On Thu, Aug 12, 2021 at 06:30:51PM +0200, Vlastimil Babka wrote:

quoted

+/**
+ * folio_redirty_for_writepage - Decline to write a dirty folio.
+ * @wbc: The writeback control.
+ * @folio: The folio.
+ *
+ * When a writepage implementation decides that it doesn't want to write
+ * @folio for some reason, it should call this function, unlock @folio and
+ * return 0.

s/0/false

... no?  This sentence describes what a writepage implementation should
do, and writepage returns an int, not bool.