netbsd/share/examples/puffs/pgfs/pgfs_waitq.c
2013-04-06 16:48:33 +02:00

100 lines
2.4 KiB
C

/* $NetBSD: pgfs_waitq.c,v 1.1 2011/10/12 01:05:00 yamt Exp $ */
/*-
* Copyright (c)2010,2011 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.
*/
/*
* a dumb wait queue on puffs_cc
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: pgfs_waitq.c,v 1.1 2011/10/12 01:05:00 yamt Exp $");
#endif /* not lint */
#include <assert.h>
#include <puffs.h>
#include "pgfs_waitq.h"
#include "pgfs_debug.h"
struct waiter {
TAILQ_ENTRY(waiter) list;
struct puffs_cc *cc;
};
void
waitq_init(struct waitq *wq)
{
TAILQ_INIT(wq);
}
void
waiton(struct waitq *wq, struct puffs_cc *cc)
{
struct waiter w;
/*
* insert to the tail of the queue.
* some users rely on the FIFO behaviour.
*/
w.cc = cc;
TAILQ_INSERT_TAIL(wq, &w, list);
puffs_cc_yield(cc);
}
struct puffs_cc *
wakeup_one(struct waitq *wq)
{
struct waiter *w;
w = TAILQ_FIRST(wq);
if (w != NULL) {
TAILQ_REMOVE(wq, w, list);
puffs_cc_schedule(w->cc);
DPRINTF("waking up %p\n", w->cc);
return w->cc;
}
return NULL;
}
#if 0
static void
wakeup(struct waitq *wq)
{
struct waiter *w;
TAILQ_FOREACH(w, wq, list) {
puffs_cc_schedule(w->cc);
DPRINTF("waking up %p\n", w->cc);
}
TAILQ_INIT(wq);
}
#endif