[IUCV]: wrong irq-disabling locking at module load time

Linux may hang when running af_iucv socket programs concurrently
with a load of module netiucv. iucv_register() tries to take the
iucv_table_lock with spin_lock_irq. This conflicts with
iucv_connect() which has a need for an smp_call_function while
holding the iucv_table_lock.
Solution: use bh-disabling locking in iucv_register()
Signed-off-by: NUrsula Braun <braunu@de.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/iucv/iucv.c

@@ -693,9 +693,9 @@ int iucv_register(struct iucv_handler *handler, int smp)
 		iucv_setmask_up();
 	INIT_LIST_HEAD(&handler->paths);
 
-	spin_lock_irq(&iucv_table_lock);
+	spin_lock_bh(&iucv_table_lock);
 	list_add_tail(&handler->list, &iucv_handler_list);
-	spin_unlock_irq(&iucv_table_lock);
+	spin_unlock_bh(&iucv_table_lock);
 	rc = 0;
 out_mutex:
 	mutex_unlock(&iucv_register_mutex);