linux-kernel - Re: [PATCH] drm: mediatek: Drop unnecessary check for property presence

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Message-ID: <f138b86dd8a19951a577687edada04ce3831c401.camel@mediatek.com>
Date: Wed, 21 Aug 2024 01:54:13 +0000
From: CK Hu (胡俊光) <ck.hu@...iatek.com>
To: "robh@...nel.org" <robh@...nel.org>, "p.zabel@...gutronix.de"
	<p.zabel@...gutronix.de>, "airlied@...il.com" <airlied@...il.com>,
	"daniel@...ll.ch" <daniel@...ll.ch>, "chunkuang.hu@...nel.org"
	<chunkuang.hu@...nel.org>, "angelogioacchino.delregno@...labora.com"
	<angelogioacchino.delregno@...labora.com>, "matthias.bgg@...il.com"
	<matthias.bgg@...il.com>
CC: "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] drm: mediatek: Drop unnecessary check for property
 presence

Hi, Rob:

On Wed, 2024-07-31 at 14:13 -0600, Rob Herring (Arm) wrote:
>  	 
> External email : Please do not click links or open attachments until you have verified the sender or the content.
>  of_property_read_u32() returns -EINVAL if a property is not present, so
> the preceeding check for presence with of_find_property() can be
> dropped. Really, what the errno is shouldn't matter. Either the property
> can be read and used or it can't and is ignored.
> 
> This is part of a larger effort to remove callers of of_find_property()
> and similar functions. of_find_property() leaks the DT struct property
> and data pointers which is a problem for dynamically allocated nodes
> which may be freed.

Reviewed-by: CK Hu <ck.hu@...iatek.com>

> 
> Signed-off-by: Rob Herring (Arm) <robh@...nel.org>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_rdma.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> index 634bbba5d43f..07243f372260 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_rdma.c
> @@ -341,14 +341,11 @@ static int mtk_disp_rdma_probe(struct platform_device *pdev)
>  		dev_dbg(dev, "get mediatek,gce-client-reg fail!\n");
>  #endif
>  
> -	if (of_find_property(dev->of_node, "mediatek,rdma-fifo-size", &ret)) {
> -		ret = of_property_read_u32(dev->of_node,
> -					   "mediatek,rdma-fifo-size",
> -					   &priv->fifo_size);
> -		if (ret)
> -			return dev_err_probe(dev, ret,
> -					     "Failed to get rdma fifo size\n");
> -	}
> +	ret = of_property_read_u32(dev->of_node,
> +				   "mediatek,rdma-fifo-size",
> +				   &priv->fifo_size);
> +	if (ret && (ret != -EINVAL))
> +		return dev_err_probe(dev, ret, "Failed to get rdma fifo size\n");
>  
>  	/* Disable and clear pending interrupts */
>  	writel(0x0, priv->regs + DISP_REG_RDMA_INT_ENABLE);
> -- 
> 2.43.0