Re: [dpdk-dev] [PATCH v1 1/6] bbdev: add capability for CRC16 check

["Chautru, Nicolas" <nicolas.chautru@intel.com>]

Hi Thomas, 

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Monday, October 11, 2021 11:53 PM
> To: Chautru, Nicolas <nicolas.chautru@intel.com>
> Cc: gakhil@marvell.com; dev@dpdk.org; trix@redhat.com;
> hemant.agrawal@nxp.com; Zhang, Mingshan <mingshan.zhang@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v1 1/6] bbdev: add capability for CRC16
> check
> 
> 11/10/2021 22:38, Chautru, Nicolas:
> > From: Thomas Monjalon <thomas@monjalon.net>
> > > 13/08/2021 18:51, Nicolas Chautru:
> > > > Adding a missing operation when CRC16 is being used for TB CRC
> > > > check.
> > > >
> > > > Signed-off-by: Nicolas Chautru <nicolas.chautru@intel.com>
> > > > ---
> > > > --- a/doc/guides/rel_notes/release_21_11.rst
> > > > +++ b/doc/guides/rel_notes/release_21_11.rst
> > > > @@ -84,6 +84,7 @@ API Changes
> > > >     Also, make sure to start the actual text at the margin.
> > > >
> =======================================================
> > > >
> > > > +* bbdev: Added capability related to more comprehensive CRC
> options.
> > >
> > > That's not an API change, the enum symbols are the same.
> > > Only enum values are changed so it impacts only ABI.
> >
> > Hi Thomas,
> > How is that not a API change when new additional capability are exposed?
> Ie. new enums defined for new capabilities.
> 
> API change is when the app source code has to be updated.

Thanks. What you are referring to may be strictly API breakage as opposed to generic API change. I would expect an API change could be either backward compatible (extending API but application only has to change if it wants to use the new functionality) vs an actual API breakage (application needs to change regardless even to keep same functionality as before). 
In case the intent is to use the 2 terms interchangeably (change vs breakage) then I agree that these 2 bbdev changes do not constitute an API breakage (only ABI). 
It might be good to capture this more explicitly except if you believe this is obvious (doc describes ABI change, not API change). Regardless for next time I will use that distinction (change == breakage). 
Thanks

> ABI change is when the app binary has to be rebuilt.
>
> > I think I see other similar cases in the same release notes " * cryptodev:
> ``RTE_CRYPTO_AEAD_LIST_END`` from ``enum rte_crypto_aead_algo ...".
> 
> I don't see this one.
> 
> > You know best, just checking the intent, maybe worth clarifying the
> guideline except in case this is just me.
> 
> Given my explanation above, how would you classify your change?
> 
>