This is a second try to fix the long chain call lengths in netfilter.
The difference with the previous patch is that I got rid of the extra
argument. I somehow didn't see it could be done without using the 'int
*ret2' argument.

A comment on the number of arguments to nf_hook_slow: I don't think the
number of arguments should be decreased. For the bridge-nf code, f.e.,
the indev argument does not equal (*pskb)->dev (this is an answer to a
question of Rusty in the old thread).

A comment on the argument change of nf_hook_slow (sk_buff * to sk_buff
**) and the bad influence on tail call optimization possibilities. From
the discussion in the old thread it became clear that no tail call is
generated for the current code. So, I don't see why this is a reason not
to accept the patch. Furthermore, if gcc ever would become able of doing
the current code with a tail call, it should be very easy to change the
code back to the original. In the meantime, I think this patch is the
best known solution.
Signed-off-by: David S. Miller <davem@davemloft.net>