summaryrefslogtreecommitdiffstats
path: root/net/rxrpc/krxtimod.c
blob: 3e7466900bd4e1260728ed63759d60794a88c69e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
/* krxtimod.c: RXRPC 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 <rxrpc/rxrpc.h>
#include <rxrpc/krxtimod.h>
#include <asm/errno.h>
#include "internal.h"

static DECLARE_COMPLETION(krxtimod_alive);
static DECLARE_COMPLETION(krxtimod_dead);
static DECLARE_WAIT_QUEUE_HEAD(krxtimod_sleepq);
static int krxtimod_die;

static LIST_HEAD(krxtimod_list);
static DEFINE_SPINLOCK(krxtimod_lock);

static int krxtimod(void *arg);

/*****************************************************************************/
/*
 * start the timeout daemon
 */
int rxrpc_krxtimod_start(void)
{
	int ret;

	ret = kernel_thread(krxtimod, NULL, 0);
	if (ret < 0)
		return ret;

	wait_for_completion(&krxtimod_alive);

	return ret;
} /* end rxrpc_krxtimod_start() */

/*****************************************************************************/
/*
 * stop the timeout daemon
 */
void rxrpc_krxtimod_kill(void)
{
	/* get rid of my daemon */
	krxtimod_die = 1;
	wake_up(&krxtimod_sleepq);
	wait_for_completion(&krxtimod_dead);

} /* end rxrpc_krxtimod_kill() */

/*****************************************************************************/
/*
 * timeout processing daemon
 */
static int krxtimod(void *arg)
{
	DECLARE_WAITQUEUE(myself, current);

	rxrpc_timer_t *timer;

	printk("Started krxtimod %d\n", current->pid);

	daemonize("krxtimod");

	complete(&krxtimod_alive);

	/* loop around looking for things to attend to */
 loop:
	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&krxtimod_sleepq, &myself);

	for (;;) {
		unsigned long jif;
		long timeout;

		/* deal with the server being asked to die */
		if (krxtimod_die) {
			remove_wait_queue(&krxtimod_sleepq, &myself);
			_leave("");
			complete_and_exit(&krxtimod_dead, 0);
		}

		try_to_freeze();

		/* discard pending signals */
		rxrpc_discard_my_signals();

		/* work out the time to elapse before the next event */
		spin_lock(&krxtimod_lock);
		if (list_empty(&krxtimod_list)) {
			timeout = MAX_SCHEDULE_TIMEOUT;
		}
		else {
			timer = list_entry(krxtimod_list.next,
					   rxrpc_timer_t, 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(&krxtimod_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(&krxtimod_sleepq, &myself);
	set_current_state(TASK_RUNNING);

	_debug("@@@ Begin Timeout of %p", timer);

	/* dequeue the timer */
	list_del_init(&timer->link);
	spin_unlock(&krxtimod_lock);

	/* call the timeout function */
	timer->ops->timed_out(timer);

	_debug("@@@ End Timeout");
	goto loop;

} /* end krxtimod() */

/*****************************************************************************/
/*
 * (re-)queue a timer
 */
void rxrpc_krxtimod_add_timer(rxrpc_timer_t *timer, unsigned long timeout)
{
	struct list_head *_p;
	rxrpc_timer_t *ptimer;

	_enter("%p,%lu", timer, timeout);

	spin_lock(&krxtimod_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, &krxtimod_list) {
		ptimer = list_entry(_p, rxrpc_timer_t, link);
		if (time_before(timer->timo_jif, ptimer->timo_jif))
			break;
	}

	list_add_tail(&timer->link, _p); /* insert before stopping point */

	spin_unlock(&krxtimod_lock);

	wake_up(&krxtimod_sleepq);

	_leave("");
} /* end rxrpc_krxtimod_add_timer() */

/*****************************************************************************/
/*
 * dequeue a timer
 * - returns 0 if the timer was deleted or -ENOENT if it wasn't queued
 */
int rxrpc_krxtimod_del_timer(rxrpc_timer_t *timer)
{
	int ret = 0;

	_enter("%p", timer);

	spin_lock(&krxtimod_lock);

	if (list_empty(&timer->link))
		ret = -ENOENT;
	else
		list_del_init(&timer->link);

	spin_unlock(&krxtimod_lock);

	wake_up(&krxtimod_sleepq);

	_leave(" = %d", ret);
	return ret;
} /* end rxrpc_krxtimod_del_timer() */
OpenPOWER on IntegriCloud