[v13,051/137] mm: Add folio_pfn()

Commit Message

Matthew Wilcox July 12, 2021, 3:05 a.m. UTC

This is the folio equivalent of page_to_pfn().

Signed-off-by: Matthew Wilcox (Oracle) <[e-mail]>
---
 include/linux/mm.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80f27eb151ba..fa5974870660 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1622,6 +1622,20 @@  static inline unsigned long page_to_section(const struct page *page)
 }
 #endif
 
+/**
+ * folio_pfn - Return the Page Frame Number of a folio.
+ * @folio: The folio.
+ *
+ * A folio may contain multiple pages.  The pages have consecutive
+ * Page Frame Numbers.
+ *
+ * Return: The Page Frame Number of the first page in the folio.
+ */
+static inline unsigned long folio_pfn(struct folio *folio)
+{
+	return page_to_pfn(&folio->page);
+}
+
 /* MIGRATE_CMA and ZONE_MOVABLE do not allow pin pages */
 #ifdef CONFIG_MIGRATION
 static inline bool is_pinnable_page(struct page *page)