net/virtio: update memory ordering comment for VQ notify

We're not using IO ports in case of modern device even on IA.
Also, this comment useless for other architectures.

Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index dffa036..53aeac2 100644 (file)
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -437,14 +437,13 @@ virtqueue_kick_prepare_packed(struct virtqueue *vq)
        return flags != RING_EVENT_FLAGS_DISABLE;
 }
 
+/*
+ * virtqueue_kick_prepare*() or the virtio_wmb() should be called
+ * before this function to be sure that all the data is visible to vhost.
+ */
 static inline void
 virtqueue_notify(struct virtqueue *vq)
 {
-       /*
-        * Ensure updated avail->idx is visible to host.
-        * For virtio on IA, the notificaiton is through io port operation
-        * which is a serialization instruction itself.
-        */
        VTPCI_OPS(vq->hw)->notify_queue(vq->hw, vq);
 }