SUNRPC: New xdr_streams XDR encoder API

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

Also, all the client-side encoder functions return 0 now, making a
return value superfluous.  Take this opportunity to convert them to
return void instead.

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/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 6529534..c363efd 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -499,34 +499,28 @@
 /*
  * NB: Without this zero space reservation, callbacks over krb5p fail
  */
-static int nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p, void *__unused)
+static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
+				 void *__unused)
 {
-	struct xdr_stream xdrs, *xdr = &xdrs;
-
-	xdr_init_encode(&xdrs, &req->rq_snd_buf, p);
 	xdr_reserve_space(xdr, 0);
-	return 0;
 }
 
 /*
  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
  */
-static int nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, __be32 *p,
-				  const struct nfsd4_callback *cb)
+static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
+				   const struct nfsd4_callback *cb)
 {
-	struct xdr_stream xdr;
 	const struct nfs4_delegation *args = cb->cb_op;
 	struct nfs4_cb_compound_hdr hdr = {
 		.ident = cb->cb_clp->cl_cb_ident,
 		.minorversion = cb->cb_minorversion,
 	};
 
-	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
-	encode_cb_compound4args(&xdr, &hdr);
-	encode_cb_sequence4args(&xdr, cb, &hdr);
-	encode_cb_recall4args(&xdr, args, &hdr);
+	encode_cb_compound4args(xdr, &hdr);
+	encode_cb_sequence4args(xdr, cb, &hdr);
+	encode_cb_recall4args(xdr, args, &hdr);
 	encode_cb_nops(&hdr);
-	return 0;
 }
 
 
@@ -583,7 +577,7 @@
 #define PROC(proc, call, argtype, restype)				\
 [NFSPROC4_CLNT_##proc] = {						\
 	.p_proc    = NFSPROC4_CB_##call,				\
-	.p_encode  = (kxdrproc_t)nfs4_xdr_enc_##argtype,		\
+	.p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,		\
 	.p_decode  = (kxdrproc_t)nfs4_xdr_dec_##restype,		\
 	.p_arglen  = NFS4_enc_##argtype##_sz,				\
 	.p_replen  = NFS4_dec_##restype##_sz,				\