[PATCH v6 39/46] parisc: Use get/put_online_cpus_atomic() to preventCPU offline

From: Srivatsa S. Bhat
Date: Mon Feb 18 2013 - 07:45:57 EST

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: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxxxxx>
Cc: linux-parisc@xxxxxxxxxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

arch/parisc/kernel/smp.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 6266730..f7851b7 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -229,11 +229,13 @@ static inline void
send_IPI_allbutself(enum ipi_message_type op)
int i;
+ get_online_cpus_atomic();
for_each_online_cpu(i) {
if (i != smp_processor_id())
send_IPI_single(i, op);
+ put_online_cpus_atomic();

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