diff --git a/gfx/layers/D3D11YCbCrImage.cpp b/gfx/layers/D3D11YCbCrImage.cpp
index 590d55fcb9..de2d209d28 100644
--- a/gfx/layers/D3D11YCbCrImage.cpp
+++ b/gfx/layers/D3D11YCbCrImage.cpp
@@ -71,7 +71,7 @@ D3D11YCbCrImage::SetData(KnowsCompositor* aAllocator,
     return false;
   }
 
-  mt->Enter();
+  D3D11MTAutoEnter mtAutoEnter(mt.forget());
 
   RefPtr<ID3D11DeviceContext> ctx;
   allocator->GetDevice()->GetImmediateContext(getter_AddRefs(ctx));
@@ -99,9 +99,7 @@ D3D11YCbCrImage::SetData(KnowsCompositor* aAllocator,
                          aData.mCbCrStride,
                          aData.mCbCrStride * aData.mCbCrSize.height);
 
-  mt->Leave();
-
-  return true;
+return true;
 }
 
 IntSize
@@ -162,21 +160,7 @@ D3D11YCbCrImage::GetAsSourceSurface()
     return nullptr;
   }
 
-  class D3D11MTAutoEnter
-  {
-  public:
-    explicit D3D11MTAutoEnter(already_AddRefed<ID3D10Multithread> aMT)
-      : mMT(aMT)
-    {
-      mMT->Enter();
-    }
-    ~D3D11MTAutoEnter()
-    {
-      mMT->Leave();
-    }
-  private:
-    RefPtr<ID3D10Multithread> mMT;
-  } mtAutoEnter(mt.forget());
+  D3D11MTAutoEnter mtAutoEnter(mt.forget());
 
   texY->GetDesc(&desc);
   desc.BindFlags = 0;
diff --git a/gfx/layers/IMFYCbCrImage.cpp b/gfx/layers/IMFYCbCrImage.cpp
index e0f64b9c65..9890fb1e68 100644
--- a/gfx/layers/IMFYCbCrImage.cpp
+++ b/gfx/layers/IMFYCbCrImage.cpp
@@ -201,11 +201,10 @@ IMFYCbCrImage::GetTextureClient(KnowsCompositor* aForwarder)
     return mTextureClient;
   }
 
-  RefPtr<ID3D11Device> device =
-    gfx::DeviceManagerDx::Get()->GetContentDevice();
+  RefPtr<ID3D11Device> device = gfx::DeviceManagerDx::Get()->GetContentDevice();
+
   if (!device) {
-    device =
-      gfx::DeviceManagerDx::Get()->GetCompositorDevice();
+    device = gfx::DeviceManagerDx::Get()->GetCompositorDevice();
   }
 
   LayersBackend backend = aForwarder->GetCompositorBackendType();
@@ -274,7 +273,7 @@ IMFYCbCrImage::GetTextureClient(KnowsCompositor* aForwarder)
     AutoLockD3D11Texture lockCr(textureCr);
     AutoLockD3D11Texture lockCb(textureCb);
 
-    mt->Enter();
+    D3D11MTAutoEnter mtAutoEnter(mt.forget());
 
     RefPtr<ID3D11DeviceContext> ctx;
     device->GetImmediateContext((ID3D11DeviceContext**)getter_AddRefs(ctx));
@@ -290,8 +289,6 @@ IMFYCbCrImage::GetTextureClient(KnowsCompositor* aForwarder)
     box.bottom = mData.mCbCrSize.height;
     ctx->UpdateSubresource(textureCb, 0, &box, mData.mCbChannel, mData.mCbCrStride, 0);
     ctx->UpdateSubresource(textureCr, 0, &box, mData.mCrChannel, mData.mCbCrStride, 0);
-
-    mt->Leave();
   }
 
   mTextureClient = TextureClient::CreateWithData(
diff --git a/gfx/layers/d3d11/TextureD3D11.h b/gfx/layers/d3d11/TextureD3D11.h
index 001444fae1..86db51df13 100644
--- a/gfx/layers/d3d11/TextureD3D11.h
+++ b/gfx/layers/d3d11/TextureD3D11.h
@@ -461,6 +461,20 @@ private:
   RefPtr<IDXGIKeyedMutex> mMutex;
 };
 
+class D3D11MTAutoEnter
+{
+public:
+  explicit D3D11MTAutoEnter(already_AddRefed<ID3D10Multithread> aMT)
+    : mMT(aMT)
+  {
+    mMT->Enter();
+  }
+  ~D3D11MTAutoEnter() { mMT->Leave(); }
+
+private:
+  RefPtr<ID3D10Multithread> mMT;
+};
+
 }
 }