Re: [PATCH 28/31] memblock: Export MEMBLOCK_ERROR again

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Tue, 2010-07-27 at 23:01 -0700, David Miller wrote:
> > On x86, physical address 0 contains the real-mode IVT and will thus be
> > reserved, at least for the forseeable future.  Other architectures may
> > very well have non-special RAM there.
> 
> 0 is very much possible on sparc64 

Yup, we need to fix that.

For now I made MEMBLOCK_ERROR 0 and added a blurb to prevent allocating
the first page since it would cause other problems with the current code
(0 is after all the normal error result from membloc_alloc(), ie, our
API wasn't quite consistent there).

So I don't think I'm introducing a regression here, on the contrary. But
if we are going to allow lmb_alloc() to return 0, we need to fix all
callers first and then we can look into turning MEMBLOCK_ERROR back to
~0

Cheers,
Ben.