sunrpc: properly type argument to kxdreproc_t

Pass struct rpc_request as the first argument instead of an untyped blob,
and mark the data object as const.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

include/linux/sunrpc/xdr.h

@@ -17,6 +17,8 @@
 #include <asm/unaligned.h>
 #include <linux/scatterlist.h>
 
+struct rpc_rqst;
+
 /*
  * Buffer adjustment
  */
@@ -222,7 +224,8 @@ struct xdr_stream {
 /*
  * These are the xdr_stream style generic XDR encode and decode functions.
  */
-typedef void	(*kxdreproc_t)(void *rqstp, struct xdr_stream *xdr, void *obj);
+typedef void	(*kxdreproc_t)(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
+		const void *obj);
 typedef int	(*kxdrdproc_t)(void *rqstp, struct xdr_stream *xdr, void *obj);
 
 extern void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);

net/sunrpc/clnt.c

@@ -2476,7 +2476,8 @@ out_overflow:
 	goto out_garbage;
 }
 
-static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
+static void rpcproc_encode_null(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
+		const void *obj)
 {
 }