Commit ab020c41 authored by Petri Gynther's avatar Petri Gynther Committed by Ben Hutchings

net: bcmgenet: fix skb_len in bcmgenet_xmit_single()

commit 7dd39913 upstream.

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: 1c1008c7 ("net: bcmgenet: add main driver file")
Signed-off-by: default avatarPetri Gynther <pgynther@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 6ab3a433
...@@ -979,7 +979,7 @@ static int bcmgenet_xmit_single(struct net_device *dev, ...@@ -979,7 +979,7 @@ static int bcmgenet_xmit_single(struct net_device *dev,
tx_cb_ptr->skb = skb; 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); mapping = dma_map_single(kdev, skb->data, skb_len, DMA_TO_DEVICE);
ret = dma_mapping_error(kdev, mapping); ret = dma_mapping_error(kdev, mapping);
......
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