sx.h revision 85412 
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 85412 2001-10-24 14:18:33Z jhb $
28 */
29
30#ifndef	_SYS_SX_H_
31#define	_SYS_SX_H_
32
33#ifndef	LOCORE
34#include <sys/_lock.h>
35#include <sys/_mutex.h>
36#include <sys/condvar.h>	/* XXX */
37
38struct sx {
39	struct lock_object sx_object;	/* Common lock properties. */
40	struct mtx	sx_lock;	/* General protection lock. */
41	int		sx_cnt;		/* -1: xlock, > 0: slock count. */
42	struct cv	sx_shrd_cv;	/* slock waiters. */
43	int		sx_shrd_wcnt;	/* Number of slock waiters. */
44	struct cv	sx_excl_cv;	/* xlock waiters. */
45	int		sx_excl_wcnt;	/* Number of xlock waiters. */
46	struct thread	*sx_xholder;	/* Thread presently holding xlock. */
47};
48
49#ifdef _KERNEL
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
64#define	sx_slock(sx)		_sx_slock((sx), LOCK_FILE, LOCK_LINE)
65#define	sx_xlock(sx)		_sx_xlock((sx), LOCK_FILE, LOCK_LINE)
66#define	sx_try_slock(sx)	_sx_try_slock((sx), LOCK_FILE, LOCK_LINE)
67#define	sx_try_xlock(sx)	_sx_try_xlock((sx), LOCK_FILE, LOCK_LINE)
68#define	sx_sunlock(sx)		_sx_sunlock((sx), LOCK_FILE, LOCK_LINE)
69#define	sx_xunlock(sx)		_sx_xunlock((sx), LOCK_FILE, LOCK_LINE)
70#define	sx_try_upgrade(sx)	_sx_try_upgrade((sx), LOCK_FILE, LOCK_LINE)
71#define	sx_downgrade(sx)	_sx_downgrade((sx), LOCK_FILE, LOCK_LINE)
72
73#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
74#define	SX_LOCKED		LA_LOCKED
75#define	SX_SLOCKED		LA_SLOCKED
76#define	SX_XLOCKED		LA_XLOCKED
77#endif	/* INVARIANTS || INVARIANT_SUPPORT */
78
79#ifdef INVARIANTS
80#define	sx_assert(sx, what)	_sx_assert((sx), (what), LOCK_FILE, LOCK_LINE)
81#else	/* INVARIANTS */
82#define	sx_assert(sx, what)
83#endif	/* INVARIANTS */
84
85#endif	/* _KERNEL */
86#endif	/* !LOCORE */
87#endif	/* _SYS_SX_H_ */
88