Is topology_core_siblings for use by drivers?

Is topology_core_siblings for use by drivers?

[Matthew Wilcox]

allmodconfig currently dies with:

ERROR: "cpu_core_map" [drivers/net/sfc/sfc.ko] undefined!

$ grep -r cpu_core_map include/asm-ia64/
include/asm-ia64/smp.h:extern cpumask_t cpu_core_map[NR_CPUS];
include/asm-ia64/topology.h:#define topology_core_siblings(cpu) (cpu_core_map[cpu])

OK ... it's not exported to modules.  Do other architectures have this
problem?

$ grep topology_core_siblings include/asm-*/topology.h
include/asm-ia64/topology.h:#define topology_core_siblings(cpu) (cpu_core_map[cpu])
include/asm-powerpc/topology.h:#define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu))
include/asm-s390/topology.h:#define topology_core_siblings(cpu) (cpu_core_map[cpu])
include/asm-x86/topology.h:#define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu))

s390, I guess.  But they don't have PCI device drivers.

If device drivers are supposed to call this, please apply this patch:

----

Export cpu_core_map so modules can call topology_core_siblings()

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 03f1a99..6cb0927 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -138,6 +138,7 @@ cpumask_t cpu_possible_map = CPU_MASK_NONE;
 EXPORT_SYMBOL(cpu_possible_map);
 
 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
+EXPORT_SYMBOL(cpu_core_map);
 DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
 

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

Re: Is topology_core_siblings for use by drivers?

[Heiko Carstens]

On Tue, Jul 29, 2008 at 01:14:22AM -0600, Matthew Wilcox wrote:
> 
> allmodconfig currently dies with:
> 
> ERROR: "cpu_core_map" [drivers/net/sfc/sfc.ko] undefined!
> 
> $ grep -r cpu_core_map include/asm-ia64/
> include/asm-ia64/smp.h:extern cpumask_t cpu_core_map[NR_CPUS];
> include/asm-ia64/topology.h:#define topology_core_siblings(cpu) (cpu_core_map[cpu])
> 
> OK ... it's not exported to modules.  Do other architectures have this
> problem?
> 
> $ grep topology_core_siblings include/asm-*/topology.h
> include/asm-ia64/topology.h:#define topology_core_siblings(cpu) (cpu_core_map[cpu])
> include/asm-powerpc/topology.h:#define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu))
> include/asm-s390/topology.h:#define topology_core_siblings(cpu) (cpu_core_map[cpu])
> include/asm-x86/topology.h:#define topology_core_siblings(cpu) (per_cpu(cpu_core_map, cpu))
> 
> s390, I guess.  But they don't have PCI device drivers.

Yes, luckily it doesn't get compiled on s390. Btw. the for_each_online_cpu
loop where this gets used doesn't seem to be save wrt cpu hotplug.