linux-kernel - Re: [PATCH v4 3/3] mm: restructure memfd code

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Date:   Tue, 17 Apr 2018 17:42:57 -0600
From:   Khalid Aziz <khalid.aziz@...cle.com>
To:     Mike Kravetz <mike.kravetz@...cle.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     Matthew Wilcox <willy@...radead.org>,
        Hugh Dickins <hughd@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Michal Hocko <mhocko@...nel.org>,
        Marc-André Lureau <marcandre.lureau@...il.com>,
        David Herrmann <dh.herrmann@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v4 3/3] mm: restructure memfd code

On 04/15/2018 12:21 PM, Mike Kravetz 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 resided in shmem.c.
> 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
> lack of potentially desired functionality.
> 
> Code is restructured in the following way:
> - include/linux/memfd.h is a new file containing memfd specific
>    definitions previously contained in shmem_fs.h.
> - mm/memfd.c is a new file containing memfd specific code previously
>    contained in shmem.c.
> - memfd specific code is removed from shmem_fs.h and shmem.c.
> - A new config option MEMFD_CREATE is added that is defined if TMPFS
>    or HUGETLBFS is defined.
> 
> No functional changes are made to the code: restructuring only.
> 
> Signed-off-by: Mike Kravetz <mike.kravetz@...cle.com>
> ---
>   fs/Kconfig               |   3 +
>   fs/fcntl.c               |   2 +-
>   include/linux/memfd.h    |  16 +++
>   include/linux/shmem_fs.h |  13 --
>   mm/Makefile              |   1 +
>   mm/memfd.c               | 345 +++++++++++++++++++++++++++++++++++++++++++++++
>   mm/shmem.c               | 324 --------------------------------------------
>   7 files changed, 366 insertions(+), 338 deletions(-)
>   create mode 100644 include/linux/memfd.h
>   create mode 100644 mm/memfd.c

Reviewed-by: Khalid Aziz <khalid.aziz@...cle.com>