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Date: Wed, 21 Jan 2026 17:37:55 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Bobby Eshleman <bobbyeshleman@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>, Eric Dumazet
 <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Simon Horman
 <horms@kernel.org>, Kuniyuki Iwashima <kuniyu@google.com>, Willem de Bruijn
 <willemb@google.com>, Neal Cardwell <ncardwell@google.com>, David Ahern
 <dsahern@kernel.org>, Mina Almasry <almasrymina@google.com>, Arnd Bergmann
 <arnd@arndb.de>, Jonathan Corbet <corbet@lwn.net>, Andrew Lunn
 <andrew+netdev@lunn.ch>, Shuah Khan <shuah@kernel.org>, Donald Hunter
 <donald.hunter@gmail.com>, Stanislav Fomichev <sdf@fomichev.me>,
 netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-arch@vger.kernel.org, linux-doc@vger.kernel.org,
 linux-kselftest@vger.kernel.org, asml.silence@gmail.com,
 matttbe@kernel.org, skhawaja@google.com, Bobby Eshleman
 <bobbyeshleman@meta.com>
Subject: Re: [PATCH net-next v10 0/5] net: devmem: improve cpu cost of RX
 token management
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On Tue, 20 Jan 2026 21:29:36 -0800 Bobby Eshleman wrote:
> > IDK if the cmsg approach is still right for this flow TBH.
> > IIRC when Stan talked about this a while back we were considering doing
> > this via Netlink. Anything that proves that the user owns the binding
> > would work. IIUC the TCP socket in this design just proves that socket
> > has received a token from a given binding right?  
> 
> In both designs the owner of the binding starts of as the netlink opener,
> and then ownership spreads out to TCP sockets as packets are steered to
> them. Tokens are received by the user which gives them a share in the
> form of references on the pp and binding. This design follows the same
> approach... but I may be misinterpreting what you mean by ownership?

What I was getting at was the same point about socket A vs socket B as
I made on the doc patch. IOW the kernel only tracks how many tokens it
gave out for a net_iov, there's no socket state beyond the binding
pointer. Right?