Re: [PATCH 1/3] powerpc: export cpu_to_core_id()

Hi Michael,

On 06/02/2016 04:41 AM, Michael Ellerman wrote:

On Wed, 2016-06-01 at 17:16 -0300, Mauricio Faria de Oliveira wrote:

quoted

Export cpu_to_core_id().  This will be used by the lpfc driver.

Can you explain why?

Yup,

I would have thought there'd be architecture neutral APIs you can use - and if
there aren't maybe we should write them.

I actually use topology_core_id() from  <kernel/topology.h> in lpfc [1]
(defined to cpu_to_core_id() by arch/powerpc/include/asm/topology.h).

That is arch-neutral, used by eg /sys/devices/system/cpu/cpu*/topology,
but drivers/base/topology.c is built-in (obj-y in ./Makefile), and thus
didn't need the export.

Thus, since the module uses topology_core_id() and this is defined to
cpu_to_core_id(), it needs the export:

     ERROR: "cpu_to_core_id" [drivers/scsi/lpfc/lpfc.ko] undefined!
     make[1]: *** [__modpost] Error 1
     make: *** [modules] Error 2

Thanks,

[1] http://marc.info/?l=linux-scsi&m=146481382301686

-- 
Mauricio Faria de Oliveira
IBM Linux Technology Center