1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 32 #ifndef __SYS_BLOCKCOUNT_H__ 33 #define __SYS_BLOCKCOUNT_H__ 34 35 #ifdef _KERNEL 36 37 #include <sys/systm.h> 38 #include <sys/_blockcount.h> 39 40 struct lock_object; 41 42 int _blockcount_sleep(blockcount_t *bc, struct lock_object *, const char *wmesg, 43 int prio); 44 void _blockcount_wakeup(blockcount_t *bc, u_int old); 45 46 static __inline void 47 blockcount_init(blockcount_t *bc) 48 { 49 atomic_store_int(&bc->__count, 0); 50 } 51 52 static __inline void 53 blockcount_acquire(blockcount_t *bc, u_int n) 54 { 55 #ifdef INVARIANTS 56 u_int old; 57 58 old = atomic_fetchadd_int(&bc->__count, n); 59 KASSERT(old + n > old, ("%s: counter overflow %p", __func__, bc)); 60 #else 61 atomic_add_int(&bc->__count, n); 62 #endif 63 } 64 65 static __inline void 66 blockcount_release(blockcount_t *bc, u_int n) 67 { 68 u_int old; 69 70 atomic_thread_fence_rel(); 71 old = atomic_fetchadd_int(&bc->__count, -n); 72 KASSERT(old >= n, ("%s: counter underflow %p", __func__, bc)); 73 if (_BLOCKCOUNT_COUNT(old) == n && _BLOCKCOUNT_WAITERS(old)) 74 _blockcount_wakeup(bc, old); 75 } 76 77 static __inline void 78 _blockcount_wait(blockcount_t *bc, struct lock_object *lo, const char *wmesg, 79 int prio) 80 { 81 KASSERT((prio & ~PRIMASK) == 0, ("%s: invalid prio %x", __func__, prio)); 82 83 while (_blockcount_sleep(bc, lo, wmesg, prio) == EAGAIN) 84 ; 85 } 86 87 #define blockcount_sleep(bc, lo, wmesg, prio) \ 88 _blockcount_sleep((bc), (struct lock_object *)(lo), (wmesg), (prio)) 89 #define blockcount_wait(bc, lo, wmesg, prio) \ 90 _blockcount_wait((bc), (struct lock_object *)(lo), (wmesg), (prio)) 91 92 #endif /* _KERNEL */ 93 #endif /* !__SYS_BLOCKCOUNT_H__ */ 94