From patchwork Thu Jun 27 19:56:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. 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Bhat" Subject: [PATCH v3 19/45] 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, 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, Frederic Weisbecker , Thomas Gleixner , Andrew Morton , Sedat Dilek , "Paul E. McKenney" , "Srivatsa S. Bhat" Date: Fri, 28 Jun 2013 01:26:01 +0530 Message-ID: <20130627195601.29830.15576.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 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13062719-0260-0000-0000-0000033B2F78 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-8.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 linux-pm" 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 */