NFSD: Replace READ* macros that decode the fattr4 mode attribute

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index ac2f259..e6c3b67 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -351,8 +351,11 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
 	} else
 		*acl = NULL;
 	if (bmval[1] & FATTR4_WORD1_MODE) {
-		READ_BUF(4);
-		iattr->ia_mode = be32_to_cpup(p++);
+		u32 mode;
+
+		if (xdr_stream_decode_u32(argp->xdr, &mode) < 0)
+			return nfserr_bad_xdr;
+		iattr->ia_mode = mode;
 		iattr->ia_mode &= (S_IFMT | S_IALLUGO);
 		iattr->ia_valid |= ATTR_MODE;
 	}