Hi Andrew,

After merging the akpm-current tree, today's linux-next build (lots with
CONFIG_MMU not set) failed like this:

fs/built-in.o:(.rodata+0x1060): undefined reference to `filemap_page_mkwrite'

Caused by commit

  fb416a02f75c ("mm: move ->mremap() from file_operations to vm_operations_struct").

filemap_page_mkwrite only exists when CONFIG_MMU is set.

-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au