Initial commit for TRIM/DISCARD support

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/io_ddir.h b/io_ddir.h
index 87cded4..f83fc9b 100644
--- a/io_ddir.h
+++ b/io_ddir.h
@@ -8,6 +8,7 @@
 	DDIR_DATASYNC,
 	DDIR_SYNC_FILE_RANGE,
 	DDIR_WAIT,
+	DDIR_TRIM,
 	DDIR_INVAL = -1,
 };