BLK_SYNC_QUEUE(9) Block Devices BLK_SYNC_QUEUE(9)NAME
blk_sync_queue - cancel any pending callbacks on a queue
void blk_sync_queue(struct request_queue * q);
The block layer may perform asynchronous callback activity on a queue,
such as calling the unplug function after a timeout. A block device may
call blk_sync_queue to ensure that any such activity is cancelled, thus
allowing it to release resources that the callbacks might use. The
caller must already have made sure that its ->make_request_fn will not
re-add plugging prior to calling this function.
This function does not cancel any asynchronous activity arising out of
elevator or throttling code. That would require elevaotor_exit and
blkcg_exit_queue to be called with queue lock initialized.
COPYRIGHTKernel Hackers Manual 3.8. June 2014 BLK_SYNC_QUEUE(9)