From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit 39fba7835aacda65284a86e611774cbba71dac20 upstream.
We can use skb_cow_head() to properly deal with clones,
especially the ones coming from TCP stack that allow their head being
modified. This avoids a copy.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: James Hughes <james.hughes@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
- This was applied upstream in v4.11
- Should be applied to stable v4.9.y
---
drivers/net/usb/kaweth.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/drivers/net/usb/kaweth.c b/drivers/net/usb/kaweth.c
index 66b34ddbe216..72d9e7954b0a 100644
--- a/drivers/net/usb/kaweth.c
+++ b/drivers/net/usb/kaweth.c
@@ -803,18 +803,12 @@ static netdev_tx_t kaweth_start_xmit(struct sk_buff *skb,
}
/* We now decide whether we can put our special header into the sk_buff */
- if (skb_cloned(skb) || skb_headroom(skb) < 2) {
- /* no such luck - we make our own */
- struct sk_buff *copied_skb;
- copied_skb = skb_copy_expand(skb, 2, 0, GFP_ATOMIC);
- dev_kfree_skb_irq(skb);
- skb = copied_skb;
- if (!copied_skb) {
- kaweth->stats.tx_errors++;
- netif_start_queue(net);
- spin_unlock_irq(&kaweth->device_lock);
- return NETDEV_TX_OK;
- }
+ if (skb_cow_head(skb, 2)) {
+ kaweth->stats.tx_errors++;
+ netif_start_queue(net);
+ spin_unlock_irq(&kaweth->device_lock);
+ dev_kfree_skb_any(skb);
+ return NETDEV_TX_OK;
}
private_header = (__le16 *)__skb_push(skb, 2);
--
2.20.1
