Re: [PATCH v9 1/4] liburing: add api to set napi busy poll settings

[Jens Axboe <axboe@kernel.dk>]

On Feb 2, 2024, at 1:11 PM, Olivier Langlois <olivier@trillion01.com> wrote:
> 
> On Fri, 2024-02-02 at 10:48 -0700, Jens Axboe wrote:
>>> On Feb 2, 2024, at 10:41 AM, Olivier Langlois
>>> <olivier@trillion01.com> wrote:
>>> 
>>> On Fri, 2024-02-02 at 09:42 -0700, Jens Axboe wrote:
>>>>> On 2/2/24 9:41 AM, Olivier Langlois wrote:
>>>>> On Tue, 2023-04-25 at 11:20 -0700, Stefan Roesch wrote:
>>>>>> +
>>>>>> +int io_uring_register_napi(struct io_uring *ring, struct
>>>>>> io_uring_napi *napi)
>>>>>> +{
>>>>>> +    return __sys_io_uring_register(ring->ring_fd,
>>>>>> +                IORING_REGISTER_NAPI, napi, 0);
>>>>>> +}
>>>>>> +
>>>>>> +int io_uring_unregister_napi(struct io_uring *ring, struct
>>>>>> io_uring_napi *napi)
>>>>>> +{
>>>>>> +    return __sys_io_uring_register(ring->ring_fd,
>>>>>> +                IORING_UNREGISTER_NAPI, napi,
>>>>>> 0);
>>>>>> +}
>>>>> 
>>>>> my apologies if this is not the latest version of the patch but
>>>>> I
>>>>> think
>>>>> that it is...
>>>>> 
>>>>> nr_args should be 1 to match what __io_uring_register() in the
>>>>> current
>>>>> corresponding kernel patch expects:
>>>>> 
>>>>> https://git.kernel.dk/cgit/linux/commit/?h=io_uring-napi&id=787d81d3132aaf4eb4a4a5f24ff949e350e537d0
>>>> 
>>>> Can you send a patch I can fold in?
>>>> 
>>> Jens,
>>> 
>>> I am unsure of what you are asking me.
>>> 
>>> You would like me to send a patch to fix a liburing patch that has
>>> never been applied AFAIK?
>>> 
>>> if the v9 patch has never been applied. Wouldn't just editing
>>> Stefan
>>> patch by replacing the nr_args param from 0 to 1 directly do it?
>> 
>> The current version is what is in that branch you referenced. If you
>> see anything in there that needs changing, send a patch for that.
>> 
>> I can send out the series again if needed.
>> 
> AFAIK, the kernel patch is fine.
> 
> my comment was referring the liburing patch that is calling
> __sys_io_uring_register() by passing a nr_args value of 0.
> 
> This is problematic because on the kernel side, io_uring_register()
> returns -EINVAL if nr_args is not 1.

Ah gotcha, yeah that’s odd and could not ever have worked. I wonder how that was tested…

I’ll setup a liburing branch as well.


— 
Jens Axboe