> > But the minimum fragment size is (probably) 4k.
> > For the network stack an OUT transfer might have a lot (and I mean lots)
> > of fragments (there may be constraints, and linearising the skb is a
> > option).
> [...]
>
> The maximum number of fragments in the skb is going to be 17 (including
> the 'head' area). (I'm ignoring NETIF_F_FRAGLIST which is not normally
> supported by physical device drivers.)
>
> I don't know how many fragments that can end up as, at the USB level.
If you assume that every fragment crosses a 64k boundary that would be 34.
OTOH I've not seen a fragment of a 64k TSO send crossing a 32k
boundary, and I think the 'head' area is constrained to be part of
a single (4k or larger) page.
Isn't there something odd about skb merged by receive offload?
I've not entirely sorted out the full structure of skb.
David
