Re: [PATCH net-next v5 05/13] net: pcs: add Renesas MII converter driver

[Clément Léger]

Le Fri, 20 May 2022 11:49:14 +0300,
Vladimir Oltean <olteanv@xxxxxxxxx> a écrit :

> On Fri, May 20, 2022 at 09:52:41AM +0200, Clément Léger wrote:
> > > Also, as a request to unbind this driver would be disasterous to users,
> > > I think you should set ".suppress_bind_attrs = true" to prevent the
> > > sysfs bind/unbind facility being available. This doesn't completely
> > > solve the problem.  
> > 
> > Acked. What should I do to make it more robust ? Should I use a
> > refcount per pdev and check that in the remove() callback to avoid
> > removing the pdev if used ?  
> 
> I wonder, if you call device_link_add(ds->dev, miic->dev, DL_FLAG_AUTOREMOVE_CONSUMER),
> wouldn't that be enough to auto-unbind the DSA driver when the MII
> converter driver unbinds?

I looiked at that a bit and I'm not sure how to achieve that cleanly. If
I need to create this link, then I need to do it once for the dsa switch
device. However, currently, the way I get the references to the MII
converter are via the pcs-handle properties which are for each port.

So, I'm not sure creating the link multiple times in miic_create() would
be ok and also, I'm not sure how to create the link once without adding
a specific property which points on the MII converter node and use that
to create the link by adding miic_device_add_link() for instance.

Do you have any preference ?

Thanks,

-- 
Clément Léger,
Embedded Linux and Kernel engineer at Bootlin
https://bootlin.com