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Diffstat (limited to 'sys/sys/rangelock.h')
| -rw-r--r-- | sys/sys/rangelock.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/sys/sys/rangelock.h b/sys/sys/rangelock.h new file mode 100644 index 0000000..fb0d252 --- /dev/null +++ b/sys/sys/rangelock.h @@ -0,0 +1,78 @@ +/*- + * Copyright (c) 2009 Konstantin Belousov <kib@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice unmodified, this list of conditions, and the following + * disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#ifndef _SYS_RANGELOCK_H +#define _SYS_RANGELOCK_H + +#include <sys/queue.h> + +#define RL_LOCK_READ 0x0001 +#define RL_LOCK_WRITE 0x0002 +#define RL_LOCK_TYPE_MASK 0x0003 +#define RL_LOCK_GRANTED 0x0004 + +struct rl_q_entry; + +/* + * The structure representing the range lock. Caller may request + * read or write access to the range of bytes. Access is granted if + * all existing lock owners are compatible with the request. Two lock + * owners are compatible if their ranges do not overlap, or both + * owners are for read. + * + * Access to the structure itself is synchronized with the externally + * supplied mutex. + * + * rl_waiters is the queue of lock requests in the order of arrival. + * rl_currdep is the first lock request that cannot be granted now due + * to the preceding requests conflicting with it. + */ +struct rangelock { + TAILQ_HEAD(, rl_q_entry) rl_waiters; + struct rl_q_entry *rl_currdep; +}; + +#ifdef _KERNEL + +struct mtx; + +void rangelock_init(struct rangelock *lock); +void rangelock_destroy(struct rangelock *lock); +void rangelock_unlock(struct rangelock *lock, void *cookie, + struct mtx *ilk); +void *rangelock_unlock_range(struct rangelock *lock, void *cookie, + off_t start, off_t end, struct mtx *ilk); +void *rangelock_rlock(struct rangelock *lock, off_t start, off_t end, + struct mtx *ilk); +void *rangelock_wlock(struct rangelock *lock, off_t start, off_t end, + struct mtx *ilk); +void rlqentry_free(struct rl_q_entry *rlqe); + +#endif /* _KERNEL */ + +#endif /* _SYS_RANGELOCK_H */ |
