Matthew Wilcox (Oracle) [off-list ref] wrote:

+/**
+ * readahead_folio - Get the next folio to read.
+ * @ractl: The current readahead request.
+ *
+ * Context: The folio is locked.  The caller should unlock the folio once
+ * all I/O to that folio has completed.
+ * Return: A pointer to the next folio, or %NULL if we are done.
+ */
+static inline struct folio *readahead_folio(struct readahead_control *ractl)
+{
+	struct folio *folio = __readahead_folio(ractl);
 
-	return page;
+	folio_put(folio);

This will oops if __readahead_folio() returns NULL.

+	return folio;
 }