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>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index ee022714eadb985a19ce8fe160edf735046c9050..ff208d2787d386f27acb2b2e8e1d3fd6ebd3152f 100644 (file)
--- 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.