disable large folios for shmem file used by xfs xfile

[Matthew Wilcox]

On Wed, Jan 10, 2024 at 10:21:07AM +0100, Christoph Hellwig wrote:
> Hi all,
> 
> 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.
> 
> I've added most of you to the CC list as I suspect most other users of
> shmem_file_setup and friends will have similar issues.

The graphics users _want_ to use large folios.  I'm pretty sure they've
been tested with this.  It's just XFS that didn't know about this
feature of shmem.