sx.h revision 76166
1295367Sdes/* 2261287Sdes * Copyright (C) 2001 Jason Evans <jasone@freebsd.org>. All rights reserved. 3261287Sdes * 4261287Sdes * Redistribution and use in source and binary forms, with or without 5261287Sdes * modification, are permitted provided that the following conditions 6261287Sdes * are met: 7261287Sdes * 1. Redistributions of source code must retain the above copyright 8261287Sdes * notice(s), this list of conditions and the following disclaimer as 9261287Sdes * the first lines of this file unmodified other than the possible 10261287Sdes * addition of one or more copyright notices. 11261287Sdes * 2. Redistributions in binary form must reproduce the above copyright 12261287Sdes * notice(s), this list of conditions and the following disclaimer in the 13261287Sdes * documentation and/or other materials provided with the distribution. 14261287Sdes * 15261287Sdes * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 16261287Sdes * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17261287Sdes * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18261287Sdes * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 19261287Sdes * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20261287Sdes * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21261287Sdes * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 22261287Sdes * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23261287Sdes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24261287Sdes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 25261287Sdes * DAMAGE. 26261287Sdes * 27261287Sdes * $FreeBSD: head/sys/sys/sx.h 76166 2001-05-01 08:13:21Z markm $ 28261287Sdes */ 29261287Sdes 30261287Sdes#ifndef _SYS_SX_H_ 31295367Sdes#define _SYS_SX_H_ 32261287Sdes 33261287Sdes#ifndef LOCORE 34261287Sdes#include <sys/_mutex.h> 35261287Sdes#include <sys/condvar.h> /* XXX */ 36261287Sdes 37261287Sdesstruct sx { 38261287Sdes struct lock_object sx_object; /* Common lock properties. */ 39261287Sdes struct mtx sx_lock; /* General protection lock. */ 40261287Sdes int sx_cnt; /* -1: xlock, > 0: slock count. */ 41261287Sdes struct cv sx_shrd_cv; /* slock waiters. */ 42261287Sdes int sx_shrd_wcnt; /* Number of slock waiters. */ 43261287Sdes struct cv sx_excl_cv; /* xlock waiters. */ 44 int sx_excl_wcnt; /* Number of xlock waiters. */ 45 struct proc *sx_xholder; /* Thread presently holding xlock. */ 46}; 47 48#ifdef _KERNEL 49void sx_init(struct sx *sx, const char *description); 50void sx_destroy(struct sx *sx); 51void _sx_slock(struct sx *sx, const char *file, int line); 52void _sx_xlock(struct sx *sx, const char *file, int line); 53void _sx_sunlock(struct sx *sx, const char *file, int line); 54void _sx_xunlock(struct sx *sx, const char *file, int line); 55 56#define sx_slock(sx) _sx_slock((sx), __FILE__, __LINE__) 57#define sx_xlock(sx) _sx_xlock((sx), __FILE__, __LINE__) 58#define sx_sunlock(sx) _sx_sunlock((sx), __FILE__, __LINE__) 59#define sx_xunlock(sx) _sx_xunlock((sx), __FILE__, __LINE__) 60 61#ifdef INVARIANTS 62/* 63 * SX_ASSERT_SLOCKED() can only detect that at least *some* thread owns an 64 * slock, but it cannot guarantee that *this* thread owns an slock. 65 */ 66#define SX_ASSERT_SLOCKED(sx) do { \ 67 mtx_lock(&(sx)->sx_lock); \ 68 _SX_ASSERT_SLOCKED((sx)); \ 69 mtx_unlock(&(sx)->sx_lock); \ 70} while (0) 71#define _SX_ASSERT_SLOCKED(sx) do { \ 72 KASSERT(((sx)->sx_cnt > 0), ("%s: lacking slock %s\n", \ 73 __FUNCTION__, (sx)->sx_object.lo_name)); \ 74} while (0) 75 76/* 77 * SX_ASSERT_XLOCKED() detects and guarantees that *we* own the xlock. 78 */ 79#define SX_ASSERT_XLOCKED(sx) do { \ 80 mtx_lock(&(sx)->sx_lock); \ 81 _SX_ASSERT_XLOCKED((sx)); \ 82 mtx_unlock(&(sx)->sx_lock); \ 83} while (0) 84#define _SX_ASSERT_XLOCKED(sx) do { \ 85 KASSERT(((sx)->sx_xholder == curproc), \ 86 ("%s: thread %p lacking xlock %s\n", __FUNCTION__, \ 87 curproc, (sx)->sx_object.lo_name)); \ 88} while (0) 89 90#else /* INVARIANTS */ 91#define SX_ASSERT_SLOCKED(sx) 92#define SX_ASSERT_XLOCKED(sx) 93#define _SX_ASSERT_SLOCKED(sx) 94#define _SX_ASSERT_XLOCKED(sx) 95#endif /* INVARIANTS */ 96 97#endif /* _KERNEL */ 98#endif /* !LOCORE */ 99#endif /* _SYS_SX_H_ */ 100