/* krxiod.c: Rx I/O 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/sched.h>
#include <linux/completion.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/freezer.h>
#include <rxrpc/krxiod.h>
#include <rxrpc/transport.h>
#include <rxrpc/peer.h>
#include <rxrpc/call.h>
#include "internal.h"
static DECLARE_WAIT_QUEUE_HEAD(rxrpc_krxiod_sleepq);
static DECLARE_COMPLETION(rxrpc_krxiod_dead);
static atomic_t rxrpc_krxiod_qcount = ATOMIC_INIT(0);
static LIST_HEAD(rxrpc_krxiod_transportq);
static DEFINE_SPINLOCK(rxrpc_krxiod_transportq_lock);
static LIST_HEAD(rxrpc_krxiod_callq);
static DEFINE_SPINLOCK(rxrpc_krxiod_callq_lock);
static volatile int rxrpc_krxiod_die;
/*****************************************************************************/
/*
* Rx I/O daemon
*/
static int rxrpc_krxiod(void *arg)
{
DECLARE_WAITQUEUE(krxiod,current);
printk("Started krxiod %d\n",current->pid);
daemonize("krxiod");
/* loop around waiting for work to do */
do {
/* wait for work or to be told to exit */
_debug("### Begin Wait");
if (!atomic_read(&rxrpc_krxiod_qcount)) {
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&rxrpc_krxiod_sleepq, &krxiod);
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
if (atomic_read(&rxrpc_krxiod_qcount) ||
rxrpc_krxiod_die ||
signal_pending(current))
break;
schedule();
}
remove_wait_queue(&rxrpc_krxiod_sleepq, &krxiod);
set_current_state(TASK_RUNNING);
}
_debug("### End Wait");
/* do work if been given some to do */
_debug("### Begin Work");
/* see if there's a transport in need of attention */
if (!list_empty(&rxrpc_krxiod_transportq)) {
struct rxrpc_transport *trans = NULL;
spin_lock_irq(&rxrpc_krxiod_transportq_lock);
if (!list_empty(&rxrpc_krxiod_transportq)) {
trans = list_entry(
rxrpc_krxiod_transportq.next,
struct rxrpc_transport,
krxiodq_link);
list_del_init(&trans->krxiodq_link);
atomic_dec(&rxrpc_krxiod_qcount);
/* make sure it hasn't gone away and doesn't go
* away */
if (atomic_read(&trans->usage)>0)
rxrpc_get_transport(trans);
else
trans = NULL;
}
spin_unlock_irq(&rxrpc_krxiod_transportq_lock);
if (trans) {
rxrpc_trans_receive_packet(trans);
rxrpc_put_transport(trans);
}
}
/* see if there's a call in need of attention */
if (!list_empty(&rxrpc_krxiod_callq)) {
struct rxrpc_call *call = NULL;
spin_lock_irq(&rxrpc_krxiod_callq_lock);
if (!list_empty(&rxrpc_krxiod_callq)) {
call = list_entry(rxrpc_krxiod_callq.next,
struct rxrpc_call,
rcv_krxiodq_lk);
list_del_init(&call->rcv_krxiodq_lk);
atomic_dec(&rxrpc_krxiod_qcount);
/* make sure it hasn't gone away and doesn't go
* away */
if (atomic_read(&call->usage) > 0) {
_debug("@@@ KRXIOD"
" Begin Attend Call %p", call);
rxrpc_get_call(call);
}
else {
call = NULL;
}
}
spin_unlock_irq(&rxrpc_krxiod_callq_lock);
if (call) {
rxrpc_call_do_stuff(call);
rxrpc_put_call(call);
_debug("@@@ KRXIOD End Attend Call %p", call);
}
}
_debug("### End Work");
try_to_freeze();
/* discard pending signals */
rxrpc_discard_my_signals();
} while (!rxrpc_krxiod_die);
/* and that's all */
complete_and_exit(&rxrpc_krxiod_dead, 0);
} /* end rxrpc_krxiod() */
/*****************************************************************************/
/*
* start up a krxiod daemon
*/
int __init rxrpc_krxiod_init(void)
{
return kernel_thread(rxrpc_krxiod, NULL, 0);
} /* end rxrpc_krxiod_init() */
/*****************************************************************************/
/*
* kill the krxiod daemon and wait for it to complete
*/
void rxrpc_krxiod_kill(void)
{
rxrpc_krxiod_die = 1;
wake_up_all(&rxrpc_krxiod_sleepq);
wait_for_completion(&rxrpc_krxiod_dead);
} /* end rxrpc_krxiod_kill() */
/*****************************************************************************/
/*
* queue a transport for attention by krxiod
*/
void rxrpc_krxiod_queue_transport(struct rxrpc_transport *trans)
{
unsigned long flags;
_enter("");
if (list_empty(&trans->krxiodq_link)) {
spin_lock_irqsave(&rxrpc_krxiod_transportq_lock, flags);
if (list_empty(&trans->krxiodq_link)) {
if (atomic_read(&trans->usage) > 0) {
list_add_tail(&trans->krxiodq_link,
&rxrpc_krxiod_transportq);
atomic_inc(&rxrpc_krxiod_qcount);
}
}
spin_unlock_irqrestore(&rxrpc_krxiod_transportq_lock, flags);
wake_up_all(&rxrpc_krxiod_sleepq);
}
_leave("");
} /* end rxrpc_krxiod_queue_transport() */
/*****************************************************************************/
/*
* dequeue a transport from krxiod's attention queue
*/
void rxrpc_krxiod_dequeue_transport(struct rxrpc_transport *trans)
{
unsigned long flags;
_enter("");
spin_lock_irqsave(&rxrpc_krxiod_transportq_lock, flags);
if (!list_empty(&trans->krxiodq_link)) {
list_del_init(&trans->krxiodq_link);
atomic_dec(&rxrpc_krxiod_qcount);
}
spin_unlock_irqrestore(&rxrpc_krxiod_transportq_lock, flags);
_leave("");
} /* end rxrpc_krxiod_dequeue_transport() */
/*****************************************************************************/
/*
* queue a call for attention by krxiod
*/
void rxrpc_krxiod_queue_call(struct rxrpc_call *call)
{
unsigned long flags;
if (list_empty(&call->rcv_krxiodq_lk)) {
spin_lock_irqsave(&rxrpc_krxiod_callq_lock, flags);
if (atomic_read(&call->usage) > 0) {
list_add_tail(&call->rcv_krxiodq_lk,
&rxrpc_krxiod_callq);
atomic_inc(&rxrpc_krxiod_qcount);
}
spin_unlock_irqrestore(&rxrpc_krxiod_callq_lock, flags);
}
wake_up_all(&rxrpc_krxiod_sleepq);
} /* end rxrpc_krxiod_queue_call() */
/*****************************************************************************/
/*
* dequeue a call from krxiod's attention queue
*/
void rxrpc_krxiod_dequeue_call(struct rxrpc_call *call)
{
unsigned long flags;
spin_lock_irqsave(&rxrpc_krxiod_callq_lock, flags);
if (!list_empty(&call->rcv_krxiodq_lk)) {
list_del_init(&call->rcv_krxiodq_lk);
atomic_dec(&rxrpc_krxiod_qcount);
}
spin_unlock_irqrestore(&rxrpc_krxiod_callq_lock, flags);
} /* end rxrpc_krxiod_dequeue_call() */
