Re: [PATCH] select appropriate skb size in tcp_sendmsg when TSO is used

[Jeff Garzik <jgarzik@xxxxxxxxx>]

On Wed, Oct 27, 2004 at 10:07:24AM +1000, Herbert Xu wrote:
> On Tue, Oct 26, 2004 at 07:54:35PM -0400, Jeff Garzik wrote:
> > Herbert Xu wrote:
> > >+static int __ethtool_set_sg(struct net_device *dev, u32 data)
> > >+{
> > >+  int err;
> > >+
> > >+  if (!data && dev->ethtool_ops->set_tso) {
> > >+          err = dev->ethtool_ops->set_tso(dev, 0);
> > >+          if (err)
> > >+                  return err;
> > >+  }
> > >+
> > >+  return dev->ethtool_ops->set_sg(dev, data);
> > >+}
> > 
> > you want to disable tx-csum also
> 
> IMHO it is valid to disable SG without disabling checksums, no?

It's useless:  The packet header is always in a separate memory
location from the packet data, when using zerocopy sendfile(2).

When not using zerocopy sendfile, you are copying the data _anyway_.

        Jeff