Commit bc60abfb authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: add folio_flush_mapping() 

This is the folio equivalent of page_mapping_file(), but rename it to make
it clear that it's very different from page_file_mapping(). 
Theoretically, there's nothing flush-only about it, but there are no other
users today, and I doubt there will be; it's almost always more useful to
know the swapfile's mapping or the swapcache's mapping.

Link: https://lkml.kernel.org/r/20230802151406.3735276-5-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: default avatarMike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3a255267

include/linux/pagemap.h

+21 −5
Original line number Diff line number Diff line
@@ -389,6 +389,26 @@ static inline struct address_space *folio_file_mapping(struct folio *folio) 
	return folio->mapping;

}



/**

 * folio_flush_mapping - Find the file mapping this folio belongs to.

 * @folio: The folio.

 *

 * For folios which are in the page cache, return the mapping that this

 * page belongs to.  Anonymous folios return NULL, even if they're in

 * the swap cache.  Other kinds of folio also return NULL.

 *

 * This is ONLY used by architecture cache flushing code.  If you aren't

 * writing cache flushing code, you want either folio_mapping() or

 * folio_file_mapping().

 */

static inline struct address_space *folio_flush_mapping(struct folio *folio)

{

	if (unlikely(folio_test_swapcache(folio)))

		return NULL;



	return folio_mapping(folio);

}



static inline struct address_space *page_file_mapping(struct page *page)

{

	return folio_file_mapping(page_folio(page));
@@ -399,11 +419,7 @@ static inline struct address_space *page_file_mapping(struct page *page) 
 */

static inline struct address_space *page_mapping_file(struct page *page)

{

	struct folio *folio = page_folio(page);



	if (unlikely(folio_test_swapcache(folio)))

		return NULL;

	return folio_mapping(folio);

	return folio_flush_mapping(page_folio(page));

}



/**