[RFC PATCH] mm: Replace ->launder_folio() with flush and wait

[Christoph Hellwig]

On Thu, Mar 07, 2024 at 10:36:28AM +0000, David Howells wrote:
> There are some places that should perhaps be using kiocb_invalidate_pages()
> and kiocb_invalidate_post_direct_write() instead - assuming Christoph has no
> objection to the latter function being exported.

These are intended as helpers for direct I/O implementation, so I
very much expected them to eventually get exported.