[Nouveau] [PATCH 08/25] memremap: move dev_pagemap callbacks into a separate structure

[Christoph Hellwig]

On Mon, Jun 17, 2019 at 10:51:35AM -0700, Dan Williams wrote:
> > -       struct dev_pagemap *pgmap = _pgmap;
> 
> Whoops, needed to keep this line to avoid:
> 
> tools/testing/nvdimm/test/iomap.c:109:11: error: ‘pgmap’ undeclared
> (first use in this function); did you mean ‘_pgmap’?

So I really shouldn't be tripping over this anymore, but can we somehow
this mess?

 - at least add it to the normal build system and kconfig deps instead
   of stashing it away so that things like buildbot can build it?
 - at least allow building it (under COMPILE_TEST) if needed even when
   pmem.ko and friends are built in the kernel?