
static int io_req_defer_prep(struct io_kiocb *req)
{
	if (!io_op_defs[req->opcode].needs_async_data)
		return 0;
	/* some opcodes init it during the inital prep */
	if (req->async_data)
		return 0;
	if (__io_alloc_async_data(req))
		return -EAGAIN;
	return io_req_prep_async(req);

static int io_req_defer_prep(struct io_kiocb *req)
{
	if (!io_op_defs[req->opcode].needs_async_data)
		return 0;
	 
	if (req->async_data)
		return 0;
	if (__io_alloc_async_data(req))
		return -EAGAIN;
	return io_req_prep_async(req);