From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938802AbdEXI3H (ORCPT ); Wed, 24 May 2017 04:29:07 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:58018 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765686AbdEXI0a (ORCPT ); Wed, 24 May 2017 04:26:30 -0400 Message-Id: <20170524081548.331016542@linutronix.de> User-Agent: quilt/0.63-1 Date: Wed, 24 May 2017 10:15:27 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Steven Rostedt , Sebastian Siewior , Paul McKenney , Benjamin Herrenschmidt , Michael Ellerman , linuxppc-dev@lists.ozlabs.org Subject: [patch V3 16/32] powerpc/powernv: Use stop_machine_cpuslocked() References: <20170524081511.203800767@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=powerpcpowernv_Use_stop_machine_cpuslocked().patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sebastian Andrzej Siewior 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. Convert *_online_cpus() to the new interfaces while at it. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Benjamin Herrenschmidt Cc: Steven Rostedt Cc: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org --- arch/powerpc/platforms/powernv/subcore.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/arch/powerpc/platforms/powernv/subcore.c +++ b/arch/powerpc/platforms/powernv/subcore.c @@ -348,7 +348,7 @@ static int set_subcores_per_core(int new state->master = 0; } - get_online_cpus(); + cpus_read_lock(); /* This cpu will update the globals before exiting stop machine */ this_cpu_ptr(&split_state)->master = 1; @@ -356,9 +356,10 @@ 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(); + cpus_read_unlock(); return 0; }