3 files changed, 10 insertions, 6 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e575df83e5c2..b58472cf76f8 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -203,8 +203,11 @@ again:
         if (received < budget) {
                 netif_rx_complete(vi->dev, napi);
                 if (unlikely(!vi->rvq->vq_ops->enable_cb(vi->rvq))
-                    && netif_rx_reschedule(vi->dev, napi))
+                    && napi_schedule_prep(napi)) {
+                        vi->rvq->vq_ops->disable_cb(vi->rvq);
+                        __netif_rx_schedule(vi->dev, napi);
                         goto again;
+                }
         }
 
         return received;
@@ -278,10 +281,11 @@ again:
                 pr_debug("%s: virtio not prepared to send\n", dev->name);
                 netif_stop_queue(dev);
 
-                /* Activate callback for using skbs: if this fails it
+                /* Activate callback for using skbs: if this returns false it
                  * means some were used in the meantime. */
                 if (unlikely(!vi->svq->vq_ops->enable_cb(vi->svq))) {
-                        printk("Unlikely: restart svq failed\n");
+                        printk("Unlikely: restart svq race\n");
+                        vi->svq->vq_ops->disable_cb(vi->svq);
                         netif_start_queue(dev);
                         goto again;
                 }
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 3a28c1382131..aa714028641e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -232,7 +232,6 @@ static bool vring_enable_cb(struct virtqueue *_vq)
         vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
         mb();
         if (unlikely(more_used(vq))) {
-                vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
                 END_USE(vq);
                 return false;
         }
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 260d1fcf29a4..12c18ac1b973 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -43,8 +43,9 @@ struct virtqueue
  *      vq: the struct virtqueue we're talking about.
  * @enable_cb: restart callbacks after disable_cb.
  *      vq: the struct virtqueue we're talking about.
- *      This returns "false" (and doesn't re-enable) if there are pending
- *      buffers in the queue, to avoid a race.
+ *      This re-enables callbacks; it returns "false" if there are pending
+ *      buffers in the queue, to detect a possible race between the driver
+ *      checking for more work, and enabling callbacks.
  *
  * Locking rules are straightforward: the driver is responsible for
  * locking.  No two operations may be invoked simultaneously.