[PATCH v2 34/45] hexagon/smp: Use get/put_online_cpus_atomic() toprevent CPU offline

From: Srivatsa S. Bhat
Date: Tue Jun 25 2013 - 16:39:59 EST


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@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-hexagon@xxxxxxxxxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---

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

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)

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