[$] Auditing io_uring

The io_uring subsystem, first introduced in2019, has quickly become the leading way to perform high-bandwidth,asynchronous I/O. It has drawn the attention of many developers, including,more recently,those who are focused more on security than performance. Now some membersof the security community are lamenting a perceived lack of thought about security support inio_uring, and are trying to remedy that shortcoming by adding audit andLinux security module support there. That process is proving difficult,and has raised the prospect of an unpleasant fallback solution.