FreeBSD/Linux Kernel Cross Reference
sys/sys/sx.h
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: src/sys/sys/sx.h,v 1.20.2.1 2005/01/31 23:26:57 imp Exp $
28 */
29
30 #ifndef _SYS_SX_H_
31 #define _SYS_SX_H_
32
33 #include <sys/queue.h>
34 #include <sys/_lock.h>
35 #include <sys/condvar.h> /* XXX */
36
37 struct sx {
38 struct lock_object sx_object; /* Common lock properties. */
39 struct mtx *sx_lock; /* General protection lock. */
40 int sx_cnt; /* -1: xlock, > 0: slock count. */
41 struct cv sx_shrd_cv; /* slock waiters. */
42 int sx_shrd_wcnt; /* Number of slock waiters. */
43 struct cv sx_excl_cv; /* xlock waiters. */
44 int sx_excl_wcnt; /* Number of xlock waiters. */
45 struct thread *sx_xholder; /* Thread presently holding xlock. */
46 };
47
48 #ifdef _KERNEL
49 void sx_sysinit(void *arg);
50 void sx_init(struct sx *sx, const char *description);
51 void sx_destroy(struct sx *sx);
52 void _sx_slock(struct sx *sx, const char *file, int line);
53 void _sx_xlock(struct sx *sx, const char *file, int line);
54 int _sx_try_slock(struct sx *sx, const char *file, int line);
55 int _sx_try_xlock(struct sx *sx, const char *file, int line);
56 void _sx_sunlock(struct sx *sx, const char *file, int line);
57 void _sx_xunlock(struct sx *sx, const char *file, int line);
58 int _sx_try_upgrade(struct sx *sx, const char *file, int line);
59 void _sx_downgrade(struct sx *sx, const char *file, int line);
60 #ifdef INVARIANT_SUPPORT
61 void _sx_assert(struct sx *sx, int what, const char *file, int line);
62 #endif
63
64 struct sx_args {
65 struct sx *sa_sx;
66 const char *sa_desc;
67 };
68
69 #define SX_SYSINIT(name, sxa, desc) \
70 static struct sx_args name##_args = { \
71 sxa, \
72 desc \
73 }; \
74 SYSINIT(name##_sx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
75 sx_sysinit, &name##_args)
76
77 #define sx_slock(sx) _sx_slock((sx), LOCK_FILE, LOCK_LINE)
78 #define sx_xlock(sx) _sx_xlock((sx), LOCK_FILE, LOCK_LINE)
79 #define sx_try_slock(sx) _sx_try_slock((sx), LOCK_FILE, LOCK_LINE)
80 #define sx_try_xlock(sx) _sx_try_xlock((sx), LOCK_FILE, LOCK_LINE)
81 #define sx_sunlock(sx) _sx_sunlock((sx), LOCK_FILE, LOCK_LINE)
82 #define sx_xunlock(sx) _sx_xunlock((sx), LOCK_FILE, LOCK_LINE)
83 #define sx_try_upgrade(sx) _sx_try_upgrade((sx), LOCK_FILE, LOCK_LINE)
84 #define sx_downgrade(sx) _sx_downgrade((sx), LOCK_FILE, LOCK_LINE)
85 #define sx_unlock(sx) \
86 do { \
87 if ((sx)->sx_cnt < 0) \
88 sx_xunlock(sx); \
89 else \
90 sx_sunlock(sx); \
91 } while (0)
92
93 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
94 #define SX_LOCKED LA_LOCKED
95 #define SX_SLOCKED LA_SLOCKED
96 #define SX_XLOCKED LA_XLOCKED
97 #define SX_UNLOCKED LA_UNLOCKED
98 #endif
99
100 #ifdef INVARIANTS
101 #define sx_assert(sx, what) _sx_assert((sx), (what), LOCK_FILE, LOCK_LINE)
102 #else
103 #define sx_assert(sx, what)
104 #endif
105
106 #endif /* _KERNEL */
107
108 #endif /* !_SYS_SX_H_ */
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