145 lines
3.7 KiB
C
145 lines
3.7 KiB
C
/* $NetBSD: subr_callback.c,v 1.4 2006/06/23 16:17:23 drochner Exp $ */
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/*-
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* Copyright (c)2006 YAMAMOTO Takashi,
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* All rights reserved.
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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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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_callback.c,v 1.4 2006/06/23 16:17:23 drochner Exp $");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/callback.h>
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#define CH_WANT 1
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void
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callback_head_init(struct callback_head *ch)
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{
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memset(ch, 0, sizeof(struct callback_head));
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simple_lock_init(&ch->ch_lock);
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TAILQ_INIT(&ch->ch_q);
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#if 0 /* already zero-initialized */
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ch->ch_next = NULL;
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ch->ch_nentries = 0;
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ch->ch_running = 0;
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ch->ch_flags = 0;
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#endif
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}
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void
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callback_register(struct callback_head *ch, struct callback_entry *ce,
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void *obj, int (*fn)(struct callback_entry *, void *, void *))
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{
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ce->ce_func = fn;
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ce->ce_obj = obj;
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simple_lock(&ch->ch_lock);
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TAILQ_INSERT_TAIL(&ch->ch_q, ce, ce_q);
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ch->ch_nentries++;
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simple_unlock(&ch->ch_lock);
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}
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void
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callback_unregister(struct callback_head *ch, struct callback_entry *ce)
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{
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simple_lock(&ch->ch_lock);
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while (ch->ch_running > 0) {
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ch->ch_flags |= CH_WANT;
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ltsleep(&ch->ch_running, PVM, "recunreg", 0, &ch->ch_lock);
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}
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if (__predict_false(ch->ch_next == ce)) {
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ch->ch_next = TAILQ_NEXT(ce, ce_q);
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}
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TAILQ_REMOVE(&ch->ch_q, ce, ce_q);
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ch->ch_nentries--;
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simple_unlock(&ch->ch_lock);
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}
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static int
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callback_runone(struct callback_head *ch, void *arg)
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{
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struct callback_entry *ce;
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int result;
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KASSERT(ch->ch_nentries > 0);
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KASSERT(ch->ch_running > 0);
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ce = ch->ch_next;
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if (ce == NULL) {
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ce = TAILQ_FIRST(&ch->ch_q);
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}
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KASSERT(ce != NULL);
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result = (*ce->ce_func)(ce, ce->ce_obj, arg);
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ch->ch_next = TAILQ_NEXT(ce, ce_q);
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return result;
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}
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static void
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callback_run_enter(struct callback_head *ch)
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{
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simple_lock(&ch->ch_lock);
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ch->ch_running++;
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simple_unlock(&ch->ch_lock);
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}
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static void
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callback_run_leave(struct callback_head *ch)
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{
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simple_lock(&ch->ch_lock);
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KASSERT(ch->ch_running > 0);
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ch->ch_running--;
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if (ch->ch_running == 0 && (ch->ch_flags & CH_WANT) != 0) {
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ch->ch_flags &= ~CH_WANT;
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wakeup(&ch->ch_running);
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}
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simple_unlock(&ch->ch_lock);
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}
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int
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callback_run_roundrobin(struct callback_head *ch, void *arg)
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{
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int i;
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int n;
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int result = 0;
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callback_run_enter(ch);
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n = ch->ch_nentries;
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for (i = 0; i < n; i++) {
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result = callback_runone(ch, arg);
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if (result != CALLBACK_CHAIN_CONTINUE) {
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break;
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}
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}
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callback_run_leave(ch);
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return result;
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}
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