freebsd-dev/lib/libkse/sys/lock.h
Daniel Eischen e4c2ac1637 Sorry folks; I accidentally committed a patch from what I was working
on a couple of days ago.  This should be the most recent changes.

Noticed by:	davidxu
2003-04-18 07:09:43 +00:00

90 lines
3.4 KiB
C

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