---

yaml
---
r: 87418
b: refs/heads/master
c: 4265f16
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: da74e89d40995600b3b07ac500084920247687ce
+refs/heads/master: 4265f161b6bb7b31163671329b1142b9023bf4e3

trunk/drivers/net/virtio_net.c

@@ -203,8 +203,11 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
 	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 @@ static int start_xmit(struct sk_buff *skb, struct net_device *dev)
 		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;
 		}

trunk/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;
 	}

trunk/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.