/* expect a 16 byte uuid encoded as \xXXXX... */
        len = qword_get(mesg, buf, PAGE_SIZE);
-       if (len != 16)
+       if (len != EX_UUID_LEN)
                return -EINVAL;
 
-       *puuid = kmemdup(buf, 16, GFP_KERNEL);
+       *puuid = kmemdup(buf, EX_UUID_LEN, GFP_KERNEL);
        if (*puuid == NULL)
                return -ENOMEM;
 
                if (exp->ex_uuid) {
                        int i;
                        seq_puts(m, ",uuid=");
-                       for (i=0; i<16; i++) {
+                       for (i = 0; i < EX_UUID_LEN; i++) {
                                if ((i&3) == 0 && i)
                                        seq_putc(m, ':');
                                seq_printf(m, "%02x", exp->ex_uuid[i]);
 
                        *p++ = cpu_to_be32(MINOR(stat.dev));
                        break;
                case FSIDSOURCE_UUID:
-                       p = xdr_encode_opaque_fixed(p, exp->ex_uuid, 16);
+                       p = xdr_encode_opaque_fixed(p, exp->ex_uuid,
+                                                               EX_UUID_LEN);
                        break;
                }
        }