virtio_net: fix oom handling on tx (58eba97d) · Commits · 戴 / test

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 <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:

David S. Miller <davem@davemloft.net>

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);

Admin message