sx.h revision 125444 
1/*
2 * Copyright (C) 2001 Jason Evans <jasone@freebsd.org>.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice(s), this list of conditions and the following disclaimer as
9 *    the first lines of this file unmodified other than the possible
10 *    addition of one or more copyright notices.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice(s), this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
25 * DAMAGE.
26 *
27 * $FreeBSD: head/sys/sys/sx.h 125444 2004-02-04 14:18:21Z bde $
28 */
29
30#ifndef	_SYS_SX_H_
31#define	_SYS_SX_H_
32
33#include <sys/queue.h>
34#include <sys/_lock.h>
35#include <sys/condvar.h>	/* XXX */
36
37struct sx {
38	struct lock_object sx_object;	/* Common lock properties. */
39	struct mtx	*sx_lock;	/* General protection lock. */
40	int		sx_cnt;		/* -1: xlock, > 0: slock count. */
41	struct cv	sx_shrd_cv;	/* slock waiters. */
42	int		sx_shrd_wcnt;	/* Number of slock waiters. */
43	struct cv	sx_excl_cv;	/* xlock waiters. */
44	int		sx_excl_wcnt;	/* Number of xlock waiters. */
45	struct thread	*sx_xholder;	/* Thread presently holding xlock. */
46};
47
48#ifdef _KERNEL
49void	sx_sysinit(void *arg);
50void	sx_init(struct sx *sx, const char *description);
51void	sx_destroy(struct sx *sx);
52void	_sx_slock(struct sx *sx, const char *file, int line);
53void	_sx_xlock(struct sx *sx, const char *file, int line);
54int	_sx_try_slock(struct sx *sx, const char *file, int line);
55int	_sx_try_xlock(struct sx *sx, const char *file, int line);
56void	_sx_sunlock(struct sx *sx, const char *file, int line);
57void	_sx_xunlock(struct sx *sx, const char *file, int line);
58int	_sx_try_upgrade(struct sx *sx, const char *file, int line);
59void	_sx_downgrade(struct sx *sx, const char *file, int line);
60#ifdef INVARIANT_SUPPORT
61void	_sx_assert(struct sx *sx, int what, const char *file, int line);
62#endif
63
64struct sx_args {
65	struct sx 	*sa_sx;
66	const char	*sa_desc;
67};
68
69#define	SX_SYSINIT(name, sxa, desc)					\
70	static struct sx_args name##_args = {				\
71		sxa,							\
72		desc							\
73	};								\
74	SYSINIT(name##_sx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
75	    sx_sysinit, &name##_args)
76
77#define	sx_slock(sx)		_sx_slock((sx), LOCK_FILE, LOCK_LINE)
78#define	sx_xlock(sx)		_sx_xlock((sx), LOCK_FILE, LOCK_LINE)
79#define	sx_try_slock(sx)	_sx_try_slock((sx), LOCK_FILE, LOCK_LINE)
80#define	sx_try_xlock(sx)	_sx_try_xlock((sx), LOCK_FILE, LOCK_LINE)
81#define	sx_sunlock(sx)		_sx_sunlock((sx), LOCK_FILE, LOCK_LINE)
82#define	sx_xunlock(sx)		_sx_xunlock((sx), LOCK_FILE, LOCK_LINE)
83#define	sx_try_upgrade(sx)	_sx_try_upgrade((sx), LOCK_FILE, LOCK_LINE)
84#define	sx_downgrade(sx)	_sx_downgrade((sx), LOCK_FILE, LOCK_LINE)
85
86#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
87#define	SX_LOCKED		LA_LOCKED
88#define	SX_SLOCKED		LA_SLOCKED
89#define	SX_XLOCKED		LA_XLOCKED
90#define	SX_UNLOCKED		LA_UNLOCKED
91#endif
92
93#ifdef INVARIANTS
94#define	sx_assert(sx, what)	_sx_assert((sx), (what), LOCK_FILE, LOCK_LINE)
95#else
96#define	sx_assert(sx, what)
97#endif
98
99#endif /* _KERNEL */
100
101#endif /* !_SYS_SX_H_ */
102