swap: clean-up #ifdef in page_mapping()

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>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 24db914..c03c139 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -447,6 +447,7 @@ 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..eaf63fc 100644 (file)
--- 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;
 }