ixgb: remove lock access in the fast path

This mimics a change made in the e1000 driver that imitates a slick
tg3 way of avoiding grabbing the lock around restarting the tx queue.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>

diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index b825850..a714c4d 100644 (file)
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1800,13 +1800,13 @@ ixgb_clean_tx_irq(struct ixgb_adapter *adapter)
 
        tx_ring->next_to_clean = i;
 
-       spin_lock(&adapter->tx_lock);
-       if(cleaned && netif_queue_stopped(netdev) && netif_carrier_ok(netdev) &&
-          (IXGB_DESC_UNUSED(tx_ring) > IXGB_TX_QUEUE_WAKE)) {
-
-               netif_wake_queue(netdev);
+       if (unlikely(netif_queue_stopped(netdev))) {
+               spin_lock(&adapter->tx_lock);
+               if (netif_queue_stopped(netdev) && netif_carrier_ok(netdev) &&
+                   (IXGB_DESC_UNUSED(tx_ring) > IXGB_TX_QUEUE_WAKE))
+                       netif_wake_queue(netdev);
+               spin_unlock(&adapter->tx_lock);
        }
-       spin_unlock(&adapter->tx_lock);
 
        if(adapter->detect_tx_hung) {
                /* detect a transmit hang in hardware, this serializes the