From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net 3/3] Drivers: net: hyperv: Address UDP checksum issues
Date: Wed, 09 Apr 2014 14:36:55 -0400 (EDT)
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From: KY Srinivasan <kys@microsoft.com>
Date: Wed, 9 Apr 2014 18:08:47 +0000

> Thanks Dave. I will COW the SKB before changing the checksum
> value. I do have a question though.  I looked at a bunch of hardware
> drivers and they modify the header information, specially checksum
> field and I could not see where they had COWed the skb. I was
> grepping for skb_cow in these drivers.

Look for skb_cow_head(), for example, the tg3.c driver uses this.