[PATCH] powerpc/vio: dispose of virq mapping on vdevice unregister

[Tyrel Datwyler]

When a vdevice is DLPAR removed from the system the vio subsystem doesn't
bother unmapping the virq from the irq_domain. As a result we have a virq
mapped to a hardware irq that is no longer valid for the irq_domain. A side
effect is that we are left with /proc/irq/<irq#> affinity entries, and
attempts to modify the smp_affinity of the irq will fail.

In the following observed example the kernel log is spammed by
ics_rtas_set_affinity errors after the removal of a VSCSI adapter. This is a
result of irqbalance trying to adjust the affinity every 10 seconds.

rpadlpar_io: slot U8408.E8E.10A7ACV-V5-C25 removed
ics_rtas_set_affinity: ibm,set-xive irq=655385 returns -3
ics_rtas_set_affinity: ibm,set-xive irq=655385 returns -3

This patch fixes the issue by calling irq_dispose_mapping() on the virq of the
viodev on unregister.

Cc: stable at vger.kernel.org
Signed-off-by: Tyrel Datwyler <tyreld at linux.vnet.ibm.com>
---
 arch/powerpc/kernel/vio.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/vio.c b/arch/powerpc/kernel/vio.c
index 5f8dcda..a3228d6 100644
--- a/arch/powerpc/kernel/vio.c
+++ b/arch/powerpc/kernel/vio.c
@@ -1577,6 +1577,8 @@ static struct device_attribute vio_dev_attrs[] = {
 void vio_unregister_device(struct vio_dev *viodev)
 {
 	device_unregister(&viodev->dev);
+	if (viodev->family == VDEVICE)
+		irq_dispose_mapping(viodev->irq);
 }
 EXPORT_SYMBOL(vio_unregister_device);
 
-- 
1.7.12.4