[PATCH v2 3/6] mm/page_io: use swap entries directly in zeromap helpers

[Tal Zussman]

Increment swp_entry_t::val directly instead of recomputing each entry
with page_swap_entry(). This removes the last struct page usage in
page_io.c and saves one call to compound_head() per page.

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
Signed-off-by: Tal Zussman <tz2294@xxxxxxxxxxxx>
---
 mm/page_io.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index fbcf58ff292d..dd95cdb0cd7a 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -160,7 +160,7 @@ static void swap_zeromap_folio_set(struct folio *folio)
 	struct obj_cgroup *objcg = get_obj_cgroup_from_folio(folio);
 	int nr_pages = folio_nr_pages(folio);
 	struct swap_cluster_info *ci;
-	swp_entry_t entry;
+	swp_entry_t entry = folio->swap;
 	unsigned int i;
 
 	VM_WARN_ON_ONCE_FOLIO(!folio_test_swapcache(folio), folio);
@@ -168,8 +168,8 @@ static void swap_zeromap_folio_set(struct folio *folio)
 
 	ci = swap_cluster_get_and_lock(folio);
 	for (i = 0; i < folio_nr_pages(folio); i++) {
-		entry = page_swap_entry(folio_page(folio, i));
 		__swap_table_set_zero(ci, swp_cluster_offset(entry));
+		entry.val++;
 	}
 	swap_cluster_unlock(ci);
 
@@ -183,7 +183,7 @@ static void swap_zeromap_folio_set(struct folio *folio)
 static void swap_zeromap_folio_clear(struct folio *folio)
 {
 	struct swap_cluster_info *ci;
-	swp_entry_t entry;
+	swp_entry_t entry = folio->swap;
 	unsigned int i;
 
 	VM_WARN_ON_ONCE_FOLIO(!folio_test_swapcache(folio), folio);
@@ -191,8 +191,8 @@ static void swap_zeromap_folio_clear(struct folio *folio)
 
 	ci = swap_cluster_get_and_lock(folio);
 	for (i = 0; i < folio_nr_pages(folio); i++) {
-		entry = page_swap_entry(folio_page(folio, i));
 		__swap_table_clear_zero(ci, swp_cluster_offset(entry));
+		entry.val++;
 	}
 	swap_cluster_unlock(ci);
 }

-- 
2.39.5