Patchwork [v6,43/46] tile: Use get/put_online_cpus_atomic() to prevent CPU offline

mail settings
Submitter Srivatsa S. Bhat
Date Feb. 18, 2013, 12:44 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/221288/
State Not Applicable
Delegated to: David Miller
Headers show


Srivatsa S. Bhat - Feb. 18, 2013, 12:44 p.m.
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: Chris Metcalf <>
Signed-off-by: Srivatsa S. Bhat <>

 arch/tile/kernel/smp.c |    4 ++++
 1 file changed, 4 insertions(+)

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at


diff --git a/arch/tile/kernel/smp.c b/arch/tile/kernel/smp.c
index cbc73a8..fb30624 100644
--- a/arch/tile/kernel/smp.c
+++ b/arch/tile/kernel/smp.c
@@ -15,6 +15,7 @@ 
 #include <linux/smp.h>
+#include <linux/cpu.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/irq.h>
@@ -82,9 +83,12 @@  void send_IPI_many(const struct cpumask *mask, int tag)
 void send_IPI_allbutself(int tag)
 	struct cpumask mask;
+	get_online_cpus_atomic();
 	cpumask_copy(&mask, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &mask);
 	send_IPI_many(&mask, tag);
+	put_online_cpus_atomic();