From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net 4/6] lan78xx: use skb_cow_head() to deal with cloned skbs Date: Wed, 19 Apr 2017 09:59:24 -0700 Message-ID: <20170419165926.30631-5-edumazet@google.com> References: <20170419165926.30631-1-edumazet@google.com> Cc: netdev , James Hughes , Eric Dumazet , Eric Dumazet , Woojung Huh To: "David S . Miller" Return-path: Received: from mail-yb0-f182.google.com ([209.85.213.182]:35653 "EHLO mail-yb0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967463AbdDSQ7v (ORCPT ); Wed, 19 Apr 2017 12:59:51 -0400 Received: by mail-yb0-f182.google.com with SMTP id 6so7397392ybq.2 for ; Wed, 19 Apr 2017 09:59:45 -0700 (PDT) In-Reply-To: <20170419165926.30631-1-edumazet@google.com> Sender: netdev-owner@vger.kernel.org List-ID: 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 --- drivers/net/usb/lan78xx.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index 9889a70ff4f6fece5bfabbfb45a3470f721a5a32..636f48f19d1eacae67c050de4fc3e651bffdf825 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2607,14 +2607,9 @@ static struct sk_buff *lan78xx_tx_prep(struct lan78xx_net *dev, { 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) -- 2.12.2.816.g2cccc81164-goog