[v7 1/1] net/af_xdp: fix multi interface support for K8s

[Ferruh Yigit]

On 1/11/2024 12:21 PM, Maryam Tahhan wrote:
> On 11/01/2024 11:35, Ferruh Yigit wrote:
>> Devarg is user interface, changing it impacts the user.
>>
>> Assume that user of '22.11.3' using 'use_cni' dev_arg, it will be broken
>> when user upgrades DPDK to '22.11.4', which is not expected.
>>
>> dev_arg is not API/ABI but as it impacts the user, it is in the gray
>> area to backport to the LTS release.
> Fair enough
>> Current patch doesn't have Fixes tag or stable tag, so it doesn't
>> request to be backported to LTS release. I took this as an improvement,
>> more than a fix.
> 
> This was overlooked by me apologies. It's been a while since I've
> contributed to DPDK and I must've missed this detail in the contribution
> guide.
>> As far as I understand existing code (that use 'use_cni' dev_arg)
>> supports only single netdev, this patch adds support for multiple netdevs.
> 
> The use_cni implementation will no longer work with the AF_XDP DP as the
> use_cni was originally implemented as it has hard coded what's now an
> incorrect path for the UDS.
> 
>> So what do you think keep LTS with 'use_cni' dev_arg, is there a
>> requirement to update LTS release?
>> If so, can it be an option to keep 'use_cni' for backward compatibility
>> but add only add 'uds_path' and remove 'use_cni' in next LTS?
> 
> 
> Yeah we can go back to the version of the patch that had the 'use_cni'
> flag that was used in combination with the path argument. We can add
> better documentation re the "use_cni" misnomer... What we can then do is
> if no path argument is set by the user assume their intent and and
> generate the path internally in the AF_XDP PMD (which was suggested by
> Shibin at some stage). That way there should be no surprises to the End
> User.
> 

Ack, this keeps backward compatibility,

BUT if 'use_cni' is already broken in v23.11 (that is what I understand
from your above comment), means there is no user of it in LTS, and we
can be more pragmatic and replace the dev_args, by backporting this
patch, assuming LTS maintainer is also OK with it.


> Long term I would like to keep a (renamed) path argument (in case the
> path does ever change from the AF_XDP DP POV) and use it also in
> combination with another (maybe boolean) param for passing pinned bpf
> maps rather than another separate path.
> 
> WDYT? Would this work for the LTS release?
> 
>