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