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Bhat" Subject: [PATCH v5 32/45] cris/smp: 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: Tue, 22 Jan 2013 13:11:51 +0530 Message-ID: <20130122074146.13822.86691.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13012207-5490-0000-0000-000002DB2F1C X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130122_024359_700287_EFC8347D X-CRM114-Status: GOOD ( 11.96 ) 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 [202.81.31.144 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, 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: Mikael Starvik Cc: Jesper Nilsson Cc: linux-cris-kernel@axis.com Signed-off-by: Srivatsa S. Bhat --- arch/cris/arch-v32/kernel/smp.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/cris/arch-v32/kernel/smp.c b/arch/cris/arch-v32/kernel/smp.c index 04a16ed..644b358 100644 --- a/arch/cris/arch-v32/kernel/smp.c +++ b/arch/cris/arch-v32/kernel/smp.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -208,9 +209,12 @@ int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle) void smp_send_reschedule(int cpu) { cpumask_t cpu_mask; + + get_online_cpus_atomic(); cpumask_clear(&cpu_mask); cpumask_set_cpu(cpu, &cpu_mask); send_ipi(IPI_SCHEDULE, 0, cpu_mask); + put_online_cpus_atomic(); } /* TLB flushing @@ -224,6 +228,7 @@ void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned unsigned long flags; cpumask_t cpu_mask; + get_online_cpus_atomic(); spin_lock_irqsave(&tlbstate_lock, flags); cpu_mask = (mm == FLUSH_ALL ? cpu_all_mask : *mm_cpumask(mm)); cpumask_clear_cpu(smp_processor_id(), &cpu_mask); @@ -232,6 +237,7 @@ void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned flush_addr = addr; send_ipi(IPI_FLUSH_TLB, 1, cpu_mask); spin_unlock_irqrestore(&tlbstate_lock, flags); + put_online_cpus_atomic(); } void flush_tlb_all(void) @@ -312,6 +318,7 @@ int smp_call_function(void (*func)(void *info), void *info, int wait) struct call_data_struct data; int ret; + get_online_cpus_atomic(); cpumask_setall(&cpu_mask); cpumask_clear_cpu(smp_processor_id(), &cpu_mask); @@ -325,6 +332,7 @@ int smp_call_function(void (*func)(void *info), void *info, int wait) call_data = &data; ret = send_ipi(IPI_CALL, wait, cpu_mask); spin_unlock(&call_lock); + put_online_cpus_atomic(); return ret; }