x86: Force irq complete move during cpu offline

When a cpu goes offline, fixup_irqs() try to move irq's
currently destined to the offline cpu to a new cpu. But this
attempt will fail if the irq is recently moved to this cpu and
the irq still hasn't arrived at this cpu (for non intr-remapping
platforms this is when we free the vector allocation at the
previous destination) that is about to go offline.

This will endup with the interrupt subsystem still pointing the
irq to the offline cpu, causing that irq to not work any more.

Fix this by forcing the irq to complete its move (its been a
long time we moved the irq to this cpu which we are offlining
now) and then move this irq to a new cpu before this cpu goes
offline.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Gary Hade <garyhade@us.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
LKML-Reference: <20091026230001.848830905@sbs-t61.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 342bcbca19b4..b10a5e1da06c 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -305,6 +305,13 @@ void fixup_irqs(void)
 			continue;
 		}
 
+		/*
+		 * Complete the irq move. This cpu is going down and for
+		 * non intr-remapping case, we can't wait till this interrupt
+		 * arrives at this cpu before completing the irq move.
+		 */
+		irq_force_complete_move(irq);
+
 		if (cpumask_any_and(affinity, cpu_online_mask) >= nr_cpu_ids) {
 			break_affinity = 1;
 			affinity = cpu_all_mask;