virtio_net: verify if virtqueue_kick() succeeded

Verify if a host kick succeeded by checking return value of virtqueue_kick().

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 5 insertions, 4 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ee022714eadb..ff208d2787d3 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -545,7 +545,8 @@ static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp)
         } while (rq->vq->num_free);
         if (unlikely(rq->num > rq->max))
                 rq->max = rq->num;
-        virtqueue_kick(rq->vq);
+        if (unlikely(!virtqueue_kick(rq->vq)))
+                return false;
         return !oom;
 }
 
@@ -751,7 +752,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
         err = xmit_skb(sq, skb);
 
         /* This should not happen! */
-        if (unlikely(err)) {
+        if (unlikely(err) || unlikely(!virtqueue_kick(sq->vq))) {
                 dev->stats.tx_fifo_errors++;
                 if (net_ratelimit())
                         dev_warn(&dev->dev,
@@ -760,7 +761,6 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
                 kfree_skb(skb);
                 return NETDEV_TX_OK;
         }
-        virtqueue_kick(sq->vq);
 
         /* Don't wait up for transmitted skbs to be freed. */
         skb_orphan(skb);
@@ -819,7 +819,8 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
         BUG_ON(virtqueue_add_sgs(vi->cvq, sgs, out_num, in_num, vi, GFP_ATOMIC)
                < 0);
 
-        virtqueue_kick(vi->cvq);
+        if (unlikely(!virtqueue_kick(vi->cvq)))
+                return status == VIRTIO_NET_OK;
 
         /* Spin for a response, the kick causes an ioport write, trapping
          * into the hypervisor, so the request should be handled immediately.