This creates a mythical gfp_t for passing gfp states, and conversion
macros __GFP() and __UNGFP(), to give warnings, It's 55k, so
compressed and attached.

[Jens, bio_alloc() has the args reversed from normal (Grrr!)]

It's worse than I'd hoped, better than I feared.  I didn't find any
bugs (but then I didn't try compiling with "allyesconfig").

Notes:
o People use GFP_KERNEL instead of SLAB_KERNEL for kmem_cache_alloc,
  so I changed the slab types too.

o If we really want to do this, maybe introduce gfp_t as a typedef to
  int, and use it in all the interfaces first, then change the
  definition later.

BTW, I'm leaving in a couple of hours, so I'm leaving this here for
someone else to get enthusiastic about 8)

Cheers,
Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.