NFS: Create a common results structure for reads and writes

Reads and writes have very similar results.  This patch combines the two
structs together with comments to show where the differing fields are
used.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index 461cd8b..5f61b83 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -103,7 +103,7 @@
 /*
  *	typedef opaque	nfsdata<>;
  */
-static int decode_nfsdata(struct xdr_stream *xdr, struct nfs_readres *result)
+static int decode_nfsdata(struct xdr_stream *xdr, struct nfs_pgio_res *result)
 {
 	u32 recvd, count;
 	__be32 *p;
@@ -857,7 +857,7 @@
  *	};
  */
 static int nfs2_xdr_dec_readres(struct rpc_rqst *req, struct xdr_stream *xdr,
-				struct nfs_readres *result)
+				struct nfs_pgio_res *result)
 {
 	enum nfs_stat status;
 	int error;
@@ -878,7 +878,7 @@
 }
 
 static int nfs2_xdr_dec_writeres(struct rpc_rqst *req, struct xdr_stream *xdr,
-				 struct nfs_writeres *result)
+				 struct nfs_pgio_res *result)
 {
 	/* All NFSv2 writes are "file sync" writes */
 	result->verf->committed = NFS_FILE_SYNC;