[PATCH 11/25] mm: Convert mapping_get_entry to return a folio

From: Matthew Wilcox (Oracle)
Date: Wed Dec 16 2020 - 13:25:40 EST


The pagecache only contains folios, so this is the right thing to do.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/filemap.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 654bba53442a..b9f25a2d8312 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1673,33 +1673,33 @@ EXPORT_SYMBOL(page_cache_prev_miss);
* @index: The page cache index.
*
* Looks up the page cache slot at @mapping & @offset. If there is a
- * page cache page, the head page is returned with an increased refcount.
+ * page cache page, the folio is returned with an increased refcount.
*
* If the slot holds a shadow entry of a previously evicted page, or a
* swap entry from shmem/tmpfs, it is returned.
*
- * Return: The head page or shadow entry, %NULL if nothing is found.
+ * Return: The folio or shadow entry, %NULL if nothing is found.
*/
-static struct page *mapping_get_entry(struct address_space *mapping,
+static struct folio *mapping_get_entry(struct address_space *mapping,
pgoff_t index)
{
XA_STATE(xas, &mapping->i_pages, index);
- struct page *page;
+ struct folio *folio;

rcu_read_lock();
repeat:
xas_reset(&xas);
- page = xas_load(&xas);
- if (xas_retry(&xas, page))
+ folio = xas_load(&xas);
+ if (xas_retry(&xas, folio))
goto repeat;
/*
* A shadow entry of a recently evicted page, or a swap entry from
* shmem/tmpfs. Return it without attempting to raise page count.
*/
- if (!page || xa_is_value(page))
+ if (!folio || xa_is_value(folio))
goto out;

- if (!page_cache_get_speculative(page))
+ if (!page_cache_get_speculative(&folio->page))
goto repeat;

/*
@@ -1707,14 +1707,14 @@ static struct page *mapping_get_entry(struct address_space *mapping,
* This is part of the lockless pagecache protocol. See
* include/linux/pagemap.h for details.
*/
- if (unlikely(page != xas_reload(&xas))) {
- put_page(page);
+ if (unlikely(folio != xas_reload(&xas))) {
+ put_folio(folio);
goto repeat;
}
out:
rcu_read_unlock();

- return page;
+ return folio;
}

/**
@@ -1757,7 +1757,7 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
struct page *page;

repeat:
- page = mapping_get_entry(mapping, index);
+ page = &mapping_get_entry(mapping, index)->page;
if (xa_is_value(page)) {
if (fgp_flags & FGP_ENTRY)
return page;
--
2.29.2