DMF_SUSPENDED
set_bit(DMF_SUSPENDED, &md->flags);
r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED);
clear_bit(DMF_SUSPENDED, &md->flags);
set_bit(DMF_SUSPENDED, &md->flags);
return test_bit(DMF_SUSPENDED, &md->flags);