From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033207AbdEXI34 (ORCPT ); Wed, 24 May 2017 04:29:56 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:57988 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1765113AbdEXI0X (ORCPT ); Wed, 24 May 2017 04:26:23 -0400 Message-Id: <20170524081548.250203087@linutronix.de> User-Agent: quilt/0.63-1 Date: Wed, 24 May 2017 10:15:26 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Ingo Molnar , Steven Rostedt , Sebastian Siewior , Paul McKenney , linux-s390@vger.kernel.org, Heiko Carstens , David Hildenbrand , Martin Schwidefsky Subject: [patch V3 15/32] s390/kernel: 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=s390kernel_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 stp_work_fn() 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: linux-s390@vger.kernel.org Cc: Peter Zijlstra Cc: Heiko Carstens Cc: Steven Rostedt Cc: David Hildenbrand Cc: Martin Schwidefsky --- arch/s390/kernel/time.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -636,10 +636,10 @@ static void stp_work_fn(struct work_stru goto out_unlock; memset(&stp_sync, 0, sizeof(stp_sync)); - get_online_cpus(); + cpus_read_lock(); atomic_set(&stp_sync.cpus, num_online_cpus() - 1); - stop_machine(stp_sync_clock, &stp_sync, cpu_online_mask); - put_online_cpus(); + stop_machine_cpuslocked(stp_sync_clock, &stp_sync, cpu_online_mask); + cpus_read_unlock(); if (!check_sync_clock()) /*