Re: cmpxchg in 2.5.38

["David S. Miller" <davem@redhat.com>]

   From: Ingo Molnar <mingo@elte.hu>
   Date: Wed, 25 Sep 2002 10:26:34 +0200 (CEST)
   
   It's only this place in the code that ever modifies that word, and
   that happens only once during the lifetime of this address, so i'll rather
   add a spinlock to the generic PID allocator code, it's a very very rare
   slowpath.

You can't define a crippled primitive like this Ingo.

What if someone else starts to use it?

And more importantly, if you can't use it on a datum shared between
userspace and the kernel, you have to name it something other than
cmpxchg or make the DRM use something else.