[0/3] drm: logicvc: add of_node_put() and switch to a more secure approach

Message

Javier Carrasco Oct. 10, 2024, 11:11 p.m. UTC

This driver has faced several issues due to the wrong or missing usage
of of_node_put() to release device nodes after they are no longer
required.

The first implementation was missing the of_node_put() for
'layers_node', and it put 'layer_node' twice. Then commit
'd3a453416270 ("drm: fix device_node_continue.cocci warnings")'
removed the extra of_node_put(layer_node), which would have been ok if
it had stayed only in the error path. Later, commit
'e9fcc60ddd29 ("drm/logicvc: add missing of_node_put() in
logicvc_layers_init()")' added the missing of_node_put(layers_node),
but not the one for the child node.

It should be clear how easy someone can mess up with this pattern,
especially with variables that have similar names.

To fix the bug for stable kernels, and provide a more robust solution
that accounts for new error paths, this series provides a first patch
with the classical approach of adding the missing of_node_put(), and two
more patches to use the cleanup attribute and avoid issues with
device nodes again.

Signed-off-by: Javier Carrasco <[e-mail]>
---
Javier Carrasco (3):
      drm: logicvc: fix missing of_node_put() in for_each_child_of_node()
      drm: logicvc: switch to for_each_child_of_node_scoped()
      drm: logicvc: use automatic cleanup facility for layers_node

 drivers/gpu/drm/logicvc/logicvc_layer.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)
---
base-commit: 0cca97bf23640ff68a6e8a74e9b6659fdc27f48c
change-id: 20241010-logicvc_layer_of_node_put-bc4cb207280b

Best regards,