Subject: Re: [Question] net: dsa: tag_qca: QCA tag and headroom size?

From: Andrew Lunn <[email-masked]>
Date: Thu, 13 Feb 2020 13:53:32 +0100

On Thu, Feb 13, 2020 at 05:23:59AM +0000, Per Förlin wrote:
> 
> > > -     if (skb_cow_head(skb, 0) < 0)
> > > >  Is it really safe to assume there is enough headroom for the QCA tag?
> > >
> > > +     if (skb_cow_head(skb, QCA_HDR_LEN) < 0)
> > > > My proposal. Specify QCA tag size to make sure there is headroom.
> > >
> > >               return NULL;
> > >
> > >       skb_push(skb, QCA_HDR_LEN);
> 
> > > Hi Per
> 
> > > Yes, your change looks correct. ar9331_tag_xmit() also seems to have
> > > the same problem.
> 
> >> Do you want to submit a patch?
> Thanks for your response,

> I can submit a patch on both drivers, however I only have hardware
> to perform an actual test on the QCA switch.

Hi Per

That is fine. This should be low risk. Cc: Oleksij Rempel
<[email-masked]> when you post the patch, so he can review and
test it.

Thanks
	Andrew