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/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 498ab93..a21cf53 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -33,8 +33,8 @@
 };
 
 /*
- * This is the generic XDR function. rqstp is either a rpc_rqst (client
- * side) or svc_rqst pointer (server side).
+ * This is the legacy generic XDR function. rqstp is either a rpc_rqst
+ * (client side) or svc_rqst pointer (server side).
  * Encode functions always assume there's enough room in the buffer.
  */
 typedef int	(*kxdrproc_t)(void *rqstp, __be32 *data, void *obj);
@@ -203,6 +203,11 @@
 	struct kvec *iov;	/* pointer to the current kvec */
 };
 
+/*
+ * This is the xdr_stream style generic XDR function.
+ */
+typedef void	(*kxdreproc_t)(void *rqstp, struct xdr_stream *xdr, void *obj);
+
 extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
 extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
 extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,