On Thu, Dec 22, 2022 at 03:02:29PM +0000, David Howells wrote:
> Make filemap_release_folio() return one of three values:
>
> (0) FILEMAP_CANT_RELEASE_FOLIO
>
> Couldn't release the folio's private data, so the folio can't itself
> be released.
>
> (1) FILEMAP_RELEASED_FOLIO
>
> The private data on the folio was released and the folio can be
> released.
>
> (2) FILEMAP_FOLIO_HAD_NO_PRIVATE
These names read really odd, due to the different placementments
of FOLIO, the present vs past tense and the fact that 2 also released
the folio, and the reliance of callers that one value of an enum
must be 0, while no unprecedented, is a bit ugly.
But do we even need them? What abut just open coding
filemap_release_folio (which is a mostly trivial function) in
shrink_folio_list, which is the only place that cares?
if (folio_has_private(folio) && folio_needs_release(folio)) {
if (folio_test_writeback(folio))
goto activate_locked;
if (mapping && mapping->a_ops->release_folio) {
if (!mapping->a_ops->release_folio(folio, gfp))
goto activate_locked;
} else {
if (!try_to_free_buffers(folio))
goto activate_locked;
}
if (!mapping && folio_ref_count(folio) == 1) {
...
alternatively just keep using filemap_release_folio and just add the
folio_needs_release in the first branch. That duplicates the test,
but makes the change a one-liner.
