rwlock_impl.h revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* 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 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#ifndef _SYS_RWLOCK_IMPL_H
#define _SYS_RWLOCK_IMPL_H
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Implementation-private definitions for readers/writer locks.
*/
#ifndef _ASM
#include <sys/rwlock.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef struct rwlock_impl {
uintptr_t rw_wwwh; /* waiters, write wanted, hold count */
} rwlock_impl_t;
#endif /* _ASM */
#define RW_HAS_WAITERS 1
#define RW_WRITE_WANTED 2
#define RW_WRITE_LOCKED 4
#define RW_READ_LOCK 8
#define RW_WRITE_LOCK(thread) ((uintptr_t)(thread) | RW_WRITE_LOCKED)
#define RW_HOLD_COUNT (-RW_READ_LOCK)
#define RW_HOLD_COUNT_SHIFT 3 /* log2(RW_READ_LOCK) */
#define RW_READ_COUNT RW_HOLD_COUNT
#define RW_OWNER RW_HOLD_COUNT
#define RW_LOCKED RW_HOLD_COUNT
#define RW_WRITE_CLAIMED (RW_WRITE_LOCKED | RW_WRITE_WANTED)
#define RW_DOUBLE_LOCK (RW_WRITE_LOCK(0) | RW_READ_LOCK)
/*
* These macros are used by both the implementation of rw_*() routines and
* by the implementation of the rwlock-related DTrace subroutines. (DTrace
* cannot make calls into the rw_*() routines; it must use the macros.)
*/
#define _RW_READ_HELD(rwlp, tmp) \
((((tmp) = ((rwlock_impl_t *)(rwlp))->rw_wwwh) & RW_LOCKED) && \
!((tmp) & RW_WRITE_LOCKED))
#define _RW_WRITE_HELD(rwlp) \
((((rwlock_impl_t *)(rwlp))->rw_wwwh & \
(RW_OWNER | RW_WRITE_LOCKED)) == RW_WRITE_LOCK(curthread))
#define _RW_LOCK_HELD(rwlp) \
((((rwlock_impl_t *)(rwlp))->rw_wwwh & RW_LOCKED) ? 1 : 0)
#define _RW_ISWRITER(rwlp) \
((((rwlock_impl_t *)(rwlp))->rw_wwwh & RW_WRITE_CLAIMED) ? 1 : 0)
#ifdef __cplusplus
}
#endif
#endif /* _SYS_RWLOCK_IMPL_H */