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Commit 58eba97d authored by Rusty Russell's avatar Rusty Russell Committed by David S. Miller
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virtio_net: fix oom handling on tx 



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: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (...and avoid TX_BUSY)
Cc: stable@kernel.org  # .34.x (s/virtqueue_/vi->svq->vq_ops->/)
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1788f495

drivers/net/virtio_net.c

+13 −8
Original line number Diff line number Diff line
@@ -562,7 +562,6 @@ 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);
@@ -571,14 +570,20 @@ 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->stats.tx_fifo_errors++;

				dev_warn(&dev->dev,

					 "Unexpected TX queue failure: %d\n",

					 capacity);

			}

		return NETDEV_TX_BUSY;

		}

		dev->stats.tx_dropped++;

		kfree_skb(skb);

		return NETDEV_TX_OK;

	}

	virtqueue_kick(vi->svq);