[PATCH net-next v3 3/3] virtio-net: support changing the number of queue pairs through ethtool

From: Jason Wang
Date: Fri Dec 07 2012 - 12:13:40 EST


This patch implements the ethtool_{set|get}_channels method of virtio-net to
allow user to change the number of queues when the device is running on demand.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/net/virtio_net.c | 43 +++++++++++++++++++++++++++++++++++++++++++
1 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c083048..a644eeb 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1075,10 +1075,53 @@ static void virtnet_get_drvinfo(struct net_device *dev,

}

+/* 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;
+ int err;
+
+ /* 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;
+
+ if (queue_pairs > vi->max_queue_pairs)
+ return -EINVAL;
+
+ err = virtnet_set_queues(vi, queue_pairs);
+ if (!err) {
+ netif_set_real_num_tx_queues(dev, queue_pairs);
+ netif_set_real_num_rx_queues(dev, queue_pairs);
+
+ virtnet_set_affinity(vi, true);
+ }
+
+ return err;
+}
+
+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,
};

#define MIN_MTU 68
--
1.7.1

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