On Wed, 4 May 2011 23:51:38 +0300, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > Add support for the used_event idx feature: when enabling > interrupts, publish the current avail index value to > the host so that we get interrupts on the next update. > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > --- > drivers/virtio/virtio_ring.c | 14 ++++++++++++++ > 1 files changed, 14 insertions(+), 0 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 507d6eb..3a3ed75 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -320,6 +320,14 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) > ret = vq->data[i]; > detach_buf(vq, i); > vq->last_used_idx++; > + /* If we expect an interrupt for the next entry, tell host > + * by writing event index and flush out the write before > + * the read in the next get_buf call. */ > + if (!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) { > + vring_used_event(&vq->vring) = vq->last_used_idx; > + virtio_mb(); > + } > + Hmm, so you're still using the avail->flags; it's just if thresholding is enabled the host will ignore it? It's a little subtle, but it keeps this patch small. Perhaps we'll want to make it more explicit later. Thanks, Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html