skb_len needs to be skb_headlen(skb) in bcmgenet_xmit_single().
Fragmented skbs can have only Ethernet + IP + TCP headers (14+20+20=54 bytes)
in the linear buffer, followed by the rest in fragments. Bumping skb_len to
ETH_ZLEN would be incorrect for this case, as it would introduce garbage
between TCP header and the fragment data.
This also works with regular/non-fragmented small packets < ETH_ZLEN bytes.
Successfully tested this on GENETv3 with 42-byte ARP frames.
For testing, I used:
ethtool -K eth0 tx-checksum-ipv4 off
ethtool -K eth0 tx-checksum-ipv6 off
echo 0 > /proc/sys/net/ipv4/tcp_timestamps
Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file")
Signed-off-by: Petri Gynther <pgynt...@google.com>
Acked-by: Eric Dumazet <eduma...@google.com>
---
drivers/net/ethernet/broadcom/genet/bcmgenet.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index c1c7c0e..cf6445d 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -1297,7 +1297,7 @@ static int bcmgenet_xmit_single(struct net_device *dev,
tx_cb_ptr->skb = skb;
- skb_len = skb_headlen(skb) < ETH_ZLEN ? ETH_ZLEN : skb_headlen(skb);
+ skb_len = skb_headlen(skb);
mapping = dma_map_single(kdev, skb->data, skb_len, DMA_TO_DEVICE);
ret = dma_mapping_error(kdev, mapping);
--
2.8.0.rc3.226.g39d4020
