Subject: Re: [PATCH 1/2] remove CONFIG_HAVE_ARCH_DEV_ALLOC_SKB

From: Christoph Hellwig <[email-masked]>
Date: Wed, 26 Jul 2006 09:58:25 +0200

On Mon, Jul 24, 2006 at 03:44:15PM -0700, Roland Dreier wrote:
> > skbuff.h has an #ifndef CONFIG_HAVE_ARCH_DEV_ALLOC_SKB to allow
> > architectures to reimplement __dev_alloc_skb.  It's not set on any
> > architecture and now that we have an architecture-overrideable
> > NET_SKB_PAD there is not point at all to have one either.
> 
> I missed this when hch first posted it, sorry.
> 
> But my impression was that the intent of the config option was to let
> Xen hook __dev_alloc_skb() to allocate special receive skbs to handle
> their page-flipping virtual network device.  Which goes beyond
> NET_SKB_PAD.
> 
> So the real question is about Xen hooks I guess -- and given where the
> rest of Xen is, it probably does make sense to go ahead and strip this
> out.

If xen wants to use something else then dev_alloc_skb in their virtual
network driver that's totall fine.  No need to override the definiton of
dev_alloc_skb for that, though.  They can add their own xen_alloc_skb or
opencode the operation they want for it.

Note that overriding dev_alloc_skb is not just utterly pointless but would
even be harmfull in the case they'd finally add pci support for non-dom0
domains and used normaly NIC drivers in there.