TCMU_DEV_BIT_BLOCKED
if (test_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags)) {
clear_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags);
if (test_and_set_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags))
if (test_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags))