SUNRPC: Reduce asynchronous RPC task stack usage

We should just farm out asynchronous RPC tasks immediately to rpciod...
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/sched.c

@@ -699,8 +699,9 @@ static void __rpc_execute(struct rpc_task *task)
 void rpc_execute(struct rpc_task *task)
 {
 	rpc_set_active(task);
-	rpc_set_running(task);
-	__rpc_execute(task);
+	rpc_make_runnable(task);
+	if (!RPC_IS_ASYNC(task))
+		__rpc_execute(task);
 }
 
 static void rpc_async_schedule(struct work_struct *work)