diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 7e22aa7..7ba70be 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1436,7 +1436,7 @@
 
 	{
 		char cap_str_2[10], cap_str_10[10];
-		u64 sz = sdkp->capacity << ffz(~sector_size);
+		u64 sz = (u64)sdkp->capacity << ilog2(sector_size);
 
 		string_get_size(sz, STRING_UNITS_2, cap_str_2,
 				sizeof(cap_str_2));