Re: [PATCH net 1/1] bonding: fix PACKET_ORIGDEV regression on bonding masters

[David Miller <davem@davemloft.net>]

From: Michal Soltys <soltys@ziu.info>
Date: Mon,  7 Jan 2019 17:29:46 +0100

> This patch reverts:
> 
> b89f04c61efe bonding: deliver link-local packets with skb->dev set to link that packets arrived on
> 
> And its subsequent fixups:
> 
> 6a9e461f6fe4 bonding: pass link-local packets to bonding master also.
> 0f3b914c9cfc bonding: fix warning message
> 
> The intended functionality of the original patch (as explained by its
> author) has been available in the kernel since v2.6.21-350-g80feaacb8a64
> via PACKET_ORIGDEV socket option. The patch also broke that feature, as
> it's now no longer possible to get the original incoming device. Quoting
> the report:
> 
>> Unfortunately, this doesn't completely restore the previous
>> functionality as PACKET_ORIGDEV is broken for the copy: the original
>> interface is lost through the call to netif_rx(). A LLDP daemon
>> listening to the master interface won't get the original interface like
>> it was able to before 4.12.
> 
> The patch reverts to pre-b89f04c61efe state, so:
> 
> - both master and original (via PACKET_ORIGDEV) devices are available
>   when listening on the master
> - original device is available when listening directly on one of its
>   slaves
> 
> Reported-by: Vincent Bernat <vincent@bernat.ch>
> Signed-off-by: Michal Soltys <soltys@ziu.info>

It is tiring and disappointing to see the behavior sway back and forth
multiple times like this.  We are breaking someone, then breaking them
again if they adjusted to the new behavior.

Pretty much unacceptable.

I'm not applying anything until someone can convince me the full scope
of the situation and why this time it's "right."