/* * net/tipc/handler.c: TIPC signal handling * * Copyright (c) 2000-2006, Ericsson AB * Copyright (c) 2005, Wind River Systems * 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 struct kmem_cache *tipc_queue_item_cache;static struct list_head signal_queue_head;static DEFINE_SPINLOCK(qitem_lock);static int handler_enabled; static void process_signal_queue(unsigned long dummy); static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0);  unsigned int tipc_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 tipc_handler_start(void){	tipc_queue_item_cache =		kmem_cache_create("tipc_queue_items", sizeof(struct queue_item),				  0, SLAB_HWCACHE_ALIGN, NULL);	if (!tipc_queue_item_cache)		return -ENOMEM; 	INIT_LIST_HEAD(&signal_queue_head);	tasklet_enable(&tipc_tasklet);	handler_enabled = 1;	return 0;} void tipc_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);}