From d4ca73591916b760478d2b04334d5dcadc028e9c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 19 Apr 2017 09:59:24 -0700 Subject: [PATCH] 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: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet device driver") Signed-off-by: Eric Dumazet Cc: James Hughes Cc: Woojung Huh Signed-off-by: David S. Miller --- drivers/net/usb/lan78xx.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2419,14 +2419,9 @@ static struct sk_buff *lan78xx_tx_prep(s { 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)