Re: [PATCH] powerpc/eeh: Fix PE location code

[Sam Mendoza-Jonas <sam@mendozajonas.com>]

On Wed, Jan 20, 2016 at 02:56:13PM +1100, Russell Currey wrote:
> On Wed, 2015-12-02 at 16:25 +1100, Gavin Shan wrote:
> > In eeh_pe_loc_get(), the PE location code is retrieved from the
> > "ibm,loc-code" property of the device node for the bridge of the
> > PE's primary bus. It's not correct because the property indicates
> > the parent PE's location code.
> > 
> > This reads the correct PE location code from "ibm,io-base-loc-code"
> > or "ibm,slot-location-code" property of PE parent bus's device node.
> > 
> > Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
> > ---
> 
> Tested-by: Russell Currey <ruscur@russell.cc>

Thanks Russell!

W.R.T including this in stable, I don't believe anything actively breaks
without the patch, but in the event of an EEH freeze the wrong slot for
the device will be identified, making troubleshooting more difficult.
> >  arch/powerpc/kernel/eeh_pe.c | 33 +++++++++++++++------------------
> >  1 file changed, 15 insertions(+), 18 deletions(-)
> > 
> > diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
> > index 8654cb1..ca9e537 100644
> > --- a/arch/powerpc/kernel/eeh_pe.c
> > +++ b/arch/powerpc/kernel/eeh_pe.c
> > @@ -883,32 +883,29 @@ void eeh_pe_restore_bars(struct eeh_pe *pe)
> >  const char *eeh_pe_loc_get(struct eeh_pe *pe)
> >  {
> >  	struct pci_bus *bus = eeh_pe_bus_get(pe);
> > -	struct device_node *dn = pci_bus_to_OF_node(bus);
> > +	struct device_node *dn;
> >  	const char *loc = NULL;
> >  
> > -	if (!dn)
> > -		goto out;
> > +	while (bus) {
> > +		dn = pci_bus_to_OF_node(bus);
> > +		if (!dn) {
> > +			bus = bus->parent;
> > +			continue;
> > +		}
> >  
> > -	/* PHB PE or root PE ? */
> > -	if (pci_is_root_bus(bus)) {
> > -		loc = of_get_property(dn, "ibm,loc-code", NULL);
> > -		if (!loc)
> > +		if (pci_is_root_bus(bus))
> >  			loc = of_get_property(dn, "ibm,io-base-loc-
> > code", NULL);
> > +		else
> > +			loc = of_get_property(dn, "ibm,slot-location-
> > code",
> > +					      NULL);
> > +
> >  		if (loc)
> > -			goto out;
> > +			return loc;
> >  
> > -		/* Check the root port */
> > -		dn = dn->child;
> > -		if (!dn)
> > -			goto out;
> > +		bus = bus->parent;
> >  	}
> >  
> > -	loc = of_get_property(dn, "ibm,loc-code", NULL);
> > -	if (!loc)
> > -		loc = of_get_property(dn, "ibm,slot-location-code",
> > NULL);
> > -
> > -out:
> > -	return loc ? loc : "N/A";
> > +	return "N/A";
> >  }
> >  
> >  /**
> 
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