[linux-2.6-block.git] / net / tipc / handler.c

/*
 * net/tipc/handler.c: TIPC signal handling
 * 
 * Copyright (c) 2003-2005, Ericsson Research Canada
 * Copyright (c) 2005, Wind River Systems
 * Copyright (c) 2005-2006, Ericsson AB
 * 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 kmem_cache_t *tipc_queue_item_cache;
static struct list_head signal_queue_head;
static spinlock_t qitem_lock = SPIN_LOCK_UNLOCKED;
static int handler_enabled = 0;

static void process_signal_queue(unsigned long dummy);

static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0);


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

	if (!handler_enabled) {
		err("Signal request ignored by handler\n");
		return -ENOPROTOOPT;
	}

	spin_lock_bh(&qitem_lock);
	item = kmem_cache_alloc(tipc_queue_item_cache, GFP_ATOMIC);
	if (!item) {
		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 handler_start(void)
{
	tipc_queue_item_cache = 
		kmem_cache_create("tipc_queue_items", sizeof(struct queue_item),
				  0, SLAB_HWCACHE_ALIGN, NULL, NULL);
	if (!tipc_queue_item_cache)
		return -ENOMEM;

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

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

	if (!handler_enabled)
		return;

	handler_enabled = 0;
	tasklet_disable(&tipc_tasklet);
	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);
}
Commit	Line	Data
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	*
9ea1fd3c	9	* Redistribution and use in source and binary forms, with or without
b97bf3fd PL	10	* modification, are permitted provided that the following conditions are met:
b97bf3fd PL	11	*
9ea1fd3c PL	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.
b97bf3fd	20	*
9ea1fd3c PL	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
b97bf3fd PL	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