Re: [RFC PATCH 0/3] restructure memfd code

From: Marc-Andrà Lureau
Date: Mon Nov 20 2017 - 05:29:17 EST


Hi

On Thu, Nov 9, 2017 at 2:41 AM, Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
> With the addition of memfd hugetlbfs support, we now have the situation
> where memfd depends on TMPFS -or- HUGETLBFS. Previously, memfd was only
> supported on tmpfs, so it made sense that the code resides in shmem.c.
>
> This patch series moves the memfd code to separate files (memfd.c and
> memfd.h). It creates a new config option MEMFD_CREATE that is defined
> if either TMPFS or HUGETLBFS is defined.

That looks good to me

>
> In the current code, memfd is only functional if TMPFS is defined. If
> HUGETLFS is defined and TMPFS is not defined, then memfd functionality
> will not be available for hugetlbfs. This does not cause BUGs, just a
> potential lack of desired functionality.
>

Indeed

> Another way to approach this issue would be to simply make HUGETLBFS
> depend on TMPFS.
>
> This patch series is built on top of the Marc-Andrà Lureau v3 series
> "memfd: add sealing to hugetlb-backed memory":
> http://lkml.kernel.org/r/20171107122800.25517-1-marcandre.lureau@xxxxxxxxxx

Are you waiting for this series to be merged before resending as non-rfc?

>
> Mike Kravetz (3):
> mm: hugetlbfs: move HUGETLBFS_I outside #ifdef CONFIG_HUGETLBFS
> mm: memfd: split out memfd for use by multiple filesystems
> mm: memfd: remove memfd code from shmem files and use new memfd files
>
> fs/Kconfig | 3 +
> fs/fcntl.c | 2 +-
> include/linux/hugetlb.h | 27 ++--
> include/linux/memfd.h | 16 +++
> include/linux/shmem_fs.h | 13 --
> mm/Makefile | 1 +
> mm/memfd.c | 341 +++++++++++++++++++++++++++++++++++++++++++++++
> mm/shmem.c | 323 --------------------------------------------
> 8 files changed, 378 insertions(+), 348 deletions(-)
> create mode 100644 include/linux/memfd.h
> create mode 100644 mm/memfd.c
>
> --
> 2.13.6
>

Thanks

--
Marc-Andrà Lureau