sx.h revision 167387
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 167387 2007-03-09 22:41:01Z jhb $ 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#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 61void _sx_assert(struct sx *sx, int what, const char *file, int line); 62#endif 63#ifdef DDB 64int sx_chain(struct thread *td, struct thread **ownerp); 65#endif 66 67struct sx_args { 68 struct sx *sa_sx; 69 const char *sa_desc; 70}; 71 72#define SX_SYSINIT(name, sxa, desc) \ 73 static struct sx_args name##_args = { \ 74 (sxa), \ 75 (desc) \ 76 }; \ 77 SYSINIT(name##_sx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 78 sx_sysinit, &name##_args); \ 79 SYSUNINIT(name##_sx_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \ 80 sx_destroy, (sxa)) 81 82#define sx_xlocked(sx) ((sx)->sx_cnt < 0 && (sx)->sx_xholder == curthread) 83#define sx_slock(sx) _sx_slock((sx), LOCK_FILE, LOCK_LINE) 84#define sx_xlock(sx) _sx_xlock((sx), LOCK_FILE, LOCK_LINE) 85#define sx_try_slock(sx) _sx_try_slock((sx), LOCK_FILE, LOCK_LINE) 86#define sx_try_xlock(sx) _sx_try_xlock((sx), LOCK_FILE, LOCK_LINE) 87#define sx_sunlock(sx) _sx_sunlock((sx), LOCK_FILE, LOCK_LINE) 88#define sx_xunlock(sx) _sx_xunlock((sx), LOCK_FILE, LOCK_LINE) 89#define sx_try_upgrade(sx) _sx_try_upgrade((sx), LOCK_FILE, LOCK_LINE) 90#define sx_downgrade(sx) _sx_downgrade((sx), LOCK_FILE, LOCK_LINE) 91#define sx_unlock(sx) do { \ 92 if (sx_xlocked(sx)) \ 93 sx_xunlock(sx); \ 94 else \ 95 sx_sunlock(sx); \ 96} while (0) 97#define sx_sleep(chan, sx, pri, wmesg, timo) \ 98 _sleep((chan), &(sx)->sx_object, (pri), (wmesg), (timo)) 99 100#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT) 101#define SX_LOCKED LA_LOCKED 102#define SX_SLOCKED LA_SLOCKED 103#define SX_XLOCKED LA_XLOCKED 104#define SX_UNLOCKED LA_UNLOCKED 105#endif 106 107#ifdef INVARIANTS 108#define sx_assert(sx, what) _sx_assert((sx), (what), LOCK_FILE, LOCK_LINE) 109#else 110#define sx_assert(sx, what) 111#endif 112 113#endif /* _KERNEL */ 114 115#endif /* !_SYS_SX_H_ */ 116