NLM: Don't hang forever on NLM unlock requests

If the NLM daemon is killed on the NFS server, we can currently end up
hanging forever on an 'unlock' request, instead of aborting. Basically,
if the rpcbind request fails, or the server keeps returning garbage, we
really want to quit instead of retrying.

Tested-by: Vasily Averin <vvs@sw.ru>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
{
	spin_lock_bh(&queue->lock);
	rpc_wake_up_task_queue_locked(queue, task);
	spin_unlock_bh(&queue->lock);
}

void rpc_wake_up_queued_task(struct rpc_wait_queue *queue, struct rpc_task *task)
{
	spin_lock_bh(&queue->lock);
	rpc_wake_up_task_queue_locked(queue, task);
	spin_unlock_bh(&queue->lock);
}
