netdev - Re: [PATCH net] rxrpc: Restore removed timer deletion

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Date:   Wed, 13 Apr 2022 10:53:12 -0700
From:   Eric Dumazet <edumazet@...gle.com>
To:     David Howells <dhowells@...hat.com>
Cc:     netdev@...r.kernel.org, Marc Dionne <marc.dionne@...istor.com>,
        linux-afs@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] rxrpc: Restore removed timer deletion

On Wed, Apr 13, 2022 at 10:41 AM David Howells <dhowells@...hat.com> wrote:
>
> Eric Dumazet <edumazet@...gle.com> wrote:
>
> > ok... so we have a timer and a work queue, both activating each other
> > in kind of a ping pong ?
>
> Yes.  I want to emit regular keepalive pokes.
>
> > Any particular reason not using delayed works ?
>
> Because there's a race between starting the keepalive timer when a new peer is
> added and when the keepalive worker is resetting the timer for the next peer
> in the list.  This is why I'm using timer_reduce().  delayed_work doesn't
> currently have such a facility.  It's not simple to add because
> try_to_grab_pending() as called from mod_delayed_work_on() cancels the timer -
> which is not what I want it to do.
>

SGTM, thanks !

Reviewed-by: Eric Dumazet <edumazet@...gle.com>