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Date: Fri, 25 Apr 2014 17:43:22 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com,
        jasowang@redhat.com, stable@kernel.org
Subject: Re: [PATCH net-next 1/1]  hyperv: Properly handle checksum offload
Message-ID: <20140425174322.589ed9f1@samsung-9>
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On Fri, 25 Apr 2014 11:45:14 -0700
"K. Y. Srinivasan" <kys@microsoft.com> wrote:

> @@ -474,6 +477,9 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
>  	csum_info = (struct ndis_tcp_ip_checksum_info *)((void *)ppi +
>  			ppi->ppi_offset);
>  
> +	ip_hdr(skb)->check = 0;
> +	csum_info->transmit.ip_header_checksum = 1;
> +
>  	if (net_trans_info & (INFO_IPV4 << 16))
>  		csum_info->transmit.is_ipv4 = 1;
>  	else

Linux doesn't need or want IP checksum offload.
It will not have any performance gain.