[PATCH 32/45] blackfin/smp: Use get/put_online_cpus_atomic() toprevent CPU offline

From: Srivatsa S. Bhat
Date: Sun Jun 23 2013 - 09:49:01 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: Mike Frysinger <vapier@xxxxxxxxxx>
Cc: Bob Liu <lliubbo@xxxxxxxxx>
Cc: Steven Miao <realmz6@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: uclinux-dist-devel@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>

arch/blackfin/mach-common/smp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c
index 1bc2ce6..11496cd 100644
--- a/arch/blackfin/mach-common/smp.c
+++ b/arch/blackfin/mach-common/smp.c
@@ -238,13 +238,13 @@ void smp_send_stop(void)
cpumask_t callmap;

- preempt_disable();
+ get_online_cpus_atomic();
cpumask_copy(&callmap, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &callmap);
if (!cpumask_empty(&callmap))
send_ipi(&callmap, BFIN_IPI_CPU_STOP);

- preempt_enable();
+ put_online_cpus_atomic();


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