[3.13.y-ckt stable] Patch "virtio_pci: Clear stale cpumask when setting irq affinity" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    virtio_pci: Clear stale cpumask when setting irq affinity

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt23.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 2944e7faba1b200e0588602636ecd3a7af08a78f Mon Sep 17 00:00:00 2001
From: Jiang Liu <jiang.liu at linux.intel.com>
Date: Thu, 4 Jun 2015 16:41:44 +0800
Subject: virtio_pci: Clear stale cpumask when setting irq affinity

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>
[ luis: backported to 3.16:
  - file rename: virtio_pci_common.c -> virtio_pci.c ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/virtio/virtio_pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 6b35f925..9aa37a7 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -647,6 +647,7 @@ static 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