xen: fix unbind_from_irq()

Rearrange the tests in unbind_from_irq() so that we can still unbind
an irq even if the underlying event channel is bad.  This allows a
device driver to shuffle its irqs on save/restore before the
underlying event channels have been fixed up.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/xen/events.c

@@ -355,7 +355,7 @@ static void unbind_from_irq(unsigned int irq)
 
 	spin_lock(&irq_mapping_update_lock);
 
-	if (VALID_EVTCHN(evtchn) && (--irq_bindcount[irq] == 0)) {
+	if ((--irq_bindcount[irq] == 0) && VALID_EVTCHN(evtchn)) {
 		close.port = evtchn;
 		if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
 			BUG();
@@ -375,7 +375,7 @@ static void unbind_from_irq(unsigned int irq)
 		evtchn_to_irq[evtchn] = -1;
 		irq_info[irq] = IRQ_UNBOUND;
 
-		dynamic_irq_init(irq);
+		dynamic_irq_cleanup(irq);
 	}
 
 	spin_unlock(&irq_mapping_update_lock);