Re: [PATCH v4 01/20] drm/atomic: Document atomic commit lifetime

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The documentation incorrectly states that drm_atomic_commit_clear() frees the struct drm_atomic_commit instance.
--

commit fdfb916c25c456b6e4d4d1ec325dd4bd7d5f24d3
Author: Maxime Ripard <mripard@kernel.org>
drm/atomic: Document atomic commit lifetime

This commit adds kernel-doc comments detailing the lifetime and allocation
process of the drm_atomic_commit structures.

> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index 170de30c28ae4..04bc3e736cbdb 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c

[ ... ]

> + *   + After the state is populated, it is checked. If the check is
> + *     successful, the update is committed. Part of the commit is a call
> + *     to drm_atomic_helper_swap_state() which will turn the new states
> + *     into the active states. Doing so involves updating the object's
> + *     state pointer (&drm_crtc.state or similar) to point to the new
> + *     state, and state_to_destroy will now point to the old states,
> + *     that used to be active but aren't anymore.
> + *
> + *   + When the commit is done, and when all references to our &struct
> + *     drm_atomic_commit are put, drm_atomic_commit_clear() runs and
> + *     will free all state_to_destroy (ie. old states), and the &struct
> + *     drm_atomic_commit instance.

Is this documentation accurate about drm_atomic_commit_clear() freeing the
struct drm_atomic_commit instance?

Looking at the implementation, drm_atomic_commit_clear() only resets the
internal arrays and frees the individual object states.

It appears the struct drm_atomic_commit instance is actually freed by
__drm_atomic_commit_free(), which is invoked via drm_atomic_commit_put().
__drm_atomic_commit_free() calls drm_atomic_commit_clear() first, and then
frees the memory.

Should the documentation reflect that __drm_atomic_commit_free() is
responsible for freeing the instance?

> + *
> + *   + Now, we don't have any active &struct drm_atomic_commit anymore,
> + *     and only the entity active states remain allocated.
> + */

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260512-drm-mode-config-init-v4-0-591dfdcc1bf9@kernel.org?part=1