[net-next rfc v7 3/3] virtio-net: change the number of queues through ethtool

Jason Wang
2012-11-27T10:16:00Z

This patch implement the {set|get}_channels method of ethool to allow user to
change the number of queues dymaically when the device is running. This would
let the user to configure it on demand.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/virtio_net.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index bcaa6e5..f08ec2a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1578,10 +1578,51 @@ static struct virtio_driver virtio_net_driver = {
#endif
};

+/* TODO: Eliminate OOO packets during switching */
+static int virtnet_set_channels(struct net_device *dev,
+ struct ethtool_channels *channels)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ u16 queue_pairs = channels->combined_count;
+
+ /* We don't support separate rx/tx channels.
+ * We don't allow setting 'other' channels.
+ */
+ if (channels->rx_count || channels->tx_count || channels->other_count)
+ return -EINVAL;
+
+ /* Only two modes were support currently */
+ if (queue_pairs != vi->max_queue_pairs && queue_pairs != 1)
+ return -EINVAL;
+
+ vi->curr_queue_pairs = queue_pairs;
+ BUG_ON(virtnet_set_queues(vi));
+
+ netif_set_real_num_tx_queues(dev, vi->curr_queue_pairs);
+ netif_set_real_num_rx_queues(dev, vi->curr_queue_pairs);
+
+ return 0;
+}
+
+static void virtnet_get_channels(struct net_device *dev,
+ struct ethtool_channels *channels)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+
+ channels->combined_count = vi->curr_queue_pairs;
+ channels->max_combined = vi->max_queue_pairs;
+ channels->max_other = 0;
+ channels->rx_count = 0;
+ channels->tx_count = 0;
+ channels->other_count = 0;
+}
+
static const struct ethtool_ops virtnet_ethtool_ops = {
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
+ .set_channels = virtnet_set_channels,
+ .get_channels = virtnet_get_channels,
};

static int __init init(void)
--
1.7.1