-next build failures on ARM in fs/dax.c

On Thu, Jan 29, 2015 at 09:27:30AM +0000, Build bot for Mark Brown wrote:

For a little while now (about a week IIRC) fs/dax.c has been breaking the ARM allmodconfig build due to a missing declaration of copy_user_page():

arm-allmodconfig ../fs/dax.c:266:2: error: implicit declaration of function 'copy_user_page' [-Werror=implicit-function-declaration]

I have to confess I'm not 100% sure this isn't an ARM bug as it looks like include/mm.h ought to pull it in from asm/page.h but I'm not 100% sure where it *should* be coming from.