net: txq_trans_update() helper

We would like to get rid of netdev->trans_start = jiffies; that about all net
drivers have to use in their start_xmit() function, and use txq->trans_start
instead.

This can be done generically in core network, as suggested by David.

Some devices, (particularly loopback) dont need trans_start update, because
they dont have transmit watchdog. We could add a new device flag, or rely
on fact that txq->tran_start can be updated is txq->xmit_lock_owner is
different than -1. Use a helper function to hide our choice.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 241613f6dd2f..5eb3e48ab31d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1698,6 +1698,8 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
                         skb->dst = NULL;
                 }
                 rc = ops->ndo_start_xmit(skb, dev);
+                if (rc == 0)
+                        txq_trans_update(txq);
                 /*
                  * TODO: if skb_orphan() was called by
                  * dev->hard_start_xmit() (for example, the unmodified
@@ -1727,6 +1729,7 @@ gso:
                         skb->next = nskb;
                         return rc;
                 }
+                txq_trans_update(txq);
                 if (unlikely(netif_tx_queue_stopped(txq) && skb->next))
                         return NETDEV_TX_BUSY;
         } while (skb->next);