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b97bf3fd PL |
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 | * Redistributions of source code must retain the above copyright notice, this | |
13 | * list of conditions and the following disclaimer. | |
14 | * Redistributions in binary form must reproduce the above copyright notice, | |
15 | * this list of conditions and the following disclaimer in the documentation | |
16 | * and/or other materials provided with the distribution. | |
17 | * Neither the names of the copyright holders nor the names of its | |
18 | * contributors may be used to endorse or promote products derived from this | |
19 | * software without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
22 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
25 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
26 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
27 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
30 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
31 | * POSSIBILITY OF SUCH DAMAGE. | |
32 | */ | |
33 | ||
34 | #include "core.h" | |
35 | ||
36 | struct queue_item { | |
37 | struct list_head next_signal; | |
38 | void (*handler) (unsigned long); | |
39 | unsigned long data; | |
40 | }; | |
41 | ||
42 | static kmem_cache_t *tipc_queue_item_cache; | |
43 | static struct list_head signal_queue_head; | |
44 | static spinlock_t qitem_lock = SPIN_LOCK_UNLOCKED; | |
45 | static int handler_enabled = 0; | |
46 | ||
47 | static void process_signal_queue(unsigned long dummy); | |
48 | ||
49 | static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0); | |
50 | ||
51 | ||
52 | unsigned int k_signal(Handler routine, unsigned long argument) | |
53 | { | |
54 | struct queue_item *item; | |
55 | ||
56 | if (!handler_enabled) { | |
57 | err("Signal request ignored by handler\n"); | |
58 | return -ENOPROTOOPT; | |
59 | } | |
60 | ||
61 | spin_lock_bh(&qitem_lock); | |
62 | item = kmem_cache_alloc(tipc_queue_item_cache, GFP_ATOMIC); | |
63 | if (!item) { | |
64 | err("Signal queue out of memory\n"); | |
65 | spin_unlock_bh(&qitem_lock); | |
66 | return -ENOMEM; | |
67 | } | |
68 | item->handler = routine; | |
69 | item->data = argument; | |
70 | list_add_tail(&item->next_signal, &signal_queue_head); | |
71 | spin_unlock_bh(&qitem_lock); | |
72 | tasklet_schedule(&tipc_tasklet); | |
73 | return 0; | |
74 | } | |
75 | ||
76 | static void process_signal_queue(unsigned long dummy) | |
77 | { | |
78 | struct queue_item *__volatile__ item; | |
79 | struct list_head *l, *n; | |
80 | ||
81 | spin_lock_bh(&qitem_lock); | |
82 | list_for_each_safe(l, n, &signal_queue_head) { | |
83 | item = list_entry(l, struct queue_item, next_signal); | |
84 | list_del(&item->next_signal); | |
85 | spin_unlock_bh(&qitem_lock); | |
86 | item->handler(item->data); | |
87 | spin_lock_bh(&qitem_lock); | |
88 | kmem_cache_free(tipc_queue_item_cache, item); | |
89 | } | |
90 | spin_unlock_bh(&qitem_lock); | |
91 | } | |
92 | ||
93 | int handler_start(void) | |
94 | { | |
95 | tipc_queue_item_cache = | |
96 | kmem_cache_create("tipc_queue_items", sizeof(struct queue_item), | |
97 | 0, SLAB_HWCACHE_ALIGN, NULL, NULL); | |
98 | if (!tipc_queue_item_cache) | |
99 | return -ENOMEM; | |
100 | ||
101 | INIT_LIST_HEAD(&signal_queue_head); | |
102 | tasklet_enable(&tipc_tasklet); | |
103 | handler_enabled = 1; | |
104 | return 0; | |
105 | } | |
106 | ||
107 | void handler_stop(void) | |
108 | { | |
109 | struct list_head *l, *n; | |
110 | struct queue_item *item; | |
111 | ||
112 | if (!handler_enabled) | |
113 | return; | |
114 | ||
115 | handler_enabled = 0; | |
116 | tasklet_disable(&tipc_tasklet); | |
117 | tasklet_kill(&tipc_tasklet); | |
118 | ||
119 | spin_lock_bh(&qitem_lock); | |
120 | list_for_each_safe(l, n, &signal_queue_head) { | |
121 | item = list_entry(l, struct queue_item, next_signal); | |
122 | list_del(&item->next_signal); | |
123 | kmem_cache_free(tipc_queue_item_cache, item); | |
124 | } | |
125 | spin_unlock_bh(&qitem_lock); | |
126 | ||
127 | kmem_cache_destroy(tipc_queue_item_cache); | |
128 | } | |
129 |