Re: [PATCH net v4 1/1] ip6_tunnel: snapshot encap in xmit

[Artem Lytkin <iprintercanon@gmail.com>]

On Sun, Sep 06, 2026 at 07:54:34PM +0200, Eric Dumazet wrote:
> The general answer is : convert tunnels to RCU based configuration.
> In my quest for RTNL-less ip link dumps, I converted SIT tunnels to
> RCU configuration.

I have ip6_tunnel and ip6_gre done the same way, after your geneve
conversion: the encap and header lengths in a config under an __rcu
pointer, changelink validates and then publishes, fill_info without
RTNL. Seven patches, built and sparse clean, waiting for the nebusec
fix to reach net-next so I can rebase on it. I mentioned it on the v2
thread two weeks ago:

  https://lore.kernel.org/netdev/20260824194741.215979-1-iprintercanon@gmail.com/

Two things I'd like to line up with your sit series. Your patch 2 and
my first one both touch ip_tunnel_encap_setup() and the encap ops in
ip_tunnels.h, so I'd rather rebase on yours; is it close to posting?
And you put sit_parms under RCU as well, while I kept parms out of the
first round because it keys the hash. If you'd rather have parms in
from the start, I'll do that instead of a second series.

Artem