sx.h revision 125444
1/* 2 * Copyright (C) 2001 Jason Evans <jasone@freebsd.org>. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice(s), this list of conditions and the following disclaimer as 9 * the first lines of this file unmodified other than the possible 10 * addition of one or more copyright notices. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice(s), this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 22 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 25 * DAMAGE. 26 * 27 * $FreeBSD: head/sys/sys/sx.h 125444 2004-02-04 14:18:21Z bde $ 28 */ 29 30#ifndef _SYS_SX_H_ 31#define _SYS_SX_H_ 32 33#include <sys/queue.h> 34#include <sys/_lock.h> 35#include <sys/condvar.h> /* XXX */ 36 37struct sx { 38 struct lock_object sx_object; /* Common lock properties. */ 39 struct mtx *sx_lock; /* General protection lock. */ 40 int sx_cnt; /* -1: xlock, > 0: slock count. */ 41 struct cv sx_shrd_cv; /* slock waiters. */ 42 int sx_shrd_wcnt; /* Number of slock waiters. */ 43 struct cv sx_excl_cv; /* xlock waiters. */ 44 int sx_excl_wcnt; /* Number of xlock waiters. */ 45 struct thread *sx_xholder; /* Thread presently holding xlock. */ 46}; 47 48#ifdef _KERNEL 49void sx_sysinit(void *arg); 50void sx_init(struct sx *sx, const char *description); 51void sx_destroy(struct sx *sx); 52void _sx_slock(struct sx *sx, const char *file, int line); 53void _sx_xlock(struct sx *sx, const char *file, int line); 54int _sx_try_slock(struct sx *sx, const char *file, int line); 55int _sx_try_xlock(struct sx *sx, const char *file, int line); 56void _sx_sunlock(struct sx *sx, const char *file, int line); 57void _sx_xunlock(struct sx *sx, const char *file, int line); 58int _sx_try_upgrade(struct sx *sx, const char *file, int line); 59void _sx_downgrade(struct sx *sx, const char *file, int line); 60#ifdef INVARIANT_SUPPORT 61void _sx_assert(struct sx *sx, int what, const char *file, int line); 62#endif 63 64struct sx_args { 65 struct sx *sa_sx; 66 const char *sa_desc; 67}; 68 69#define SX_SYSINIT(name, sxa, desc) \ 70 static struct sx_args name##_args = { \ 71 sxa, \ 72 desc \ 73 }; \ 74 SYSINIT(name##_sx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 75 sx_sysinit, &name##_args) 76 77#define sx_slock(sx) _sx_slock((sx), LOCK_FILE, LOCK_LINE) 78#define sx_xlock(sx) _sx_xlock((sx), LOCK_FILE, LOCK_LINE) 79#define sx_try_slock(sx) _sx_try_slock((sx), LOCK_FILE, LOCK_LINE) 80#define sx_try_xlock(sx) _sx_try_xlock((sx), LOCK_FILE, LOCK_LINE) 81#define sx_sunlock(sx) _sx_sunlock((sx), LOCK_FILE, LOCK_LINE) 82#define sx_xunlock(sx) _sx_xunlock((sx), LOCK_FILE, LOCK_LINE) 83#define sx_try_upgrade(sx) _sx_try_upgrade((sx), LOCK_FILE, LOCK_LINE) 84#define sx_downgrade(sx) _sx_downgrade((sx), LOCK_FILE, LOCK_LINE) 85 86#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 87#define SX_LOCKED LA_LOCKED 88#define SX_SLOCKED LA_SLOCKED 89#define SX_XLOCKED LA_XLOCKED 90#define SX_UNLOCKED LA_UNLOCKED 91#endif 92 93#ifdef INVARIANTS 94#define sx_assert(sx, what) _sx_assert((sx), (what), LOCK_FILE, LOCK_LINE) 95#else 96#define sx_assert(sx, what) 97#endif 98 99#endif /* _KERNEL */ 100 101#endif /* !_SYS_SX_H_ */ 102