sx.h revision 83366
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 83366 2001-09-12 08:38:13Z julian $ 28 */ 29 30#ifndef _SYS_SX_H_ 31#define _SYS_SX_H_ 32 33#ifndef LOCORE 34#include <sys/_lock.h> 35#include <sys/_mutex.h> 36#include <sys/condvar.h> /* XXX */ 37 38struct sx { 39 struct lock_object sx_object; /* Common lock properties. */ 40 struct mtx sx_lock; /* General protection lock. */ 41 int sx_cnt; /* -1: xlock, > 0: slock count. */ 42 struct cv sx_shrd_cv; /* slock waiters. */ 43 int sx_shrd_wcnt; /* Number of slock waiters. */ 44 struct cv sx_excl_cv; /* xlock waiters. */ 45 int sx_excl_wcnt; /* Number of xlock waiters. */ 46 struct thread *sx_xholder; /* Thread presently holding xlock. */ 47}; 48 49#ifdef _KERNEL 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 61#define sx_slock(sx) _sx_slock((sx), __FILE__, __LINE__) 62#define sx_xlock(sx) _sx_xlock((sx), __FILE__, __LINE__) 63#define sx_try_slock(sx) _sx_try_slock((sx), __FILE__, __LINE__) 64#define sx_try_xlock(sx) _sx_try_xlock((sx), __FILE__, __LINE__) 65#define sx_sunlock(sx) _sx_sunlock((sx), __FILE__, __LINE__) 66#define sx_xunlock(sx) _sx_xunlock((sx), __FILE__, __LINE__) 67#define sx_try_upgrade(sx) _sx_try_upgrade((sx), __FILE__, __LINE__) 68#define sx_downgrade(sx) _sx_downgrade((sx), __FILE__, __LINE__) 69 70#ifdef INVARIANTS 71/* 72 * In the non-WITNESS case, SX_ASSERT_LOCKED() and SX_ASSERT_SLOCKED() 73 * can only detect that at least *some* thread owns an slock, but it cannot 74 * guarantee that *this* thread owns an slock. 75 */ 76#ifdef WITNESS 77#define _SX_ASSERT_LOCKED(sx, file, line) \ 78 witness_assert(&(sx)->sx_object, LA_LOCKED, file, line) 79#define _SX_ASSERT_SLOCKED(sx, file, line) \ 80 witness_assert(&(sx)->sx_object, LA_SLOCKED, file, line) 81#else 82#define _SX_ASSERT_LOCKED(sx, file, line) do { \ 83 KASSERT(((sx)->sx_cnt > 0 || (sx)->sx_xholder == curthread), \ 84 ("Lock %s not locked @ %s:%d", (sx)->sx_object.lo_name, \ 85 file, line)); \ 86} while (0) 87#define _SX_ASSERT_SLOCKED(sx, file, line) do { \ 88 KASSERT(((sx)->sx_cnt > 0), ("Lock %s not share locked @ %s:%d",\ 89 (sx)->sx_object.lo_name, file, line)); \ 90} while (0) 91#endif 92#define SX_ASSERT_LOCKED(sx) _SX_ASSERT_LOCKED((sx), __FILE__, __LINE__) 93#define SX_ASSERT_SLOCKED(sx) _SX_ASSERT_SLOCKED((sx), __FILE__, __LINE__) 94 95/* 96 * SX_ASSERT_XLOCKED() detects and guarantees that *we* own the xlock. 97 */ 98#define _SX_ASSERT_XLOCKED(sx, file, line) do { \ 99 KASSERT(((sx)->sx_xholder == curthread), \ 100 ("Lock %s not exclusively locked @ %s:%d", \ 101 (sx)->sx_object.lo_name, file, line)); \ 102} while (0) 103#define SX_ASSERT_XLOCKED(sx) _SX_ASSERT_XLOCKED((sx), __FILE__, __LINE__) 104 105#else /* INVARIANTS */ 106#define SX_ASSERT_SLOCKED(sx) 107#define SX_ASSERT_XLOCKED(sx) 108#define _SX_ASSERT_SLOCKED(sx, file, line) 109#define _SX_ASSERT_XLOCKED(sx, file, line) 110#endif /* INVARIANTS */ 111 112#endif /* _KERNEL */ 113#endif /* !LOCORE */ 114#endif /* _SYS_SX_H_ */ 115