Re: [PATCH] of: return NUMA_NO_NODE from fallback of_node_to_nid()

[Konstantin Khlebnikov]

On 13.04.2015 16:22, Rob Herring wrote:
> On Wed, Apr 8, 2015 at 11:59 AM, Konstantin Khlebnikov
> <khlebnikov@xxxxxxxxxxxxxx> wrote:
> > Node 0 might be offline as well as any other numa node,
> > in this case kernel cannot handle memory allocation and crashes.
> >
> > Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> > Fixes: 0c3f061c195c ("of: implement of_node_to_nid as a weak function")
> > ---
> >   drivers/of/base.c  |    2 +-
> >   include/linux/of.h |    5 ++++-
> >   2 files changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/of/base.c b/drivers/of/base.c
> > index 8f165b112e03..51f4bd16e613 100644
> > --- a/drivers/of/base.c
> > +++ b/drivers/of/base.c
> > @@ -89,7 +89,7 @@ EXPORT_SYMBOL(of_n_size_cells);
> >   #ifdef CONFIG_NUMA
> >   int __weak of_node_to_nid(struct device_node *np)
> >   {
> > -       return numa_node_id();
> > +       return NUMA_NO_NODE;
>
> This is going to break any NUMA machine that enables OF and expects
> the weak function to work.

Why? NUMA_NO_NODE == -1 -- this's standard "no-affinity" signal.
As I see powerpc/sparc versions of of_node_to_nid returns -1 if they
cannot find out which node should be used.

> Rob
>
> >   }
> >   #endif
> >
> > diff --git a/include/linux/of.h b/include/linux/of.h
> > index dfde07e77a63..78a04ee85a9c 100644
> > --- a/include/linux/of.h
> > +++ b/include/linux/of.h
> > @@ -623,7 +623,10 @@ static inline const char *of_prop_next_string(struct property *prop,
> >   #if defined(CONFIG_OF) && defined(CONFIG_NUMA)
> >   extern int of_node_to_nid(struct device_node *np);
> >   #else
> > -static inline int of_node_to_nid(struct device_node *device) { return 0; }
> > +static inline int of_node_to_nid(struct device_node *device)
> > +{
> > +       return NUMA_NO_NODE;
> > +}
> >   #endif
> >
> >   static inline struct device_node *of_find_matching_node(
> >
> > --
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--
Konstantin
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