diff --git a/common/rc b/common/rc
index 8e5282c1..23f86ce6 100644
--- a/common/rc
+++ b/common/rc
@@ -3777,7 +3777,7 @@ _get_available_space()
 # return device size in kb
 _get_device_size()
 {
-	grep -w `_short_dev $1` /proc/partitions | awk '{print $3}'
+	echo $(($(blockdev --getsz $1) >> 1))
 }
 
 # Make sure we actually have dmesg checking set up.