| 1 | /*- |
| 2 | * SPDX-License-Identifier: BSD-2-Clause |
| 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 | |
| 31 | #ifndef __SYS__BLOCKCOUNT_H__ |
| 32 | #define __SYS__BLOCKCOUNT_H__ |
| 33 | |
| 34 | #include <machine/atomic.h> |
| 35 | |
| 36 | typedef struct _blockcount { |
| 37 | unsigned int __count; |
| 38 | } blockcount_t; |
| 39 | |
| 40 | #define _BLOCKCOUNT_WAITERS_FLAG (1U << 31) |
| 41 | #define _BLOCKCOUNT_COUNT(c) ((c) & ~_BLOCKCOUNT_WAITERS_FLAG) |
| 42 | #define _BLOCKCOUNT_WAITERS(c) (((c) & _BLOCKCOUNT_WAITERS_FLAG) != 0) |
| 43 | |
| 44 | static inline unsigned int |
| 45 | blockcount_read(blockcount_t *count) |
| 46 | { |
| 47 | return (_BLOCKCOUNT_COUNT(atomic_load_int(&count->__count))); |
| 48 | } |
| 49 | |
| 50 | #endif /* !__SYS__BLOCKCOUNT_H__ */ |