ucc_geth: Fix full TX queue processing

commit 7583605b6d29f1f7f6fc505b883328089f3485ad ("ucc_geth: Fix empty
TX queue processing") fixed empty TX queue mishandling, but didn't
account another corner case: when TX queue becomes full.

Without this patch the driver will stop transmiting when TX queue
becomes full since 'bd == ugeth->txBd[txQ]' actually checks for
two things: queue empty or full.

Let's better check for NULL skb, which unambiguously signals an empty
queue.

Signed-off-by: Jiajun Wu <b06378@freescale.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Stable <stable@vger.kernel.org> [2.6.32]
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c
index 96bdc0b43889..eb8fe7e16c6c 100644
--- a/drivers/net/ucc_geth.c
+++ b/drivers/net/ucc_geth.c
@@ -3279,13 +3279,12 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ)
                 /* Handle the transmitted buffer and release */
                 /* the BD to be used with the current frame  */
 
-                if (bd == ugeth->txBd[txQ]) /* queue empty? */
+                skb = ugeth->tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]];
+                if (!skb)
                         break;
 
                 dev->stats.tx_packets++;
 
-                skb = ugeth->tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]];
-
                 if (skb_queue_len(&ugeth->rx_recycle) < RX_BD_RING_LEN &&
                              skb_recycle_check(skb,
                                     ugeth->ug_info->uf_info.max_rx_buf_length +