| /*- |
| * Copyright (c) 2005 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. |
| * 3. Neither the name of the author nor the names of any co-contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * 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 _BSD__SYS_REFCOUNT_H__ |
| #define _BSD__SYS_REFCOUNT_H__ |
| |
| #include <machine/bsd_atomic.h> |
| |
| #ifdef _FREEBSD_KERNEL |
| #include <sys/bsd_systm.h> |
| #else |
| #define KASSERT(exp, msg) /* */ |
| #endif |
| |
| static __inline void |
| refcount_init(volatile u_int *count, u_int value) |
| { |
| |
| *count = value; |
| } |
| |
| static __inline void |
| refcount_acquire(volatile u_int *count) |
| { |
| |
| atomic_add_acq_int(count, 1); |
| } |
| |
| static __inline int |
| refcount_release(volatile u_int *count) |
| { |
| u_int old; |
| |
| /* XXX: Should this have a rel membar? */ |
| old = atomic_fetchadd_int(count, -1); |
| KASSERT(old > 0, ("negative refcount %p", count)); |
| return (old == 1); |
| } |
| |
| #endif /* ! _BSD__SYS_REFCOUNT_H__ */ |
