1 files changed, 21 insertions, 2 deletions

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 72bf8bc09014..6eb5303fed11 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -18,6 +18,7 @@
  */
 #include <linux/virtio.h>
 #include <linux/virtio_ring.h>
+#include <linux/virtio_config.h>
 #include <linux/device.h>
 
 #ifdef DEBUG
@@ -87,8 +88,11 @@ static int vring_add_buf(struct virtqueue *_vq,
         if (vq->num_free < out + in) {
                 pr_debug("Can't add buf len %i - avail = %i\n",
                          out + in, vq->num_free);
-                /* We notify *even if* VRING_USED_F_NO_NOTIFY is set here. */
-                vq->notify(&vq->vq);
+                /* FIXME: for historical reasons, we force a notify here if
+                 * there are outgoing parts to the buffer.  Presumably the
+                 * host should service the ring ASAP. */
+                if (out)
+                        vq->notify(&vq->vq);
                 END_USE(vq);
                 return -ENOSPC;
         }
@@ -320,4 +324,19 @@ void vring_del_virtqueue(struct virtqueue *vq)
 }
 EXPORT_SYMBOL_GPL(vring_del_virtqueue);
 
+/* Manipulates transport-specific feature bits. */
+void vring_transport_features(struct virtio_device *vdev)
+{
+        unsigned int i;
+
+        for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {
+                switch (i) {
+                default:
+                        /* We don't understand this bit. */
+                        clear_bit(i, vdev->features);
+                }
+        }
+}
+EXPORT_SYMBOL_GPL(vring_transport_features);
+
 MODULE_LICENSE("GPL");