Tue, Mar 26, 2019 at 11:31:15AM CET, mkubecek@suse.cz wrote:

On Tue, Mar 26, 2019 at 11:08:36AM +0100, Jiri Pirko wrote:

quoted

I don't think we should put permaddr if driver did not set it. 2
solutions:
1) provide a helper that driver will use to set the perm_addr. This
   helper sets a "valid bit". Then you only put IFLA_PERM_ADDRESS
   in case the "valid bit" is set.
2) Assuming that no driver would set permaddr to all zeroes,
   don't put IFLA_PERM_ADDRESS in case permadd is all zeroes.

I already replied to similar suggestion in v4 discussion:

 http://patchwork.ozlabs.org/patch/1060164/#2117512

But I don't have really strong opinion about this. The problem with not
being able to distinguish between "no/unknown permanent address" and
"old kernel not providing the information" is going to become less
important over time.

If the attribute is sent to userspace, it should mean the permaddr is
there and valid.

Michal