Hi Laurent,
On 26/02/18 21:45, Laurent Pinchart wrote:
> The DRM pipeline handling code uses the entity's pipe list head to check
> whether the entity is already included in a pipeline. This method is a
> bit fragile in the sense that it uses list_empty() on a list_head that
> is a list member. Replace it by a simpler check for the entity pipe
> pointer.
Yes, excellent.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/platform/vsp1/vsp1_drm.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/media/platform/vsp1/vsp1_drm.c b/drivers/media/platform/vsp1/vsp1_drm.c
> index a7ad85ab0b08..e210917fdc3f 100644
> --- a/drivers/media/platform/vsp1/vsp1_drm.c
> +++ b/drivers/media/platform/vsp1/vsp1_drm.c
> @@ -119,9 +119,9 @@ int vsp1_du_setup_lif(struct device *dev, unsigned int pipe_index,
> * Remove the RPF from the pipe and the list of BRU
> * inputs.
> */
> - WARN_ON(list_empty(&rpf->entity.list_pipe));
> + WARN_ON(!rpf->entity.pipe);
Does this WARN_ON() have much value any more ?
I think it could probably be removed... unless there is a race between potential
calls through vsp1_du_atomic_flush() and vsp1_du_setup_lif() - but I would be
very surprised if that wasn't protected at the DRM levels.
(Removing it if chosen doesn't need to be in this patch though)
> rpf->entity.pipe = NULL;
> - list_del_init(&rpf->entity.list_pipe);
> + list_del(&rpf->entity.list_pipe);
> pipe->inputs[i] = NULL;
>
> bru->inputs[rpf->bru_input].rpf = NULL;
> @@ -537,7 +537,7 @@ void vsp1_du_atomic_flush(struct device *dev, unsigned int pipe_index)
> continue;
> }
>
> - if (list_empty(&rpf->entity.list_pipe)) {
> + if (!rpf->entity.pipe) {
> rpf->entity.pipe = pipe;
> list_add_tail(&rpf->entity.list_pipe, &pipe->entities);
> }
> @@ -566,7 +566,7 @@ void vsp1_du_atomic_flush(struct device *dev, unsigned int pipe_index)
> VI6_DPR_NODE_UNUSED);
>
> entity->pipe = NULL;
> - list_del_init(&entity->list_pipe);
> + list_del(&entity->list_pipe);
>
> continue;
> }
>
