diff --git a/actionpack/lib/action_controller.rb b/actionpack/lib/action_controller.rb
index f808bdd910..7a71c64695 100644
--- a/actionpack/lib/action_controller.rb
+++ b/actionpack/lib/action_controller.rb
@@ -56,7 +56,6 @@ module ActionController
   autoload :Integration, 'action_controller/integration'
   autoload :IntegrationTest, 'action_controller/integration'
   autoload :Layout, 'action_controller/layout'
-  autoload :Lock, 'action_controller/lock'
   autoload :MiddlewareStack, 'action_controller/middleware_stack'
   autoload :MimeResponds, 'action_controller/mime_responds'
   autoload :PolymorphicRoutes, 'action_controller/polymorphic_routes'
diff --git a/actionpack/lib/action_controller/lock.rb b/actionpack/lib/action_controller/lock.rb
deleted file mode 100644
index c50762216e..0000000000
--- a/actionpack/lib/action_controller/lock.rb
+++ /dev/null
@@ -1,16 +0,0 @@
-module ActionController
-  class Lock
-    FLAG = 'rack.multithread'.freeze
-
-    def initialize(app, lock = Mutex.new)
-      @app, @lock = app, lock
-    end
-
-    def call(env)
-      old, env[FLAG] = env[FLAG], false
-      @lock.synchronize { @app.call(env) }
-    ensure
-      env[FLAG] = old
-    end
-  end
-end
diff --git a/actionpack/lib/action_controller/middlewares.rb b/actionpack/lib/action_controller/middlewares.rb
index 0f038b8856..cbcb5cb3e4 100644
--- a/actionpack/lib/action_controller/middlewares.rb
+++ b/actionpack/lib/action_controller/middlewares.rb
@@ -1,4 +1,4 @@
-use "ActionController::Lock", :if => lambda {
+use "Rack::Lock", :if => lambda {
   !ActionController::Base.allow_concurrency
 }
 
diff --git a/actionpack/lib/action_controller/rack_ext.rb b/actionpack/lib/action_controller/rack_ext.rb
index 3d6f1f9256..17cd08f39a 100644
--- a/actionpack/lib/action_controller/rack_ext.rb
+++ b/actionpack/lib/action_controller/rack_ext.rb
@@ -1,22 +1,2 @@
-module Rack
-  module Utils
-    module Multipart
-      class << self
-        def parse_multipart_with_rewind(env)
-          result = parse_multipart_without_rewind(env)
-
-          begin
-            env['rack.input'].rewind
-          rescue NoMethodError, Errno::ESPIPE
-            # Handles exceptions raised by input streams that cannot be rewound
-            # such as when using plain CGI under Apache
-          end
-
-          result
-        end
-
-        alias_method_chain :parse_multipart, :rewind
-      end
-    end
-  end
-end
+require 'action_controller/rack_ext/lock'
+require 'action_controller/rack_ext/multipart'
diff --git a/actionpack/lib/action_controller/rack_ext/lock.rb b/actionpack/lib/action_controller/rack_ext/lock.rb
new file mode 100644
index 0000000000..9bf1889065
--- /dev/null
+++ b/actionpack/lib/action_controller/rack_ext/lock.rb
@@ -0,0 +1,21 @@
+module Rack
+  # Rack::Lock was commited to Rack core
+  # http://github.com/rack/rack/commit/7409b0c
+  # Remove this when Rack 1.0 is released
+  unless defined? Lock
+    class Lock
+      FLAG = 'rack.multithread'.freeze
+
+      def initialize(app, lock = Mutex.new)
+        @app, @lock = app, lock
+      end
+
+      def call(env)
+        old, env[FLAG] = env[FLAG], false
+        @lock.synchronize { @app.call(env) }
+      ensure
+        env[FLAG] = old
+      end
+    end
+  end
+end
diff --git a/actionpack/lib/action_controller/rack_ext/multipart.rb b/actionpack/lib/action_controller/rack_ext/multipart.rb
new file mode 100644
index 0000000000..3d6f1f9256
--- /dev/null
+++ b/actionpack/lib/action_controller/rack_ext/multipart.rb
@@ -0,0 +1,22 @@
+module Rack
+  module Utils
+    module Multipart
+      class << self
+        def parse_multipart_with_rewind(env)
+          result = parse_multipart_without_rewind(env)
+
+          begin
+            env['rack.input'].rewind
+          rescue NoMethodError, Errno::ESPIPE
+            # Handles exceptions raised by input streams that cannot be rewound
+            # such as when using plain CGI under Apache
+          end
+
+          result
+        end
+
+        alias_method_chain :parse_multipart, :rewind
+      end
+    end
+  end
+end