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[SC92031] Using padto turned driver into an IPv6-only interface 

IPv4 would work with this driver only with static arp table entries,
the patch  reverts a padto introduced in

 commit 26a17b7bbb
 sc92031: start transmit return value bugfix

The padto does not work because the driver code evaluates `len' later on and
there are cases where skb->len is not updated accordingly.

This was observed with ARP frames (skb->len = 42 bytes, !skb_cloned(),
skb_tailroom = 84 bytes). Then in skb_pad(), the first condition is true, where
skb->len is not updated. As a consequence, the driver uses 42 bytes instead of
the 60 bytes, and the ARP frame never makes it onto the wire.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This commit is contained in:
Gerrit Renker 2008-05-17 08:35:36 +01:00 committed by Jeff Garzik
parent 789585e968
commit 5a0a92e67b
1 changed files with 5 additions and 3 deletions
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8
drivers/net/sc92031.c
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@ -953,9 +953,6 @@ static int sc92031_start_xmit(struct sk_buff *skb, struct net_device *dev)
unsigned entry;
u32 tx_status;
if (skb_padto(skb, ETH_ZLEN))
return NETDEV_TX_OK;
if (unlikely(skb->len > TX_BUF_SIZE)) {
dev->stats.tx_dropped++;
goto out;
@ -975,6 +972,11 @@ static int sc92031_start_xmit(struct sk_buff *skb, struct net_device *dev)
skb_copy_and_csum_dev(skb, priv->tx_bufs + entry * TX_BUF_SIZE);
len = skb->len;
if (unlikely(len < ETH_ZLEN)) {
memset(priv->tx_bufs + entry * TX_BUF_SIZE + len,
0, ETH_ZLEN - len);
len = ETH_ZLEN;
}
wmb();