Re: [PATCH net-next v2 2/4] net: gso: support bounded TCP segmentation

[Wang Zhan <wang.zhan@smartx.com>]

On Sat, 19 Sep 2026 11:35:17 -0400 Willem de Bruijn wrote:
> > -		struct sk_buff *segs = __skb_gso_segment(skb, features, false);
> > +		struct sk_buff *segs;
> >  		struct sk_buff *next;
> > +		segs = __skb_gso_segment(skb, features, false, 0);
>
> irrelevant?

Not unrelated: with the extra argument that line is 82 columns, so the
initializer moved to its own line.  The call itself is unchanged.

> > +	unsigned int max_segs = SKB_GSO_CB(head_skb)->max_segs;
>
> could this be computed inside skb_segment, rather than having to be
> passed through SKB_GSO_CB. I haven't checked, but it would simplify.

I tried it: https://github.com/zwtop/linux/pull/3

It does read better, but whether to resegment is the caller's choice: the
qdiscs strip the GSO bits to get one packet per segment (sch_netem.c:443),
and a device-derived limit groups that output instead - which sch_netem then
drops, because skb_checksum_help() on the first segment rejects a GSO skb
(sch_netem.c:538, net/core/dev.c:3626).  The features cannot tell the two
cases apart either: gso_features_check() clears the same bits for an
over-limit skb (net/core/dev.c:3843).

So the bound stays an input from the caller.