On Thu, Nov 29, 2018 at 1:46 PM Eric Dumazet <eric.duma...@gmail.com> wrote: > > > > On 11/29/2018 01:13 PM, Duyck, Alexander H wrote: > > > Instead of just checking for the max it might make more sense to do a > > check using skb_is_gso, and then if true use gso_segs, otherwise just > > default to 1. > > > > Also your bytes are going to be totally messed up as well since the > > headers are trimmed in the GSO frames. It might be worthwhile to just > > have a branch based on skb_is_gso that sets the packets and bytes based > > on the GSO values, and one that sets it for the default case. > > > Note that __dev_queue_xmit() is already doing that, no need > to re-implement in each driver. > > It calls qdisc_pkt_len_init(), meaning that drivers can use > qdisc_skb_cb(skb)->pkt_len instead of skb->len > > (Qdisc layers should not modify qdisc_skb_cb(skb)->pkt_len )
It should not modify, but, on the other hand, it is neither supposed to be used for non-qdisc layer. At very least, you have to audit each ->ndo_start_xmit() to see if it uses its own skb->cb first.
