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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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.
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.
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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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
);