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Message-ID: <af4995cf-6ea5-4214-a133-af260e2c517f@web.de>
Date: Sun, 3 Mar 2024 09:36:09 +0100
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Subject: Re: [PATCH] media: rcar-csi2: Use common error handling code in
 rcsi2_parse_dt()
To: Dan Carpenter <dan.carpenter@linaro.org>,
 Geert Uytterhoeven <geert@linux-m68k.org>,
 Sakari Ailus <sakari.ailus@linux.intel.com>,
 linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org,
 kernel-janitors@vger.kernel.org, Mauro Carvalho Chehab <mchehab@kernel.org>,
 =?UTF-8?Q?Niklas_S=C3=B6derlund?= <niklas.soderlund@ragnatech.se>
Cc: LKML <linux-kernel@vger.kernel.org>
References: <8b4203dc-bc0a-4c00-8862-e2d0ed6e346b@web.de>
 <CAMuHMdWwegdks3eEviEsBJE3AvUVKbZqHduYdhuwz=8xTMDs5g@mail.gmail.com>
 <260d82b6-e7fc-40c3-b414-50a883709fd7@moroto.mountain>
Content-Language: en-GB
From: Markus Elfring <Markus.Elfring@web.de>
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> Sakari Ailus pointed out in another thread that we could use __free() in=
stead.

See also:
Contributions by Jonathan Cameron from 2024-02-17

* device property: Move fwnode_handle_put() into property.h
  https://lore.kernel.org/r/20240217164249.921878-2-jic23@kernel.org

* device property: Add cleanup.h based fwnode_handle_put() scope based cle=
anup.
  https://lore.kernel.org/r/20240217164249.921878-3-jic23@kernel.org


> Something like this:
>
> diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/=
platform/renesas/rcar-csi2.c
> index 582d5e35db0e..c569df6057b7 100644
> --- a/drivers/media/platform/renesas/rcar-csi2.c
> +++ b/drivers/media/platform/renesas/rcar-csi2.c
> @@ -1372,8 +1372,8 @@ static int rcsi2_parse_v4l2(struct rcar_csi2 *priv=
,
>  static int rcsi2_parse_dt(struct rcar_csi2 *priv)
>  {
>  	struct v4l2_async_connection *asc;
> -	struct fwnode_handle *fwnode;
> -	struct fwnode_handle *ep;
> +	struct fwnode_handle *fwnode __free(fwnode_handle) =3D NULL;
> +	struct fwnode_handle *ep __free(fwnode_handle);
>  	struct v4l2_fwnode_endpoint v4l2_ep =3D {
>  		.bus_type =3D V4L2_MBUS_UNKNOWN,
>  	};

I suggest to reconsider the position for the adjusted variable declaration=
s
a bit more.


> @@ -1388,18 +1388,14 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv=
)
>  	ret =3D v4l2_fwnode_endpoint_parse(ep, &v4l2_ep);
>  	if (ret) {
>  		dev_err(priv->dev, "Could not parse v4l2 endpoint\n");
> -		fwnode_handle_put(ep);
>  		return -EINVAL;
>  	}
>
>  	ret =3D rcsi2_parse_v4l2(priv, &v4l2_ep);
> -	if (ret) {
> -		fwnode_handle_put(ep);
> +	if (ret)
>  		return ret;
> -	}
>
>  	fwnode =3D fwnode_graph_get_remote_endpoint(ep);
> -	fwnode_handle_put(ep);
>
>  	dev_dbg(priv->dev, "Found '%pOF'\n", to_of_node(fwnode));
>
> @@ -1408,7 +1404,6 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv)
>
>  	asc =3D v4l2_async_nf_add_fwnode(&priv->notifier, fwnode,
>  				       struct v4l2_async_connection);
> -	fwnode_handle_put(fwnode);
>  	if (IS_ERR(asc))
>  		return PTR_ERR(asc);
>

I find that two function calls marked the end of scopes here
which obviously are not at the end of the discussed function implementatio=
n.
Thus I imagine that the known source code transformation =E2=80=9CReduce s=
cope for variables=E2=80=9D
will become relevant.
https://refactoring.com/catalog/reduceScopeOfVariable.html

Regards,
Markus