lock.h revision 173967 
1/*
2 * Copyright (c) 2001, 2003 Daniel Eischen <deischen@freebsd.org>.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/lib/libkse/sys/lock.h 173967 2007-11-27 03:16:44Z jasone $
27 */
28
29#ifndef _LOCK_H_
30#define	_LOCK_H_
31
32struct lockreq;
33struct lockuser;
34struct lock;
35
36enum lock_type {
37	LCK_DEFAULT	= 0x0000,	/* default is FIFO spin locks */
38	LCK_PRIORITY	= 0x0001,
39	LCK_ADAPTIVE 	= 0x0002	/* call user-supplied handlers */
40};
41
42typedef void lock_handler_t(struct lock *, struct lockuser *);
43
44struct lock {
45	struct lockreq	*l_head;
46	struct lockreq	*l_tail;	/* only used for priority locks */
47	enum lock_type	l_type;
48	lock_handler_t	*l_wait;	/* only used for adaptive locks */
49	lock_handler_t	*l_wakeup;	/* only used for adaptive locks */
50};
51
52/* Try to make this >= CACHELINESIZE */
53struct lockreq {
54	struct lockuser	*lr_watcher;	/* only used for priority locks */
55	struct lockuser	*lr_owner;	/* only used for priority locks */
56	volatile int	lr_locked;	/* lock granted = 0, busy otherwise */
57	volatile int	lr_active;	/* non-zero if the lock is last lock for thread */
58};
59
60struct lockuser {
61	struct lockreq	*lu_myreq;	/* request to give up/trade */
62	struct lockreq	*lu_watchreq;	/* watch this request */
63	int		lu_priority;	/* only used for priority locks */
64	void		*lu_private1;	/* private{1,2} are initialized to */
65	void		*lu_private2;	/*   NULL and can be used by caller */
66#define	lu_private	lu_private1
67};
68
69#define	_LCK_INITIALIZER(lck_req)	{ &lck_req, NULL, LCK_DEFAULT, \
70					  NULL, NULL }
71#define	_LCK_REQUEST_INITIALIZER	{ 0, NULL, NULL, 0 }
72
73#define	_LCK_BUSY(lu)			((lu)->lu_watchreq->lr_locked != 0)
74#define	_LCK_ACTIVE(lu)			((lu)->lu_watchreq->lr_active != 0)
75#define	_LCK_GRANTED(lu)		((lu)->lu_watchreq->lr_locked == 3)
76
77#define	_LCK_SET_PRIVATE(lu, p)		(lu)->lu_private = (void *)(p)
78#define	_LCK_GET_PRIVATE(lu)		(lu)->lu_private
79#define	_LCK_SET_PRIVATE2(lu, p)	(lu)->lu_private2 = (void *)(p)
80#define	_LCK_GET_PRIVATE2(lu)		(lu)->lu_private2
81
82void	_lock_acquire(struct lock *, struct lockuser *, int);
83void	_lock_destroy(struct lock *);
84void	_lock_grant(struct lock *, struct lockuser *);
85int	_lock_init(struct lock *, enum lock_type,
86	    lock_handler_t *, lock_handler_t *, void *(size_t, size_t));
87int	_lock_reinit(struct lock *, enum lock_type,
88	    lock_handler_t *, lock_handler_t *);
89void	_lock_release(struct lock *, struct lockuser *);
90int	_lockuser_init(struct lockuser *lu, void *priv);
91void	_lockuser_destroy(struct lockuser *lu);
92int	_lockuser_reinit(struct lockuser *lu, void *priv);
93void	_lockuser_setactive(struct lockuser *lu, int active);
94
95#endif
96