virtio net will never try to overflow the TX ring, so the only reason
add_buf may fail is out of memory. Thus, we can not stop the
device until some request completes - there's no guarantee anything
at all is outstanding.

Make the error message clearer as well: error here does not
indicate queue full.

Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
 drivers/net/virtio_net.c |   15 ++++++++-------
 1 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 85615a3..e48a06f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -563,7 +563,6 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct 
net_device *dev)
        struct virtnet_info *vi = netdev_priv(dev);
        int capacity;
 
-again:
        /* Free up any pending old buffers before queueing new ones. */
        free_old_xmit_skbs(vi);
 
@@ -572,12 +571,14 @@ again:
 
        /* This can happen with OOM and indirect buffers. */
        if (unlikely(capacity < 0)) {
-               netif_stop_queue(dev);
-               dev_warn(&dev->dev, "Unexpected full queue\n");
-               if (unlikely(!virtqueue_enable_cb(vi->svq))) {
-                       virtqueue_disable_cb(vi->svq);
-                       netif_start_queue(dev);
-                       goto again;
+               if (net_ratelimit()) {
+                       if (likely(capacity == -ENOMEM))
+                               dev_warn(&dev->dev,
+                                        "TX queue failure: out of memory\n");
+                       else
+                               dev_warn(&dev->dev,
+                                        "Unexpected TX queue failure: %d\n",
+                                        capacity);
                }
                return NETDEV_TX_BUSY;
        }
-- 
1.7.1.12.g42b7f
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