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-rw-r--r--net/tipc/handler.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/net/tipc/handler.c b/net/tipc/handler.c
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+++ b/net/tipc/handler.c
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+/*
+ * 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:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * 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.
+ * 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.
+ *
+ * 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);
+}
+