mm/migrate: remove unused function, fail_migrate_page()

fail_migrate_page() isn't used anywhere, so remove it.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Reviewed-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NWanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/migrate.h

@@ -41,9 +41,6 @@ extern int migrate_page(struct address_space *,
 extern int migrate_pages(struct list_head *l, new_page_t x,
 		unsigned long private, enum migrate_mode mode, int reason);
 
-extern int fail_migrate_page(struct address_space *,
-			struct page *, struct page *);
-
 extern int migrate_prep(void);
 extern int migrate_prep_local(void);
 extern int migrate_vmas(struct mm_struct *mm,
@@ -84,7 +81,6 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
 
 /* Possible settings for the migrate_page() method in address_operations */
 #define migrate_page NULL
-#define fail_migrate_page NULL
 
 #endif /* CONFIG_MIGRATION */
 

mm/migrate.c

@@ -552,14 +552,6 @@ void migrate_page_copy(struct page *newpage, struct page *page)
  *                    Migration functions
  ***********************************************************/
 
-/* Always fail migration. Used for mappings that are not movable */
-int fail_migrate_page(struct address_space *mapping,
-			struct page *newpage, struct page *page)
-{
-	return -EIO;
-}
-EXPORT_SYMBOL(fail_migrate_page);
-
 /*
  * Common logic to directly migrate a single page suitable for
  * pages that do not use PagePrivate/PagePrivate2.