NFSD: Replace READ* macros in nfsd4_decode_open_downgrade()

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4xdr.c

@@ -1172,21 +1172,19 @@ nfsd4_decode_open_confirm(struct nfsd4_compoundargs *argp, struct nfsd4_open_con
 static __be32
 nfsd4_decode_open_downgrade(struct nfsd4_compoundargs *argp, struct nfsd4_open_downgrade *open_down)
 {
-	DECODE_HEAD;
+	__be32 status;
 
-	status = nfsd4_decode_stateid(argp, &open_down->od_stateid);
+	status = nfsd4_decode_stateid4(argp, &open_down->od_stateid);
 	if (status)
 		return status;
-	READ_BUF(4);
-	open_down->od_seqid = be32_to_cpup(p++);
+	if (xdr_stream_decode_u32(argp->xdr, &open_down->od_seqid) < 0)
+		return nfserr_bad_xdr;
+	/* deleg_want is ignored */
 	status = nfsd4_decode_share_access(argp, &open_down->od_share_access,
 					   &open_down->od_deleg_want, NULL);
 	if (status)
 		return status;
-	status = nfsd4_decode_share_deny(argp, &open_down->od_share_deny);
-	if (status)
-		return status;
-	DECODE_TAIL;
+	return nfsd4_decode_share_deny(argp, &open_down->od_share_deny);
 }
 
 static __be32