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

["David S. Miller" <davem@xxxxxxxxxxxxx>]

On Wed, 27 Oct 2004 10:22:09 +1000
Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:

> On Tue, Oct 26, 2004 at 08:15:31PM -0400, Jeff Garzik wrote:
> >
> > > 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_.
> 
> I'm fine with adding this check.  However I think that belongs in
> another patch since we don't check that in register_netdev currently.
> 
> Dave, what do you think?

I believe that allowing TX csum support without SG _is_
useful even though it is not _effective_.

It is quite desirable for a driver author to be able to
test out his TX csum offload support first, then add
SG support next.  Similarly, if a driver author suspects
some issues with either SG or TX csum support, he can
better isolate the problem if we allow this.

Jeff do you agree?