/* kafstimod.c: 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 "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; } /* end afs_kafstimod_start() */ /*****************************************************************************/ /* * 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); } /* end afs_kafstimod_stop() */ /*****************************************************************************/ /* * 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(PF_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; else { 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; } /* end kafstimod() */ /*****************************************************************************/ /* * (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(""); } /* end afs_kafstimod_add_timer() */ /*****************************************************************************/ /* * 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; } /* end afs_kafstimod_del_timer() */