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| author | Helmut Buchsbaum <helmut.buchsbaum@gmail.com> | 2016-09-04 18:09:47 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-09-06 13:43:39 -0700 |
| commit | 007e4ba3ee137f4700f39aa6dbaf01a71047c5f6 (patch) | |
| tree | 0514552489d077fa1b0c493c3bc6b5919fcc2261 | |
| parent | 03c2778a938aaba0893f6d6cdc29511d91a79848 (diff) | |
| download | linux-007e4ba3ee137f4700f39aa6dbaf01a71047c5f6.tar.gz | |
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>
| -rw-r--r-- | drivers/net/ethernet/cadence/macb.c | 23 |
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); |