From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Wed, 14 Jan 2009 11:51:10 +1100

We can probably do that for spliced data that end up going to
the networking stack again.  However, as splice is generic the
data may be headed to a destination other than the network stack.

In that case to make dataref work we'd need some mechanism
that allows non-network entities to get/drop this ref count.

I see.

I'll think about this some more.