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authorLinus Torvalds <torvalds@linux-foundation.org>2010-05-14 07:56:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-14 07:56:45 -0700
commit508ff9d41c9aa7e178f6330e703a22af03090dd5 (patch)
treed0098fad8ac34f2f3ee7f162a83ba1ae18edd77f
parent3ac4e829bd8575e9adea2ba1b9329da363881ffb (diff)
parentd77f873fdd21912803836da78f627d2efd267082 (diff)
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
-rw-r--r--drivers/vhost/vhost.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e69d238c5af..49fa953aaf6 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1035,7 +1035,12 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
/* 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;