[PATCH] prevent ia64 from invoking irq handlers on offline CPUs

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

Make ia64 refrain from clearing a given to-be-offlined CPU's bit in the
cpu_online_mask until it has processed pending irqs.  This change
prevents other CPUs from being blindsided by an apparently offline CPU
nevertheless changing globally visible state.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---

 smpboot.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index bcea81e..7a90f42 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -741,8 +741,6 @@ int __cpu_disable(void)
 			return -EBUSY;
 	}
 
-	cpu_clear(cpu, cpu_online_map);
-
 	if (migrate_platform_irqs(cpu)) {
 		cpu_set(cpu, cpu_online_map);
 		return (-EBUSY);
@@ -751,6 +749,7 @@ int __cpu_disable(void)
 	remove_siblinginfo(cpu);
 	cpu_clear(cpu, cpu_online_map);
 	fixup_irqs();
+	cpu_clear(cpu, cpu_online_map);
 	local_flush_tlb_all();
 	cpu_clear(cpu, cpu_callin_map);
 	return 0;