According to Documentation/networking/driver.txt the ndo_start_xmit method should not return NETDEV_TX_BUSY under normal circumstances.
Stop the transmit queue when tx_ring is full.

Signed-off-by: Ondrej Puzman <redacted>
---
 .../net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c   |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
index 27ffe0e..6764e59 100644
--- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
+++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c

@@ -2157,6 +2157,10 @@ static int pch_gbe_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 
 	/* CRC,ITAG no support */
 	pch_gbe_tx_queue(adapter, tx_ring, skb);
+
+	if (unlikely(!PCH_GBE_DESC_UNUSED(tx_ring)))
+		netif_stop_queue(netdev);
+
 	spin_unlock_irqrestore(&tx_ring->tx_lock, flags);
 	return NETDEV_TX_OK;
 }

-- 
1.7.2.3