[TIPC] License header update
[linux-2.6.git] / net / tipc / handler.c
1 /*
2  * net/tipc/handler.c: TIPC signal handling
3  * 
4  * Copyright (c) 2003-2005, Ericsson Research Canada
5  * Copyright (c) 2005, Wind River Systems
6  * Copyright (c) 2005-2006, Ericsson AB
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the names of the copyright holders nor the names of its
18  *    contributors may be used to endorse or promote products derived from
19  *    this software without specific prior written permission.
20  *
21  * Alternatively, this software may be distributed under the terms of the
22  * GNU General Public License ("GPL") version 2 as published by the Free
23  * Software Foundation.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
26  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
29  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37
38 #include "core.h"
39
40 struct queue_item {
41         struct list_head next_signal;
42         void (*handler) (unsigned long);
43         unsigned long data;
44 };
45
46 static kmem_cache_t *tipc_queue_item_cache;
47 static struct list_head signal_queue_head;
48 static spinlock_t qitem_lock = SPIN_LOCK_UNLOCKED;
49 static int handler_enabled = 0;
50
51 static void process_signal_queue(unsigned long dummy);
52
53 static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0);
54
55
56 unsigned int k_signal(Handler routine, unsigned long argument)
57 {
58         struct queue_item *item;
59
60         if (!handler_enabled) {
61                 err("Signal request ignored by handler\n");
62                 return -ENOPROTOOPT;
63         }
64
65         spin_lock_bh(&qitem_lock);
66         item = kmem_cache_alloc(tipc_queue_item_cache, GFP_ATOMIC);
67         if (!item) {
68                 err("Signal queue out of memory\n");
69                 spin_unlock_bh(&qitem_lock);
70                 return -ENOMEM;
71         }
72         item->handler = routine;
73         item->data = argument;
74         list_add_tail(&item->next_signal, &signal_queue_head);
75         spin_unlock_bh(&qitem_lock);
76         tasklet_schedule(&tipc_tasklet);
77         return 0;
78 }
79
80 static void process_signal_queue(unsigned long dummy)
81 {
82         struct queue_item *__volatile__ item;
83         struct list_head *l, *n;
84
85         spin_lock_bh(&qitem_lock);
86         list_for_each_safe(l, n, &signal_queue_head) {
87                 item = list_entry(l, struct queue_item, next_signal);
88                 list_del(&item->next_signal);
89                 spin_unlock_bh(&qitem_lock);
90                 item->handler(item->data);
91                 spin_lock_bh(&qitem_lock);
92                 kmem_cache_free(tipc_queue_item_cache, item);
93         }
94         spin_unlock_bh(&qitem_lock);
95 }
96
97 int handler_start(void)
98 {
99         tipc_queue_item_cache = 
100                 kmem_cache_create("tipc_queue_items", sizeof(struct queue_item),
101                                   0, SLAB_HWCACHE_ALIGN, NULL, NULL);
102         if (!tipc_queue_item_cache)
103                 return -ENOMEM;
104
105         INIT_LIST_HEAD(&signal_queue_head);
106         tasklet_enable(&tipc_tasklet);
107         handler_enabled = 1;
108         return 0;
109 }
110
111 void handler_stop(void)
112 {
113         struct list_head *l, *n;
114         struct queue_item *item; 
115
116         if (!handler_enabled)
117                 return;
118
119         handler_enabled = 0;
120         tasklet_disable(&tipc_tasklet);
121         tasklet_kill(&tipc_tasklet);
122
123         spin_lock_bh(&qitem_lock);
124         list_for_each_safe(l, n, &signal_queue_head) {
125                 item = list_entry(l, struct queue_item, next_signal);
126                 list_del(&item->next_signal);
127                 kmem_cache_free(tipc_queue_item_cache, item);
128         }
129         spin_unlock_bh(&qitem_lock);
130
131         kmem_cache_destroy(tipc_queue_item_cache);
132 }
133