1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org> 5 * Copyright (c) 2020 The FreeBSD Foundation 6 * 7 * Portions of this software were developed by Mark Johnston under 8 * sponsorship from the FreeBSD Foundation. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $FreeBSD$ 32 */ 33 34 #ifndef __SYS_BLOCKCOUNT_H__ 35 #define __SYS_BLOCKCOUNT_H__ 36 37 #ifdef _KERNEL 38 39 #include <sys/systm.h> 40 #include <sys/_blockcount.h> 41 42 struct lock_object; 43 44 int _blockcount_sleep(blockcount_t *bc, struct lock_object *, const char *wmesg, 45 int prio); 46 void _blockcount_wakeup(blockcount_t *bc, u_int old); 47 48 static __inline void 49 blockcount_init(blockcount_t *bc) 50 { 51 atomic_store_int(&bc->__count, 0); 52 } 53 54 static __inline void 55 blockcount_acquire(blockcount_t *bc, u_int n) 56 { 57 #ifdef INVARIANTS 58 u_int old; 59 60 old = atomic_fetchadd_int(&bc->__count, n); 61 KASSERT(old + n > old, ("%s: counter overflow %p", __func__, bc)); 62 #else 63 atomic_add_int(&bc->__count, n); 64 #endif 65 } 66 67 static __inline void 68 blockcount_release(blockcount_t *bc, u_int n) 69 { 70 u_int old; 71 72 atomic_thread_fence_rel(); 73 old = atomic_fetchadd_int(&bc->__count, -n); 74 KASSERT(old >= n, ("%s: counter underflow %p", __func__, bc)); 75 if (_BLOCKCOUNT_COUNT(old) == n && _BLOCKCOUNT_WAITERS(old)) 76 _blockcount_wakeup(bc, old); 77 } 78 79 static __inline void 80 _blockcount_wait(blockcount_t *bc, struct lock_object *lo, const char *wmesg, 81 int prio) 82 { 83 KASSERT((prio & ~PRIMASK) == 0, ("%s: invalid prio %x", __func__, prio)); 84 85 while (_blockcount_sleep(bc, lo, wmesg, prio) == EAGAIN) 86 ; 87 } 88 89 #define blockcount_sleep(bc, lo, wmesg, prio) \ 90 _blockcount_sleep((bc), (struct lock_object *)(lo), (wmesg), (prio)) 91 #define blockcount_wait(bc, lo, wmesg, prio) \ 92 _blockcount_wait((bc), (struct lock_object *)(lo), (wmesg), (prio)) 93 94 #endif /* _KERNEL */ 95 #endif /* !__SYS_BLOCKCOUNT_H__ */ 96