90 lines
3.4 KiB
C
90 lines
3.4 KiB
C
/*
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* Copyright (c) 2001, 2003 Daniel Eischen <deischen@freebsd.org>.
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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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* 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 AUTHORS 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 AUTHOR 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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* $FreeBSD$
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*/
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#ifndef _LOCK_H_
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#define _LOCK_H_
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struct lockreq;
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struct lockuser;
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struct lock;
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enum lock_type {
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LCK_DEFAULT = 0x0000, /* default is FIFO spin locks */
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LCK_PRIORITY = 0x0001,
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LCK_ADAPTIVE = 0x0002 /* call user-supplied handlers */
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};
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typedef void lock_handler_t(struct lock *, struct lockuser *);
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struct lock {
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struct lockreq *l_head;
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struct lockreq *l_tail; /* only used for priority locks */
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enum lock_type l_type;
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lock_handler_t *l_wait; /* only used for adaptive locks */
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lock_handler_t *l_wakeup; /* only used for adaptive locks */
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};
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/* Try to make this >= CACHELINESIZE */
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struct lockreq {
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volatile long lr_locked; /* lock granted = 0, busy otherwise */
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struct lockuser *lr_watcher; /* only used for priority locks */
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struct lockuser *lr_owner; /* only used for priority locks */
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long lr_waiting; /* non-zero when wakeup needed */
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};
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struct lockuser {
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struct lockreq *lu_myreq; /* request to give up/trade */
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struct lockreq *lu_watchreq; /* watch this request */
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int lu_priority; /* only used for priority locks */
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void *lu_private1; /* private{1,2} are initialized to */
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void *lu_private2; /* NULL and can be used by caller */
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#define lu_private lu_private1
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};
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#define _LCK_INITIALIZER(lck_req) { &lck_req, NULL, LCK_DEFAULT, \
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NULL, NULL }
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#define _LCK_REQUEST_INITIALIZER { 0, NULL, NULL, 0 }
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#define _LCK_BUSY(lu) ((lu)->lu_watchreq->lr_locked != 0)
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#define _LCK_GRANTED(lu) ((lu)->lu_watchreq->lr_locked == 0)
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#define _LCK_SET_PRIVATE(lu, p) (lu)->lu_private = (void *)(p)
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#define _LCK_GET_PRIVATE(lu) (lu)->lu_private
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#define _LCK_SET_PRIVATE2(lu, p) (lu)->lu_private2 = (void *)(p)
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#define _LCK_GET_PRIVATE2(lu) (lu)->lu_private2
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void _lock_destroy(struct lock *);
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int _lock_init(struct lock *, enum lock_type,
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lock_handler_t *, lock_handler_t *);
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int _lockuser_init(struct lockuser *lu, void *priv);
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void _lockuser_destroy(struct lockuser *lu);
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void _lock_acquire(struct lock *, struct lockuser *, int);
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void _lock_release(struct lock *, struct lockuser *);
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#endif
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