[PATCH v5 38/45] parisc: Use get/put_online_cpus_atomic() to prevent CPU offline

Srivatsa S. Bhat srivatsa.bhat at linux.vnet.ibm.com
Tue Jan 22 18:43:39 EST 2013

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 at parisc-linux.org>
Cc: linux-parisc at vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat at linux.vnet.ibm.com>

 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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