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Viewing changes to kernel/generic/include/synch/rwlock.h

  • Committer: Martin Decky
  • Date: 2009-08-04 11:19:19 UTC
  • Revision ID: martin@uranus.dsrg.hide.ms.mff.cuni.cz-20090804111919-evyclddlr3v5lhmp
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kernel/generic/include/synch/rwlock.h
 
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/*
 
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 * Copyright (c) 2001-2004 Jakub Jermar
 
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 * All rights reserved.
 
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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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 *
 
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 * - 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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 * - 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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 * - The name of the author may not be used to endorse or promote products
 
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 *   derived from this software without specific prior written permission.
 
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 *
 
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
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 */
 
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/** @addtogroup sync
 
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 * @{
 
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 */
 
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/** @file
 
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 */
 
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#ifndef KERN_RWLOCK_H_
 
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#define KERN_RWLOCK_H_
 
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#include <arch/types.h>
 
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#include <synch/mutex.h>
 
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#include <synch/synch.h>
 
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#include <synch/spinlock.h>
 
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typedef enum {
 
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        RWLOCK_NONE,
 
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        RWLOCK_READER,
 
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        RWLOCK_WRITER
 
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} rwlock_type_t;
 
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typedef struct {
 
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        SPINLOCK_DECLARE(lock);
 
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        /**
 
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         * Mutex for writers, readers can bypass it if readers_in is positive.
 
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         */
 
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        mutex_t exclusive;
 
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        /** Number of readers in critical section. */
 
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        size_t readers_in;
 
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} rwlock_t;
 
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#define rwlock_write_lock(rwl) \
 
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        _rwlock_write_lock_timeout((rwl), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE)
 
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#define rwlock_read_lock(rwl) \
 
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        _rwlock_read_lock_timeout((rwl), SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE)
 
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#define rwlock_write_trylock(rwl) \
 
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        _rwlock_write_lock_timeout((rwl), SYNCH_NO_TIMEOUT, \
 
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            SYNCH_FLAGS_NON_BLOCKING)
 
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#define rwlock_read_trylock(rwl) \
 
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        _rwlock_read_lock_timeout((rwl), SYNCH_NO_TIMEOUT, \
 
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            SYNCH_FLAGS_NON_BLOCKING)
 
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#define rwlock_write_lock_timeout(rwl, usec) \
 
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        _rwlock_write_lock_timeout((rwl), (usec), SYNCH_FLAGS_NONE)
 
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#define rwlock_read_lock_timeout(rwl, usec) \
 
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        _rwlock_read_lock_timeout((rwl), (usec), SYNCH_FLAGS_NONE)
 
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extern void rwlock_initialize(rwlock_t *rwl);
 
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extern void rwlock_read_unlock(rwlock_t *rwl);
 
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extern void rwlock_write_unlock(rwlock_t *rwl);
 
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extern int _rwlock_read_lock_timeout(rwlock_t *rwl, uint32_t usec, int flags);
 
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extern int _rwlock_write_lock_timeout(rwlock_t *rwl, uint32_t usec, int flags);
 
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#endif
 
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/** @}
 
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 */