On 2/2/21 12:31 PM, Axel Rasmussen wrote: > For background, mm/userfaultfd.c provides a general mcopy_atomic > implementation. But some types of memory (e.g., hugetlb and shmem) need > a slightly different implementation, so they provide their own helpers > for this. In other words, userfaultfd is the only caller of this > function. > > This patch achieves two things: > > 1. Don't spend time compiling code which will end up never being > referenced anyway (a small build time optimization). > > 2. In future patches (e.g. [1]), we plan to extend the signature of > these helpers with UFFD-specific state (e.g., enums or structs defined > conditionally in userfaultfd_k.h). Once this happens, this patch will be > needed to avoid build errors (or, we'd need to define more UFFD-only > stuff unconditionally, which seems messier to me). > > Peter Xu suggested this be sent as a standalone patch, in the mailing > list discussion for [1]. > > [1] https://patchwork.kernel.org/project/linux-mm/list/?series=424091 > > Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx> > --- > include/linux/hugetlb.h | 4 ++++ > mm/hugetlb.c | 2 ++ > 2 files changed, 6 insertions(+) When you move this back into the "userfaultfd: add minor fault handling" series, feel free to add: Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Thanks, -- Mike Kravetz
