blockdev: add usage comment, no code changes

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

1 files changed, 11 insertions, 1 deletions

diff --git a/util-linux/blockdev.c b/util-linux/blockdev.c
index e9b5b8bf9..e60bbe609 100644
--- 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>