umtx.h revision 139013 
1/*
2 * Copyright (c) 2002, Jeffrey Roberson <jeff@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 unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, 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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/sys/umtx.h 139013 2004-12-18 12:52:44Z davidxu $
27 *
28 */
29
30#ifndef _SYS_UMTX_H_
31#define	_SYS_UMTX_H_
32
33/*
34 * See pthread_*
35 */
36
37#define	UMTX_UNOWNED	0x0
38
39struct umtx {
40	void	*u_owner;	/* Owner of the mutex. */
41};
42
43/* op code for _umtx_op */
44#define UMTX_OP_LOCK		0
45#define UMTX_OP_UNLOCK		1
46#define UMTX_OP_UNLOCK_AND_WAIT	2
47#define UMTX_OP_WAKE		3
48
49#ifndef _KERNEL
50
51/*
52 * System calls for acquiring and releasing contested mutexes.
53 */
54/* deprecated becaues it can only use thread id */
55int _umtx_lock(struct umtx *mtx);
56/* deprecated becaues it can only use thread id */
57int _umtx_unlock(struct umtx *mtx);
58int _umtx_op(struct umtx *umtx, int op, long id, void *uaddr,
59	struct timespec *abstime);
60
61/*
62 * Standard api.  Try uncontested acquire/release and asks the
63 * kernel to resolve failures.
64 */
65static __inline int
66umtx_lock(struct umtx *umtx, long id)
67{
68	if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
69	    (void *)id) == 0)
70		if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0, 0) == -1)
71			return (errno);
72	return (0);
73}
74
75static __inline int
76umtx_trylock(struct umtx *umtx, long id)
77{
78	if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
79	    (void *)id) == 0)
80		return (EBUSY);
81	return (0);
82}
83
84static __inline int
85umtx_timedlock(struct umtx *umtx, long id, struct timespec *abstime)
86{
87	if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
88	    (void *)id) == 0)
89		if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0, abstime) == -1)
90			return (errno);
91	return (0);
92}
93
94static __inline int
95umtx_unlock(struct umtx *umtx, long id)
96{
97	if (atomic_cmpset_rel_ptr(&umtx->u_owner, (void *)id,
98	    (void *)UMTX_UNOWNED) == 0)
99		if (_umtx_op(umtx, UMTX_OP_UNLOCK, id, 0, 0) == -1)
100			return (errno);
101	return (0);
102}
103
104/* Unlock umtx and wait on a user address. */
105
106static __inline int
107umtx_wait(struct umtx *umtx, long id, void *uaddr)
108{
109	if (_umtx_op(umtx, UMTX_OP_UNLOCK_AND_WAIT, id, uaddr, 0) == -1)
110		return (errno);
111	return (0);
112}
113
114static __inline int
115umtx_timedwait(struct umtx *umtx, long id, void *uaddr,
116	struct timespec *abstime)
117{
118	if (_umtx_op(umtx, UMTX_OP_UNLOCK_AND_WAIT, id, uaddr, abstime) == -1)
119		return (errno);
120	return (0);
121}
122
123/* Wake threads waiting on a user address. */
124static __inline int
125umtx_wake(void *uaddr, int broadcast)
126{
127	if (_umtx_op(0, UMTX_OP_WAKE, broadcast, uaddr, 0) == -1)
128		return (errno);
129	return (0);
130}
131
132#endif /* !_KERNEL */
133#endif /* !_SYS_UMTX_H_ */
134