virtio-net: fix total qstat values

Another small fix discovered after we enabled virtio multi-queue in netdev CI. The queue stat test fails:

# Exception| Exception: Qstats are lower, fetched later not ok 3 stats.pkt_byte_sum

The queue stats from disabled queues are supposed to be reported in the "base" stats.

Jakub Kicinski (2):
net: export a helper for adding up queue stats
virtio-net: fix total qstat values

 include/net/netdev_queues.h |  6 ++++
 drivers/net/virtio_net.c    |  4 +++
 net/core/netdev-genl.c      | 69 +++++++++++++++++++++++++++----------
 3 files changed, 60 insertions(+), 19 deletions(-)

2.49.0

Older drivers and drivers with lower queue counts often have a static array of queues, rather than allocating structs for each queue on demand. Add a helper for adding up qstats from a queue range. Expectation is that driver will pass a queue range [netdev->real_num_*x_queues, MAX). It was tempting to always use num_*x_queues as the end, but virtio seems to clamp its queue count after allocating the netdev. And this way we can trivaly reuse the helper for [0, real_..).

---
 include/net/netdev_queues.h |  6 ++++
 net/core/netdev-genl.c      | 69 +++++++++++++++++++++++++++----------
 2 files changed, 56 insertions(+), 19 deletions(-)

index ea709b59d827..069ff35a72de 100644
@@ -105,6 +105,12 @@ struct netdev_stat_ops {
 			       struct netdev_queue_stats_tx *tx);
 };
 
+void netdev_stat_queue_sum(struct net_device *netdev,
+			   int rx_start, int rx_end,
+			   struct netdev_queue_stats_rx *rx_sum,
+			   int tx_start, int tx_end,
+			   struct netdev_queue_stats_tx *tx_sum);
+
 /**
  * struct netdev_queue_mgmt_ops - netdev ops for queue management
  *

2.49.0

NIPA tests report that the interface statistics reported via qstat are lower than those reported via ip link. Looks like this is because some tests flip the queue count up and down, and we end up with some of the traffic accounted on disabled queues.

Add up counters from disabled queues.

---
 drivers/net/virtio_net.c | 4 ++++
 1 file changed, 4 insertions(+)

index f9e3e628ec4d..e53ba600605a 100644
@@ -5678,6 +5678,10 @@ static void virtnet_get_base_stats(struct net_device *dev,
 
 	if (vi->device_stats_cap & VIRTIO_NET_STATS_TYPE_TX_SPEED)
 		tx->hw_drop_ratelimits = 0;
+
+	netdev_stat_queue_sum(dev,
+			      dev->real_num_rx_queues, vi->max_queue_pairs, rx,
+			      dev->real_num_tx_queues, vi->max_queue_pairs, tx);
 }
 
 static const struct netdev_stat_ops virtnet_stat_ops = {

2.49.0