81 lines
2.9 KiB
C
81 lines
2.9 KiB
C
/*
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* Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
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* The President and Fellows of Harvard College.
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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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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef _WCHAN_H_
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#define _WCHAN_H_
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/*
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* Wait channel.
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*/
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struct spinlock; /* in spinlock.h */
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struct wchan; /* Opaque */
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/*
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* Create a wait channel. Use NAME as a symbolic name for the channel.
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* NAME should be a string constant; if not, the caller is responsible
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* for freeing it after the wchan is destroyed.
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*/
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struct wchan *wchan_create(const char *name);
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/*
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* Destroy a wait channel. Must be empty and unlocked.
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*/
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void wchan_destroy(struct wchan *wc);
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/*
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* Return nonzero if there are no threads sleeping on the channel.
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* This is meant to be used only for diagnostic purposes.
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*/
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bool wchan_isempty(struct wchan *wc, struct spinlock *lk);
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/*
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* Go to sleep on a wait channel. The current thread is suspended
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* until awakened by someone else, at which point this function
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* returns.
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*
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* The associated lock must be locked. It will be unlocked while
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* sleeping, and relocked upon return.
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*/
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void wchan_sleep(struct wchan *wc, struct spinlock *lk);
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/*
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* Wake up one thread, or all threads, sleeping on a wait channel.
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* The associated spinlock should be locked.
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*
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* The current implementation is FIFO but this is not promised by the
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* interface.
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*/
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void wchan_wakeone(struct wchan *wc, struct spinlock *lk);
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void wchan_wakeall(struct wchan *wc, struct spinlock *lk);
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#endif /* _WCHAN_H_ */
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