diff --git a/autoload/airline/extensions/whitespace.vim b/autoload/airline/extensions/whitespace.vim
index da76bf5..17f9c08 100644
--- a/autoload/airline/extensions/whitespace.vim
+++ b/autoload/airline/extensions/whitespace.vim
@@ -70,10 +70,10 @@ function! airline#extensions#whitespace#toggle()
   endif
 endfunction
 
-function! airline#extensions#whitespace#init(ext)
+function! airline#extensions#whitespace#init(...)
   if !s:initialized
     let s:initialized = 1
-    call a:ext.add_statusline_funcref(function('airline#extensions#whitespace#apply'))
+    call add(g:airline_statusline_funcrefs, function('airline#extensions#whitespace#apply'))
   endif
 
   unlet! b:airline_whitespace_check