[Intel-wired-lan] [next PATCH 1/5] i40e: Introduce devlink interface.

[John Fastabend <john.fastabend@gmail.com>]

On 16-08-10 09:01 AM, Alexander Duyck wrote:
> On Thu, Aug 4, 2016 at 9:49 AM, Sridhar Samudrala
> <sridhar.samudrala@intel.com> wrote:
>> Add initial devlink support to set/get the mode of SRIOV switch.
>> This patch allows the mode to be set to either 'legacy' or 'switchdev', but
>> doesn't implement any functionality to create vf representors in switchdev
>> mode.
>>
>> With smode support in iproute2 'devlink' utility, switch mode can be set
>> and get via following commands.
>>
>>     # devlink dev smode pci/0000:05:00.0
>>     mode: legacy
>>     # devlink dev set pci/0000:05:00.0 smode switchdev
>>     # devlink dev smode pci/0000:05:00.0
>>     mode: switchdev
>>
>> Signed-off-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
> 
> I really don't see much value in this patch.  If you are going to
> support SwitchDev then just do it.  Otherwise you are adding extra
> overhead for maintaining two different modes.
> 
> I would recommend putting this series out to netdev as an RFC.
> Submitting it to intel-wired-lan is kind of pointless as the audience
> it to small to get any valuable review.
> 
> - Alex

I argued at length about this already. Jiri and company wanted this flag
to push device in and out of this mode. Here we are just following the
already upstreamed and debated decision.

This is less about switchdev and more about generating VF netdevs to
use with ip tools and friends.

Another option would be to just always enable VF netdevs and have no
legacy mode at all. I think that would be fine it just depends on if
you think having extra netdevs around will confuse the stack at all.
It might create a few corner cases but one reasonable thing to do
would be to just fix those cases as they appear.

Thanks,
John