Re: [PATCH mptcp-next v6 1/3] mptcp: pm: userspace: drop delete_local_addr helper

Hi Geliang,

On 24/07/2026 20:48, Matthieu Baerts wrote:
> Hi Geliang,
> 
> On 27/06/2026 00:45, Geliang Tang wrote:
>> From: Geliang Tang <[email protected]>
>>
>> Address entries should not be removed from local_addr_list when a subflow
>> is deleted by the userspace PM, should only be removed when sending a
>> REMOVE_ADDR.
>>
>> So mptcp_userspace_pm_delete_local_addr() helper shouldn't be called in
>> mptcp_pm_nl_subflow_create_doit() and mptcp_pm_nl_subflow_destroy_doit().
>>
>> Since this helper is open-coding in mptcp_pm_nl_remove_doit(), it can be
>> dropped now.
>>
>> Address entries are removed from local_addr_list when sending a REMOVE_ADDR
>> by the userspace PM, the local_addr_used counter of PM should also be
>> decremented accordingly.
> 
> I was re-reviewing this series after having read the comments from Sashiko:
> 
> https://sashiko.dev/#/patchset/[email protected]
> 
> I think the series is correct, but it feels like additional fixes are
> required:
> 
> - msk->pm.userspace_pm_local_addr_list doesn't contain an entry for the
> ID0 when initialised
>   - That's probably fine, but then it means the ID0 case needs to be
> handled separately, like it is with the in-kernel PM.
>   - Or maybe easier to add it when the userspace PM is used, to avoid
> all these exceptions?
>     - If yes, then the remove_doit should no longer handle the ID0
> differently as well.
>     - same for announce_doit?
>     - maybe better to do that to avoid all these exceptions?
> 
> - When creating a subflow with ID0, an entry can be added to the list
> (to be checked)
>   - If the ID0 is not added at init time, then an exception should be
> added there
>   - (also there is a check to avoid announcing ID0 → I think it is valid
> to re-announce the ID0 if this address is no longer used, an exception
> should be added there too, no?)
> 
> - each time the list is traversed, it doesn't take into account the ID0
> case:
>   - If the ID0 is not added at init time, then an extra check should be
> added there
> 
> WDYT?
> 
> If yes, maybe this kind of patch can help? (not tested)
> 
>   https://github.com/matttbe/mptcp_net-next/commit/e03ee2728e98

I just sent this: WDYT?

https://lore.kernel.org/mptcp/20260727-mptcp-pm-userspace-id0-case-v1-0-9877f02a9bae@kernel.org/

Would it be compatible with your series?

Cheers,
Matt
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