1/* 2 * net/tipc/handler.c: TIPC signal handling 3 * 4 * Copyright (c) 2000-2006, Ericsson AB 5 * Copyright (c) 2005, Wind River Systems 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the names of the copyright holders nor the names of its 17 * contributors may be used to endorse or promote products derived from 18 * this software without specific prior written permission. 19 * 20 * Alternatively, this software may be distributed under the terms of the 21 * GNU General Public License ("GPL") version 2 as published by the Free 22 * Software Foundation. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 25 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 28 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 * POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37#include "core.h" 38 39struct queue_item { 40 struct list_head next_signal; 41 void (*handler) (unsigned long); 42 unsigned long data; 43}; 44 45static struct kmem_cache *tipc_queue_item_cache; 46static struct list_head signal_queue_head; 47static DEFINE_SPINLOCK(qitem_lock); 48static int handler_enabled = 0; 49 50static void process_signal_queue(unsigned long dummy); 51 52static DECLARE_TASKLET_DISABLED(tipc_tasklet, process_signal_queue, 0); 53 54 55unsigned int tipc_k_signal(Handler routine, unsigned long argument) 56{ 57 struct queue_item *item; 58 59 if (!handler_enabled) { 60 err("Signal request ignored by handler\n"); 61 return -ENOPROTOOPT; 62 } 63 64 spin_lock_bh(&qitem_lock); 65 item = kmem_cache_alloc(tipc_queue_item_cache, GFP_ATOMIC); 66 if (!item) { 67 err("Signal queue out of memory\n"); 68 spin_unlock_bh(&qitem_lock); 69 return -ENOMEM; 70 } 71 item->handler = routine; 72 item->data = argument; 73 list_add_tail(&item->next_signal, &signal_queue_head); 74 spin_unlock_bh(&qitem_lock); 75 tasklet_schedule(&tipc_tasklet); 76 return 0; 77} 78 79static void process_signal_queue(unsigned long dummy) 80{ 81 struct queue_item *__volatile__ item; 82 struct list_head *l, *n; 83 84 spin_lock_bh(&qitem_lock); 85 list_for_each_safe(l, n, &signal_queue_head) { 86 item = list_entry(l, struct queue_item, next_signal); 87 list_del(&item->next_signal); 88 spin_unlock_bh(&qitem_lock); 89 item->handler(item->data); 90 spin_lock_bh(&qitem_lock); 91 kmem_cache_free(tipc_queue_item_cache, item); 92 } 93 spin_unlock_bh(&qitem_lock); 94} 95 96int tipc_handler_start(void) 97{ 98 tipc_queue_item_cache = 99 kmem_cache_create("tipc_queue_items", sizeof(struct queue_item), 100 0, SLAB_HWCACHE_ALIGN, NULL, NULL); 101 if (!tipc_queue_item_cache) 102 return -ENOMEM; 103 104 INIT_LIST_HEAD(&signal_queue_head); 105 tasklet_enable(&tipc_tasklet); 106 handler_enabled = 1; 107 return 0; 108} 109 110void tipc_handler_stop(void) 111{ 112 struct list_head *l, *n; 113 struct queue_item *item; 114 115 if (!handler_enabled) 116 return; 117 118 handler_enabled = 0; 119 tasklet_disable(&tipc_tasklet); 120 tasklet_kill(&tipc_tasklet); 121 122 spin_lock_bh(&qitem_lock); 123 list_for_each_safe(l, n, &signal_queue_head) { 124 item = list_entry(l, struct queue_item, next_signal); 125 list_del(&item->next_signal); 126 kmem_cache_free(tipc_queue_item_cache, item); 127 } 128 spin_unlock_bh(&qitem_lock); 129 130 kmem_cache_destroy(tipc_queue_item_cache); 131} 132