| /*- |
| * Copyright (c) 2006 John Baldwin <jhb@FreeBSD.org> |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * |
| * $FreeBSD$ |
| */ |
| |
| #ifndef _SYS__RWLOCK_H_ |
| #define _SYS__RWLOCK_H_ |
| |
| #include <machine/param.h> |
| |
| /* |
| * Reader/writer lock. |
| * |
| * All reader/writer lock implementations must always have a member |
| * called rw_lock. Other locking primitive structures are not allowed to |
| * use this name for their members. |
| * If this rule needs to change, the bits in the reader/writer lock |
| * implementation must be modified appropriately. |
| */ |
| struct rwlock { |
| struct lock_object lock_object; |
| volatile uintptr_t rw_lock; |
| }; |
| |
| /* |
| * Members of struct rwlock_padalign must mirror members of struct rwlock. |
| * rwlock_padalign rwlocks can use the rwlock(9) API transparently without |
| * modification. |
| * Pad-aligned rwlocks used within structures should generally be the |
| * first member of the struct. Otherwise, the compiler can generate |
| * additional padding for the struct to keep a correct alignment for |
| * the rwlock. |
| */ |
| struct rwlock_padalign { |
| struct lock_object lock_object; |
| volatile uintptr_t rw_lock; |
| } __aligned(CACHE_LINE_SIZE); |
| |
| #endif /* !_SYS__RWLOCK_H_ */ |