There is broad agreement that we should eliminate __GFP_FS in favour of
using memalloc_nofs_save().  This is a small step in that direction by
getting rid of FGP_NOFS.  It's also a nice simplification in its own right.

I added the documentation improvement at the start of this series, not
because anything depends on that (obviously it doesn't), but because
I thought the existing documentation was rather MM centric and it needs
to be FS centric.  Hopefully the cc'd filesystem maintainers will have
the chance to look at patch 1 and see if it makes sense to them.

There's a few different solutions here:

 - Filesystems specifying both FGP_NOWAIT and FGP_NOFS.  If you're not
   waiting, it doesn't matter if you're allowed to reclaim from FS
   context or not, you're just not doing reclaim.
 - We're already under memalloc_nofs.
 - We can prove that the MM should be allowed to reclaim from
   filesystem memory (and so specifying FGP_NOFS was wrong).
 - We can add a call to memalloc_nofs_save().

Matthew Wilcox (Oracle) (9):
  mm: Improve memalloc_nofs_save() documentation
  ext4: Remove uses of FGP_NOFS
  erofs: Remove redundant FGP_NOFS
  nfs: Remove redundant FGP_NOFS
  ntfs: Remove FGP_NOFS from __ntfs_inode_resident_attr_pwrite()
  ntfs: Remove redundant FGP_NOFS from ntfs_wof_collect_dest()
  squashfs: Remove use of FGP_NOFS
  filemap: Remove redundant FGP_NOFS
  filemap: Remove FGP_NOFS

 fs/erofs/internal.h      |  2 +-
 fs/ext4/inline.c         |  6 ++----
 fs/nfs/dir.c             |  2 +-
 fs/ntfs/inode.c          |  2 +-
 fs/ntfs/wof.c            |  7 +++----
 fs/squashfs/file.c       |  5 ++++-
 include/linux/pagemap.h  | 12 +++++-------
 include/linux/sched/mm.h | 31 +++++++++++++++++++++++--------
 mm/filemap.c             |  2 --
 mm/readahead.c           | 14 ++------------
 10 files changed, 42 insertions(+), 41 deletions(-)

-- 
2.47.3