__QUEUE_STATE_STACK_XOFF
set_bit(__QUEUE_STATE_STACK_XOFF, &dev_queue->state);
clear_bit(__QUEUE_STATE_STACK_XOFF, &dev_queue->state);
if (test_and_clear_bit(__QUEUE_STATE_STACK_XOFF, &dev_queue->state))
clear_bit(__QUEUE_STATE_STACK_XOFF, &q->state);
#define QUEUE_STATE_STACK_XOFF (1 << __QUEUE_STATE_STACK_XOFF)