On Thu, Dec 31, 2020 at 08:29:14PM -0800, Randy Dunlap wrote: > fs/dax.c uses copy_user_page() but ARC does not provide that interface, > resulting in a build error. > > Provide copy_user_page() in <asm/page.h> (beside copy_page()) and > add <asm/page.h> to fs/dax.c to fix the build error. > > ../fs/dax.c: In function 'copy_cow_page_dax': > ../fs/dax.c:702:2: error: implicit declaration of function 'copy_user_page'; did you mean 'copy_to_user_page'? [-Werror=implicit-function-declaration] Could somebody explain what the force-cast is doing in there? I mean, the call is copy_user_page(vto, (void __force *)kaddr, vaddr, to); kaddr is a local variable there, declared as void *; AFAICS, that had been pure cargo-cult since commit 7a9eb20666317794d0279843fbd091af93907780 Author: Dan Williams <dan.j.williams@xxxxxxxxx> Date: Fri Jun 3 18:06:47 2016 -0700 pmem: kill __pmem address space I mean, it's been more than 4 years, time to bury that body...