• Mike Kravetz's avatar
    mm: restructure memfd code · 5d752600
    Mike Kravetz authored
    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.
    
    Link: http://lkml.kernel.org/r/20180415182119.4517-4-mike.kravetz@oracle.comSigned-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
    Reviewed-by: default avatarKhalid Aziz <khalid.aziz@oracle.com>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: David Herrmann <dh.herrmann@gmail.com>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: Marc-Andr Lureau <marcandre.lureau@gmail.com>
    Cc: Matthew Wilcox <willy@infradead.org>
    Cc: Michal Hocko <mhocko@kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    5d752600