[PATCH 4/4] swap: clean-up #ifdef in page_mapping()

Joonsoo Kim
2013-08-02T02:08:25Z

PageSwapCache() is always false when !CONFIG_SWAP, so compiler
properly discard related code. Therefore, we don't need #ifdef explicitly.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index d95cde5..c638a71 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -414,6 +414,7 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)

#else /* CONFIG_SWAP */

+#define swap_address_space(entry) (NULL)
#define get_nr_swap_pages() 0L
#define total_swap_pages 0L
#define total_swapcache_pages() 0UL
diff --git a/mm/util.c b/mm/util.c
index 7441c41..eaf63fc2 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -388,15 +388,12 @@ struct address_space *page_mapping(struct page *page)
struct address_space *mapping = page->mapping;

VM_BUG_ON(PageSlab(page));
-#ifdef CONFIG_SWAP
if (unlikely(PageSwapCache(page))) {
swp_entry_t entry;

entry.val = page_private(page);
mapping = swap_address_space(entry);
- } else
-#endif
- if ((unsigned long)mapping & PAGE_MAPPING_ANON)
+ } else if ((unsigned long)mapping & PAGE_MAPPING_ANON)
mapping = NULL;
return mapping;
}
--
1.7.9.5