Re: [patch 7/9] lguest: the net driver

From: Herbert Xu
Date: Wed May 09 2007 - 06:24:30 EST


akpm@xxxxxxxxxxxxxxxxxxxx wrote:
>
> + if (desc->features & LGUEST_NET_F_NOCSUM)
> + dev->features |= NETIF_F_NO_CSUM;

Any reason why you're using NO_CSUM here instead of HW_CSUM?
Practically there is no difference but NO_CSUM could be treated
differently in future and I'm not sure whether such changes would
be desirable in this driver (i.e., not even generating a partial
checksum).

Also, there doesn't seem to be any passing of metadata to the
backend which means that neither NO_CSUM/HW_CSUM can work if
somebody needs to look at the checksum field. You could use
IP_CSUM if you do the same hack on the backend that Xen does.
Otherwise you'll have to make do with no checksum offload at all.

I think you'd also need a change_mtu function if the SG feature
is going to be of some use since the default Ethernet one limits
the MTU to 1500.

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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/