Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752312Ab3FWNoY (ORCPT ); Sun, 23 Jun 2013 09:44:24 -0400 Received: from e28smtp05.in.ibm.com ([122.248.162.5]:47954 "EHLO e28smtp05.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260Ab3FWNoS (ORCPT ); Sun, 23 Jun 2013 09:44:18 -0400 From: "Srivatsa S. Bhat" Subject: [PATCH 13/45] timer: Use get/put_online_cpus_atomic() to prevent CPU offline To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org, walken@google.com, vincent.guittot@linaro.org, laijs@cn.fujitsu.com Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, fweisbec@gmail.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner Date: Sun, 23 Jun 2013 19:10:56 +0530 Message-ID: <20130623134053.19094.23654.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> References: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062313-8256-0000-0000-0000080B6441 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1799 Lines: 56 Once stop_machine() is gone from the CPU offline path, we won't be able to depend on disabling preemption to prevent CPUs from going offline from under us. Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going offline, while invoking from atomic context. Cc: Thomas Gleixner Signed-off-by: Srivatsa S. Bhat --- kernel/timer.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/timer.c b/kernel/timer.c index 15ffdb3..5db594c 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -729,6 +729,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, timer_stats_timer_set_start_info(timer); BUG_ON(!timer->function); + get_online_cpus_atomic(); base = lock_timer_base(timer, &flags); ret = detach_if_pending(timer, base, false); @@ -768,6 +769,7 @@ __mod_timer(struct timer_list *timer, unsigned long expires, out_unlock: spin_unlock_irqrestore(&base->lock, flags); + put_online_cpus_atomic(); return ret; } @@ -926,6 +928,7 @@ void add_timer_on(struct timer_list *timer, int cpu) timer_stats_timer_set_start_info(timer); BUG_ON(timer_pending(timer) || !timer->function); + get_online_cpus_atomic(); spin_lock_irqsave(&base->lock, flags); timer_set_base(timer, base); debug_activate(timer, timer->expires); @@ -940,6 +943,7 @@ void add_timer_on(struct timer_list *timer, int cpu) */ wake_up_nohz_cpu(cpu); spin_unlock_irqrestore(&base->lock, flags); + put_online_cpus_atomic(); } EXPORT_SYMBOL_GPL(add_timer_on); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/