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[Xen-devel] Re: [NET] front: Fix features on resume when csum is off

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: [Xen-devel] Re: [NET] front: Fix features on resume when csum is off
From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 16 Aug 2006 23:04:25 +1000
Cc: Anton Burtsev <aburtsev@xxxxxxxxxxxxx>, Xen Development Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On Wed, Aug 16, 2006 at 02:00:02PM +0100, Keir Fraser wrote:
> 
> This seems a bit odd. Shouldn't it be up to the network stack to not use
> SG/TSO if it can't use them with a non-checksumming interface? What is the
> failure mode currently?

As it is it's the partly the responsibility of the drivers to maintain
the consistency of the features set.  The network stack assists this
task by turning off SG/TSO when TX checksum is turned off through
ethtool.  It also ensures that when the user tries to enable SG/TSO
that TX checksum must be enabled.

In this case, SG/TSO is being turned on by the driver (as opposed to
the user) so the driver needs to ensure that TX checksum is supported.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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