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authorHelmut Buchsbaum <helmut.buchsbaum@gmail.com>2016-09-04 18:09:47 +0200
committerDavid S. Miller <davem@davemloft.net>2016-09-06 13:43:39 -0700
commit007e4ba3ee137f4700f39aa6dbaf01a71047c5f6 (patch)
tree0514552489d077fa1b0c493c3bc6b5919fcc2261 /drivers/net/ethernet/cadence
parent03c2778a938aaba0893f6d6cdc29511d91a79848 (diff)
downloadlinux-007e4ba3ee137f4700f39aa6dbaf01a71047c5f6.tar.bz2
net: macb: initialize checksum when using checksum offloading
I'm still struggling to get this fix right.. Changes since v2: - do not blindly modify SKB contents according to Dave's legitimate objection Changes since v1: - dropped disabling HW checksum offload for Zynq - initialize checksum similar to net/ethernet/freescale/fec_main.c -- >8 -- MACB/GEM needs the checksum field initialized to 0 to get correct results on transmit in all cases, e.g. on Zynq, UDP packets with payload <= 2 otherwise contain a wrong checksums. Signed-off-by: Helmut Buchsbaum <helmut.buchsbaum@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/cadence')
-rw-r--r--drivers/net/ethernet/cadence/macb.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 89c0cfa9719f..d954a97b0b0b 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -1323,6 +1323,24 @@ 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);
@@ -1362,6 +1380,11 @@ 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);