[PATCH 1/6] mm: Make mapping_evict_folio() the preferred way to evict clean folios

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

invalidate_inode_page() does very little beyond calling
mapping_evict_folio().  Move the check for mapping being NULL into
mapping_evict_folio() and make it available to the rest of the MM
for use in the next few patches.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/internal.h |  1 +
 mm/truncate.c | 33 ++++++++++++++++-----------------
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index b61034bd50f5..687d89d317d0 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -138,6 +138,7 @@ void filemap_free_folio(struct address_space *mapping, struct folio *folio);
 int truncate_inode_folio(struct address_space *mapping, struct folio *folio);
 bool truncate_inode_partial_folio(struct folio *folio, loff_t start,
 		loff_t end);
+long mapping_evict_folio(struct address_space *mapping, struct folio *folio);
 long invalidate_inode_page(struct page *page);
 unsigned long mapping_try_invalidate(struct address_space *mapping,
 		pgoff_t start, pgoff_t end, unsigned long *nr_failed);
diff --git a/mm/truncate.c b/mm/truncate.c
index 8e3aa9e8618e..1d516e51e29d 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -266,9 +266,22 @@ int generic_error_remove_page(struct address_space *mapping, struct page *page)
 }
 EXPORT_SYMBOL(generic_error_remove_page);
 
-static long mapping_evict_folio(struct address_space *mapping,
-		struct folio *folio)
+/**
+ * mapping_evict_folio() - Remove an unused folio from the page-cache.
+ * @mapping: The mapping this folio belongs to.
+ * @folio: The folio to remove.
+ *
+ * Safely remove one folio from the page cache.
+ * It only drops clean, unused folios.
+ *
+ * Context: Folio must be locked.
+ * Return: The number of pages successfully removed.
+ */
+long mapping_evict_folio(struct address_space *mapping, struct folio *folio)
 {
+	/* The page may have been truncated before it was locked */
+	if (!mapping)
+		return 0;
 	if (folio_test_dirty(folio) || folio_test_writeback(folio))
 		return 0;
 	/* The refcount will be elevated if any page in the folio is mapped */
@@ -281,25 +294,11 @@ static long mapping_evict_folio(struct address_space *mapping,
 	return remove_mapping(mapping, folio);
 }
 
-/**
- * invalidate_inode_page() - Remove an unused page from the pagecache.
- * @page: The page to remove.
- *
- * Safely invalidate one page from its pagecache mapping.
- * It only drops clean, unused pages.
- *
- * Context: Page must be locked.
- * Return: The number of pages successfully removed.
- */
 long invalidate_inode_page(struct page *page)
 {
 	struct folio *folio = page_folio(page);
-	struct address_space *mapping = folio_mapping(folio);
 
-	/* The page may have been truncated before it was locked */
-	if (!mapping)
-		return 0;
-	return mapping_evict_folio(mapping, folio);
+	return mapping_evict_folio(folio_mapping(folio), folio);
 }
 
 /**
-- 
2.42.0