Re: [PATCH][RFC] Add default CPU topology information

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 31 Mar 2008 12:44:13 +0100 Ben Hutchings <bhutchings@solarflare.com> wrote:

> Not all architectures and configurations define CPU topology information.
> This can result in an empty topology directory in sysfs, and requires
> in-kernel users to protect all uses with #ifdef - see
> <http://marc.info/?l=linux-netdev&m=120639033904472&w=2>.
> 
> The documentation of CPU topology specifies what the defaults should be
> if only partial information is available from the hardware.  So we can
> provide these defaults as a fallback.

powerpc allmodconfig:

arch/powerpc/kernel/pci_64.c:655: error: expected identifier or '(' before 'void'
arch/powerpc/kernel/pci_64.c:655: error: expected ')' before '(' token

Because this:

#ifdef CONFIG_NUMA
int pcibus_to_node(struct pci_bus *bus)
{
	struct pci_controller *phb = pci_bus_to_host(bus);
	return phb->node;
}
#endif

is expanding to

int ((void)(bus), -1)(struct pci_bus *bus)

which the compiler has trouble with.

This:

+++ a/include/asm-powerpc/topology.h
@@ -109,6 +109,8 @@ static inline void sysfs_remove_device_f
 #endif
 #endif
 
+#define pcibus_to_node pcibus_to_node
+
 #include <asm-generic/topology.h>
 
 #endif /* __KERNEL__ */
_

gets it working, by tricking the preprocessor into expanding pcibus_to_node
to itself, but it isn't exactly pleasing.