Re: [PATCH v1 1/2] device property: Keep secondary firmware node secondary by type

[Ferry Toth]

Hi

Op 23-10-2020 om 14:34 schreef Heikki Krogerus:
> On Thu, Oct 22, 2020 at 09:40:59PM +0300, Andy Shevchenko wrote:
> > Behind primary and secondary we understand the type of the nodes
> > which might define their ordering. However, if primary node gone,
> > we can't maintain the ordering by definition of the linked list.
> > Thus, by ordering secondary node becomes first in the list.
> > But in this case the meaning of it is still secondary (or auxiliary).
> > The type of the node is maintained by the secondary pointer in it:
> >
> > 	secondary pointer		Meaning
> > 	NULL or valid			primary node
> > 	ERR_PTR(-ENODEV)		secondary node
> >
> > So, if by some reason we do the following sequence of calls
> >
> > 	set_primary_fwnode(dev, NULL);
> > 	set_primary_fwnode(dev, primary);
> >
> > we should preserve secondary node.
> >
> > This concept is supported by the description of set_primary_fwnode()
> > along with implementation of set_secondary_fwnode(). Hence, fix
> > the commit c15e1bdda436 to follow this as well.
> >
> > Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()")
> > Cc: Ferry Toth<fntoth@xxxxxxxxx>
> > Signed-off-by: Andy Shevchenko<andriy.shevchenko@xxxxxxxxxxxxxxx>
> FWIW:
>
> Reviewed-by: Heikki Krogerus<heikki.krogerus@xxxxxxxxxxxxxxx>
> Tested-by: Ferry Toth<fntoth@xxxxxxxxx>
> > ---
> >   drivers/base/core.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index c852f16c111b..41feab679fa1 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -4278,7 +4278,7 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
> >   	} else {
> >   		if (fwnode_is_primary(fn)) {
> >   			dev->fwnode = fn->secondary;
> > -			fn->secondary = NULL;
> > +			fn->secondary = ERR_PTR(-ENODEV);
> >   		} else {
> >   			dev->fwnode = NULL;
> >   		}
> > --
> > 2.28.0