[PATCH] drm/atomic-helper: fix parameter order in drm_format_conv_state_copy() call

[Lucas Stach]

Am Donnerstag, dem 04.04.2024 um 10:17 +0200 schrieb Lucas Stach:
> Old and new state parameters are swapped, so the old state was cleared
> instead of the new duplicated state.
> 
To be clear, as the commit message may do a poor job at conveying the
consequences: this fixes a major memory leak when a temporary buffer is
used for the format conversion, as clearing the wrong state lets us
forget about the existence of the temporary buffer on each atomic
commit. So each commit allocates a new temp buffer while the old one is
never freed.

As such I would appreciate if this commit is added to the next round of
-fixes.

Regards,
Lucas

> Fixes: 903674588a48 ("drm/atomic-helper: Add format-conversion state to shadow-plane state")
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> Tested-by: Leonard Göhrs <l.goehrs at pengutronix.de>
> ---
>  drivers/gpu/drm/drm_gem_atomic_helper.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
> index e440f458b663..93337543aac3 100644
> --- a/drivers/gpu/drm/drm_gem_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
> @@ -224,8 +224,8 @@ __drm_gem_duplicate_shadow_plane_state(struct drm_plane *plane,
>  
>  	__drm_atomic_helper_plane_duplicate_state(plane, &new_shadow_plane_state->base);
>  
> -	drm_format_conv_state_copy(&shadow_plane_state->fmtcnv_state,
> -				   &new_shadow_plane_state->fmtcnv_state);
> +	drm_format_conv_state_copy(&new_shadow_plane_state->fmtcnv_state,
> +				   &shadow_plane_state->fmtcnv_state);
>  }
>  EXPORT_SYMBOL(__drm_gem_duplicate_shadow_plane_state);
>