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

[Srivatsa S. Bhat]

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 at gentoo.org>
Cc: Bob Liu <lliubbo at gmail.com>
Cc: Steven Miao <realmz6 at gmail.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: uclinux-dist-devel at blackfin.uclinux.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat at linux.vnet.ibm.com>
---

 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();
 
 	return;
 }