304dcfb0d8
blockcount_wait() still unconditionally waits for the count to reach zero before returning. Tested by: pho (a larger patch) Reviewed by: kib Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D24513
96 lines
3.0 KiB
C
96 lines
3.0 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org>
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* Copyright (c) 2020 The FreeBSD Foundation
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*
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* Portions of this software were developed by Mark Johnston under
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* sponsorship from the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef __SYS_BLOCKCOUNT_H__
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#define __SYS_BLOCKCOUNT_H__
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#ifdef _KERNEL
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#include <sys/systm.h>
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#include <sys/_blockcount.h>
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struct lock_object;
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int _blockcount_sleep(blockcount_t *bc, struct lock_object *, const char *wmesg,
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int prio);
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void _blockcount_wakeup(blockcount_t *bc, u_int old);
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static __inline void
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blockcount_init(blockcount_t *bc)
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{
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atomic_store_int(&bc->__count, 0);
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}
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static __inline void
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blockcount_acquire(blockcount_t *bc, u_int n)
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{
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#ifdef INVARIANTS
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u_int old;
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old = atomic_fetchadd_int(&bc->__count, n);
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KASSERT(old + n > old, ("%s: counter overflow %p", __func__, bc));
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#else
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atomic_add_int(&bc->__count, n);
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#endif
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}
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static __inline void
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blockcount_release(blockcount_t *bc, u_int n)
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{
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u_int old;
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atomic_thread_fence_rel();
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old = atomic_fetchadd_int(&bc->__count, -n);
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KASSERT(old >= n, ("%s: counter underflow %p", __func__, bc));
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if (_BLOCKCOUNT_COUNT(old) == n && _BLOCKCOUNT_WAITERS(old))
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_blockcount_wakeup(bc, old);
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}
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static __inline void
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_blockcount_wait(blockcount_t *bc, struct lock_object *lo, const char *wmesg,
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int prio)
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{
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KASSERT((prio & ~PRIMASK) == 0, ("%s: invalid prio %x", __func__, prio));
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while (_blockcount_sleep(bc, lo, wmesg, prio) == EAGAIN)
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;
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}
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#define blockcount_sleep(bc, lo, wmesg, prio) \
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_blockcount_sleep((bc), (struct lock_object *)(lo), (wmesg), (prio))
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#define blockcount_wait(bc, lo, wmesg, prio) \
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_blockcount_wait((bc), (struct lock_object *)(lo), (wmesg), (prio))
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#endif /* _KERNEL */
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#endif /* !__SYS_BLOCKCOUNT_H__ */
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