Re: [PATCH net-next v7 4/5] net/x25: fix restart request/confirm handling

[Martin Schiller]

On 2020-12-09 10:17, Xie He wrote:
> On Wed, Dec 9, 2020 at 1:01 AM Xie He <xie.he.0141@xxxxxxxxx> wrote:
> > On Wed, Nov 25, 2020 at 10:36 PM Martin Schiller <ms@xxxxxxxxxx> 
> > wrote:
> > >
> > >         switch (nb->state) {
> > >         case X25_LINK_STATE_0:
> > > -               nb->state = X25_LINK_STATE_2;
> > > -               break;
> > >         case X25_LINK_STATE_1:
> > >                 x25_transmit_restart_request(nb);
> > >                 nb->state = X25_LINK_STATE_2;
> >
> > What is the reason for this change? Originally only the connecting
> > side will transmit a Restart Request; the connected side will not and
> > will only wait for the Restart Request to come. Now both sides will
> > transmit Restart Requests at the same time. I think we should better
> > avoid collision situations like this.
>
> Oh. I see. Because in other patches we are giving L2 the ability to
> connect by itself, both sides can now appear here to be the
> "connected" side. So we can't make the "connected" side wait as we did
> before.

Right.
By the way: A "Restart Collision" is in practice a very common event to
establish the Layer 3.