From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754741Ab3F0T7q (ORCPT ); Thu, 27 Jun 2013 15:59:46 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:49652 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754605Ab3F0T7n (ORCPT ); Thu, 27 Jun 2013 15:59:43 -0400 From: "Srivatsa S. Bhat" Subject: [PATCH v3 20/45] irq: 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, David.Laight@aculab.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 , "Srivatsa S. Bhat" Date: Fri, 28 Jun 2013 01:26:15 +0530 Message-ID: <20130627195614.29830.86515.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130627195136.29830.10445.stgit@srivatsabhat.in.ibm.com> References: <20130627195136.29830.10445.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: 13062719-0260-0000-0000-0000033B2F80 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 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/irq/manage.c | 7 +++++++ kernel/irq/proc.c | 3 +++ 2 files changed, 10 insertions(+) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index e16caa8..4d89f19 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "internals.h" @@ -202,9 +203,11 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *mask) if (!desc) return -EINVAL; + get_online_cpus_atomic(); raw_spin_lock_irqsave(&desc->lock, flags); ret = __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask); raw_spin_unlock_irqrestore(&desc->lock, flags); + put_online_cpus_atomic(); return ret; } @@ -343,9 +346,11 @@ int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask) unsigned long flags; int ret; + get_online_cpus_atomic(); raw_spin_lock_irqsave(&desc->lock, flags); ret = setup_affinity(irq, desc, mask); raw_spin_unlock_irqrestore(&desc->lock, flags); + put_online_cpus_atomic(); return ret; } @@ -1128,7 +1133,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) } /* Set default affinity mask once everything is setup */ + get_online_cpus_atomic(); setup_affinity(irq, desc, mask); + put_online_cpus_atomic(); } else if (new->flags & IRQF_TRIGGER_MASK) { unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK; diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 19ed5c4..47f9a74 100644 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -7,6 +7,7 @@ */ #include +#include #include #include #include @@ -441,6 +442,7 @@ int show_interrupts(struct seq_file *p, void *v) if (!desc) return 0; + get_online_cpus_atomic(); raw_spin_lock_irqsave(&desc->lock, flags); for_each_online_cpu(j) any_count |= kstat_irqs_cpu(i, j); @@ -477,6 +479,7 @@ int show_interrupts(struct seq_file *p, void *v) seq_putc(p, '\n'); out: raw_spin_unlock_irqrestore(&desc->lock, flags); + put_online_cpus_atomic(); return 0; } #endif