[PATCH v2 4/5] mm/migrate, swap: drop usage of folio_index

[Kairui Song <ryncsn@gmail.com>]

From: Kairui Song <kasong@tencent.com>

This helper was used when swap cache was mixed with page cache. Now they
are completely separate from each other, access to the swap cache is all
wrapped by the swap_cache_* helpers, which expect the folio's swap entry
as a parameter.

This helper is no longer used, remove the last redundant user and drop it.

Acked-by: Chris Li <chrisl@kernel.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/migrate.c |  4 ++--
 mm/swap.h    | 21 ---------------------
 2 files changed, 2 insertions(+), 23 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index 4324fc01bfce..ceee354ef215 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -563,7 +563,7 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
 static int __folio_migrate_mapping(struct address_space *mapping,
 		struct folio *newfolio, struct folio *folio, int expected_count)
 {
-	XA_STATE(xas, &mapping->i_pages, folio_index(folio));
+	XA_STATE(xas, &mapping->i_pages, folio->index);
 	struct swap_cluster_info *ci = NULL;
 	struct zone *oldzone, *newzone;
 	int dirty;
@@ -716,7 +716,7 @@ EXPORT_SYMBOL(folio_migrate_mapping);
 int migrate_huge_page_move_mapping(struct address_space *mapping,
 				   struct folio *dst, struct folio *src)
 {
-	XA_STATE(xas, &mapping->i_pages, folio_index(src));
+	XA_STATE(xas, &mapping->i_pages, src->index);
 	int rc, expected_count = folio_expected_ref_count(src) + 1;
 
 	if (folio_ref_count(src) != expected_count)
diff --git a/mm/swap.h b/mm/swap.h
index 8d8efdf1297a..d034c13d8dd2 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -445,25 +445,4 @@ static inline int non_swapcache_batch(swp_entry_t entry, int max_nr)
 	return 0;
 }
 #endif /* CONFIG_SWAP */
-
-/**
- * folio_index - File index of a folio.
- * @folio: The folio.
- *
- * For a folio which is either in the page cache or the swap cache,
- * return its index within the address_space it belongs to.  If you know
- * the folio is definitely in the page cache, you can look at the folio's
- * index directly.
- *
- * Return: The index (offset in units of pages) of a folio in its file.
- */
-static inline pgoff_t folio_index(struct folio *folio)
-{
-#ifdef CONFIG_SWAP
-	if (unlikely(folio_test_swapcache(folio)))
-		return swp_offset(folio->swap);
-#endif
-	return folio->index;
-}
-
 #endif /* _MM_SWAP_H */

-- 
2.51.0