From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e23smtp07.au.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id AFE512C076C for ; Sun, 23 Jun 2013 23:45:37 +1000 (EST) Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 23 Jun 2013 23:34:08 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp01.au.ibm.com (Postfix) with ESMTP id BF1632CE8044 for ; Sun, 23 Jun 2013 23:45:34 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5NDUlvT12648598 for ; Sun, 23 Jun 2013 23:30:47 +1000 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5NDjWOT016027 for ; Sun, 23 Jun 2013 23:45:34 +1000 From: "Srivatsa S. Bhat" Subject: [PATCH 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 Date: Sun, 23 Jun 2013 19:12:03 +0530 Message-ID: <20130623134200.19094.98717.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> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Cc: linux-arch@vger.kernel.org, nikunj@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, linux-pm@vger.kernel.org, Frederic Weisbecker , linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu, wangyun@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, netdev@vger.kernel.org, Sedat Dilek , Thomas Gleixner , "Paul E. McKenney" , linuxppc-dev@lists.ozlabs.org, Andrew Morton List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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(+) 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 */