[PATCH] mv643xx: fix outstanding tx skb counter

This patch corrects the accounting of outstanding tx skbs.  It fixes
a bug that causes "Error on Queue Full" messages seen since scatter-gather
was enabled by using the hardware tcp/udp checksum generator.

Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

1 files changed, 9 insertions, 15 deletions

diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index ab74d4583c4..8ea00471464 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -369,15 +369,6 @@ static int mv643xx_eth_free_tx_queue(struct net_device *dev,
 
                         dev_kfree_skb_irq(pkt_info.return_info);
                         released = 0;
-
-                        /*
-                         * Decrement the number of outstanding skbs counter on
-                         * the TX queue.
-                         */
-                        if (mp->tx_ring_skbs == 0)
-                                panic("ERROR - TX outstanding SKBs"
-                                                " counter is corrupted");
-                        mp->tx_ring_skbs--;
                 } else
                         dma_unmap_page(NULL, pkt_info.buf_ptr,
                                         pkt_info.byte_cnt, DMA_TO_DEVICE);
@@ -1042,9 +1033,6 @@ static void mv643xx_tx(struct net_device *dev)
                                                 DMA_TO_DEVICE);
 
                         dev_kfree_skb_irq(pkt_info.return_info);
-
-                        if (mp->tx_ring_skbs)
-                                mp->tx_ring_skbs--;
                 } else
                         dma_unmap_page(NULL, pkt_info.buf_ptr,
                                         pkt_info.byte_cnt, DMA_TO_DEVICE);
@@ -1187,7 +1175,6 @@ linear:
                 pkt_info.buf_ptr = dma_map_single(NULL, skb->data, skb->len,
                                                         DMA_TO_DEVICE);
                 pkt_info.return_info = skb;
-                mp->tx_ring_skbs++;
                 status = eth_port_send(mp, &pkt_info);
                 if ((status == ETH_ERROR) || (status == ETH_QUEUE_FULL))
                         printk(KERN_ERR "%s: Error on transmitting packet\n",
@@ -1272,7 +1259,6 @@ linear:
                                 pkt_info.cmd_sts |= ETH_TX_ENABLE_INTERRUPT |
                                                         ETH_TX_LAST_DESC;
                                 pkt_info.return_info = skb;
-                                mp->tx_ring_skbs++;
                         } else {
                                 pkt_info.return_info = 0;
                         }
@@ -1309,7 +1295,6 @@ linear:
         pkt_info.buf_ptr = dma_map_single(NULL, skb->data, skb->len,
                                                                 DMA_TO_DEVICE);
         pkt_info.return_info = skb;
-        mp->tx_ring_skbs++;
         status = eth_port_send(mp, &pkt_info);
         if ((status == ETH_ERROR) || (status == ETH_QUEUE_FULL))
                 printk(KERN_ERR "%s: Error on transmitting packet\n",
@@ -2526,6 +2511,9 @@ static ETH_FUNC_RET_STATUS eth_port_send(struct mv643xx_private *mp,
                 return ETH_ERROR;
         }
 
+        mp->tx_ring_skbs++;
+        BUG_ON(mp->tx_ring_skbs > mp->tx_ring_size);
+
         /* Get the Tx Desc ring indexes */
         tx_desc_curr = mp->tx_curr_desc_q;
         tx_desc_used = mp->tx_used_desc_q;
@@ -2592,6 +2580,9 @@ static ETH_FUNC_RET_STATUS eth_port_send(struct mv643xx_private *mp,
         if (mp->tx_resource_err)
                 return ETH_QUEUE_FULL;
 
+        mp->tx_ring_skbs++;
+        BUG_ON(mp->tx_ring_skbs > mp->tx_ring_size);
+
         /* Get the Tx Desc ring indexes */
         tx_desc_curr = mp->tx_curr_desc_q;
         tx_desc_used = mp->tx_used_desc_q;
@@ -2692,6 +2683,9 @@ static ETH_FUNC_RET_STATUS eth_tx_return_desc(struct mv643xx_private *mp,
         /* Any Tx return cancels the Tx resource error status */
         mp->tx_resource_err = 0;
 
+        BUG_ON(mp->tx_ring_skbs == 0);
+        mp->tx_ring_skbs--;
+
         return ETH_OK;
 }