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Date: Mon, 25 Feb 2002 11:22:37 -0500 (EST)
From: Ion Badulescu <ionut@cs.columbia.edu>
To: harish.vasudeva@amd.com
cc: linux-kernel@vger.kernel.org
Subject: RE: Need some help with IP/TCP Checksum Offload
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On Fri, 22 Feb 2002 harish.vasudeva@amd.com wrote:

> i tried setting the NETIF_F_SG flag, but the stack still gives the right checksum. 

Correct, not all packets will use the zerocopy framework. Using sendfile
is one way of generating them; I believe NFS will also do zerocopy but
I haven't checked it.

> Now, i have this 1 more question. If @ all the stack does offload chksum
> to the hardware, how will the driver come to know about this? Is there a
> per packet indication from the stack asking the driver
> TO-DO/OR-NOT-TO-DO chksum offloading?

Yes: skb->ip_summed == CHECKSUM_HW says the hardware is expected to 
generate the checksum.

Ion

-- 
  It is better to keep your mouth shut and be thought a fool,
            than to open it and remove all doubt.

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