Re: [PATCH] hashed device lookup (Does NOT meet Linus' sumission

[Matti Aarnio]

On Sun, Jan 07, 2001 at 02:10:52PM -0500, jamal wrote:
> On Sun, 7 Jan 2001, Matti Aarnio wrote:
> > 	Read what I wrote about the issue to Alan.
> > 	Ben's code has no problems with receiving VLANs with network
> > 	cards which have "hardware support" for VLANs.
> 
> OK. I suppose an skb->vlan_tag is passed to the driver and it will know
> what to do with it (pass it on a descriptor etc).

	Sure, nice.  WHY SHOULD THERE BE MORE LAYER-2 STUFF ADDED TO
	SKB OBJECTS ?

	One of important abstraction issues is to isolate device specific
	new things (like what VLAN/PVC/SVC is used at your favourtite
	802.1Q/ATM/X.25/FrameRelay connection).

	The less we leak that kind of things to SKB, the better, IMO.
	They are net_device issues, after all.

	Tell me (if you can), why packet sender calls hardware-header
	generation for packet, if the card can insert it for you ?
	Consider the structure of Ethernet MAC header, where is source
	address ?  Where is the destination address ?  If you write the
	destination, why should you not write the source there too ?

	No doubt some cards can fill in the source address while doing
	frame transmit, but is it worth the hazzle ?

> cheers,
> jamal

/Matti Aarnio