smsc95xx: Use skb_cow_head to deal with cloned skbs

The driver was failing to check that the SKB wasn't cloned
before adding checksum data.
Replace existing handling to extend/copy the header buffer
with skb_cow_head.

Signed-off-by: James Hughes <james.hughes@raspberrypi.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: Woojung Huh <Woojung.Huh@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
James Hughes 2017-04-19 11:13:40 +01:00 committed by David S. Miller
parent 74d209b835
commit e9156cd26a

View file

@ -2001,13 +2001,13 @@ static struct sk_buff *smsc95xx_tx_fixup(struct usbnet *dev,
/* We do not advertise SG, so skbs should be already linearized */
BUG_ON(skb_shinfo(skb)->nr_frags);
if (skb_headroom(skb) < overhead) {
struct sk_buff *skb2 = skb_copy_expand(skb,
overhead, 0, flags);
/* Make writable and expand header space by overhead if required */
if (skb_cow_head(skb, overhead)) {
/* Must deallocate here as returning NULL to indicate error
* means the skb won't be deallocated in the caller.
*/
dev_kfree_skb_any(skb);
skb = skb2;
if (!skb)
return NULL;
return NULL;
}
if (csum) {