lan78xx: use skb_cow_head() to deal with cloned skbs

We need to ensure there is enough headroom to push extra header,
but we also need to check if we are allowed to change headers.

skb_cow_head() is the proper helper to deal with this.

Fixes: 55d7de9de6 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: James Hughes <james.hughes@raspberrypi.org>
Cc: Woojung Huh <woojung.huh@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2017-04-19 09:59:24 -07:00 committed by David S. Miller
parent d532c1082f
commit d4ca735919

View File

@ -2607,14 +2607,9 @@ static struct sk_buff *lan78xx_tx_prep(struct lan78xx_net *dev,
{
u32 tx_cmd_a, tx_cmd_b;
if (skb_headroom(skb) < TX_OVERHEAD) {
struct sk_buff *skb2;
skb2 = skb_copy_expand(skb, TX_OVERHEAD, 0, flags);
if (skb_cow_head(skb, TX_OVERHEAD)) {
dev_kfree_skb_any(skb);
skb = skb2;
if (!skb)
return NULL;
return NULL;
}
if (lan78xx_linearize(skb) < 0)