io-wq: use helper for worker refcounting

Use io_worker_release() instead of hand coding it in io_worker_exit().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6f95f09d2cdbafcbb2e22ad0d1a2bc4d3962bf65.1634987320.git.asml.silence@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/io-wq.c

@@ -178,8 +178,7 @@ static void io_worker_exit(struct io_worker *worker)
 {
 	struct io_wqe *wqe = worker->wqe;
 
-	if (refcount_dec_and_test(&worker->ref))
-		complete(&worker->ref_done);
+	io_worker_release(worker);
 	wait_for_completion(&worker->ref_done);
 
 	raw_spin_lock(&wqe->lock);