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

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

fs/nfsd/nfs4xdr.c

@@ -358,7 +358,6 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
 {
 	unsigned int starting_pos;
 	u32 attrlist4_count;
-	u32 dummy32;
 
 	DECODE_HEAD;
 	iattr->ia_valid = 0;
@@ -474,13 +473,16 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
 			return status;
 	}
 	if (bmval[2] & FATTR4_WORD2_MODE_UMASK) {
+		u32 mode, mask;
+
 		if (!umask)
-			goto xdr_error;
-		READ_BUF(8);
-		dummy32 = be32_to_cpup(p++);
-		iattr->ia_mode = dummy32 & (S_IFMT | S_IALLUGO);
-		dummy32 = be32_to_cpup(p++);
-		*umask = dummy32 & S_IRWXUGO;
+			return nfserr_bad_xdr;
+		if (xdr_stream_decode_u32(argp->xdr, &mode) < 0)
+			return nfserr_bad_xdr;
+		iattr->ia_mode = mode & (S_IFMT | S_IALLUGO);
+		if (xdr_stream_decode_u32(argp->xdr, &mask) < 0)
+			return nfserr_bad_xdr;
+		*umask = mask & S_IRWXUGO;
 		iattr->ia_valid |= ATTR_MODE;
 	}