DMF_BLOCK_IO_FOR_SUSPEND
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)))
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);