Patchwork [v3,34/45] hexagon/smp: Use get/put_online_cpus_atomic() to prevent CPU offline

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Submitter Srivatsa S. Bhat
Date June 27, 2013, 7:58 p.m.
Message ID <20130627195830.29830.70085.stgit@srivatsabhat.in.ibm.com>
Download mbox | patch
Permalink /patch/255145/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Srivatsa S. Bhat - June 27, 2013, 7:58 p.m.
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: Richard Kuo <rkuo@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-hexagon@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---

 arch/hexagon/kernel/smp.c |    3 +++
 1 file changed, 3 insertions(+)


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Patch

diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c
index 0e364ca..30d4318 100644
--- a/arch/hexagon/kernel/smp.c
+++ b/arch/hexagon/kernel/smp.c
@@ -241,9 +241,12 @@  void smp_send_reschedule(int cpu)
 void smp_send_stop(void)
 {
 	struct cpumask targets;
+
+	get_online_cpus_atomic();
 	cpumask_copy(&targets, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &targets);
 	send_ipi(&targets, IPI_CPU_STOP);
+	put_online_cpus_atomic();
 }
 
 void arch_send_call_function_single_ipi(int cpu)