[PATCH] Always notify a virtio_ring when it's full

[PATCH] Always notify a virtio_ring when it's full

[Anthony Liguori]

I saw that the tx timer was removed in your patch queue but you weren't
notifying when full.  I decided to do it here instead of in the error case on
add_buf for really no great reason other than I thought it made more sense
for it to happen in the notify().

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 7fa1c72..57b7ad3 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -146,7 +146,8 @@ static void vring_kick(struct virtqueue *_vq)
 	/* Need to update avail index before checking if we should notify */
 	mb();
 
-	if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY))
+	/* Always notify when the queue is full */
+	if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY) || !vq->num_free)
 		/* Prod other side to tell it about changes. */
 		vq->notify(&vq->vq);

Re: [PATCH] Always notify a virtio_ring when it's full

[Rusty Russell]

On Wednesday 09 January 2008 07:54:10 Anthony Liguori wrote:
> I saw that the tx timer was removed in your patch queue but you weren't
> notifying when full.  I decided to do it here instead of in the error case
> on add_buf for really no great reason other than I thought it made more
> sense for it to happen in the notify().

Erk, my bad, I put a ->notify call in the get_buf fail path, not the add_buf 
fail path.

Fixed in latest, thanks.

Rusty.