linux-kernel - Re: [PATCH v1 2/2] media: platform: mtk-mdp3: fix error handling about components clock

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Date:   Fri, 30 Sep 2022 14:12:51 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Moudy Ho <moudy.ho@...iatek.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>
Cc:     linux-media@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH v1 2/2] media: platform: mtk-mdp3: fix error handling
 about components clock_on

Il 30/09/22 12:23, Moudy Ho ha scritto:
> Add goto statement in mdp_comp_clock_on() to avoid error code not being
> propagated or returning positive values.
> This change also performs a well-timed clock_off when an error occurs, and
> reduces unnecessary error logging in mdp_cmdq_send().
> 
> Fixes: 61890ccaefaf ("media: platform: mtk-mdp3: add MediaTek MDP3 driver")
> Signed-off-by: Moudy Ho <moudy.ho@...iatek.com>
> ---
>   .../platform/mediatek/mdp3/mtk-mdp3-cmdq.c    |  4 +---
>   .../platform/mediatek/mdp3/mtk-mdp3-comp.c    | 24 ++++++++++++++-----
>   2 files changed, 19 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c
> index e194dec8050a..124c1b96e96b 100644
> --- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c
> +++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-cmdq.c
> @@ -433,10 +433,8 @@ int mdp_cmdq_send(struct mdp_dev *mdp, struct mdp_cmdq_param *param)
>   	cmd->mdp_ctx = param->mdp_ctx;
>   
>   	ret = mdp_comp_clocks_on(&mdp->pdev->dev, cmd->comps, cmd->num_comps);
> -	if (ret) {
> -		dev_err(dev, "comp %d failed to enable clock!\n", ret);
> +	if (ret)
>   		goto err_free_path;
> -	}
>   
>   	dma_sync_single_for_device(mdp->cmdq_clt->chan->mbox->dev,
>   				   cmd->pkt.pa_base, cmd->pkt.cmd_buf_size,
> diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-comp.c b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-comp.c
> index d3eaf8884412..fe6a39315e88 100644
> --- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-comp.c
> +++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-comp.c
> @@ -699,12 +699,22 @@ int mdp_comp_clock_on(struct device *dev, struct mdp_comp *comp)
>   			dev_err(dev,
>   				"Failed to enable clk %d. type:%d id:%d\n",
>   				i, comp->type, comp->id);
> -			pm_runtime_put(comp->comp_dev);
> -			return ret;
> +			goto err_unwind;
>   		}
>   	}
>   
>   	return 0;
> +
> +err_unwind:

For this label to be clearer, I would rename it as `err_revert`, or
`clocks_off`, or even simply `err`, as the `unwind` word may create
some confusion here.

> +	while (--i >= 0) {
> +		if (IS_ERR_OR_NULL(comp->clks[i]))
> +			continue;
> +		clk_disable_unprepare(comp->clks[i]);
> +	}
> +	if (comp->comp_dev)
> +		pm_runtime_put_sync(comp->comp_dev);
> +
> +	return ret;
>   }
>   
>   void mdp_comp_clock_off(struct device *dev, struct mdp_comp *comp)
> @@ -723,11 +733,13 @@ void mdp_comp_clock_off(struct device *dev, struct mdp_comp *comp)
>   
>   int mdp_comp_clocks_on(struct device *dev, struct mdp_comp *comps, int num)
>   {
> -	int i;
> +	int i, ret;
>   
> -	for (i = 0; i < num; i++)
> -		if (mdp_comp_clock_on(dev, &comps[i]) != 0)
> -			return ++i;
> +	for (i = 0; i < num; i++) {
> +		ret = mdp_comp_clock_on(dev, &comps[i]);
> +		if (ret)
> +			return ret;
> +	}
>   
>   	return 0;
>   }
>