diff --git a/Documentation/device-mapper/delay.txt b/Documentation/device-mapper/delay.txt
index 15adc55359e5..a07b5927f4a8 100644
--- a/Documentation/device-mapper/delay.txt
+++ b/Documentation/device-mapper/delay.txt
@@ -8,6 +8,7 @@ Parameters:
     <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
 
 With separate write parameters, the first set is only used for reads.
+Offsets are specified in sectors.
 Delays are specified in milliseconds.
 
 Example scripts
diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c
index 9a4362d53508..b4c356a21123 100644
--- a/drivers/md/dm-delay.c
+++ b/drivers/md/dm-delay.c
@@ -122,6 +122,7 @@ static void flush_expired_bios(struct work_struct *work)
  *    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
  *
  * With separate write parameters, the first set is only used for reads.
+ * Offsets are specified in sectors.
  * Delays are specified in milliseconds.
  */
 static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)