Re: [PATCH v6 04/28] drm/bridge: Add drm_private_obj_is_bridge()

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] drm/bridge: typo in drm_private_obj_is_bridge NULL guard
--

commit 4aa8371c67584717cdc9bfc67e2f423ff8e526fe
Author: Maxime Ripard <mripard@kernel.org>

drm/bridge: Add drm_private_obj_is_bridge()

This commit introduces drm_private_obj_is_bridge() to identify if a private
object is backed by a bridge. This is necessary because bridges require
special readout ordering during encoder chain handling.

> diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> index 447fe6d333b3b..9d5529765f5fb 100644
> --- a/drivers/gpu/drm/drm_bridge.c
> +++ b/drivers/gpu/drm/drm_bridge.c
> @@ -582,6 +582,21 @@ static const struct drm_private_state_funcs drm_bridge_priv_state_funcs = {
[ ... ]
> +/**
> + * drm_private_obj_is_bridge - check if a private object backs a bridge
> + * @obj: private object to check
> + *
> + * RETURNS:
> + *
> + * True if @obj is the &drm_private_obj embedded in a &struct drm_bridge,
> + * false otherwise.
> + */
> +bool drm_private_obj_is_bridge(struct drm_private_obj *obj)
> +{
> +	return obj->funcs && obj->funcs == &drm_bridge_priv_state_funcs;

[Severity: Low]
Is there a typo in the null guard here?

If the intent is to protect against a null obj pointer, checking obj->funcs
first will cause a null pointer dereference.

If obj is instead guaranteed to be non-null, the left side of the && is
redundant dead code, because comparing a potentially null obj->funcs pointer
to a valid static address safely evaluates to false.

Should this instead be return obj && obj->funcs == ... or just the right
side if obj is guaranteed to be non-null?

> +}
> +EXPORT_SYMBOL(drm_private_obj_is_bridge);

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261015-drm-state-readout-v6-0-6cc02cd10998@kernel.org?part=4