BITMAP_IO
if (test_bit(BITMAP_IO, &device->flags))
if (ap_bio == 0 && test_bit(BITMAP_IO, &device->flags)) {
clear_bit_unlock(BITMAP_IO, &device->flags);
D_ASSERT(device, !test_bit(BITMAP_IO, &device->flags));
set_bit(BITMAP_IO, &device->flags);
wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));
wait_event(device->misc_wait, !test_bit(BITMAP_IO, &device->flags));