Re: [RFC v1 0/3] introduce io_uring querying

[Pavel Begunkov <asml.silence@gmail.com>]

On 8/27/25 16:35, Jens Axboe wrote:
> On 8/27/25 7:21 AM, Pavel Begunkov wrote:
>> Introduce a versatile interface to query auxilary io_uring parameters.
>> It will be used to close a couple of API gaps, but in this series can
>> only tell what request and register opcodes, features and setup flags
>> are available. It'll replace IORING_REGISTER_PROBE  but with a much
>> more convenient interface. Patch 3 for API description.
>>
>> Can be tested with:
>>
>> https://github.com/isilence/liburing.git io_uring/query-v1
>>
>> Note: RFC as I've got a last minute uapi adjustment I want to try.
> 
> Nice, was actually just dabbling in this yesterday, there are some
> half assed patches here:
> 
> https://git.kernel.dk/cgit/linux/log/?h=io_uring-features

I can add some of it if you need them, e.g. enter_flags sounds
like a good idea, sqe flags is probably as well. Buffers/files
can go into a separate type.

> Your patch I had the identical one of, but moved it to a separate header
> instead for adding more limits.
> 
> But I like your query style better than Yet Another
> struct-with-resv-fields. I think that direction is good for sure.

A single struct with reserved fields won't help with my main use
case either, i.e. rings/SQ/CQ size calculation. That requires a
good bunch of parameters to be passed.

-- 
Pavel Begunkov