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From: Andi Kleen <ak@muc.de>
To: "" <simon@baydel.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: TCP zero-copy
Date: 06 Aug 2001 02:32:36 +0200	[thread overview]
Message-ID: <k2elqqdo4b.fsf@zero.aec.at> (raw)
In-Reply-To: <663CE32D.1D4A9213.0F45C3B8@netscape.net> <15210.4821.318434.454971@pizda.ninka.net> <3B6A7B96.1591.241743@localhost>
In-Reply-To: ""'s message of "Fri, 03 Aug 2001 11:30:11 +0200"

In article <3B6A7B96.1591.241743@localhost>,
"" <simon@baydel.com> writes:

> I have written a driver for an Intel ixf1002 chip, which has some 
> surrounding HW, and is capable of checksumming and processing 
> dma in fragments. Is there any information on what changes I 
> would have to make to the driver to support zerocopy/checksum ?  

The driver has to set dev->features to its checksum  capabilities (see skbuff.h
for more details) and implement them. It should also be able to process
skbs with multiple skb fragments in hard_start_xmit for true zero copy;
in this case set NETIF_F_SG and also NETIF_F_HIGHDMA if it supports 64bit
addresses. When NETIF_F_SG and NETIF_F_IP_CSUM or NETIFI_F_HW_CSUM are set
the stack will do zero copy IO on TX with sendfile.

-Andi


-Andi

      parent reply	other threads:[~2001-08-06  0:33 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <15210.4821.318434.454971@pizda.ninka.net>
2001-08-02 18:23 ` TCP zero-copy hochakhung
2001-08-03  9:23   ` simon
2001-08-03 15:28     ` Andrew Theurer
2001-08-06  0:32     ` Andi Kleen [this message]

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