FreeBSD/Linux Kernel Cross Reference
sys/sys/rangelock.h
1 /*-
2 * Copyright (c) 2009 Konstantin Belousov <kib@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 #ifndef _SYS_RANGELOCK_H
30 #define _SYS_RANGELOCK_H
31
32 #include <sys/queue.h>
33
34 #define RL_LOCK_READ 0x0001
35 #define RL_LOCK_WRITE 0x0002
36 #define RL_LOCK_TYPE_MASK 0x0003
37 #define RL_LOCK_GRANTED 0x0004
38
39 struct rl_q_entry;
40
41 /*
42 * The structure representing the range lock. Caller may request
43 * read or write access to the range of bytes. Access is granted if
44 * all existing lock owners are compatible with the request. Two lock
45 * owners are compatible if their ranges do not overlap, or both
46 * owners are for read.
47 *
48 * Access to the structure itself is synchronized with the externally
49 * supplied mutex.
50 *
51 * rl_waiters is the queue containing in order (a) granted write lock
52 * requests, (b) granted read lock requests, and (c) in order of arrival,
53 * lock requests which cannot be granted yet.
54 *
55 * rl_currdep is the first lock request that cannot be granted now due
56 * to the preceding requests conflicting with it (i.e., it points to
57 * position (c) in the list above).
58 */
59 struct rangelock {
60 TAILQ_HEAD(, rl_q_entry) rl_waiters;
61 struct rl_q_entry *rl_currdep;
62 };
63
64 #ifdef _KERNEL
65
66 struct mtx;
67
68 void rangelock_init(struct rangelock *lock);
69 void rangelock_destroy(struct rangelock *lock);
70 void rangelock_unlock(struct rangelock *lock, void *cookie,
71 struct mtx *ilk);
72 void *rangelock_unlock_range(struct rangelock *lock, void *cookie,
73 off_t start, off_t end, struct mtx *ilk);
74 void *rangelock_rlock(struct rangelock *lock, off_t start, off_t end,
75 struct mtx *ilk);
76 void *rangelock_wlock(struct rangelock *lock, off_t start, off_t end,
77 struct mtx *ilk);
78 void rlqentry_free(struct rl_q_entry *rlqe);
79 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
80 void _rangelock_cookie_assert(void *cookie, int what, const char *file,
81 int line);
82 #endif
83
84 #ifdef INVARIANTS
85 #define rangelock_cookie_assert_(cookie, what, file, line) \
86 _rangelock_cookie_assert((cookie), (what), (file), (line))
87 #else
88 #define rangelock_cookie_assert_(cookie, what, file, line) (void)0
89 #endif
90
91 #define rangelock_cookie_assert(cookie, what) \
92 rangelock_cookie_assert_((cookie), (what), __FILE__, __LINE__)
93
94 /*
95 * Assertion flags.
96 */
97 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
98 #define RCA_LOCKED 0x0001
99 #define RCA_RLOCKED 0x0002
100 #define RCA_WLOCKED 0x0004
101 #endif
102
103 #endif /* _KERNEL */
104
105 #endif /* _SYS_RANGELOCK_H */
Cache object: fde10b893aeb55ca3743f7d5782f3938
|