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/* AFS timeout daemon
*
* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/freezer.h>
#include "cell.h"
#include "volume.h"
#include "kafstimod.h"
#include <asm/errno.h>
#include "internal.h"
static DECLARE_COMPLETION(kafstimod_alive);
static DECLARE_COMPLETION(kafstimod_dead);
static DECLARE_WAIT_QUEUE_HEAD(kafstimod_sleepq);
static int kafstimod_die;
static LIST_HEAD(kafstimod_list);
static DEFINE_SPINLOCK(kafstimod_lock);
static int kafstimod(void *arg);
/*
* start the timeout daemon
*/
int afs_kafstimod_start(void)
{
int ret;
ret = kernel_thread(kafstimod, NULL, 0);
if (ret < 0)
return ret;
wait_for_completion(&kafstimod_alive);
return ret;
}
/*
* stop the timeout daemon
*/
void afs_kafstimod_stop(void)
{
/* get rid of my daemon */
kafstimod_die = 1;
wake_up(&kafstimod_sleepq);
wait_for_completion(&kafstimod_dead);
}
/*
* timeout processing daemon
*/
static int kafstimod(void *arg)
{
struct afs_timer *timer;
DECLARE_WAITQUEUE(myself, current);
printk("kAFS: Started kafstimod %d\n", current->pid);
daemonize("kafstimod");
complete(&kafstimod_alive);
/* loop around looking for things to attend to */
loop:
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&kafstimod_sleepq, &myself);
for (;;) {
unsigned long jif;
signed long timeout;
/* deal with the server being asked to die */
if (kafstimod_die) {
remove_wait_queue(&kafstimod_sleepq, &myself);
_leave("");
complete_and_exit(&kafstimod_dead, 0);
}
try_to_freeze();
/* discard pending signals */
afs_discard_my_signals();
/* work out the time to elapse before the next event */
spin_lock(&kafstimod_lock);
if (list_empty(&kafstimod_list)) {
timeout = MAX_SCHEDULE_TIMEOUT;
} else {
timer = list_entry(kafstimod_list.next,
struct afs_timer, link);
timeout = timer->timo_jif;
jif = jiffies;
if (time_before_eq((unsigned long) timeout, jif))
goto immediate;
timeout = (long) timeout - (long) jiffies;
}
spin_unlock(&kafstimod_lock);
schedule_timeout(timeout);
set_current_state(TASK_INTERRUPTIBLE);
}
/* the thing on the front of the queue needs processing
* - we come here with the lock held and timer pointing to the expired
* entry
*/
immediate:
remove_wait_queue(&kafstimod_sleepq, &myself);
set_current_state(TASK_RUNNING);
_debug("@@@ Begin Timeout of %p", timer);
/* dequeue the timer */
list_del_init(&timer->link);
spin_unlock(&kafstimod_lock);
/* call the timeout function */
timer->ops->timed_out(timer);
_debug("@@@ End Timeout");
goto loop;
}
/*
* (re-)queue a timer
*/
void afs_kafstimod_add_timer(struct afs_timer *timer, unsigned long timeout)
{
struct afs_timer *ptimer;
struct list_head *_p;
_enter("%p,%lu", timer, timeout);
spin_lock(&kafstimod_lock);
list_del(&timer->link);
/* the timer was deferred or reset - put it back in the queue at the
* right place */
timer->timo_jif = jiffies + timeout;
list_for_each(_p, &kafstimod_list) {
ptimer = list_entry(_p, struct afs_timer, link);
if (time_before(timer->timo_jif, ptimer->timo_jif))
break;
}
list_add_tail(&timer->link, _p); /* insert before stopping point */
spin_unlock(&kafstimod_lock);
wake_up(&kafstimod_sleepq);
_leave("");
}
/*
* dequeue a timer
* - returns 0 if the timer was deleted or -ENOENT if it wasn't queued
*/
int afs_kafstimod_del_timer(struct afs_timer *timer)
{
int ret = 0;
_enter("%p", timer);
spin_lock(&kafstimod_lock);
if (list_empty(&timer->link))
ret = -ENOENT;
else
list_del_init(&timer->link);
spin_unlock(&kafstimod_lock);
wake_up(&kafstimod_sleepq);
_leave(" = %d", ret);
return ret;
}
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