From e7b140365b86aaf94374214c6f4e6decbee2eb0a Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Sun, 31 Aug 2008 11:06:30 -0700
Subject: [IA64] prevent ia64 from invoking irq handlers on offline CPUs

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.  Also remove the existing
redundant cpu_clear(cpu, cpu_online_map).

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index bcea81e..d8f05e5 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -741,16 +741,14 @@ 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);
 	}
 
 	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;
-- 
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