1/*- 2 * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> 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, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD: stable/11/sys/sys/_rwlock.h 367457 2020-11-07 18:10:59Z dim $ 26 */ 27 28#ifndef _SYS__RWLOCK_H_ 29#define _SYS__RWLOCK_H_ 30 31#include <machine/param.h> 32 33/* 34 * Reader/writer lock. 35 * 36 * All reader/writer lock implementations must always have a member 37 * called rw_lock. Other locking primitive structures are not allowed to 38 * use this name for their members. 39 * If this rule needs to change, the bits in the reader/writer lock 40 * implementation must be modified appropriately. 41 */ 42struct rwlock { 43 struct lock_object lock_object; 44 volatile uintptr_t rw_lock; 45}; 46 47/* 48 * Members of struct rwlock_padalign must mirror members of struct rwlock. 49 * rwlock_padalign rwlocks can use the rwlock(9) API transparently without 50 * modification. 51 * Pad-aligned rwlocks used within structures should generally be the 52 * first member of the struct. Otherwise, the compiler can generate 53 * additional padding for the struct to keep a correct alignment for 54 * the rwlock. 55 */ 56struct rwlock_padalign { 57 struct lock_object lock_object; 58 volatile uintptr_t rw_lock; 59} __aligned(CACHE_LINE_SIZE); 60 61#endif /* !_SYS__RWLOCK_H_ */ 62