */
   /*
    * Control flags
    *
    * Non-persistent external flags.
    */
   #define LK_INTERLOCK    0x00010000      /* unlock passed simple lock after
                                              getting lk_interlock */
   #define LK_RETRY        0x00020000      /* vn_lock: retry until locked */
   
   /*
    * Lock return status.
    *
    * Successfully obtained locks return 0. Locks will always succeed
    * unless one of the following is true:
    *      LK_FORCEUPGRADE is requested and some other process has already
    *          requested a lock upgrade (returns EBUSY).
    *      LK_WAIT is set and a sleep would be required (returns EBUSY).
    *      LK_SLEEPFAIL is set and a sleep was done (returns ENOLCK).
    *      PCATCH is set in lock priority and a signal arrives (returns
    *          either EINTR or ERESTART if system calls is to be restarted).
    *      Non-null lock timeout and timeout expires (returns EWOULDBLOCK).
    * A failed lock attempt always returns a non-zero error value. No lock
    * is held after an error return (in particular, a failed LK_UPGRADE
    * or LK_FORCEUPGRADE will have released its shared access lock).
    */
   
   /*
    * Indicator that no process holds exclusive lock
    */
   #define LK_KERNPROC ((pid_t) -2)
   #define LK_NOPROC ((pid_t) -1)
   
   struct proc;
   
   void    lockinit __P((struct lock__bsd__ *, int prio, char *wmesg, int timo,
                           int flags));
   int     lockmgr __P((struct lock__bsd__ *, u_int flags,
                           simple_lock_t, struct proc *p));
   int     lockstatus __P((struct lock__bsd__ *));
   
   #endif /* __APPLE_API_UNSTABLE */
   
   #endif  /* _SYS_LOCK_H_ */

Cache object: ad30bb6206afb46f84924c0b82691533