mm: remove lookup_swap_cache()

All callers have now been converted to swap_cache_get_folio(), so we can
remove this wrapper.

Link: https://lkml.kernel.org/r/20220902194653.1739778-39-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memcontrol.c

@@ -5569,7 +5569,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
 		return NULL;
 
 	/*
-	 * Because lookup_swap_cache() updates some statistics counter,
+	 * Because swap_cache_get_folio() updates some statistics counter,
 	 * we call find_get_page() with swapper_space directly.
 	 */
 	page = find_get_page(swap_address_space(ent), swp_offset(ent));

mm/swap.h

@@ -41,9 +41,6 @@ void clear_shadow_from_swap_cache(int type, unsigned long begin,
 				  unsigned long end);
 struct folio *swap_cache_get_folio(swp_entry_t entry,
 		struct vm_area_struct *vma, unsigned long addr);
-struct page *lookup_swap_cache(swp_entry_t entry,
-			       struct vm_area_struct *vma,
-			       unsigned long addr);
 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
 
 struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
@@ -107,13 +104,6 @@ static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
 	return NULL;
 }
 
-static inline struct page *lookup_swap_cache(swp_entry_t swp,
-					     struct vm_area_struct *vma,
-					     unsigned long addr)
-{
-	return NULL;
-}
-
 static inline
 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
 {

mm/swap_state.c

@@ -369,16 +369,6 @@ struct folio *swap_cache_get_folio(swp_entry_t entry,
 	return folio;
 }
 
-struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma,
-			       unsigned long addr)
-{
-	struct folio *folio = swap_cache_get_folio(entry, vma, addr);
-
-	if (!folio)
-		return NULL;
-	return folio_file_page(folio, swp_offset(entry));
-}
-
 /**
  * find_get_incore_page - Find and get a page from the page or swap caches.
  * @mapping: The address_space to search.
@@ -430,7 +420,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 		int err;
 		/*
 		 * First check the swap cache.  Since this is normally
-		 * called after lookup_swap_cache() failed, re-calling
+		 * called after swap_cache_get_folio() failed, re-calling
 		 * that would confuse statistics.
 		 */
 		si = get_swap_device(entry);