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Date:   Tue, 26 Mar 2019 11:31:15 +0100
From:   Michal Kubecek <mkubecek@suse.cz>
To:     Jiri Pirko <jiri@resnulli.us>
Cc:     David Miller <davem@davemloft.net>, netdev@vger.kernel.org,
        Jakub Kicinski <jakub.kicinski@netronome.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        John Linville <linville@tuxdriver.com>,
        Stephen Hemminger <stephen@networkplumber.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v5 01/22] rtnetlink: provide permanent hardware
 address in RTM_NEWLINK
Message-ID: <20190326103115.GI26076@unicorn.suse.cz>
References: <cover.1553532199.git.mkubecek@suse.cz>
 <16ffb1fbfa8f54de587ac52f4ff95e5034c590b4.1553532199.git.mkubecek@suse.cz>
 <20190326100836.GA2230@nanopsycho>
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On Tue, Mar 26, 2019 at 11:08:36AM +0100, Jiri Pirko wrote:
> 
> 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.

Michal