Re: skb_checksum_help

[Thomas Graf <tgraf@xxxxxxx>]

* David S. Miller <20050124194328.20a106de.davem@xxxxxxxxxxxxx> 2005-01-24 19:43
> On Tue, 25 Jan 2005 03:24:31 +0100
> Thomas Graf <tgraf@xxxxxxx> wrote:
> 
> > This of course explains it, didn't think of that. I thought it would
> > inherit the checksumming features.
> 
> It should, but only in very limited cases.
> 
> For example, it probably only works properly when HW vlan assist
> is being used on TX.  It's likely that the chips which don't support
> VLAN assist also can't handle VLAN headers in their TX checksumming
> engine.

I agreed, but those who have vlan accel are likely to be able to
also do the checksumming. 

> Because it is very chip dependant whether this works or not in
> any case, we should probably create a special features flag for
> this.  Something like NETIF_F_VLAN_INHERIT_FEATURES.

Can't we just use NETIF_F_HW_VLAN_TX for this and inherit
NETIF_F_HW_CSUM | NETIF_F_IP_CSUM if it is set? I don't have any
specs at hand though.