/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#ifndef _SYS_RWSTLOCK_H
#define _SYS_RWSTLOCK_H
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Alternate rwlock that is interruptible and can be released by a thread
* other than the one that acquired the lock.
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <sys/types.h>
#include <sys/ksynch.h>
#include <sys/rwlock.h>
typedef struct rwstlock {
intptr_t rwst_count;
kcondvar_t rwst_rcv;
kcondvar_t rwst_wcv;
kmutex_t rwst_lock;
} rwstlock_t;
/*
* The interfaces below are private to Sun Microsystems,
* and these might change without notice.
*/
#define RWST_TRYENTER 0x01
#define RWST_SIG 0x02
#define RWST_HELD(l) ((l)->rwst_count != 0)
#define RWST_READ_HELD(l) ((l)->rwst_count > 0)
#define RWST_WRITE_HELD(l) ((l)->rwst_count < 0)
#define RWST_WRITE_OWNER(l) \
((l)->rwst_count == (LONG_MIN | (intptr_t)curthread))
#define RWST_OWNER(l) (RWST_WRITE_HELD(l) ? \
((struct _kthread *)((l)->rwst_count & ~LONG_MIN)) : NULL)
#define RWST_READ_WANTED(l) CV_HAS_WAITERS(&(l)->rwst_rcv)
#define RWST_WRITE_WANTED(l) CV_HAS_WAITERS(&(l)->rwst_wcv)
#define RWST_WAIT(cv, lock, f) \
((f) & RWST_SIG ? cv_wait_sig(cv, lock) : (cv_wait(cv, lock), 1))
#define RWST_READ_WAIT(l, f) RWST_WAIT(&(l)->rwst_rcv, &(l)->rwst_lock, f)
#define RWST_WRITE_WAIT(l, f) RWST_WAIT(&(l)->rwst_wcv, &(l)->rwst_lock, f)
#define RWST_READ_WAKE_ALL(l) cv_broadcast(&(l)->rwst_rcv)
#define RWST_WRITE_WAKE_ONE(l) cv_signal(&(l)->rwst_wcv)
#define RWST_READ_ENTER(l) (l)->rwst_count++
#define RWST_WRITE_ENTER(l) (l)->rwst_count = LONG_MIN | (intptr_t)curthread
#define RWST_READ_EXIT(l) (l)->rwst_count--
#define RWST_WRITE_EXIT(l) (l)->rwst_count = 0
extern void rwst_enter(rwstlock_t *, krw_t);
extern int rwst_enter_sig(rwstlock_t *, krw_t);
extern void rwst_exit(rwstlock_t *);
extern void rwst_init(rwstlock_t *, char *, krw_type_t, void *);
extern void rwst_destroy(rwstlock_t *);
extern int rwst_lock_held(rwstlock_t *, krw_t);
extern int rwst_tryenter(rwstlock_t *, krw_t);
extern struct _kthread *rwst_owner(rwstlock_t *);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_RWSTLOCK_H */