From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Add largest_zero_folio() routine so that huge_zero_folio can be
used directly when CONFIG_STATIC_HUGE_ZERO_FOLIO is enabled. This will
return ZERO_PAGE folio if CONFIG_STATIC_HUGE_ZERO_FOLIO is disabled or
if we failed to allocate a huge_zero_folio.
Co-developed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
---
include/linux/huge_mm.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 78ebceb61d0e..c44a6736704b 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -716,4 +716,21 @@ static inline int split_folio_to_order(struct folio *folio, int new_order)
return split_folio_to_list_to_order(folio, NULL, new_order);
}
+/*
+ * largest_zero_folio - Get the largest zero size folio available
+ *
+ * This function will return huge_zero_folio if CONFIG_STATIC_HUGE_ZERO_FOLIO
+ * is enabled. Otherwise, a ZERO_PAGE folio is returned.
+ *
+ * Deduce the size of the folio with folio_size instead of assuming the
+ * folio size.
+ */
+static inline struct folio *largest_zero_folio(void)
+{
+ struct folio *folio = get_static_huge_zero_folio();
+
+ if (folio)
+ return folio;
+ return page_folio(ZERO_PAGE(0));
+}
#endif /* _LINUX_HUGE_MM_H */
--
2.49.0
