[PATCH 07/12] Fix find_unbound_irq in presence of ioapic irqs.

[stefano.stabellini@eu.citrix.com]

From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Don't break the assumption that the first 16 irqs are ISA irqs;
make sure that the irq is actually free before using it.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 drivers/xen/events.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 4bd0ea3..b233564 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -340,9 +340,18 @@ static int find_unbound_irq(void)
 	int irq;
 	struct irq_desc *desc;
 
-	for (irq = 0; irq < nr_irqs; irq++)
+	for (irq = 0; irq < nr_irqs; irq++) {
+		desc = irq_to_desc(irq);
+		/* only 0->15 have init'd desc; handle irq > 16 */
+		if (desc == NULL)
+			break;
+		if (desc->chip == &no_irq_chip)
+			break;
+		if (desc->chip != &xen_dynamic_chip)
+			continue;
 		if (irq_info[irq].type == IRQT_UNBOUND)
 			break;
+	}
 
 	if (irq == nr_irqs)
 		panic("No available IRQ to bind to: increase nr_irqs!\n");
-- 
1.7.0.4