From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net 5/6] ch9200: use skb_cow_head() to deal with cloned skbs Date: Wed, 19 Apr 2017 09:59:25 -0700 Message-ID: <20170419165926.30631-6-edumazet@google.com> References: <20170419165926.30631-1-edumazet@google.com> Cc: netdev , James Hughes , Eric Dumazet , Eric Dumazet , Matthew Garrett To: "David S . Miller" Return-path: Received: from mail-yb0-f173.google.com ([209.85.213.173]:35956 "EHLO mail-yb0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967453AbdDSQ7n (ORCPT ); Wed, 19 Apr 2017 12:59:43 -0400 Received: by mail-yb0-f173.google.com with SMTP id s22so9067026ybe.3 for ; Wed, 19 Apr 2017 09:59:43 -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: 4a476bd6d1d9 ("usbnet: New driver for QinHeng CH9200 devices") Signed-off-by: Eric Dumazet Cc: James Hughes Cc: Matthew Garrett --- drivers/net/usb/ch9200.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/net/usb/ch9200.c b/drivers/net/usb/ch9200.c index 8a40202c0a1732850da1b2eb64af21470b9c85b4..c4f1c363e24b89404c6834312074f8a4451ded50 100644 --- a/drivers/net/usb/ch9200.c +++ b/drivers/net/usb/ch9200.c @@ -254,14 +254,9 @@ static struct sk_buff *ch9200_tx_fixup(struct usbnet *dev, struct sk_buff *skb, tx_overhead = 0x40; len = skb->len; - 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; } __skb_push(skb, tx_overhead); -- 2.12.2.816.g2cccc81164-goog