SUNRPC: New xdr_streams XDR decoder API

Now that all client-side XDR decoder routines use xdr_streams, there
should be no need to support the legacy calling sequence [rpc_rqst *,
__be32 *, RPC res *] anywhere.  We can construct an xdr_stream in the
generic RPC code, instead of in each decoder function.

This is a refactoring change.  It should not cause different behavior.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index d446a32..4e8210d 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1535,7 +1535,7 @@
 {
 	struct rpc_clnt	*clnt = task->tk_client;
 	struct rpc_rqst	*req = task->tk_rqstp;
-	kxdrproc_t	decode = task->tk_msg.rpc_proc->p_decode;
+	kxdrdproc_t	decode = task->tk_msg.rpc_proc->p_decode;
 	__be32		*p;
 
 	dprintk("RPC: %5u call_decode (status %d)\n",
@@ -1780,7 +1780,7 @@
 {
 }
 
-static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
+static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
 {
 	return 0;
 }