On Fri, 2008-05-16 at 10:10 +0200, Johannes Berg wrote:
> On Fri, 2008-05-16 at 09:01 +0200, Sebastian Siewior wrote:
> > * Harvey Harrison | 2008-05-15 23:17:17 [-0700]:
> > 
> > >Make the michael_block macro a function and change the calling
> > >function to take a struct michael_mic_ctx * and the value for
> > >the initial xor with ctx->l.
> > >
> > >Also open-code xswap in its one use in michael_block.
> > Does this change have any performance impact?
> > The only user is wireless (I guess). Is it used frequently (sign every
> > packet for instance) or once in a while (in every re-keying)?
> 
> Every packet. I have no idea whether it has performance impact, very
> hard to even guess.
> 

Well, the code-size difference is significant (about 200 bytes smaller
on X86-32).  This macro is essentially an inline function that is pretty
large.

Attached find the objdump -d of the original and after the patch.  As it
is, this code isn't used anywhere that I can find as mac80211 has its
own implementation, I'm trying to see if there is much advantage in
keeping the private version over moving to the crypto one.

Harvey