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From: Patrick McHardy <kaber@trash.net>
To: Ben Hutchings <bhutchings@solarflare.com>
Cc: netdev@vger.kernel.org, linux-net-drivers@solarflare.com
Subject: Re: [PATCH][RFC] TSO for VLAN devices without VLAN tag insertion
Date: Thu, 12 Jun 2008 14:02:13 +0200	[thread overview]
Message-ID: <48511045.8080805@trash.net> (raw)
In-Reply-To: <20080610195943.GO11300@solarflare.com>

Ben Hutchings wrote:
> The SFC4000 controller can set IP header, TCP and UDP checksums in IPv4
> packets, with or without VLAN encapsulation.  However it does not do VLAN
> tag insertion.
> 
> When I try to make TSO work for VLAN devices via the new vlan_features,
> dev_queue_xmit() finds skb->ip_summed == CHECKSUM_PARTIAL &&
> skb->protocol == htons(ETH_P_8021Q) and calls skb_checksum_help(), which
> sets skb->ip_summed = CHECKSUM_NONE.
> 
> This causes netif_needs_gso() to return true when called by
> dev_hard_start_xmit(), and GSO then does its worst.
> 
> Below is a patch which worked for me, but I'm not sure whether it's the
> best way to fix the problem (so I'm not submitting or signing it off yet).


It looks reasonable - I can't think of a different way to handle
this case, although its a bit unfortunate that we have to put this
in dev_queue_xmit().

      reply	other threads:[~2008-06-12 12:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-10 19:59 [PATCH][RFC] TSO for VLAN devices without VLAN tag insertion Ben Hutchings
2008-06-12 12:02 ` Patrick McHardy [this message]

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