[PATCH v5 11/12] mm: drop page_index and simplify folio_index

Kairui Song
2024-05-10T11:50:39Z

There are two helpers for retrieving the index within address space
for mixed usage of swap cache and page cache:

- page_index
- folio_index

This commit drops page_index, as we have eliminated all users, and
converts folio_index's helper __page_file_index to use folio to avoid
the page convertion.

Signed-off-by: Kairui Song <kasong@tencent.com>
---
include/linux/mm.h | 13 -------------
include/linux/pagemap.h | 8 ++++----
mm/swapfile.c | 7 +++----
3 files changed, 7 insertions(+), 21 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9849dfda44d4..e2718cac0fda 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2290,19 +2290,6 @@ static inline void *folio_address(const struct folio *folio)
return page_address(&folio->page);
}

-extern pgoff_t __page_file_index(struct page *page);
-
-/*
- * Return the pagecache index of the passed page. Regular pagecache pages
- * use ->index whereas swapcache pages use swp_offset(->private)
- */
-static inline pgoff_t page_index(struct page *page)
-{
- if (unlikely(PageSwapCache(page)))
- return __page_file_index(page);
- return page->index;
-}
-
/*
* Return true only if the page has been allocated with
* ALLOC_NO_WATERMARKS and the low watermark was not
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index a324582ea702..0cfa5810cde3 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -778,7 +778,7 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
mapping_gfp_mask(mapping));
}

-#define swapcache_index(folio) __page_file_index(&(folio)->page)
+extern pgoff_t __folio_swap_cache_index(struct folio *folio);

/**
* folio_index - File index of a folio.
@@ -793,9 +793,9 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
*/
static inline pgoff_t folio_index(struct folio *folio)
{
- if (unlikely(folio_test_swapcache(folio)))
- return swapcache_index(folio);
- return folio->index;
+ if (unlikely(folio_test_swapcache(folio)))
+ return __folio_swap_cache_index(folio);
+ return folio->index;
}

/**
diff --git a/mm/swapfile.c b/mm/swapfile.c
index f6ca215fb92f..0b0ae6e8c764 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -3474,12 +3474,11 @@ struct address_space *swapcache_mapping(struct folio *folio)
}
EXPORT_SYMBOL_GPL(swapcache_mapping);

-pgoff_t __page_file_index(struct page *page)
+pgoff_t __folio_swap_cache_index(struct folio *folio)
{
- swp_entry_t swap = page_swap_entry(page);
- return swp_offset(swap);
+ return swp_offset(folio->swap);
}
-EXPORT_SYMBOL_GPL(__page_file_index);
+EXPORT_SYMBOL_GPL(__folio_swap_cache_index);

/*
* add_swap_count_continuation - called when a swap count is duplicated
--
2.45.0