Subject: Re: [PATCH v3 net-next 07/15] udp: Remove partial csum code in RX.

From: Jakub Kicinski <[email-masked]>
Date: Thu, 12 Mar 2026 18:04:15 -0700

On Wed, 11 Mar 2026 05:19:54 +0000 Kuniyuki Iwashima wrote:
> UDP-Lite supports the partial checksum and the coverage is
> stored in the position of the length field of struct udphdr.
> 
> In RX paths, udp4_csum_init() / udp6_csum_init() save the value
> in UDP_SKB_CB(skb)->cscov and set UDP_SKB_CB(skb)->partial_cov
> to 1 if the coverage is not full.
> 
> The subsequent processing diverges depending on the value,
> but such paths are now dead.
> 
> Also, these functions have some code guarded for UDP:
> 
>   * udp_unicast_rcv_skb / udp6_unicast_rcv_skb
>   * __udp4_lib_rcv() and __udp6_lib_rcv().
> 
> Let's remove the partial csum code and the unnecessary
> guard for UDP-Lite in RX.

Hi Willem, this lost your ack due to a bug fix, could you re-review?