Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
vhost: fix barrier pairing
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e69d238..49fa953 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1035,7 +1035,12 @@
/* This actually signals the guest, using eventfd. */
void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
{
- __u16 flags = 0;
+ __u16 flags;
+ /* Flush out used index updates. This is paired
+ * with the barrier that the Guest executes when enabling
+ * interrupts. */
+ smp_mb();
+
if (get_user(flags, &vq->avail->flags)) {
vq_err(vq, "Failed to get flags");
return;