2 * Copyright (c) 2009 Konstantin Belousov <kib@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
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.
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.
29 #ifndef _SYS_RANGELOCK_H
30 #define _SYS_RANGELOCK_H
32 #include <sys/queue.h>
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
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.
48 * Access to the structure itself is synchronized with the externally
51 * rl_waiters is the queue of lock requests in the order of arrival.
52 * rl_currdep is the first lock request that cannot be granted now due
53 * to the preceding requests conflicting with it.
56 TAILQ_HEAD(, rl_q_entry) rl_waiters;
57 struct rl_q_entry *rl_currdep;
64 void rangelock_init(struct rangelock *lock);
65 void rangelock_destroy(struct rangelock *lock);
66 void rangelock_unlock(struct rangelock *lock, void *cookie,
68 void *rangelock_unlock_range(struct rangelock *lock, void *cookie,
69 off_t start, off_t end, struct mtx *ilk);
70 void *rangelock_rlock(struct rangelock *lock, off_t start, off_t end,
72 void *rangelock_wlock(struct rangelock *lock, off_t start, off_t end,
74 void rlqentry_free(struct rl_q_entry *rlqe);
78 #endif /* _SYS_RANGELOCK_H */