On Wed, Aug 5, 2020 at 2:16 PM Kinsella, Ray <m...@ashroe.eu> wrote: > > > > On 04/08/2020 17:20, Stephen Hemminger wrote: > > On Tue, 4 Aug 2020 11:41:53 +0100 > > Bruce Richardson <bruce.richard...@intel.com> wrote: > > > >> On Mon, Aug 03, 2020 at 12:59:03PM +0530, pbhagavat...@marvell.com wrote: > >>> From: Pavan Nikhilesh <pbhagavat...@marvell.com> > >>> > >>> Add 64 byte padding at the end of event device public structure to allow > >>> future extensions. > >>> > >>> Signed-off-by: Pavan Nikhilesh <pbhagavat...@marvell.com> > >>> Acked-by: Jerin Jacob <jer...@marvell.com> > >>> --- > >>> v2 Changes: > >>> - Modify commit title. > >>> - Add patch reference to doc. > >>> > >>> doc/guides/rel_notes/deprecation.rst | 11 +++++++++++ > >>> 1 file changed, 11 insertions(+) > >>> > >>> diff --git a/doc/guides/rel_notes/deprecation.rst > >>> b/doc/guides/rel_notes/deprecation.rst > >>> index ea4cfa7a4..ec5db68e9 100644 > >>> --- a/doc/guides/rel_notes/deprecation.rst > >>> +++ b/doc/guides/rel_notes/deprecation.rst > >>> @@ -151,3 +151,14 @@ Deprecation Notices > >>> Python 2 support will be completely removed in 20.11. > >>> In 20.08, explicit deprecation warnings will be displayed when running > >>> scripts with Python 2. > >>> + > >>> +* eventdev: A 64 byte padding is added at the end of the following > >>> structures > >>> + in event device library to support future extensions: > >>> + ``rte_event_crypto_adapter_conf``, ``rte_event_eth_rx_adapter_conf``, > >>> + ``rte_event_eth_rx_adapter_queue_conf``, > >>> ``rte_event_eth_tx_adapter_conf``, > >>> + ``rte_event_timer_adapter_conf``, ``rte_event_timer_adapter_info``, > >>> + ``rte_event_dev_info``, ``rte_event_dev_config``, > >>> ``rte_event_queue_conf``, > >>> + ``rte_event_port_conf``, ``rte_event_timer_adapter``, > >>> + ``rte_event_timer_adapter_data``. > >>> + Reference: > >>> + > >>> http://patches.dpdk.org/project/dpdk/list/?series=10728&archive=both&state=* > >>> -- > >> > >> I don't like this idea of adding lots of padding to the ends of these > >> structures. For some structures, such as the public arrays for devices it > >> may be necessary, but for all the conf structures passed as parameters to > >> functions I think we can do better. Since these structures are passed by > >> the user to various functions, function versioning can be used to ensure > >> that the correct function in eventdev is always called. From there to the > >> individual PMDs, we can implement ABI compatibility by either: > >> 1. including the length of the struct as a parameter to the driver. (This > >> is > >> a bit similar to my proposal for rawdev [1]) > >> 2. including the ABI version as a parameter to the driver. > >> > >> Regards > >> /Bruce > >> > >> [1] http://inbox.dpdk.org/dev/?q=enhance+rawdev+APIs > > > > This is a bad idea. > > > > Reserved fields won't work because nothing requires that the application > > zero them. You can't start using them later because the application > > may put uninitialized or junk data there. > > > > +1, to Stephens comments.
Since the problem is not specific to one substem, if we need to add a field in config structures, What will the expected way of handling across the DPDK? How about 1) Public init functions to clear the params? 2) Different struct version for specific functions like http://mails.dpdk.org/archives/dev/2020-August/177357.html Or any other scheme in mind?
