target/linux/generic/pending-4.4/030-3-cx82310_eth-use-skb_cow_head-to-deal-with-cloned-skb.patch

   1 From a9e840a2081ed28c2b7caa6a9a0041c950b3c37d Mon Sep 17 00:00:00 2001
   2 From: Eric Dumazet <edumazet@google.com>
   3 Date: Wed, 19 Apr 2017 09:59:22 -0700
   4 Subject: [PATCH] cx82310_eth: use skb_cow_head() to deal with cloned skbs
   5
   6 We need to ensure there is enough headroom to push extra header,
   7 but we also need to check if we are allowed to change headers.
   8
   9 skb_cow_head() is the proper helper to deal with this.
  10
  11 Fixes: cc28a20e77b2 ("introduce cx82310_eth: Conexant CX82310-based ADSL router USB ethernet driver")
  12 Signed-off-by: Eric Dumazet <edumazet@google.com>
  13 Cc: James Hughes <james.hughes@raspberrypi.org>
  14 Signed-off-by: David S. Miller <davem@davemloft.net>
  15 ---
  16  drivers/net/usb/cx82310_eth.c | 7 ++-----
  17  1 file changed, 2 insertions(+), 5 deletions(-)
  18
  19 --- a/drivers/net/usb/cx82310_eth.c
  20 +++ b/drivers/net/usb/cx82310_eth.c
  21 @@ -293,12 +293,9 @@ static struct sk_buff *cx82310_tx_fixup(
  22  {
  23         int len = skb->len;
  24
  25 -       if (skb_headroom(skb) < 2) {
  26 -               struct sk_buff *skb2 = skb_copy_expand(skb, 2, 0, flags);
  27 +       if (skb_cow_head(skb, 2)) {
  28                 dev_kfree_skb_any(skb);
  29 -               skb = skb2;
  30 -               if (!skb)
  31 -                       return NULL;
  32 +               return NULL;
  33         }
  34         skb_push(skb, 2);
  35