[PATCH 2/5] zswap: Make zswap_store() take a folio

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

Only convert a few easy parts of this function to use the folio passed
in; convert back to struct page for the majority of it.  This does
remove a few hidden calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/zswap.h |  4 ++--
 mm/page_io.c          |  2 +-
 mm/zswap.c            | 13 +++++++------
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/linux/zswap.h b/include/linux/zswap.h
index 850c377d9b6d..9f318c8bc367 100644
--- a/include/linux/zswap.h
+++ b/include/linux/zswap.h
@@ -10,7 +10,7 @@ extern atomic_t zswap_stored_pages;
 
 #ifdef CONFIG_ZSWAP
 
-bool zswap_store(struct page *page);
+bool zswap_store(struct folio *folio);
 bool zswap_load(struct page *page);
 void zswap_invalidate(int type, pgoff_t offset);
 void zswap_swapon(int type);
@@ -18,7 +18,7 @@ void zswap_swapoff(int type);
 
 #else
 
-static inline bool zswap_store(struct page *page)
+static inline bool zswap_store(struct folio *folio)
 {
 	return false;
 }
diff --git a/mm/page_io.c b/mm/page_io.c
index 32afc2a52982..b9fda7fb4e75 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -198,7 +198,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 		folio_unlock(folio);
 		return ret;
 	}
-	if (zswap_store(&folio->page)) {
+	if (zswap_store(folio)) {
 		folio_start_writeback(folio);
 		folio_unlock(folio);
 		folio_end_writeback(folio);
diff --git a/mm/zswap.c b/mm/zswap.c
index f6a78e085479..ba50b186ee27 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1201,11 +1201,12 @@ static void zswap_fill_page(void *ptr, unsigned long value)
 	memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
 }
 
-bool zswap_store(struct page *page)
+bool zswap_store(struct folio *folio)
 {
-	swp_entry_t swp = { .val = page_private(page), };
+	swp_entry_t swp = folio_swap_entry(folio);
 	int type = swp_type(swp);
 	pgoff_t offset = swp_offset(swp);
+	struct page *page = &folio->page;
 	struct zswap_tree *tree = zswap_trees[type];
 	struct zswap_entry *entry, *dupentry;
 	struct scatterlist input, output;
@@ -1219,11 +1220,11 @@ bool zswap_store(struct page *page)
 	gfp_t gfp;
 	int ret;
 
-	VM_WARN_ON_ONCE(!PageLocked(page));
-	VM_WARN_ON_ONCE(!PageSwapCache(page));
+	VM_WARN_ON_ONCE(!folio_test_locked(folio));
+	VM_WARN_ON_ONCE(!folio_test_swapcache(folio));
 
-	/* THP isn't supported */
-	if (PageTransHuge(page))
+	/* Large folios aren't supported */
+	if (folio_test_large(folio))
 		return false;
 
 	if (!zswap_enabled || !tree)
-- 
2.39.2