1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2020 The FreeBSD Foundation 5 * 6 * This software was developed by Mark Johnston under sponsorship from 7 * the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions are 11 * met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD$ 31 */ 32 33 #ifndef __SYS__BLOCKCOUNT_H__ 34 #define __SYS__BLOCKCOUNT_H__ 35 36 #include <machine/atomic.h> 37 38 typedef struct _blockcount { 39 unsigned int __count; 40 } blockcount_t; 41 42 #define _BLOCKCOUNT_WAITERS_FLAG (1U << 31) 43 #define _BLOCKCOUNT_COUNT(c) ((c) & ~_BLOCKCOUNT_WAITERS_FLAG) 44 #define _BLOCKCOUNT_WAITERS(c) (((c) & _BLOCKCOUNT_WAITERS_FLAG) != 0) 45 46 static inline unsigned int 47 blockcount_read(blockcount_t *count) 48 { 49 return (_BLOCKCOUNT_COUNT(atomic_load_int(&count->__count))); 50 } 51 52 #endif /* !__SYS__BLOCKCOUNT_H__ */ 53