[Bugfix 2/3] xen/irq, ACPI: Fix regression in xen PCI passthrough caused by cffe0a2b5a34

[Jiang Liu <jiang.liu@linux.intel.com>]

Xen pciback driver assumes that pci_dev->irq won't change after calling
pci_disable_device(). But commit cffe0a2b5a34c95a4dadc9ec7132690a5b0f6687
("x86, irq: Keep balance of IOAPIC pin reference count") frees irq
resources and resets pci_dev->irq to zero when pci_disable_device() is
called.

So this is a hotfix for 3.19 to avoid resetting pci_dev->irq, and
another proper fix will be prepared for next merging window.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
---
 drivers/acpi/pci_irq.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 5277a0ee5704..b1def411c0b8 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -512,7 +512,6 @@ void acpi_pci_irq_disable(struct pci_dev *dev)
 	dev_dbg(&dev->dev, "PCI INT %c disabled\n", pin_name(pin));
 	if (gsi >= 0) {
 		acpi_unregister_gsi(gsi);
-		dev->irq = 0;
 		dev->irq_managed = 0;
 	}
 }
-- 
1.7.10.4