Re: [PATCH wpan-tools 0/7] iwpan: Support scanning/beaconing

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Alexander,

aahringo@redhat.com wrote on Tue, 30 Aug 2022 23:17:35 -0400:

> Hi,
> 
> On Mon, Aug 29, 2022 at 8:57 AM Alexander Aring <aahringo@redhat.com> wrote:
> >
> > Hi,
> >
> > On Mon, Aug 29, 2022 at 4:37 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:  
> > >
> > > Hi Alexander,
> > >
> > > aahringo@redhat.com wrote on Sun, 28 Aug 2022 09:55:24 -0400:
> > >  
> > > > Hi,
> > > >
> > > > On Fri, Aug 26, 2022 at 6:50 AM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> > > > ...  
> > > > >
> > > > > I've updated the tools so that we have:
> > > > >
> > > > > * "scan trigger" which does not block
> > > > > * "scan monitor" which displays with a pretty output the new
> > > > >   coordinators and stops blocking when the scan is over (either because
> > > > >   it reached the last channel to scan, or it got aborted)
> > > > > * "scan abort" which stops an ongoing scan
> > > > > * "scan" which is the same as "scan trigger; scan monitor", and will  
> > > >
> > > > no, there is a race in the design of "scan trigger; scan monitor".  
> > >
> > > Right, I've used pthread to first start the monitoring, before actually
> > > triggering the scan. That should be enough.
> > >  
> >
> > I think we should look at this, because it requires that all
> > applications link to pthreads if we offer such an API. Any thoughts
> > about alternative ways, can it not be done over libnl, that libnl
> > internally used e.g. select()? The above example is only regarding the
> > process context.
> >  
> 
> I think pthreads are not necessary here. If we don't close and open
> the nl socket everything should be queued.
> Forget that with select(), just send() and recv() (whatever that is
> underneath of libnl) should be enough.

That's way more clever. I've changed that, no more pthread and no more
race, thanks!

Thanks,
Miquèl