From patchwork Tue Jun 25 20:28:27 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 254374 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3A65A2C143F for ; Wed, 26 Jun 2013 06:43:11 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753429Ab3FYUcK (ORCPT ); Tue, 25 Jun 2013 16:32:10 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:49520 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753273Ab3FYUcG (ORCPT ); Tue, 25 Jun 2013 16:32:06 -0400 Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 26 Jun 2013 06:20:31 +1000 Received: from d23dlp02.au.ibm.com (202.81.31.213) by e23smtp07.au.ibm.com (202.81.31.204) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Wed, 26 Jun 2013 06:20:27 +1000 Received: from d23relay03.au.ibm.com (d23relay03.au.ibm.com [9.190.235.21]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id D8C0A2BB0051; Wed, 26 Jun 2013 06:31:59 +1000 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay03.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5PKVofq5439846; Wed, 26 Jun 2013 06:31:50 +1000 Received: from d23av03.au.ibm.com (loopback [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5PKVvQg030462; Wed, 26 Jun 2013 06:31:59 +1000 Received: from srivatsabhat.in.ibm.com ([9.79.199.80]) by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id r5PKVeqi030163; Wed, 26 Jun 2013 06:31:50 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH v2 18/45] softirq: 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, Frederic Weisbecker , Thomas Gleixner , Andrew Morton , Sedat Dilek , "Paul E. McKenney" , "Srivatsa S. Bhat" Date: Wed, 26 Jun 2013 01:58:27 +0530 Message-ID: <20130625202826.16593.21025.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> References: <20130625202452.16593.22810.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062520-0260-0000-0000-00000337C304 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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: Frederic Weisbecker Cc: Thomas Gleixner Cc: Andrew Morton Cc: Sedat Dilek Cc: "Paul E. McKenney" Signed-off-by: Srivatsa S. Bhat --- kernel/softirq.c | 3 +++ 1 file changed, 3 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/kernel/softirq.c b/kernel/softirq.c index 3d6833f..c289722 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -644,14 +644,17 @@ static void remote_softirq_receive(void *data) static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq) { + get_online_cpus_atomic(); if (cpu_online(cpu)) { cp->func = remote_softirq_receive; cp->info = &softirq; cp->flags = 0; __smp_call_function_single(cpu, cp, 0); + put_online_cpus_atomic(); return 0; } + put_online_cpus_atomic(); return 1; } #else /* CONFIG_USE_GENERIC_SMP_HELPERS */