sx.h revision 73782
156160Sru/* 2146515Sru * Copyright (C) 2001 Jason Evans <jasone@freebsd.org>. All rights reserved. 321495Sjmacd * 4146515Sru * Redistribution and use in source and binary forms, with or without 5116525Sru * modification, are permitted provided that the following conditions 621495Sjmacd * are met: 721495Sjmacd * 1. Redistributions of source code must retain the above copyright 821495Sjmacd * notice(s), this list of conditions and the following disclaimer as 921495Sjmacd * the first lines of this file unmodified other than the possible 1021495Sjmacd * addition of one or more copyright notices. 1121495Sjmacd * 2. Redistributions in binary form must reproduce the above copyright 1221495Sjmacd * notice(s), this list of conditions and the following disclaimer in the 1321495Sjmacd * documentation and/or other materials provided with the distribution. 1421495Sjmacd * 1521495Sjmacd * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 1621495Sjmacd * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 1721495Sjmacd * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 1821495Sjmacd * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 1921495Sjmacd * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 2021495Sjmacd * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 2121495Sjmacd * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 2221495Sjmacd * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2356160Sru * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2421495Sjmacd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 2521495Sjmacd * DAMAGE. 2656160Sru * 2756160Sru * $FreeBSD: head/sys/sys/sx.h 73782 2001-03-05 19:59:41Z jasone $ 2821495Sjmacd */ 2956160Sru 3021495Sjmacd#ifndef _SYS_SX_H_ 3121495Sjmacd#define _SYS_SX_H_ 3256160Sru 3356160Sru#ifndef LOCORE 3456160Sru#include <sys/mutex.h> 3556160Sru#include <sys/condvar.h> 3656160Sru 3721495Sjmacdstruct sx { 3856160Sru struct mtx sx_lock; /* General protection lock and xlock. */ 3956160Sru int sx_cnt; /* -1: xlock, > 0: slock count. */ 4056160Sru struct cv sx_shrd_cv; /* slock waiters. */ 4156160Sru int sx_shrd_wcnt; /* Number of slock waiters. */ 4221495Sjmacd struct cv sx_excl_cv; /* xlock waiters. */ 4356160Sru int sx_excl_wcnt; /* Number of xlock waiters. */ 4421495Sjmacd}; 4556160Sru 4656160Sru#ifdef _KERNEL 4756160Sruvoid sx_init(struct sx *sx, const char *description); 4856160Sruvoid sx_destroy(struct sx *sx); 4956160Sruvoid sx_slock(struct sx *sx); 5021495Sjmacdvoid sx_xlock(struct sx *sx); 5156160Sruvoid sx_sunlock(struct sx *sx); 5221495Sjmacdvoid sx_xunlock(struct sx *sx); 5321495Sjmacd 5421495Sjmacd#ifdef INVARIANTS 5521495Sjmacd/* 5621495Sjmacd * SX_ASSERT_SLOCKED() can only detect that at least *some* thread owns an 5721495Sjmacd * slock, but it cannot guarantee that *this* thread owns an slock. 5821495Sjmacd */ 5956160Sru#define SX_ASSERT_SLOCKED(sx) do { \ 6056160Sru mtx_lock(&(sx)->sx_lock); \ 6156160Sru KASSERT(((sx)->sx_cnt > 0), ("%s: lacking slock\n", \ 62146515Sru __FUNCTION__)); \ 63146515Sru mtx_unlock(&(sx)->sx_lock); \ 64146515Sru} while (0) 65146515Sru/* 6656160Sru * SX_ASSERT_XLOCKED() can only detect that at least *some* thread owns an 6756160Sru * xlock, but it cannot guarantee that *this* thread owns an xlock. 6856160Sru */ 6956160Sru#define SX_ASSERT_XLOCKED(sx) do { \ 7056160Sru mtx_lock(&(sx)->sx_lock); \ 7121495Sjmacd KASSERT(((sx)->sx_cnt == -1), ("%s: lacking xlock\n", \ 7221495Sjmacd __FUNCTION__)); \ 7356160Sru mtx_unlock(&(sx)->sx_lock); \ 7456160Sru} while (0) 7556160Sru#else /* INVARIANTS */ 7656160Sru#define SX_ASSERT_SLOCKED(sx) 7756160Sru#define SX_ASSERT_XLOCKER(sx) 7856160Sru#endif /* INVARIANTS */ 7956160Sru 8056160Sru#endif /* _KERNEL */ 8156160Sru#endif /* !LOCORE */ 8256160Sru#endif /* _SYS_SX_H_ */ 8356160Sru