sys/sys/mutex.h

   1 /*
   2  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef _SYS_MUTEX_H_
  36 #define _SYS_MUTEX_H_
  37
  38 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
  39
  40 #ifndef _SYS_TYPES_H_
  41 #include <sys/types.h>
  42 #endif
  43 #ifndef _MACHINE_ATOMIC_H_
  44 #include <machine/atomic.h>
  45 #endif
  46 #ifndef _MACHINE_CPUFUNC_H_
  47 #include <machine/cpufunc.h>
  48 #endif
  49
  50 /*
  51  * The general mutex structure provides recursive shared and exclusive
  52  * locks, downgrade, a non-blocking upgrade, and various other functions.
  53  *
  54  * The structure is 16-byte aligned and either 16 or 32 bytes, designed
  55  * for 32 or 64 bit cpus.
  56  */
  57 struct thread;
  58
  59 typedef struct mtx {
  60         volatile u_int  mtx_lock;
  61         int             mtx_refs;
  62         struct thread   *mtx_owner;
  63 #if LONG_BIT == 32
  64         int             mtx_unused;
  65 #endif
  66 } *mtx_t;
  67
  68 #define MTX_EXCLUSIVE   0x80000000
  69 #define MTX_SHWANTED    0x40000000
  70 #define MTX_EXWANTED    0x20000000
  71 #define MTX_MASK        0x0FFFFFFF
  72
  73 #define MTX_PCATCH      0x00000001
  74
  75 #define MTX_OWNER_NONE  NULL
  76 #define MTX_OWNER_ANON  (struct thread *)-2)
  77
  78 #endif
  79
  80 /*
  81  * See also sys/mutex2.h
  82  */
  83 #ifdef _KERNEL
  84
  85 void    _mtx_lock_ex(mtx_t mtx, const char *ident, int flags);
  86 void    _mtx_lock_sh(mtx_t mtx, const char *ident, int flags);
  87 void    _mtx_spinlock_ex(mtx_t mtx);
  88 void    _mtx_spinlock_sh(mtx_t mtx);
  89 int     _mtx_lock_ex_try(mtx_t mtx);
  90 int     _mtx_lock_sh_try(mtx_t mtx);
  91 void    _mtx_downgrade(mtx_t mtx);
  92 int     _mtx_upgrade_try(mtx_t mtx);
  93 void    _mtx_unlock(mtx_t mtx);
  94
  95 #endif
  96
  97 #endif