Sorry. I was thinking the pointer of io_uring will be passed with
io_uring_setup. My fault.
> 2020年8月5日 下午1:17，Jiufei Xue <jiufei.xue@xxxxxxxxxxxxxxxxx> 写道：
>
>
>
> On 2020/8/5 上午11:28, Carter Li 李通洲 wrote:
>>> diff --git a/src/include/liburing.h b/src/include/liburing.h
>>> index 0505a4f..82c2980 100644
>>> --- a/src/include/liburing.h
>>> +++ b/src/include/liburing.h
>>> @@ -56,6 +56,9 @@ struct io_uring {
>>> struct io_uring_sq sq;
>>> struct io_uring_cq cq;
>>> unsigned flags;
>>> + unsigned flags_internal;
>>> + unsigned features;
>>> + unsigned pad[4];
>>> int ring_fd;
>>> };
>>
>> Won't it break existing code runs on newer kernel?
>
> io_uring is a structure that used in userspace. It breaks the API
> with existing compiled application. So I have changed the soname
> to 2.0.7.
>
> And for syscall io_uring_enter(), I have added a new feature bit
> IORING_FEAT_GETEVENTS_TIMEOUT and io_uring_enter() flag
> IORING_ENTER_GETEVENTS_TIMEOUT. Here are 3 cases below:
>
> 1) old liburing <-> new kernel: old liburing can not pass the flag
> IORING_ENTER_GETEVENTS_TIMEOUT, so new kernel will parse the arguments
> the original way.
>
> 2) new liburing <-> old kernel: feature IORING_FEAT_GETEVENTS_TIMEOUT
> not supported, liburing will do things like before.
>
> 3) new liburing <-> new kernel: feature IORING_FEAT_GETEVENTS_TIMEOUT
> supported, liburing pass the new arguments with the flag
> IORING_ENTER_GETEVENTS_TIMEOUT which helps kernel parse the arguments
> correctly.
>
> Thanks,
> Jiufei.
>
>> Won't it break code compiled with new liburing but runs on older kernel?
>>
>
>> IMO In this case, a new syscall `io_uring_setup2` is required at least.
>>
>> Regards,
>> Carter
