doc: deprecation notice for change of ether struct alignment

  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(+)
  

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.
  

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