pktgen: Avoid dirtying skb->users when txq is full

We can avoid two atomic ops on skb->users if packet is not going to be
sent to the device (because hardware txqueue is full)

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

1 files changed, 7 insertions, 4 deletions

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index b69455217ed6..e856ab0d0745 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3441,12 +3441,14 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
         txq = netdev_get_tx_queue(odev, queue_map);
 
         __netif_tx_lock_bh(txq);
-        atomic_inc(&(pkt_dev->skb->users));
 
-        if (unlikely(netif_tx_queue_stopped(txq) || netif_tx_queue_frozen(txq)))
+        if (unlikely(netif_tx_queue_stopped(txq) || netif_tx_queue_frozen(txq))) {
                 ret = NETDEV_TX_BUSY;
-        else
-                ret = (*xmit)(pkt_dev->skb, odev);
+                pkt_dev->last_ok = 0;
+                goto unlock;
+        }
+        atomic_inc(&(pkt_dev->skb->users));
+        ret = (*xmit)(pkt_dev->skb, odev);
 
         switch (ret) {
         case NETDEV_TX_OK:
@@ -3468,6 +3470,7 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
                 atomic_dec(&(pkt_dev->skb->users));
                 pkt_dev->last_ok = 0;
         }
+unlock:
         __netif_tx_unlock_bh(txq);
 
         /* If pkt_dev->count is zero, then run forever */