Re: [PATCH v2] io_uring: Avoid polling configuration errors

From: hexue
Date: Tue Jul 16 2024 - 03:22:27 EST


On 7/15/24 10:59 AM, Jens Axboe wrote:
>On 7/14/24 8:39 PM, hexue wrote:
>>> My stance is still the same - why add all of this junk just to detect a
>>> misuse of polled IO? It doesn't make sense to me, it's the very
>>> definition of "doctor it hurts when I do this" - don't do it.
>>>
>>> So unless this has _zero_ overhead or extra code, which obviously isn't
>>> possible, or extraordinary arguments exists for why this should be
>>> added, I don't see this going anywhere.
>>
>> Actually, I just want users to know why they got wrong data, just a
>> warning of an error, like doctor tell you why you do this will hurt. I
>> think it's helpful for users to use tools accurately. and yes, this
>> should be as simple as possible, I'll working on it. I'm not sure if I
>> made myself clear and make sense to you?
>
>Certainly agree that that is an issue and a much more worthy reason for
>the addition. It's the main reason why -EOPNOTSUPP return would be more
>useful, and I'd probably argue the better way then to do it. It may
>indeed break existing use cases, but probably only because they are
>misconfigured.
>
>That then means that it'd be saner to do this on the block layer side,
>imho, as that's when the queue is resolved anyway, rather than attempt
>to hack around this on the issuing side.

Implementing it at the block layer is indeed more reasonable, thanks for
your affirmation and suggestion, I will look for an appropriate place in
the path to perform the check. Thanks.