diff mbox series

media: rcar-csi2: Use common error handling code in rcsi2_parse_dt()

Message ID 8b4203dc-bc0a-4c00-8862-e2d0ed6e346b@web.de
State New
Headers
Series media: rcar-csi2: Use common error handling code in rcsi2_parse_dt() |

Commit Message

Markus Elfring March 1, 2024, 12:10 p.m. UTC 
  From: Markus Elfring <elfring@users.sourceforge.net>
Date: Fri, 1 Mar 2024 13:02:18 +0100

Add a label so that a bit of exception handling can be better reused
in an if branch of this function implementation.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/media/platform/renesas/rcar-csi2.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--
2.44.0

Comments

Geert Uytterhoeven March 1, 2024, 1:05 p.m. UTC | #1 
Hi Markus,

On Fri, Mar 1, 2024 at 1:10 PM Markus Elfring <Markus.Elfring@web.de> wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Fri, 1 Mar 2024 13:02:18 +0100
>
> Add a label so that a bit of exception handling can be better reused
> in an if branch of this function implementation.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

Thanks for your patch!

> --- a/drivers/media/platform/renesas/rcar-csi2.c
> +++ b/drivers/media/platform/renesas/rcar-csi2.c
> @@ -1388,12 +1388,13 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv)
>         ret = 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 = -EINVAL;
> +               goto put_fwnode_ep;
>         }
>
>         ret = rcsi2_parse_v4l2(priv, &v4l2_ep);
>         if (ret) {
> +put_fwnode_ep:
>                 fwnode_handle_put(ep);
>                 return ret;
>         }

Please do not use goto to jump to random positions buried deep inside
a function,as this makes the code harder to read.

Gr{oetje,eeting}s,

                        Geert
Laurent Pinchart March 1, 2024, 1:15 p.m. UTC | #2 
On Fri, Mar 01, 2024 at 01:10:15PM +0100, Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Fri, 1 Mar 2024 13:02:18 +0100
> 
> Add a label so that a bit of exception handling can be better reused
> in an if branch of this function implementation.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

Just in case someone may be tempted to apply this:

NAK

Markus, don't bother replying to this e-mail, I will delete your reply
without reading it.

> ---
>  drivers/media/platform/renesas/rcar-csi2.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
> index 582d5e35db0e..621c92c31965 100644
> --- a/drivers/media/platform/renesas/rcar-csi2.c
> +++ b/drivers/media/platform/renesas/rcar-csi2.c
> @@ -1388,12 +1388,13 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv)
>  	ret = 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 = -EINVAL;
> +		goto put_fwnode_ep;
>  	}
> 
>  	ret = rcsi2_parse_v4l2(priv, &v4l2_ep);
>  	if (ret) {
> +put_fwnode_ep:
>  		fwnode_handle_put(ep);
>  		return ret;
>  	}
Dan Carpenter March 1, 2024, 1:42 p.m. UTC | #3 
Sakari Ailus pointed out in another thread that we could use __free()
instead.  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) = NULL;
+	struct fwnode_handle *ep __free(fwnode_handle);
 	struct v4l2_fwnode_endpoint v4l2_ep = {
 		.bus_type = V4L2_MBUS_UNKNOWN,
 	};
@@ -1388,18 +1388,14 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv)
 	ret = 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 = rcsi2_parse_v4l2(priv, &v4l2_ep);
-	if (ret) {
-		fwnode_handle_put(ep);
+	if (ret)
 		return ret;
-	}
 
 	fwnode = 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 = v4l2_async_nf_add_fwnode(&priv->notifier, fwnode,
 				       struct v4l2_async_connection);
-	fwnode_handle_put(fwnode);
 	if (IS_ERR(asc))
 		return PTR_ERR(asc);
Markus Elfring March 3, 2024, 8:36 a.m. UTC | #4 
> Sakari Ailus pointed out in another thread that we could use __free() instead.

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 cleanup.
  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) = NULL;
> +	struct fwnode_handle *ep __free(fwnode_handle);
>  	struct v4l2_fwnode_endpoint v4l2_ep = {
>  		.bus_type = V4L2_MBUS_UNKNOWN,
>  	};

I suggest to reconsider the position for the adjusted variable declarations
a bit more.


> @@ -1388,18 +1388,14 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv)
>  	ret = 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 = rcsi2_parse_v4l2(priv, &v4l2_ep);
> -	if (ret) {
> -		fwnode_handle_put(ep);
> +	if (ret)
>  		return ret;
> -	}
>
>  	fwnode = 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 = 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 implementation.
Thus I imagine that the known source code transformation “Reduce scope for variables”
will become relevant.
https://refactoring.com/catalog/reduceScopeOfVariable.html

Regards,
Markus
Dan Carpenter March 4, 2024, 11:16 a.m. UTC | #5 
On Mon, Mar 04, 2024 at 10:48:47AM +0000, Sakari Ailus wrote:
> Hi Dan,
> 
> On Fri, Mar 01, 2024 at 04:42:01PM +0300, Dan Carpenter wrote:
> > Sakari Ailus pointed out in another thread that we could use __free()
> > instead.  Something like this:
> > 
> 
> Looks good to me.

Thanks for checking!  I've never used these before.

> 
> We could merge this with your SoB (pending Niklas's review). :-) The driver
> has been since moved under drivers/media/platform/renesas/rcar-vin/ .

Alright.  I can resend this as a proper patch.

regards,
dan carpenter
diff mbox series

Patch

diff --git a/drivers/media/platform/renesas/rcar-csi2.c b/drivers/media/platform/renesas/rcar-csi2.c
index 582d5e35db0e..621c92c31965 100644
--- a/drivers/media/platform/renesas/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-csi2.c
@@ -1388,12 +1388,13 @@  static int rcsi2_parse_dt(struct rcar_csi2 *priv)
 	ret = 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 = -EINVAL;
+		goto put_fwnode_ep;
 	}

 	ret = rcsi2_parse_v4l2(priv, &v4l2_ep);
 	if (ret) {
+put_fwnode_ep:
 		fwnode_handle_put(ep);
 		return ret;
 	}