[PATCH 1/2] drm/fsl-dcu: remove unneeded 'ret' assignment

[PATCH 1/2] drm/fsl-dcu: remove unneeded 'ret' assignment

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@nxp.com>

When devm_kzalloc() fails there is no need to assign an error code
to the 'ret' variable as it will not be used after jumping to the
'err_node_put' label, so just remove the assignment.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
---
 drivers/gpu/drm/fsl-dcu/fsl_tcon.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
index 3194e54..2fbb7ee 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
@@ -72,10 +72,8 @@ struct fsl_tcon *fsl_tcon_init(struct device *dev)
 		return NULL;
 
 	tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
-	if (!tcon) {
-		ret = -ENOMEM;
+	if (!tcon)
 		goto err_node_put;
-	}
 
 	ret = fsl_tcon_init_regmap(dev, tcon, np);
 	if (ret) {
-- 
2.7.4

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[PATCH 2/2] drm/fsl-dcu: check for clk_prepare_enable() error

[Fabio Estevam]

From: Fabio Estevam <fabio.estevam@nxp.com>

clk_prepare_enable() may fail, so we should better check its return 
value.

Also place the of_node_put() function right after clk_prepare_enable(),
in order to avoid calling of_node_put() twice in case clk_prepare_enable()
fails.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
---
 drivers/gpu/drm/fsl-dcu/fsl_tcon.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
index 2fbb7ee..b3d70a6 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
@@ -87,9 +87,13 @@ struct fsl_tcon *fsl_tcon_init(struct device *dev)
 		goto err_node_put;
 	}
 
-	of_node_put(np);
-	clk_prepare_enable(tcon->ipg_clk);
+	ret = clk_prepare_enable(tcon->ipg_clk);
+	if (ret) {
+		dev_err(dev, "Couldn't enable the TCON clock\n");
+		goto err_node_put;
+	}
 
+	of_node_put(np);
 	dev_info(dev, "Using TCON in bypass mode\n");
 
 	return tcon;
-- 
2.7.4

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Re: [PATCH 2/2] drm/fsl-dcu: check for clk_prepare_enable() error

[Gabriel Krisman Bertazi]

Fabio Estevam <festevam@gmail.com> writes:

> From: Fabio Estevam <fabio.estevam@nxp.com>
>
> clk_prepare_enable() may fail, so we should better check its return 
> value.
>
> Also place the of_node_put() function right after clk_prepare_enable(),
> in order to avoid calling of_node_put() twice in case clk_prepare_enable()
> fails.
>
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> ---
>  drivers/gpu/drm/fsl-dcu/fsl_tcon.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> index 2fbb7ee..b3d70a6 100644
> --- a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> +++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> @@ -87,9 +87,13 @@ struct fsl_tcon *fsl_tcon_init(struct device *dev)
>  		goto err_node_put;
>  	}
>  
> -	of_node_put(np);
> -	clk_prepare_enable(tcon->ipg_clk);
> +	ret = clk_prepare_enable(tcon->ipg_clk);
> +	if (ret) {
> +		dev_err(dev, "Couldn't enable the TCON clock\n");
> +		goto err_node_put;
> +	}

This leaks tcon if clk_prepare_enable fails.

>  
> +	of_node_put(np);
>  	dev_info(dev, "Using TCON in bypass mode\n");
>  
>  	return tcon;
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Re: [PATCH 2/2] drm/fsl-dcu: check for clk_prepare_enable() error

[Fabio Estevam]

On Wed, Dec 28, 2016 at 4:38 PM, Gabriel Krisman Bertazi
<krisman@collabora.co.uk> wrote:

> This leaks tcon if clk_prepare_enable fails.

No, it does not as tcon is allocated via devm_kzalloc().
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Re: [PATCH 1/2] drm/fsl-dcu: remove unneeded 'ret' assignment

[Gabriel Krisman Bertazi]

Fabio Estevam <festevam@gmail.com> writes:

> From: Fabio Estevam <fabio.estevam@nxp.com>
>
> When devm_kzalloc() fails there is no need to assign an error code
> to the 'ret' variable as it will not be used after jumping to the
> 'err_node_put' label, so just remove the assignment.
>
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
> ---
>  drivers/gpu/drm/fsl-dcu/fsl_tcon.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> index 3194e54..2fbb7ee 100644
> --- a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> +++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> @@ -72,10 +72,8 @@ struct fsl_tcon *fsl_tcon_init(struct device *dev)
>  		return NULL;
>  
>  	tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
> -	if (!tcon) {
> -		ret = -ENOMEM;
> +	if (!tcon)
>  		goto err_node_put;
> -	}

Hi Fabio,

I'm curious if it is ok to not have a tcon even for devices that support
it?  If we hit -ENOMEM here, I suppose we're likely hit it too for
drm_dev_alloc and give up the initialization, so either way

Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>

>  
>  	ret = fsl_tcon_init_regmap(dev, tcon, np);
>  	if (ret) {


--
Gabriel Krisman Bertazi
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Re: [PATCH 2/2] drm/fsl-dcu: check for clk_prepare_enable() error

[Gabriel Krisman Bertazi]

Fabio Estevam <festevam@gmail.com> writes:

> On Wed, Dec 28, 2016 at 4:38 PM, Gabriel Krisman Bertazi
> <krisman@collabora.co.uk> wrote:
>
>> This leaks tcon if clk_prepare_enable fails.
>
> No, it does not as tcon is allocated via devm_kzalloc().

Agreed.  But I think devm_kzalloc() only drops the memory once the
device is removed, which is not the case here, since failing
fsl_tcon_init is not fatal and the initialization continues in this
case.

--
Gabriel Krisman Bertazi
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Re: [PATCH 2/2] drm/fsl-dcu: check for clk_prepare_enable() error

[Stefan Agner]

On 2016-12-28 19:53, Gabriel Krisman Bertazi wrote:
> Fabio Estevam <festevam@gmail.com> writes:
> 
>> On Wed, Dec 28, 2016 at 4:38 PM, Gabriel Krisman Bertazi
>> <krisman@collabora.co.uk> wrote:
>>
>>> This leaks tcon if clk_prepare_enable fails.
>>
>> No, it does not as tcon is allocated via devm_kzalloc().
> 
> Agreed.  But I think devm_kzalloc() only drops the memory once the
> device is removed, which is not the case here, since failing
> fsl_tcon_init is not fatal and the initialization continues in this
> case.

That is probably true, but does it matter? I guess it is anyway an
unlikely case, so why bother?

--
Stefan
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Re: [PATCH 1/2] drm/fsl-dcu: remove unneeded 'ret' assignment

[Stefan Agner]

On 2016-12-28 08:48, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@nxp.com>
> 
> When devm_kzalloc() fails there is no need to assign an error code
> to the 'ret' variable as it will not be used after jumping to the
> 'err_node_put' label, so just remove the assignment.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>

Applied both to my drm-fsl-dcu tree.

--
Stefan

> ---
>  drivers/gpu/drm/fsl-dcu/fsl_tcon.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> index 3194e54..2fbb7ee 100644
> --- a/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> +++ b/drivers/gpu/drm/fsl-dcu/fsl_tcon.c
> @@ -72,10 +72,8 @@ struct fsl_tcon *fsl_tcon_init(struct device *dev)
>  		return NULL;
>  
>  	tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
> -	if (!tcon) {
> -		ret = -ENOMEM;
> +	if (!tcon)
>  		goto err_node_put;
> -	}
>  
>  	ret = fsl_tcon_init_regmap(dev, tcon, np);
>  	if (ret) {
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