blockdev: add usage comment, no code changes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/util-linux/blockdev.c b/util-linux/blockdev.c
index e9b5b8bf9d2d426d7f7d138126f625d50d798862..e60bbe60944ec486c57c4bf8d0440746d8c772ee 100644 (file)
--- a/util-linux/blockdev.c
+++ b/util-linux/blockdev.c
@@ -29,7 +29,17 @@
 //usage:     "\n       --getsize64     Get device size in bytes"
 //usage:     "\n       --flushbufs     Flush buffers"
 //usage:     "\n       --rereadpt      Reread partition table"
-
+// util-linux 2.31 also has:
+//     --getdiscardzeroes      BLKDISCARDZEROES        Get discard zeroes support status
+//     --getpbsz               BLKPBSZGET      Get physical block (sector) size
+//     --getiomin              BLKIOMIN        Get minimum I/O size
+//     --getioopt              BLKIOOPT        Get optimal I/O size
+//     --getalignoff           BLKALIGNOFF     Get alignment offset in bytes
+//     --getmaxsect            BLKSECTGET      Get max sectors per request
+//     --setra SECTORS         BLKRASET        Set readahead
+//     --getra                 BLKRAGET        Get readahead
+//     --setfra SECTORS        BLKFRASET       Set filesystem readahead
+//     --getfra                BLKFRAGET       Get filesystem readahead
 
 #include "libbb.h"
 #include <linux/fs.h>