linux-kernel - Re: [PATCH] drm/mediatek: add missing put_device() call in mtk_ddp_comp

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Message-ID: <CAAOTY_-BQx0rozw0qoGj1bt4hO2rFmYvKrjQHbA-K04txUWW+w@mail.gmail.com>
Date:   Tue, 8 Sep 2020 06:56:36 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Yu Kuai <yukuai3@...wei.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Matthias Brugger <matthias.bgg@...il.com>,
        yt.shen@...iatek.com, CK Hu <ck.hu@...iatek.com>,
        Bibby Hsieh <bibby.hsieh@...iatek.com>,
        Yongqiang Niu <yongqiang.niu@...iatek.com>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>, yi.zhang@...wei.com
Subject: Re: [PATCH] drm/mediatek: add missing put_device() call in mtk_ddp_comp_init()

Hi Yu Kuai:

Yu Kuai <yukuai3@...wei.com> 於 2020年9月5日 週六 下午4:31寫道：
>
> if of_find_device_by_node() succeed, mtk_ddp_comp_init() doesn't have
> a corresponding put_device(). Thus add put_device() to fix the exception
> handling for this function implementation.
>

This patch looks good to me, but I find another thing related to this.
mtk_ddp_comp_init() is called in a loop in mtk_drm_probe(), when this
component init fail, I think we should uninitialize previous
successive init component and put their device. Would you like to make
this patch more complete?

Regards,
Chun-Kuang.

> Fixes: d0afe37f5209 ("drm/mediatek: support CMDQ interface in ddp component")
> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> index 57c88de9a329..526648885b97 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -496,6 +496,7 @@ int mtk_ddp_comp_init(struct device *dev, struct device_node *node,
>  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
>         if (of_address_to_resource(node, 0, &res) != 0) {
>                 dev_err(dev, "Missing reg in %s node\n", node->full_name);
> +               put_device(&larb_pdev->dev);
>                 return -EINVAL;
>         }
>         comp->regs_pa = res.start;
> --
> 2.25.4
>