1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 1991, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 
  26 #ifndef _SYS_MUTEX_H
  27 #define _SYS_MUTEX_H
  28 
  29 #include <sys/synch.h>    /* lwp_mutex_t */
  30 
  31 #ifdef  __cplusplus
  32 extern "C" {
  33 #endif
  34 
  35 /*
  36  * Public interface to mutual exclusion locks.  See mutex(9F) for details.
  37  *
  38  * The basic mutex type is MUTEX_ADAPTIVE, which is expected to be used
  39  * in almost all of the kernel.  MUTEX_SPIN provides interrupt blocking
  40  * and must be used in interrupt handlers above LOCK_LEVEL.  The iblock
  41  * cookie argument to mutex_init() encodes the interrupt level to block.
  42  * The iblock cookie must be NULL for adaptive locks.
  43  *
  44  * MUTEX_DEFAULT is the type usually specified (except in drivers) to
  45  * mutex_init().  It is identical to MUTEX_ADAPTIVE.
  46  *
  47  * MUTEX_DRIVER is always used by drivers.  mutex_init() converts this to
  48  * either MUTEX_ADAPTIVE or MUTEX_SPIN depending on the iblock cookie.
  49  *
  50  * Mutex statistics can be gathered on the fly, without rebooting or
  51  * recompiling the kernel, via the lockstat driver (lockstat(7D)).
  52  */
  53 typedef enum {
  54         MUTEX_ADAPTIVE = 0,     /* spin if owner is running, otherwise block */
  55         MUTEX_SPIN = 1,         /* block interrupts and spin */
  56         MUTEX_DRIVER = 4,       /* driver (DDI) mutex */
  57         MUTEX_DEFAULT = 6       /* kernel default mutex */
  58 } kmutex_type_t;
  59 
  60 struct _kmutex {
  61         lwp_mutex_t m_lock;
  62         void *m_owner;
  63 };
  64 typedef struct _kmutex kmutex_t;
  65 
  66 #if defined(_KERNEL) || defined(_FAKE_KERNEL)
  67 /* See the real sys/mutex.h */
  68 typedef struct pad_mutex {
  69         kmutex_t        pad_mutex;
  70 #ifdef _LP64
  71         char            pad_pad[64 - sizeof (kmutex_t)];
  72 #endif
  73 } pad_mutex_t;
  74 #endif  /* _KERNEL */
  75 
  76 #define MUTEX_HELD(x)           (mutex_owned(x))
  77 #define MUTEX_NOT_HELD(x)       (!mutex_owned(x) || panicstr)
  78 
  79 /*
  80  * We're simulating the kernel mutex API here, and the
  81  * user-level has a different signature, so rename.
  82  */
  83 #define mutex_init      kmutex_init
  84 #define mutex_destroy   kmutex_destroy
  85 
  86 extern  void    kmutex_init(kmutex_t *, char *, kmutex_type_t, void *);
  87 extern  void    kmutex_destroy(kmutex_t *);
  88 
  89 extern  void    mutex_enter(kmutex_t *);
  90 extern  int     mutex_tryenter(kmutex_t *);
  91 extern  void    mutex_exit(kmutex_t *);
  92 extern  int     mutex_owned(const kmutex_t *);
  93 
  94 extern  void *mutex_owner(const kmutex_t *);
  95 
  96 #ifdef  __cplusplus
  97 }
  98 #endif
  99 
 100 #endif  /* _SYS_MUTEX_H */