2024-06-14 22:05:08

by Abhinav Jain

[permalink] [raw]
Subject: [PATCH] virtio_net: Eliminate OOO packets during switching

Disable the network device & turn off carrier before modifying the
number of queue pairs.
Process all the in-flight packets and then turn on carrier, followed
by waking up all the queues on the network device.

Signed-off-by: Abhinav Jain <[email protected]>
---
drivers/net/virtio_net.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 61a57d134544..d0a655a3b4c6 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3447,7 +3447,6 @@ 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)
{
@@ -3471,6 +3470,15 @@ static int virtnet_set_channels(struct net_device *dev,
if (vi->rq[0].xdp_prog)
return -EINVAL;

+ /* Disable network device to prevent packet processing during
+ * the switch.
+ */
+ netif_tx_disable(dev);
+ netif_carrier_off(dev);
+
+ /* Make certain that all in-flight packets are processed. */
+ synchronize_net();
+
cpus_read_lock();
err = virtnet_set_queues(vi, queue_pairs);
if (err) {
@@ -3482,7 +3490,12 @@ static int virtnet_set_channels(struct net_device *dev,

netif_set_real_num_tx_queues(dev, queue_pairs);
netif_set_real_num_rx_queues(dev, queue_pairs);
- err:
+
+ /* Restart the network device */
+ netif_carrier_on(dev);
+ netif_tx_wake_all_queues(dev);
+
+err:
return err;
}

--
2.34.1