From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756624Ab3AVHqp (ORCPT ); Tue, 22 Jan 2013 02:46:45 -0500 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:50496 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755998Ab3AVHql (ORCPT ); Tue, 22 Jan 2013 02:46:41 -0500 From: "Srivatsa S. Bhat" Subject: [PATCH v5 42/45] tile: 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 Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, fweisbec@gmail.com, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 22 Jan 2013 13:14:35 +0530 Message-ID: <20130122074430.13822.27480.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.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-Content-Scanned: Fidelis XPS MAILER x-cbid: 13012207-5140-0000-0000-000002A8FC07 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Once stop_machine() is gone from the CPU offline path, we won't be able to depend on preempt_disable() or local_irq_disable() 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: Chris Metcalf Signed-off-by: Srivatsa S. Bhat --- arch/tile/kernel/smp.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c index cbc73a8..fb30624 100644 --- a/arch/tile/kernel/smp.c +++ b/arch/tile/kernel/smp.c @@ -15,6 +15,7 @@ */ #include +#include #include #include #include @@ -82,9 +83,12 @@ void send_IPI_many(const struct cpumask *mask, int tag) void send_IPI_allbutself(int tag) { struct cpumask mask; + + get_online_cpus_atomic(); cpumask_copy(&mask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &mask); send_IPI_many(&mask, tag); + put_online_cpus_atomic(); } /*