From: Jeff Garzik <jeff@garzik.org>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: netdev@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
"David S. Miller" <davem@davemloft.net>,
Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [NET] IOC3: Switch hw checksumming to ethtool configurable.
Date: Mon, 30 Jul 2007 16:06:54 -0400 [thread overview]
Message-ID: <46AE44DE.8000107@garzik.org> (raw)
In-Reply-To: <20070725113157.GA29416@linux-mips.org>
Ralf Baechle wrote:
> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
applied to #upstream (2.6.24)
> I've previously sent out this patch a long time ago. At that time I was
> told NETIF_F_IP_CSUM wouldn't make any sense without NETIF_F_SG. IOC3's
> S/G abilities are very limited; it can do upto three segments of which
> the first one is upto 104 bytes and part of the packet's TX ring entry,
> the second and 3rd ones can be anywhere in the 64-bit PCI address space
> but may not cross a 16kB page boundary. So setting NETIF_F_SG isn't
> really an option unless the IOC3 was going to linearize any packet it
> can't cope with itself.
>
> So the big question, does NETIF_F_IP_CSUM without NETIF_F_SG make sense?
Conventional wisdom has always been that NETIF_F_SG is required if
NETIF_F_*CSUM is present, and vice versa.
I admit I've not verified this in the past year or two.
Jeff
prev parent reply other threads:[~2007-07-30 20:06 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-25 11:31 [NET] IOC3: Switch hw checksumming to ethtool configurable Ralf Baechle
2007-07-30 20:06 ` Jeff Garzik [this message]
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