Re: [dpdk-dev] [PATCH v4 1/2] mbuf: use C11 atomic built-ins for refcnt operations

[David Marchand <david.marchand@redhat.com>]

On Thu, Jul 16, 2020 at 3:21 PM Dodji Seketeli <dodji@redhat.com> wrote:
> Just for the sake of precision, I'd like to say that in the coming 1.8
> version of libabigail, this change won't be reported by the tooling as a
> problem anymore.  This is thanks to David filing the feature request
> https://sourceware.org/bugzilla/show_bug.cgi?id=25661 a while ago.
>
> Until then, I understand that the current tooling needs to work with
> libabigail 1.6.

That's what we have in the CI with a 1.6 libabigail compiled in Ubuntu 18.04.

I tested 20.04 in Travis (I can send a patch later), but it still has
a 1.6 version.
We will have to live with a "not that recent" version for some time.


>
> So maybe a more specific suppression rule (that you could still remove
> for the 20.11 stable branch) could look like:
>
>     [suppress_type]
>            name = rte_mbuf_ext_shared_info
>            has_data_member_inserted_between = {offset_of(refcnt_atomic), offset_of(refcnt_atomic)}
>
>
> It's a "hack" that will only suppress change reports on the
> rte_mbuf_ext_shared_info type if:
>
>   1/ it it has a data member inserted at the
>      offset of its data member 'refcnt_atomic',
>
>      AND
>
>   2/ the size of rte_mbuf_ext_shared_info doesn't change.
>
>
> There are cases where this won't work, though.  But it might work for
> this case.  If it does, then great.  I think it'd be a better solution
> than a blanket suppression of all the changes on the type.

Nice, thanks Dodji.


-- 
David Marchand