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95 lines
2.5 KiB
C
95 lines
2.5 KiB
C
/* $NetBSD: rwsem.h,v 1.1 2014/07/16 20:59:58 riastradh Exp $ */
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/*-
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* Copyright (c) 2014 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Taylor R. Campbell.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* These are not really semaphores; they are just reader/writer sleep
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* locks, whereas what Linux calls an rwlock is a reader/writer spin
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* lock.
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*
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* Notes on porting:
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*
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* - Linux does not have destroy_rwsem. You must add it yourself in
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* the appropriate place.
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*/
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#ifndef _LINUX_RWSEM_H_
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#define _LINUX_RWSEM_H_
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#include <sys/mutex.h>
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struct rw_semaphore {
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krwlock_t rws_lock;
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};
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static inline void
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init_rwsem(struct rw_semaphore *rwsem)
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{
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rw_init(&rwsem->rws_lock);
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}
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static inline void
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destroy_rwsem(struct rw_semaphore *rwsem)
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{
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rw_destroy(&rwsem->rws_lock);
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}
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static inline void
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down_read(struct rw_semaphore *rwsem)
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{
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rw_enter(&rwsem->rws_lock, RW_READER);
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}
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static inline void
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down_write(struct rw_semaphore *rwsem)
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{
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rw_enter(&rwsem->rws_lock, RW_WRITER);
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}
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static inline void
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up_read(struct rw_semaphore *rwsem)
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{
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rw_exit(&rwsem->rws_lock);
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}
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static inline void
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up_write(struct rw_semaphore *rwsem)
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{
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rw_exit(&rwsem->rws_lock);
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}
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#endif /* _LINUX_RWSEM_H_ */
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