mm: add a mapping_clear_large_folios helper

Patch series "disable large folios for shmem file used by xfs xfile".

Darrick reported that the fairly new XFS xfile code blows up when force
enabling large folio for shmem.  This series fixes this quickly by
disabling large folios for this particular shmem file for now until it can
be fixed properly, which will be a lot more invasive.


This patch (of 2):

Users of shmem_kernel_file_setup might not be able to deal with large
folios (yet).  Give them a way to disable large folio support on their
mapping.

Link: https://lkml.kernel.org/r/20240110092109.1950011-1-hch@lst.de
Link: https://lkml.kernel.org/r/20240110092109.1950011-2-hch@lst.de


Fixes: 3934e8eb ("xfs: create a big array data structure")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>