aboutsummaryrefslogtreecommitdiff
path: root/net/tipc/handler.c
blob: e4bc8a2967447fbde1f39d0d19146f2c7848ac99 (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
/*
 * net/tipc/handler.c: TIPC signal handling
 *
 * Copyright (c) 2000-2006, Ericsson AB
 * Copyright (c) 2005, Wind River Systems
 * 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.
 * 3. Neither the names of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

#include "core.h"

struct queue_item {
	struct list_head next_signal;
	void (*handler) (unsigned long);
	unsigned long data;
};

static struct kmem_cache *tipc_queue_item_cache;
static struct list_head signal_queue_head;
static DEFINE_SPINLOCK(qitem_lock);
static int handler_enabled __read_mostly;

static void process_signal_queue(unsigned long dummy);

static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0);


unsigned int tipc_k_signal(Handler routine, unsigned long argument)
{
	struct queue_item *item;

	spin_lock_bh(&qitem_lock);
	if (!handler_enabled) {
		pr_err("Signal request ignored by handler\n");
		spin_unlock_bh(&qitem_lock);
		return -ENOPROTOOPT;
	}

	item = kmem_cache_alloc(tipc_queue_item_cache, GFP_ATOMIC);
	if (!item) {
		pr_err("Signal queue out of memory\n");
		spin_unlock_bh(&qitem_lock);
		return -ENOMEM;
	}
	item->handler = routine;
	item->data = argument;
	list_add_tail(&item->next_signal, &signal_queue_head);
	spin_unlock_bh(&qitem_lock);
	tasklet_schedule(&tipc_tasklet);
	return 0;
}

static void process_signal_queue(unsigned long dummy)
{
	struct queue_item *__volatile__ item;
	struct list_head *l, *n;

	spin_lock_bh(&qitem_lock);
	list_for_each_safe(l, n, &signal_queue_head) {
		item = list_entry(l, struct queue_item, next_signal);
		list_del(&item->next_signal);
		spin_unlock_bh(&qitem_lock);
		item->handler(item->data);
		spin_lock_bh(&qitem_lock);
		kmem_cache_free(tipc_queue_item_cache, item);
	}
	spin_unlock_bh(&qitem_lock);
}

int tipc_handler_start(void)
{
	tipc_queue_item_cache =
		kmem_cache_create("tipc_queue_items", sizeof(struct queue_item),
				  0, SLAB_HWCACHE_ALIGN, NULL);
	if (!tipc_queue_item_cache)
		return -ENOMEM;

	INIT_LIST_HEAD(&signal_queue_head);
	tasklet_enable(&tipc_tasklet);
	handler_enabled = 1;
	return 0;
}

void tipc_handler_stop(void)
{
	struct list_head *l, *n;
	struct queue_item *item;

	spin_lock_bh(&qitem_lock);
	if (!handler_enabled) {
		spin_unlock_bh(&qitem_lock);
		return;
	}
	handler_enabled = 0;
	spin_unlock_bh(&qitem_lock);

	tasklet_kill(&tipc_tasklet);

	spin_lock_bh(&qitem_lock);
	list_for_each_safe(l, n, &signal_queue_head) {
		item = list_entry(l, struct queue_item, next_signal);
		list_del(&item->next_signal);
		kmem_cache_free(tipc_queue_item_cache, item);
	}
	spin_unlock_bh(&qitem_lock);

	kmem_cache_destroy(tipc_queue_item_cache);
}