2 * net/tipc/handler.c: TIPC signal handling
4 * Copyright (c) 2003-2005, Ericsson Research Canada
5 * Copyright (c) 2005, Wind River Systems
6 * Copyright (c) 2005-2006, Ericsson AB
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22 * GNU General Public License ("GPL") version 2 as published by the Free
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41 struct list_head next_signal;
42 void (*handler) (unsigned long);
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;
51 static void process_signal_queue(unsigned long dummy);
53 static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0);
56 unsigned int k_signal(Handler routine, unsigned long argument)
58 struct queue_item *item;
60 if (!handler_enabled) {
61 err("Signal request ignored by handler\n");
65 spin_lock_bh(&qitem_lock);
66 item = kmem_cache_alloc(tipc_queue_item_cache, GFP_ATOMIC);
68 err("Signal queue out of memory\n");
69 spin_unlock_bh(&qitem_lock);
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);
80 static void process_signal_queue(unsigned long dummy)
82 struct queue_item *__volatile__ item;
83 struct list_head *l, *n;
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);
94 spin_unlock_bh(&qitem_lock);
97 int handler_start(void)
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)
105 INIT_LIST_HEAD(&signal_queue_head);
106 tasklet_enable(&tipc_tasklet);
111 void handler_stop(void)
113 struct list_head *l, *n;
114 struct queue_item *item;
116 if (!handler_enabled)
120 tasklet_disable(&tipc_tasklet);
121 tasklet_kill(&tipc_tasklet);
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);
129 spin_unlock_bh(&qitem_lock);
131 kmem_cache_destroy(tipc_queue_item_cache);