Leverage XOR to simplify the code in __io_worker_busy.
Signed-off-by: NHao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/1617678525-3129-1-git-send-email-haoxu@linux.alibaba.comSigned-off-by: NJens Axboe <axboe@kernel.dk>