xref: /onnv-gate/usr/src/uts/common/sys/rwlock_impl.h (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #ifndef _SYS_RWLOCK_IMPL_H
28*0Sstevel@tonic-gate #define	_SYS_RWLOCK_IMPL_H
29*0Sstevel@tonic-gate 
30*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
31*0Sstevel@tonic-gate 
32*0Sstevel@tonic-gate /*
33*0Sstevel@tonic-gate  * Implementation-private definitions for readers/writer locks.
34*0Sstevel@tonic-gate  */
35*0Sstevel@tonic-gate 
36*0Sstevel@tonic-gate #ifndef _ASM
37*0Sstevel@tonic-gate 
38*0Sstevel@tonic-gate #include <sys/rwlock.h>
39*0Sstevel@tonic-gate 
40*0Sstevel@tonic-gate #ifdef	__cplusplus
41*0Sstevel@tonic-gate extern "C" {
42*0Sstevel@tonic-gate #endif
43*0Sstevel@tonic-gate 
44*0Sstevel@tonic-gate typedef struct rwlock_impl {
45*0Sstevel@tonic-gate 	uintptr_t	rw_wwwh;	/* waiters, write wanted, hold count */
46*0Sstevel@tonic-gate } rwlock_impl_t;
47*0Sstevel@tonic-gate 
48*0Sstevel@tonic-gate #endif	/* _ASM */
49*0Sstevel@tonic-gate 
50*0Sstevel@tonic-gate #define	RW_HAS_WAITERS		1
51*0Sstevel@tonic-gate #define	RW_WRITE_WANTED		2
52*0Sstevel@tonic-gate #define	RW_WRITE_LOCKED		4
53*0Sstevel@tonic-gate #define	RW_READ_LOCK		8
54*0Sstevel@tonic-gate #define	RW_WRITE_LOCK(thread)	((uintptr_t)(thread) | RW_WRITE_LOCKED)
55*0Sstevel@tonic-gate #define	RW_HOLD_COUNT		(-RW_READ_LOCK)
56*0Sstevel@tonic-gate #define	RW_HOLD_COUNT_SHIFT	3		/* log2(RW_READ_LOCK) */
57*0Sstevel@tonic-gate #define	RW_READ_COUNT		RW_HOLD_COUNT
58*0Sstevel@tonic-gate #define	RW_OWNER		RW_HOLD_COUNT
59*0Sstevel@tonic-gate #define	RW_LOCKED		RW_HOLD_COUNT
60*0Sstevel@tonic-gate #define	RW_WRITE_CLAIMED	(RW_WRITE_LOCKED | RW_WRITE_WANTED)
61*0Sstevel@tonic-gate #define	RW_DOUBLE_LOCK		(RW_WRITE_LOCK(0) | RW_READ_LOCK)
62*0Sstevel@tonic-gate 
63*0Sstevel@tonic-gate /*
64*0Sstevel@tonic-gate  * These macros are used by both the implementation of rw_*() routines and
65*0Sstevel@tonic-gate  * by the implementation of the rwlock-related DTrace subroutines.  (DTrace
66*0Sstevel@tonic-gate  * cannot make calls into the rw_*() routines; it must use the macros.)
67*0Sstevel@tonic-gate  */
68*0Sstevel@tonic-gate #define	_RW_READ_HELD(rwlp, tmp)					\
69*0Sstevel@tonic-gate 	((((tmp) = ((rwlock_impl_t *)(rwlp))->rw_wwwh) & RW_LOCKED) &&	\
70*0Sstevel@tonic-gate 	!((tmp) & RW_WRITE_LOCKED))
71*0Sstevel@tonic-gate 
72*0Sstevel@tonic-gate #define	_RW_WRITE_HELD(rwlp)						\
73*0Sstevel@tonic-gate 	((((rwlock_impl_t *)(rwlp))->rw_wwwh &				\
74*0Sstevel@tonic-gate 	(RW_OWNER | RW_WRITE_LOCKED)) == RW_WRITE_LOCK(curthread))
75*0Sstevel@tonic-gate 
76*0Sstevel@tonic-gate #define	_RW_LOCK_HELD(rwlp)						\
77*0Sstevel@tonic-gate 	((((rwlock_impl_t *)(rwlp))->rw_wwwh & RW_LOCKED) ? 1 : 0)
78*0Sstevel@tonic-gate 
79*0Sstevel@tonic-gate #define	_RW_ISWRITER(rwlp)						\
80*0Sstevel@tonic-gate 	((((rwlock_impl_t *)(rwlp))->rw_wwwh & RW_WRITE_CLAIMED) ? 1 : 0)
81*0Sstevel@tonic-gate 
82*0Sstevel@tonic-gate #ifdef	__cplusplus
83*0Sstevel@tonic-gate }
84*0Sstevel@tonic-gate #endif
85*0Sstevel@tonic-gate 
86*0Sstevel@tonic-gate #endif	/* _SYS_RWLOCK_IMPL_H */
87