Re: [PATCH v2 44/46] mm/filemap: Convert mapping_get_entry to return a folio

[Matthew Wilcox]

On Wed, Jun 23, 2021 at 01:32:39PM +0200, Christoph Hellwig wrote:
> On Tue, Jun 22, 2021 at 01:15:49PM +0100, Matthew Wilcox (Oracle) wrote:
> > - * Return: The head page or shadow entry, %NULL if nothing is found.
> > + * Return: The folio, swap or shadow entry, %NULL if nothing is found.
> 
> This (old and new) reads a little weird, given that it returns a
> struct folio, even if that happens to be a magic entry.

Yeah.  How about this?

- * Return: The head page or shadow entry, %NULL if nothing is found.
+ * Return: The folio, swap or shadow entry, %NULL if nothing is found.
  */
-static struct page *mapping_get_entry(struct address_space *mapping,
-               pgoff_t index)
+static void *mapping_get_entry(struct address_space *mapping, pgoff_t index)
 {

I still use a struct folio in mapping_get_entry(), but this means that
pagecache_get_page() doesn't change in this patch.