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Bhat" Subject: [PATCH v6 36/46] m32r: 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 Date: Mon, 18 Feb 2013 18:13:23 +0530 Message-ID: <20130218124323.26245.86492.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130218123714.26245.61816.stgit@srivatsabhat.in.ibm.com> References: <20130218123714.26245.61816.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13021812-8878-0000-0000-000005EFBCB4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130218_074530_471465_E964413A X-CRM114-Status: GOOD ( 11.22 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [122.248.162.7 listed in list.dnswl.org] 3.0 KHOP_BIG_TO_CC Sent to 10+ recipients instaed of Bcc or a list -0.7 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-arch@vger.kernel.org, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org, fweisbec@gmail.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, wangyun@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, netdev@vger.kernel.org, vincent.guittot@linaro.org, walken@google.com, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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: Hirokazu Takata Cc: linux-m32r@ml.linux-m32r.org Cc: linux-m32r-ja@ml.linux-m32r.org Signed-off-by: Srivatsa S. Bhat --- arch/m32r/kernel/smp.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/m32r/kernel/smp.c b/arch/m32r/kernel/smp.c index ce7aea3..0dad4d7 100644 --- a/arch/m32r/kernel/smp.c +++ b/arch/m32r/kernel/smp.c @@ -151,7 +151,7 @@ void smp_flush_cache_all(void) cpumask_t cpumask; unsigned long *mask; - preempt_disable(); + get_online_cpus_atomic(); cpumask_copy(&cpumask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &cpumask); spin_lock(&flushcache_lock); @@ -162,7 +162,7 @@ void smp_flush_cache_all(void) while (flushcache_cpumask) mb(); spin_unlock(&flushcache_lock); - preempt_enable(); + put_online_cpus_atomic(); } void smp_flush_cache_all_interrupt(void) @@ -250,7 +250,7 @@ void smp_flush_tlb_mm(struct mm_struct *mm) unsigned long *mmc; unsigned long flags; - preempt_disable(); + get_online_cpus_atomic(); cpu_id = smp_processor_id(); mmc = &mm->context[cpu_id]; cpumask_copy(&cpu_mask, mm_cpumask(mm)); @@ -268,7 +268,7 @@ void smp_flush_tlb_mm(struct mm_struct *mm) if (!cpumask_empty(&cpu_mask)) flush_tlb_others(cpu_mask, mm, NULL, FLUSH_ALL); - preempt_enable(); + put_online_cpus_atomic(); } /*==========================================================================* @@ -715,10 +715,12 @@ static void send_IPI_allbutself(int ipi_num, int try) { cpumask_t cpumask; + get_online_cpus_atomic(); cpumask_copy(&cpumask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &cpumask); send_IPI_mask(&cpumask, ipi_num, try); + put_online_cpus_atomic(); } /*==========================================================================* @@ -750,6 +752,7 @@ static void send_IPI_mask(const struct cpumask *cpumask, int ipi_num, int try) if (num_cpus <= 1) /* NO MP */ return; + get_online_cpus_atomic(); cpumask_and(&tmp, cpumask, cpu_online_mask); BUG_ON(!cpumask_equal(cpumask, &tmp)); @@ -760,6 +763,7 @@ static void send_IPI_mask(const struct cpumask *cpumask, int ipi_num, int try) } send_IPI_mask_phys(&physid_mask, ipi_num, try); + put_online_cpus_atomic(); } /*==========================================================================*