[dpdk-dev] [dpdk-dev v2 1/2] ethdev: add new tunnel type for ecpri

[Thomas Monjalon]

08/01/2021 11:43, Ferruh Yigit:
> On 1/8/2021 10:23 AM, Thomas Monjalon wrote:
> > 08/01/2021 10:22, Ferruh Yigit:
> >> On 1/7/2021 1:33 PM, Thomas Monjalon wrote:
> >>> 07/01/2021 13:47, Zhang, Qi Z:
> >>>> From: Thomas Monjalon <thomas at monjalon.net>
> >>>>> 07/01/2021 10:32, Guo, Jia:
> >>>>>> From: Thomas Monjalon <thomas at monjalon.net>
> >>>>>>> Sorry, it is a nack.
> >>>>>>> BTW, it is probably breaking the ABI because of RTE_TUNNEL_TYPE_MAX.
> >>>>
> >>>> Yes that may break the ABI but fortunately the checking-abi-compatibility tool shows negative :) , thanks Ferruh' s guide.
> >>>> https://github.com/ferruhy/dpdk/actions/runs/468859673
> >>>
> >>> That's very strange. An enum value is changed.
> >>> Why it is not flagged by libabigail?
> >>
> >> As long as the enum values not sent to the application and kept within the
> >> library, changing their values shouldn't be problem.
> > 
> > But RTE_TUNNEL_TYPE_MAX is part of lib/librte_ethdev/rte_ethdev.h
> > so it is exposed to the application.
> > I think it is a case of ABI breakage.
> 
> Yes it is exposed to the application. But in runtime does it exchanged between 
> library and application is the issue I think.
> For this case it seems it is not, so not an ABI break.

If I create a table of size RTE_TUNNEL_TYPE_MAX with DPDK 20.11,
I will get an overflow when writing to the new ECPRI index.
The question is: can I receive the ECPRI value dynamically from ethdev?
If yes, it is an ABI breakage. But I cannot think of such case now.