FreeBSD/Linux Kernel Cross Reference
sys/sys/umtx.h
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 * $FreeBSD$
27 *
28 */
29
30 #ifndef _SYS_UMTX_H_
31 #define _SYS_UMTX_H_
32
33 #include <sys/limits.h>
34
35 /*
36 * See pthread_*
37 */
38
39 #define UMTX_UNOWNED 0x0
40 #define UMTX_CONTESTED LONG_MIN
41
42 struct umtx {
43 void *u_owner; /* Owner of the mutex. */
44 };
45
46 /* op code for _umtx_op */
47 #define UMTX_OP_LOCK 0
48 #define UMTX_OP_UNLOCK 1
49 #define UMTX_OP_WAIT 2
50 #define UMTX_OP_WAKE 3
51
52 #ifndef _KERNEL
53
54 /*
55 * System calls for acquiring and releasing contested mutexes.
56 */
57 /* deprecated becaues it can only use thread id */
58 int _umtx_lock(struct umtx *mtx);
59 /* deprecated becaues it can only use thread id */
60 int _umtx_unlock(struct umtx *mtx);
61 int _umtx_op(struct umtx *umtx, int op, long id, void *uaddr, void *uaddr2);
62
63 /*
64 * Standard api. Try uncontested acquire/release and asks the
65 * kernel to resolve failures.
66 */
67 static __inline void
68 umtx_init(struct umtx *umtx)
69 {
70 umtx->u_owner = UMTX_UNOWNED;
71 }
72
73 static __inline long
74 umtx_owner(struct umtx *umtx)
75 {
76 return ((long)umtx->u_owner & ~LONG_MIN);
77 }
78
79 static __inline int
80 umtx_lock(struct umtx *umtx, long id)
81 {
82 if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
83 (void *)id) == 0)
84 if (_umtx_lock(umtx) == -1)
85 return (errno);
86 return (0);
87 }
88
89 static __inline int
90 umtx_trylock(struct umtx *umtx, long id)
91 {
92 if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
93 (void *)id) == 0)
94 return (EBUSY);
95 return (0);
96 }
97
98 static __inline int
99 umtx_timedlock(struct umtx *umtx, long id, const struct timespec *timeout)
100 {
101 if (atomic_cmpset_acq_ptr(&umtx->u_owner, (void *)UMTX_UNOWNED,
102 (void *)id) == 0)
103 if (_umtx_op(umtx, UMTX_OP_LOCK, id, 0, (void *)timeout) == -1)
104 return (errno);
105 return (0);
106 }
107
108 static __inline int
109 umtx_unlock(struct umtx *umtx, long id)
110 {
111 if (atomic_cmpset_rel_ptr(&umtx->u_owner, (void *)id,
112 (void *)UMTX_UNOWNED) == 0)
113 if (_umtx_unlock(umtx) == -1)
114 return (errno);
115 return (0);
116 }
117
118 static __inline int
119 umtx_wait(struct umtx *umtx, long id, const struct timespec *timeout)
120 {
121 if (_umtx_op(umtx, UMTX_OP_WAIT, id, 0, (void *)timeout) == -1)
122 return (errno);
123 return (0);
124 }
125
126 /* Wake threads waiting on a user address. */
127 static __inline int
128 umtx_wake(struct umtx *umtx, int nr_wakeup)
129 {
130 if (_umtx_op(umtx, UMTX_OP_WAKE, nr_wakeup, 0, 0) == -1)
131 return (errno);
132 return (0);
133 }
134 #else
135
136 struct umtx_q *umtxq_alloc(void);
137 void umtxq_free(struct umtx_q *);
138 struct thread;
139 int kern_umtx_wake(struct thread *td, void *uaddr, int n_wake);
140
141 #endif /* !_KERNEL */
142 #endif /* !_SYS_UMTX_H_ */
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