[PATCH 3.19.y-ckt 072/102] virtio_pci: Clear stale cpumask when setting irq affinity

[Kamal Mostafa]

3.19.8-ckt3 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiang Liu <jiang.liu at linux.intel.com>

commit 210d150e1f5da506875e376422ba31ead2d49621 upstream.

The cpumask vp_dev->msix_affinity_masks[info->msix_vector] may contain
staled information when vp_set_vq_affinity() gets called, so clear it
before setting the new cpu bit mask.

Signed-off-by: Jiang Liu <jiang.liu at linux.intel.com>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/virtio/virtio_pci_common.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 9756f21..ea75707 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -415,6 +415,7 @@ int vp_set_vq_affinity(struct virtqueue *vq, int cpu)
 		if (cpu == -1)
 			irq_set_affinity_hint(irq, NULL);
 		else {
+			cpumask_clear(mask);
 			cpumask_set_cpu(cpu, mask);
 			irq_set_affinity_hint(irq, mask);
 		}
-- 
1.9.1