Re: [dpdk-dev] [PATCH] doc: deprecation notice for change of ether struct alignment

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Jul 09, 2019 at 07:59:53AM -0700, Stephen Hemminger wrote:
> On Tue,  9 Jul 2019 15:58:36 +0100
> Bruce Richardson <bruce.richardson@intel.com> wrote:
> 
> > The ethernet address structure alignment will be changed to 2B alignment in
> > 19.11. Flag this to users.
> > 
> > Impact is expected to be minimal for this change since ethernet addresses
> > are generally 2B aligned anyway.
> > 
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> > ---
> >  doc/guides/rel_notes/deprecation.rst | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> > index a7796f49b..7a04b9b09 100644
> > --- a/doc/guides/rel_notes/deprecation.rst
> > +++ b/doc/guides/rel_notes/deprecation.rst
> > @@ -11,6 +11,11 @@ API and ABI deprecation notices are to be posted here.
> >  Deprecation Notices
> >  -------------------
> >  
> > +* net: The alignment of the ethernet address structure in DPDK,
> > +  ``rte_ether_addr`` will be increased to two, i.e. 16-bit aligned, in the
> > +  19.11 release. This will only affect any data structures where an ethernet
> > +  address is currently aligned on a single byte boundary.
> > +
> >  * meson: The minimum supported version of meson for configuring and building
> >    DPDK will be increased to v0.47.1 (from 0.41) from DPDK 19.05 onwards. For
> >    those users with a version earlier than 0.47.1, an updated copy of meson
> 
> We should also take the packed off of ether_header and ether_addr.
> Packed is meaningless on ether_addr anyway.

Agreed. However, I don't think that needs to be called out here as it's a
code change with zero impact. The user-impacting change is the alignment
one.

/Bruce