From b7c6d2675899cfff0180412c63fc9cbd5bacdb4d Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 19 Apr 2017 09:59:21 -0700 Subject: [PATCH] smsc75xx: 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: d0cad871703b ("smsc75xx: SMSC LAN75xx USB gigabit ethernet adapter driver") Signed-off-by: Eric Dumazet Cc: James Hughes Signed-off-by: David S. Miller --- drivers/net/usb/smsc75xx.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/drivers/net/usb/smsc75xx.c +++ b/drivers/net/usb/smsc75xx.c @@ -2205,13 +2205,9 @@ static struct sk_buff *smsc75xx_tx_fixup { u32 tx_cmd_a, tx_cmd_b; - if (skb_headroom(skb) < SMSC75XX_TX_OVERHEAD) { - struct sk_buff *skb2 = - skb_copy_expand(skb, SMSC75XX_TX_OVERHEAD, 0, flags); + if (skb_cow_head(skb, SMSC75XX_TX_OVERHEAD)) { dev_kfree_skb_any(skb); - skb = skb2; - if (!skb) - return NULL; + return NULL; } tx_cmd_a = (u32)(skb->len & TX_CMD_A_LEN) | TX_CMD_A_FCS;