[PATCH] mm/page-writeback: drop usage of folio_index

[Kairui Song <ryncsn@gmail.com>]

From: Kairui Song <kasong@tencent.com>

folio_index is only needed for mixed usage of page cache and swap cache.
The remaining three caller in page-writeback are for page cache tag
marking. Swap cache space doesn't use tag (explicitly sets
mapping_set_no_writeback_tags), so use folio->index here directly.

Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/page-writeback.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 3e248d1c3969..30c06889425f 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2739,8 +2739,8 @@ void __folio_mark_dirty(struct folio *folio, struct address_space *mapping,
 	if (folio->mapping) {	/* Race with truncate? */
 		WARN_ON_ONCE(warn && !folio_test_uptodate(folio));
 		folio_account_dirtied(folio, mapping);
-		__xa_set_mark(&mapping->i_pages, folio_index(folio),
-				PAGECACHE_TAG_DIRTY);
+		__xa_set_mark(&mapping->i_pages, folio->index,
+			      PAGECACHE_TAG_DIRTY);
 	}
 	xa_unlock_irqrestore(&mapping->i_pages, flags);
 }
@@ -3019,7 +3019,7 @@ bool __folio_end_writeback(struct folio *folio)
 
 		xa_lock_irqsave(&mapping->i_pages, flags);
 		ret = folio_xor_flags_has_waiters(folio, 1 << PG_writeback);
-		__xa_clear_mark(&mapping->i_pages, folio_index(folio),
+		__xa_clear_mark(&mapping->i_pages, folio->index,
 					PAGECACHE_TAG_WRITEBACK);
 		if (bdi->capabilities & BDI_CAP_WRITEBACK_ACCT) {
 			struct bdi_writeback *wb = inode_to_wb(inode);
@@ -3056,7 +3056,7 @@ void __folio_start_writeback(struct folio *folio, bool keep_write)
 	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
 
 	if (mapping && mapping_use_writeback_tags(mapping)) {
-		XA_STATE(xas, &mapping->i_pages, folio_index(folio));
+		XA_STATE(xas, &mapping->i_pages, folio->index);
 		struct inode *inode = mapping->host;
 		struct backing_dev_info *bdi = inode_to_bdi(inode);
 		unsigned long flags;
-- 
2.50.1