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 39struct 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 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. 54 */ 55struct rangelock { 56 TAILQ_HEAD(, rl_q_entry) rl_waiters; 57 struct rl_q_entry *rl_currdep; 58}; 59 60#ifdef _KERNEL 61 62struct mtx; 63 64void rangelock_init(struct rangelock *lock); 65void rangelock_destroy(struct rangelock *lock); 66void rangelock_unlock(struct rangelock *lock, void *cookie, 67 struct mtx *ilk); 68void *rangelock_unlock_range(struct rangelock *lock, void *cookie, 69 off_t start, off_t end, struct mtx *ilk); 70void *rangelock_rlock(struct rangelock *lock, off_t start, off_t end, 71 struct mtx *ilk); 72void *rangelock_wlock(struct rangelock *lock, off_t start, off_t end, 73 struct mtx *ilk); 74void rlqentry_free(struct rl_q_entry *rlqe); 75 76#endif /* _KERNEL */ 77 78#endif /* _SYS_RANGELOCK_H */ 79