[patch V2 13/24] powerpc/powernv: Use stop_machine_cpuslocked()

Thomas Gleixner
2017-04-18T19:53:40Z

[-- Attachment #1: powerpcpowernv_Use_stop_machine_locked.patch --]
[-- Type: text/plain, Size: 1034 bytes --]

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_cpuslocked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org

---
arch/powerpc/platforms/powernv/subcore.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/subcore.c
+++ b/arch/powerpc/platforms/powernv/subcore.c
@@ -356,7 +356,8 @@ 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_cpuslocked(cpu_update_split_mode, &new_mode,
+ cpu_online_mask);

put_online_cpus();