swap: convert add_to_swap() to take a folio

The only caller already has a folio available, so this saves a conversion.
Also convert the return type to boolean.

Link: https://lkml.kernel.org/r/20220504182857.4013401-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/swap.h b/mm/swap.h
index a6da8f6..0193797 100644 (file)
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -32,7 +32,7 @@ extern struct address_space *swapper_spaces[];
                >> SWAP_ADDRESS_SPACE_SHIFT])
 
 void show_swap_cache_info(void);
-int add_to_swap(struct page *page);
+bool add_to_swap(struct folio *folio);
 void *get_shadow_from_swap_cache(swp_entry_t entry);
 int add_to_swap_cache(struct page *page, swp_entry_t entry,
                      gfp_t gfp, void **shadowp);
@@ -119,9 +119,9 @@ struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
        return find_get_page(mapping, index);
 }
 
-static inline int add_to_swap(struct page *page)
+static inline bool add_to_swap(struct folio *folio)
 {
-       return 0;
+       return false;
 }
 
 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 2dc0d02..416aaaa 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -176,24 +176,26 @@ void __delete_from_swap_cache(struct page *page,
 }
 
 /**
- * add_to_swap - allocate swap space for a page
- * @page: page we want to move to swap
+ * add_to_swap - allocate swap space for a folio
+ * @folio: folio we want to move to swap
  *
- * Allocate swap space for the page and add the page to the
- * swap cache.  Caller needs to hold the page lock. 
+ * Allocate swap space for the folio and add the folio to the
+ * swap cache.
+ *
+ * Context: Caller needs to hold the folio lock.
+ * Return: Whether the folio was added to the swap cache.
  */
-int add_to_swap(struct page *page)
+bool add_to_swap(struct folio *folio)
 {
-       struct folio *folio = page_folio(page);
        swp_entry_t entry;
        int err;
 
-       VM_BUG_ON_PAGE(!PageLocked(page), page);
-       VM_BUG_ON_PAGE(!PageUptodate(page), page);
+       VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
+       VM_BUG_ON_FOLIO(!folio_test_uptodate(folio), folio);
 
        entry = folio_alloc_swap(folio);
        if (!entry.val)
-               return 0;
+               return false;
 
        /*
         * XArray node allocations from PF_MEMALLOC contexts could
@@ -206,7 +208,7 @@ int add_to_swap(struct page *page)
        /*
         * Add it to the swap cache.
         */
-       err = add_to_swap_cache(page, entry,
+       err = add_to_swap_cache(&folio->page, entry,
                        __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN, NULL);
        if (err)
                /*
@@ -215,22 +217,23 @@ int add_to_swap(struct page *page)
                 */
                goto fail;
        /*
-        * Normally the page will be dirtied in unmap because its pte should be
-        * dirty. A special case is MADV_FREE page. The page's pte could have
-        * dirty bit cleared but the page's SwapBacked bit is still set because
-        * clearing the dirty bit and SwapBacked bit has no lock protected. For
-        * such page, unmap will not set dirty bit for it, so page reclaim will
-        * not write the page out. This can cause data corruption when the page
-        * is swap in later. Always setting the dirty bit for the page solves
-        * the problem.
+        * Normally the folio will be dirtied in unmap because its
+        * pte should be dirty. A special case is MADV_FREE page. The
+        * page's pte could have dirty bit cleared but the folio's
+        * SwapBacked flag is still set because clearing the dirty bit
+        * and SwapBacked flag has no lock protected. For such folio,
+        * unmap will not set dirty bit for it, so folio reclaim will
+        * not write the folio out. This can cause data corruption when
+        * the folio is swapped in later. Always setting the dirty flag
+        * for the folio solves the problem.
         */
-       set_page_dirty(page);
+       folio_mark_dirty(folio);
 
-       return 1;
+       return true;
 
 fail:
-       put_swap_page(page, entry);
-       return 0;
+       put_swap_page(&folio->page, entry);
+       return false;
 }
 
 /*

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2837e7e..f2fc5aa 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1731,8 +1731,8 @@ retry:
                                                                page_list))
                                                goto activate_locked;
                                }
-                               if (!add_to_swap(page)) {
-                                       if (!PageTransHuge(page))
+                               if (!add_to_swap(folio)) {
+                                       if (!folio_test_large(folio))
                                                goto activate_locked_split;
                                        /* Fallback to swap normal pages */
                                        if (split_folio_to_list(folio,
@@ -1741,7 +1741,7 @@ retry:
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
                                        count_vm_event(THP_SWPOUT_FALLBACK);
 #endif
-                                       if (!add_to_swap(page))
+                                       if (!add_to_swap(folio))
                                                goto activate_locked_split;
                                }