I plan to replace it with lib/bitmap.c bitmap_* based allocator (similar like
it it is used by dma_declare_coherent_memory() and friends in
drivers/base/dma-coherent.c). We need something really simple for CMA area
management. 

IMHO allocate_resource and friends a bit too heavy here, but good to know 
that such allocator also exists.

Not sure I'd class allocate_resource as heavyweight but providing it's
using something that already exists rather than inventing yet another
allocator.

This wants dealing with before it goes upstream though so the chaneges in
lib/*c etc never have to reach mainline and then get changed back.

Alan