Re: [PATCH v7 1/4] tcp: Encode checksum computation flags in a single parameter

[Stefano Brivio <sbrivio@redhat.com>]

On Wed, 20 May 2026 17:10:07 +0200
Laurent Vivier <lvivier@redhat.com> wrote:

> tcp_fill_headers() takes a pointer to a previously computed IPv4 header
> checksum to avoid recalculating it when the payload length doesn't
> change, and a separate bool to skip TCP checksum computation.
> 
> Replace both parameters with a single uint32_t csum_flags that encodes:
> - IP4_CSUM (bit 31): compute IPv4 header checksum from scratch
> - TCP_CSUM (bit 30): compute TCP checksum
> - IP4_CMASK (low 16 bits): cached IPv4 header checksum value

Have you considered something like:

struct csum_state {
	bool compute_tcp;
	bool compute_ip;
	uint16_t computed_ip;
};

? I think the related documentation would look simpler and it should
also be more robust to future changes.

Not worth a respin though, if it looks like a good idea I guess it could
be done as a follow-up.

-- 
Stefano