powerpc/numa: Do not update sysfs cpu registration from invalid context

commit dd023217e17e72b46fb4d49c7734c426938c3dba upstream.

The topology update code that updates the cpu node registration in sysfs
should not be called while in stop_machine(). The register/unregister
calls take a lock and may sleep.

This patch moves these calls outside of the call to stop_machine().

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 88c0425dc0a88f41f61c38b4d01888ec468a937c..2859a1f52279068e9e1a73382df3c7a90cfa3de9 100644 (file)
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1433,11 +1433,9 @@ static int update_cpu_topology(void *data)
                if (cpu != update->cpu)
                        continue;
 
-               unregister_cpu_under_node(update->cpu, update->old_nid);
                unmap_cpu_from_node(update->cpu);
                map_cpu_to_node(update->cpu, update->new_nid);
                vdso_getcpu_init();
-               register_cpu_under_node(update->cpu, update->new_nid);
        }
 
        return 0;
@@ -1485,6 +1483,9 @@ int arch_update_cpu_topology(void)
        stop_machine(update_cpu_topology, &updates[0], &updated_cpus);
 
        for (ud = &updates[0]; ud; ud = ud->next) {
+               unregister_cpu_under_node(ud->cpu, ud->old_nid);
+               register_cpu_under_node(ud->cpu, ud->new_nid);
+
                dev = get_cpu_device(ud->cpu);
                if (dev)
                        kobject_uevent(&dev->kobj, KOBJ_CHANGE);