mm: when migrate_pages returns 0, all pages must have been released

In some cases migrate_pages could return zero while still leaving a few
pages in the pagelist (and some caller wouldn't notice it has to call
putback_lru_pages after commit cf608ac19c9 ("mm: compaction: fix
COMPACTPAGEFAILED counting")).

Add one missing putback_lru_pages not added by commit cf608ac19c95 ("mm:
compaction: fix COMPACTPAGEFAILED counting").

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/migrate.c b/mm/migrate.c
index 9f29a3b..155a2e9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -772,6 +772,7 @@
 unlock:
 	unlock_page(page);
 
+move_newpage:
 	if (rc != -EAGAIN) {
  		/*
  		 * A page that has been migrated has all references
@@ -785,8 +786,6 @@
 		putback_lru_page(page);
 	}
 
-move_newpage:
-
 	/*
 	 * Move the new page to the LRU. If migration was not successful
 	 * then this will free the page.