Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[cascardo/linux.git] / drivers / net / ethernet / cadence / macb.c

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 3256839..0294b6a 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -1339,6 +1339,24 @@ dma_error:
        return 0;
 }
 
+static inline int macb_clear_csum(struct sk_buff *skb)
+{
+       /* no change for packets without checksum offloading */
+       if (skb->ip_summed != CHECKSUM_PARTIAL)
+               return 0;
+
+       /* make sure we can modify the header */
+       if (unlikely(skb_cow_head(skb, 0)))
+               return -1;
+
+       /* initialize checksum field
+        * This is required - at least for Zynq, which otherwise calculates
+        * wrong UDP header checksums for UDP packets with UDP data len <=2
+        */
+       *(__sum16 *)(skb_checksum_start(skb) + skb->csum_offset) = 0;
+       return 0;
+}
+
 static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        u16 queue_index = skb_get_queue_mapping(skb);
@@ -1378,6 +1396,11 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
                return NETDEV_TX_BUSY;
        }
 
+       if (macb_clear_csum(skb)) {
+               dev_kfree_skb_any(skb);
+               return NETDEV_TX_OK;
+       }
+
        /* Map socket buffer for DMA transfer */
        if (!macb_tx_map(bp, queue, skb)) {
                dev_kfree_skb_any(skb);