[PATCH RFC v2 06/24] drm/display: bridge-connector: add APIs to add/remove the connector dynamically

[Luca Ceresoli]

drm_bridge_connector_init() adds a drmm-allocated connector. For bridge
hotplug drmm allocations are not suitable because a connector may have to
be added and removed multiple times in the lifetime of a card.

In preparation for bridge hotplug, add APIs to add and remove a connector
using regular non-managed allocations.

For the dynamic connector, this requires the kfree() the allocated struct
drm_bridge_connector in the destroy func. However that func will be called
even when using the pre-existing drmm API, leading to a double free
(kfree() in the destroy callback + drmm).

One option to avoid this issue is introducing two mostly identical
drm_connector_funcs instances, one with .destroy and one without. But that
would be an annoying code duplication. Instead take a different approach:
always allocate using non-drmm kzalloc_obj(), so that deallocation always
happen in destroy->kfree().

Signed-off-by: Luca Ceresoli <luca.ceresoli@xxxxxxxxxxx>

---

Uhm, maybe the change from drmm_kzalloc to kzalloc_obj and addition of
kfree to the destroy callback should eb a separate commit?
---
 drivers/gpu/drm/display/drm_bridge_connector.c | 24 +++++++++++++++++++++++-
 include/drm/drm_bridge_connector.h             |  4 ++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index 1c222e27767d..2a0065208fb8 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -285,6 +285,7 @@ static void drm_bridge_connector_dynconn_destroy(struct drm_connector *connector
 
 	drm_connector_cleanup(connector);
 	drm_bridge_connector_put_bridges(bridge_connector);
+	kfree(bridge_connector);
 }
 
 static const struct drm_connector_funcs drm_bridge_connector_funcs = {
@@ -1184,7 +1185,7 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	struct drm_connector *connector;
 	int ret;
 
-	bridge_connector = drmm_kzalloc(drm, sizeof(*bridge_connector), GFP_KERNEL);
+	bridge_connector = kzalloc_obj(*bridge_connector);
 	if (!bridge_connector)
 		return ERR_PTR(-ENOMEM);
 
@@ -1199,3 +1200,24 @@ struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 	return connector;
 }
 EXPORT_SYMBOL_GPL(drm_bridge_connector_init);
+
+struct drm_connector *drm_bridge_connector_dynamic_add(struct drm_device *drm,
+						       struct drm_encoder *encoder)
+{
+	struct drm_bridge_connector *bridge_connector;
+
+	bridge_connector = kzalloc_obj(*bridge_connector);
+	if (!bridge_connector)
+		return ERR_PTR(-ENOMEM);
+
+	return drm_bridge_connector_initialize(bridge_connector, drm, encoder);
+}
+EXPORT_SYMBOL_GPL(drm_bridge_connector_dynamic_add);
+
+void drm_bridge_connector_dynamic_remove(struct drm_connector *connector)
+{
+	struct drm_bridge_connector *bridge_connector = to_drm_bridge_connector(connector);
+
+	drm_bridge_connector_fini(bridge_connector);
+}
+EXPORT_SYMBOL_GPL(drm_bridge_connector_dynamic_remove);
diff --git a/include/drm/drm_bridge_connector.h b/include/drm/drm_bridge_connector.h
index 69630815fb09..de6ec91dbfab 100644
--- a/include/drm/drm_bridge_connector.h
+++ b/include/drm/drm_bridge_connector.h
@@ -9,8 +9,12 @@
 struct drm_connector;
 struct drm_device;
 struct drm_encoder;
+struct drm_bridge_connector;
 
 struct drm_connector *drm_bridge_connector_init(struct drm_device *drm,
 						struct drm_encoder *encoder);
+struct drm_connector *drm_bridge_connector_dynamic_add(struct drm_device *drm,
+						       struct drm_encoder *encoder);
+void drm_bridge_connector_dynamic_remove(struct drm_connector *connector);
 
 #endif /* __DRM_BRIDGE_CONNECTOR_H__ */

-- 
2.55.0