Subject: Re: [PATCH] net: linearizing skb when downgrade gso_size

From: Fred Li <[email-masked]>
Date: Fri, 12 Jul 2024 16:17:24 +0800

> No need for ternary statement.
> 
> Instead of the complex test in skb_is_nonsg, can we just assume that
> alignment will be off if having frag_list and changing gso_size.
> 
> The same will apply to bpf_skb_net_shrink too.

increase gso_size may be no problem and we can use BPF_F_ADJ_ROOM_FIXED_GSO
to avoid update gso_size when shrink.

> 
> Not sure that it is okay to linearize inside a BPF helper function.
> Hopefully bpf experts can chime in on that.

Thanks

Fred Li