mutex.h revision 6138:1b7a278742d4 
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 2008 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#ifndef _SYS_MUTEX_H
27#define	_SYS_MUTEX_H
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#ifndef	_ASM
32#include <sys/types.h>
33#endif
34
35#ifdef	__cplusplus
36extern "C" {
37#endif
38
39#ifndef	_ASM
40
41/*
42 * Public interface to mutual exclusion locks.  See mutex(9F) for details.
43 *
44 * The basic mutex type is MUTEX_ADAPTIVE, which is expected to be used
45 * in almost all of the kernel.  MUTEX_SPIN provides interrupt blocking
46 * and must be used in interrupt handlers above LOCK_LEVEL.  The iblock
47 * cookie argument to mutex_init() encodes the interrupt level to block.
48 * The iblock cookie must be NULL for adaptive locks.
49 *
50 * MUTEX_DEFAULT is the type usually specified (except in drivers) to
51 * mutex_init().  It is identical to MUTEX_ADAPTIVE.
52 *
53 * MUTEX_DRIVER is always used by drivers.  mutex_init() converts this to
54 * either MUTEX_ADAPTIVE or MUTEX_SPIN depending on the iblock cookie.
55 *
56 * Mutex statistics can be gathered on the fly, without rebooting or
57 * recompiling the kernel, via the lockstat driver (lockstat(7D)).
58 */
59typedef enum {
60	MUTEX_ADAPTIVE = 0,	/* spin if owner is running, otherwise block */
61	MUTEX_SPIN = 1,		/* block interrupts and spin */
62	MUTEX_DRIVER = 4,	/* driver (DDI) mutex */
63	MUTEX_DEFAULT = 6	/* kernel default mutex */
64} kmutex_type_t;
65
66typedef struct mutex {
67#ifdef _LP64
68	void	*_opaque[1];
69#else
70	void	*_opaque[2];
71#endif
72} kmutex_t;
73
74#ifdef _KERNEL
75
76#define	MUTEX_HELD(x)		(mutex_owned(x))
77#define	MUTEX_NOT_HELD(x)	(!mutex_owned(x) || panicstr)
78
79extern	void	mutex_init(kmutex_t *, char *, kmutex_type_t, void *);
80extern	void	mutex_destroy(kmutex_t *);
81extern	void	mutex_enter(kmutex_t *);
82extern	int	mutex_tryenter(kmutex_t *);
83extern	void	mutex_exit(kmutex_t *);
84extern	int	mutex_owned(kmutex_t *);
85extern	struct _kthread *mutex_owner(kmutex_t *);
86
87extern  ushort_t mutex_backoff_base;
88extern  uint_t mutex_backoff_cap;
89extern  ushort_t mutex_cap_factor;
90extern  uchar_t mutex_backoff_shift;
91extern  void (*mutex_lock_delay)(uint_t);
92extern  uint_t (*mutex_lock_backoff)(uint_t);
93extern  void (*mutex_delay)(void);
94extern  void mutex_delay_default(void);
95extern  void mutex_sync(void);
96
97extern	void default_lock_delay(uint_t);
98extern	uint_t default_lock_backoff(uint_t);
99
100#endif	/* _KERNEL */
101
102#endif	/* _ASM */
103
104#ifdef	__cplusplus
105}
106#endif
107
108#endif	/* _SYS_MUTEX_H */
109