[PATCH 3/3] drm/vc4: encoder: use drm managed resources

[Danilo Krummrich]

Allocate the encoder objects with drmm_simple_encoder_alloc() in order to
tie the release action to the underlying struct drm_device, where all the
userspace visible stuff is attached to, rather than to struct device.

This can prevent potential use-after free issues on driver unload or
EPROBE_DEFERRED backoff.

Signed-off-by: Danilo Krummrich <dakr@xxxxxxxxxx>
---
 drivers/gpu/drm/vc4/vc4_dpi.c  | 11 ++++++-----
 drivers/gpu/drm/vc4/vc4_dsi.c  | 10 +++++-----
 drivers/gpu/drm/vc4/vc4_hdmi.c | 10 ++++++----
 drivers/gpu/drm/vc4/vc4_vec.c  | 11 ++++++-----
 4 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
index c180eb60bee8..7f1703a42060 100644
--- a/drivers/gpu/drm/vc4/vc4_dpi.c
+++ b/drivers/gpu/drm/vc4/vc4_dpi.c
@@ -258,10 +258,12 @@ static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
 	if (!dpi)
 		return -ENOMEM;
 
-	vc4_dpi_encoder = devm_kzalloc(dev, sizeof(*vc4_dpi_encoder),
-				       GFP_KERNEL);
-	if (!vc4_dpi_encoder)
-		return -ENOMEM;
+	vc4_dpi_encoder = drmm_simple_encoder_alloc(drm, struct vc4_dpi_encoder,
+						    base.base,
+						    DRM_MODE_ENCODER_DPI);
+	if (IS_ERR(vc4_dpi_encoder))
+		return PTR_ERR(vc4_dpi_encoder);
+
 	vc4_dpi_encoder->base.type = VC4_ENCODER_TYPE_DPI;
 	vc4_dpi_encoder->dpi = dpi;
 	dpi->encoder = &vc4_dpi_encoder->base.base;
@@ -299,7 +301,6 @@ static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
 	if (ret)
 		DRM_ERROR("Failed to turn on core clock: %d\n", ret);
 
-	drm_simple_encoder_init(drm, dpi->encoder, DRM_MODE_ENCODER_DPI);
 	drm_encoder_helper_add(dpi->encoder, &vc4_dpi_encoder_helper_funcs);
 
 	ret = vc4_dpi_init_bridge(dpi);
diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
index 98308a17e4ed..8ca3b73e26dc 100644
--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -1498,10 +1498,11 @@ static int vc4_dsi_bind(struct device *dev, struct device *master, void *data)
 
 	dsi->variant = of_device_get_match_data(dev);
 
-	vc4_dsi_encoder = devm_kzalloc(dev, sizeof(*vc4_dsi_encoder),
-				       GFP_KERNEL);
-	if (!vc4_dsi_encoder)
-		return -ENOMEM;
+	vc4_dsi_encoder = drmm_simple_encoder_alloc(drm, struct vc4_dsi_encoder,
+						    base.base,
+						    DRM_MODE_ENCODER_DSI);
+	if (IS_ERR(vc4_dsi_encoder))
+		return PTR_ERR(vc4_dsi_encoder);
 
 	INIT_LIST_HEAD(&dsi->bridge_chain);
 	vc4_dsi_encoder->base.type = VC4_ENCODER_TYPE_DSI1;
@@ -1614,7 +1615,6 @@ static int vc4_dsi_bind(struct device *dev, struct device *master, void *data)
 	if (ret)
 		return ret;
 
-	drm_simple_encoder_init(drm, dsi->encoder, DRM_MODE_ENCODER_DSI);
 	drm_encoder_helper_add(dsi->encoder, &vc4_dsi_encoder_helper_funcs);
 
 	ret = drm_bridge_attach(dsi->encoder, dsi->bridge, NULL, 0);
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index ce9d16666d91..4657b09649f7 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -2834,9 +2834,12 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 	struct device_node *ddc_node;
 	int ret;
 
-	vc4_hdmi = devm_kzalloc(dev, sizeof(*vc4_hdmi), GFP_KERNEL);
-	if (!vc4_hdmi)
-		return -ENOMEM;
+	vc4_hdmi = drmm_simple_encoder_alloc(drm, struct vc4_hdmi,
+					     encoder.base,
+					     DRM_MODE_ENCODER_DSI);
+	if (IS_ERR(vc4_hdmi))
+		return PTR_ERR(vc4_hdmi);
+
 	mutex_init(&vc4_hdmi->mutex);
 	spin_lock_init(&vc4_hdmi->hw_lock);
 	INIT_DELAYED_WORK(&vc4_hdmi->scrambling_work, vc4_hdmi_scrambling_wq);
@@ -2921,7 +2924,6 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 		clk_prepare_enable(vc4_hdmi->pixel_bvb_clock);
 	}
 
-	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);
 	drm_encoder_helper_add(encoder, &vc4_hdmi_encoder_helper_funcs);
 
 	ret = vc4_hdmi_connector_init(drm, vc4_hdmi);
diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
index 11fc3d6f66b1..d6466f1ef490 100644
--- a/drivers/gpu/drm/vc4/vc4_vec.c
+++ b/drivers/gpu/drm/vc4/vc4_vec.c
@@ -546,10 +546,12 @@ static int vc4_vec_bind(struct device *dev, struct device *master, void *data)
 	if (!vec)
 		return -ENOMEM;
 
-	vc4_vec_encoder = devm_kzalloc(dev, sizeof(*vc4_vec_encoder),
-				       GFP_KERNEL);
-	if (!vc4_vec_encoder)
-		return -ENOMEM;
+	vc4_vec_encoder = drmm_simple_encoder_alloc(drm, struct vc4_vec_encoder,
+						    base.base,
+						    DRM_MODE_ENCODER_TVDAC);
+	if (IS_ERR(vc4_vec_encoder))
+		return PTR_ERR(vc4_vec_encoder);
+
 	vc4_vec_encoder->base.type = VC4_ENCODER_TYPE_VEC;
 	vc4_vec_encoder->vec = vec;
 	vec->encoder = &vc4_vec_encoder->base.base;
@@ -574,7 +576,6 @@ static int vc4_vec_bind(struct device *dev, struct device *master, void *data)
 
 	pm_runtime_enable(dev);
 
-	drm_simple_encoder_init(drm, vec->encoder, DRM_MODE_ENCODER_TVDAC);
 	drm_encoder_helper_add(vec->encoder, &vc4_vec_encoder_helper_funcs);
 
 	vec->connector = vc4_vec_connector_init(drm, vec);
-- 
2.36.1