mm/swap: optimise get_shadow_from_swap_cache

There's no need to get a reference to the page, just load the entry and
see if it's a shadow entry.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: William Kucharski <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 1 insertions, 3 deletions

diff --git a/mm/swap_state.c b/mm/swap_state.c
index c1a648d9092b..f270c30d4681 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -87,11 +87,9 @@ void *get_shadow_from_swap_cache(swp_entry_t entry)
 	pgoff_t idx = swp_offset(entry);
 	struct page *page;
 
-	page = find_get_entry(address_space, idx);
+	page = xa_load(&address_space->i_pages, idx);
 	if (xa_is_value(page))
 		return page;
-	if (page)
-		put_page(page);
 	return NULL;
 }