xen: make sure irq_desc is allocated for interrupts

Impact: bugfix

Make sure all Xen irqs have an irq_desc.

---
drivers/xen/events.c | 5 +++++

1 file changed, 5 insertions(+)

===================================================================

@@ -233,6 +233,7 @@

static int find_unbound_irq(void)

{
	int irq;

+ struct irq_desc *desc;

	/* Only allocate from dynirq range */
	for (irq = 0; irq < nr_irqs; irq++)
@@ -242,6 +243,10 @@
	if (irq == nr_irqs)
		panic("No available IRQ to bind to: increase nr_irqs!\n");

+ desc = irq_to_desc_alloc_cpu(irq, 0);
+ if (WARN_ON(desc == NULL))
+ return -1;
+

	return irq;
}

applied to tip/irq/sparseirq, thanks Jeremy!

Ingo