Re: [PATCH net-next v10 4/5] net: devmem: document NETDEV_A_DMABUF_AUTORELEASE netlink attribute

Jakub Kicinski
2026-01-22T02:50:23Z

On Wed, 21 Jan 2026 18:37:56 -0800 Bobby Eshleman wrote:
> > > Show an example of the three steps: returning the tokens, unbinding, and closing the
> > > sockets (TCP/NL)?
> >
> > TBH I read the doc before reading the code, which I guess may actually
> > be better since we don't expect users to read the code first either..
> >
> > Now after reading the code I'm not sure the doc explains things
> > properly. AFAIU there's no association of token <> socket within the
> > same binding. User can close socket A and return the tokens via socket
> > B. As written the doc made me think that there will be a leak if socket
> > is closed without releasing tokens, or that there may be a race with
> > data queued but not read. Neither is true, really?
>
> That is correct, neither is true. If the two sockets share a binding the
> kernel doesn't care which socket received the token or which one
> returned it. No token <> socket association. There is no
> queued-but-not-read race either. If any tokens are not returned, as long
> as all of the binding references are eventually released and all sockets
> that used the binding are closed, then all references will be accounted
> for and everything cleaned up.

Naming is hard, but I wonder whether the whole feature wouldn't be
better referred to as something to do with global token accounting
/ management? AUTORELEASE makes sense but seems like focusing on one
particular side effect.