net: net: add a core netdev->tx_dropped counter

Dropping packets in __dev_queue_xmit() when transmit queue
is stopped (NIC TX ring buffer full or BQL limit reached) currently
outputs a syslog message.

It would be better to get a precise count of such events available in
netdevice stats so that monitoring tools can have a clue.

This extends the work done in caf586e5f23ce
("net: add a core netdev->rx_dropped counter")

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 48dd323d5918..98ba581b89f0 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2880,6 +2880,7 @@ recursion_alert:
         rc = -ENETDOWN;
         rcu_read_unlock_bh();
 
+        atomic_long_inc(&dev->tx_dropped);
         kfree_skb(skb);
         return rc;
 out:
@@ -6238,6 +6239,7 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
                 netdev_stats_to_stats64(storage, &dev->stats);
         }
         storage->rx_dropped += atomic_long_read(&dev->rx_dropped);
+        storage->tx_dropped += atomic_long_read(&dev->tx_dropped);
         return storage;
 }
 EXPORT_SYMBOL(dev_get_stats);