ksm: unstable_tree_search_insert error checking cleanup

get_mergeable_page() can only return NULL (also in case of errors) or the
pinned mergeable page.  It can't return an error different than NULL.
This optimizes away the unnecessary error check.

Add a return after the "out:" label in the callee to make it more
readable.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Petr Holasek <pholasek@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/ksm.c

@@ -475,7 +475,8 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
 		flush_dcache_page(page);
 	} else {
 		put_page(page);
-out:		page = NULL;
+out:
+		page = NULL;
 	}
 	up_read(&mm->mmap_sem);
 	return page;
@@ -1358,7 +1359,7 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
 		cond_resched();
 		tree_rmap_item = rb_entry(*new, struct rmap_item, node);
 		tree_page = get_mergeable_page(tree_rmap_item);
-		if (IS_ERR_OR_NULL(tree_page))
+		if (!tree_page)
 			return NULL;
 
 		/*