Make tsleep/wakeup MP SAFE part 1/2.
[dragonfly.git] / sys / sys / spinlock2.h
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1/*
2 * Copyright (c) 2005 Jeffrey M. Hsu. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Jeffrey M. Hsu.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of The DragonFly Project nor the names of its
16 * contributors may be used to endorse or promote products derived
17 * from this software without specific, prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
25 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
27 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
29 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $DragonFly: src/sys/sys/spinlock2.h,v 1.1 2005/09/16 21:50:13 dillon Exp $
33 */
34
35#ifndef _SYS_SPINLOCK2_H_
36#define _SYS_SPINLOCK2_H_
37
38#include <sys/thread2.h>
39#include <machine/atomic.h>
40#include <machine/cpufunc.h>
41
42#ifdef SMP
43
44static __inline boolean_t
45spin_trylock(struct spinlock *mtx)
46{
47 if (atomic_swap_int(&mtx->lock, 1) == 0)
48 return (TRUE);
49 return (FALSE);
50}
51
52extern void spin_lock_contested(struct spinlock *mtx);
53
54static __inline void
55spin_lock(struct spinlock *mtx)
56{
57 if (atomic_swap_int(&mtx->lock, 1) != 0)
58 spin_lock_contested(mtx); /* slow path */
59}
60
61static __inline void
62spin_unlock(struct spinlock *mtx)
63{
64 cpu_sfence();
65 mtx->lock = 0; /* non-bus-locked lock release */
66}
67
68static __inline boolean_t
69spin_is_locked(struct spinlock *mtx)
70{
71 return (mtx->lock);
72}
73
74static __inline void
75spin_init(struct spinlock *mtx)
76{
77 mtx->lock = 0;
78}
79
80#else /* SMP */
81
82static __inline boolean_t
83spin_trylock(struct spinlock *mtx)
84{
85 return (TRUE);
86}
87
88static __inline boolean_t
89spin_is_locked(struct spinlock *mtx)
90{
91 return (FALSE);
92}
93
94static __inline void spin_lock(struct spinlock *mtx) { }
95static __inline void spin_unlock(struct spinlock *mtx) { }
96static __inline void spin_init(struct spinlock *mtx) { }
97
98#endif /* SMP */
99
100static __inline void
101spin_lock_crit(struct spinlock *mtx)
102{
103 crit_enter();
104 spin_lock(mtx);
105}
106
107static __inline void
108spin_unlock_crit(struct spinlock *mtx)
109{
110 spin_unlock(mtx);
111 crit_exit();
112}
113
114#endif
115