NetBSD/sys/kern/subr_callback.c

148 lines
3.7 KiB
C
Raw Normal View History

/* $NetBSD: subr_callback.c,v 1.6 2007/12/05 07:06:54 ad Exp $ */
/*-
* Copyright (c)2006 YAMAMOTO Takashi,
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_callback.c,v 1.6 2007/12/05 07:06:54 ad Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/callback.h>
void
callback_head_init(struct callback_head *ch, int ipl)
{
memset(ch, 0, sizeof(struct callback_head));
mutex_init(&ch->ch_lock, MUTEX_DEFAULT, ipl);
cv_init(&ch->ch_cv, "callback");
TAILQ_INIT(&ch->ch_q);
#if 0 /* already zero-initialized */
ch->ch_next = NULL;
ch->ch_nentries = 0;
ch->ch_running = 0;
ch->ch_flags = 0;
#endif
}
void
callback_head_destroy(struct callback_head *ch)
{
mutex_destroy(&ch->ch_lock);
cv_destroy(&ch->ch_cv);
}
void
callback_register(struct callback_head *ch, struct callback_entry *ce,
void *obj, int (*fn)(struct callback_entry *, void *, void *))
{
ce->ce_func = fn;
ce->ce_obj = obj;
mutex_enter(&ch->ch_lock);
TAILQ_INSERT_TAIL(&ch->ch_q, ce, ce_q);
ch->ch_nentries++;
mutex_exit(&ch->ch_lock);
}
void
callback_unregister(struct callback_head *ch, struct callback_entry *ce)
{
mutex_enter(&ch->ch_lock);
while (ch->ch_running > 0)
cv_wait(&ch->ch_cv, &ch->ch_lock);
if (__predict_false(ch->ch_next == ce)) {
ch->ch_next = TAILQ_NEXT(ce, ce_q);
}
TAILQ_REMOVE(&ch->ch_q, ce, ce_q);
ch->ch_nentries--;
mutex_exit(&ch->ch_lock);
}
static int
callback_runone(struct callback_head *ch, void *arg)
{
struct callback_entry *ce;
int result;
KASSERT(ch->ch_nentries > 0);
KASSERT(ch->ch_running > 0);
ce = ch->ch_next;
if (ce == NULL) {
ce = TAILQ_FIRST(&ch->ch_q);
}
KASSERT(ce != NULL);
result = (*ce->ce_func)(ce, ce->ce_obj, arg);
ch->ch_next = TAILQ_NEXT(ce, ce_q);
return result;
}
static void
callback_run_enter(struct callback_head *ch)
{
mutex_enter(&ch->ch_lock);
ch->ch_running++;
mutex_exit(&ch->ch_lock);
}
static void
callback_run_leave(struct callback_head *ch)
{
mutex_enter(&ch->ch_lock);
KASSERT(ch->ch_running > 0);
ch->ch_running--;
if (ch->ch_running == 0)
cv_broadcast(&ch->ch_cv);
mutex_exit(&ch->ch_lock);
}
int
callback_run_roundrobin(struct callback_head *ch, void *arg)
{
int i;
int n;
int result = 0;
callback_run_enter(ch);
n = ch->ch_nentries;
for (i = 0; i < n; i++) {
result = callback_runone(ch, arg);
if (result != CALLBACK_CHAIN_CONTINUE) {
break;
}
}
callback_run_leave(ch);
return result;
}