[patch 13/20] powerpc/powernv: Use stop_machine_locked()

From: Thomas Gleixner
Date: Sat Apr 15 2017 - 13:34:03 EST


set_subcores_per_core() holds get_online_cpus() while invoking stop_machine().

stop_machine() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.

Use stop_machine_locked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: linuxppc-dev@xxxxxxxxxxxxxxxx

---
arch/powerpc/platforms/powernv/subcore.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -356,7 +356,7 @@ static int set_subcores_per_core(int new
/* Ensure state is consistent before we call the other cpus */
mb();

- stop_machine(cpu_update_split_mode, &new_mode, cpu_online_mask);
+ stop_machine_locked(cpu_update_split_mode, &new_mode, cpu_online_mask);

put_online_cpus();