Re: [PATCH v3 4/4] devfreq: exynos-bus: Clean up code

["Artur Świgoń" <a.swigon@samsung.com>]

Hi,

On Tue, 2019-12-10 at 13:20 +0900, Chanwoo Choi wrote:
> Hi,
> 
> This patch contains the clean-up code related to 'goto' style.
> Please merge the the clean-up code of 'goto' to one patch with patch3/patch4.
> - patch3 related to 'goto' clean-up code
> - patch4 related to remaining clean-up code. 
> 
> And I added the comment below. Please check them.

OK, I can merge these patches. Please also see my comments below regarding
the issues you highlighted: kzalloc vs. kcalloc, fitting in 80 columns and
changing repeated expressions to variables.

> 
> On 12/9/19 7:49 PM, Artur Świgoń wrote:
> > This patch adds minor improvements to the exynos-bus driver, including
> > cleaning up header includes, variables, and return paths.
> > 
> > Signed-off-by: Artur Świgoń <a.swigon@samsung.com>
> > ---
> >  drivers/devfreq/exynos-bus.c | 56 +++++++++++++++---------------------
> >  1 file changed, 23 insertions(+), 33 deletions(-)
> > 
> > diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> > index 0b557df63666..3eb6a043284a 100644
> > --- a/drivers/devfreq/exynos-bus.c
> > +++ b/drivers/devfreq/exynos-bus.c
> > @@ -15,11 +15,10 @@
> >  #include <linux/device.h>
> >  #include <linux/export.h>
> >  #include <linux/module.h>
> > -#include <linux/of_device.h>
> > +#include <linux/of.h>
> >  #include <linux/pm_opp.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/regulator/consumer.h>
> > -#include <linux/slab.h>
> >  
> >  #define DEFAULT_SATURATION_RATIO	40
> >  
> > @@ -178,7 +177,7 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
> >  	struct device *dev = bus->dev;
> >  	struct opp_table *opp_table;
> >  	const char *vdd = "vdd";
> > -	int i, ret, count, size;
> > +	int i, ret, count;
> >  
> >  	opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
> >  	if (IS_ERR(opp_table)) {
> > @@ -201,8 +200,7 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
> >  	}
> >  	bus->edev_count = count;
> >  
> > -	size = sizeof(*bus->edev) * count;
> > -	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
> > +	bus->edev = devm_kcalloc(dev, count, sizeof(*bus->edev), GFP_KERNEL);
> 
> ditto.
> It depends on personal style. Don't change it because we cannot
> modify them at the all device driver. If is not wrong,
> just keep the original code.

Of course, this is a matter of style, but I think that Coccinelle reports
such code, compare with e.g., https://lkml.org/lkml/2019/5/8/927

Anyway, I can drop it since the purpose of this patchset as a whole was to
untangle all the goto's and I agree this is kind of unrelated.

> 
> >  	if (!bus->edev) {
> >  		ret = -ENOMEM;
> >  		goto err_regulator;
> > @@ -301,10 +299,9 @@ static int exynos_bus_profile_init(struct exynos_bus *bus,
> >  	profile->exit = exynos_bus_exit;
> >  
> >  	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
> > -	if (!ondemand_data) {
> > -		ret = -ENOMEM;
> > -		goto err;
> > -	}
> > +	if (!ondemand_data)
> > +		return -ENOMEM;
> > +
> >  	ondemand_data->upthreshold = 40;
> >  	ondemand_data->downdifferential = 5;
> >  
> > @@ -314,15 +311,14 @@ static int exynos_bus_profile_init(struct exynos_bus *bus,
> >  						ondemand_data);
> >  	if (IS_ERR(bus->devfreq)) {
> >  		dev_err(dev, "failed to add devfreq device\n");
> > -		ret = PTR_ERR(bus->devfreq);
> > -		goto err;
> > +		return PTR_ERR(bus->devfreq);
> >  	}
> >  
> >  	/* Register opp_notifier to catch the change of OPP  */
> >  	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
> >  	if (ret < 0) {
> >  		dev_err(dev, "failed to register opp notifier\n");
> > -		goto err;
> > +		return ret;
> >  	}
> >  
> >  	/*
> > @@ -332,17 +328,16 @@ static int exynos_bus_profile_init(struct exynos_bus *bus,
> >  	ret = exynos_bus_enable_edev(bus);
> >  	if (ret < 0) {
> >  		dev_err(dev, "failed to enable devfreq-event devices\n");
> > -		goto err;
> > +		return ret;
> >  	}
> >  
> >  	ret = exynos_bus_set_event(bus);
> >  	if (ret < 0) {
> >  		dev_err(dev, "failed to set event to devfreq-event devices\n");
> > -		goto err;
> > +		return ret;
> >  	}
> >  
> > -err:
> > -	return ret;
> > +	return 0;
> >  }
> >  
> >  static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
> > @@ -351,7 +346,6 @@ static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
> >  	struct device *dev = bus->dev;
> >  	struct devfreq_passive_data *passive_data;
> >  	struct devfreq *parent_devfreq;
> > -	int ret = 0;
> >  
> >  	/* Initialize the struct profile and governor data for passive device */
> >  	profile->target = exynos_bus_target;
> > @@ -359,30 +353,26 @@ static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
> >  
> >  	/* Get the instance of parent devfreq device */
> >  	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
> > -	if (IS_ERR(parent_devfreq)) {
> > -		ret = -EPROBE_DEFER;
> > -		goto err;
> > -	}
> > +	if (IS_ERR(parent_devfreq))
> > +		return -EPROBE_DEFER;
> >  
> >  	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
> > -	if (!passive_data) {
> > -		ret = -ENOMEM;
> > -		goto err;
> > -	}
> > +	if (!passive_data)
> > +		return -ENOMEM;
> > +
> >  	passive_data->parent = parent_devfreq;
> >  
> >  	/* Add devfreq device for exynos bus with passive governor */
> > -	bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
> > +	bus->devfreq = devm_devfreq_add_device(dev, profile,
> > +						DEVFREQ_GOV_PASSIVE,
> 
> It is not clean-up. It depends on personal style. Don't change it
> because we cannot modify them at the all device driver. If is not wrong,
> just keep the original code.

I wanted to make the code fit in 80 columns (issue reported by
scripts/checkpatch.pl). For the reasons stated in my previous comment,
I am happy to drop this change if you don't like it.

> 
> >  						passive_data);
> >  	if (IS_ERR(bus->devfreq)) {
> >  		dev_err(dev,
> >  			"failed to add devfreq dev with passive governor\n");
> > -		ret = PTR_ERR(bus->devfreq);
> > -		goto err;
> > +		return PTR_ERR(bus->devfreq);
> >  	}
> >  
> > -err:
> > -	return ret;
> > +	return 0;
> >  }
> >  
> >  static int exynos_bus_probe(struct platform_device *pdev)
> > @@ -400,18 +390,18 @@ static int exynos_bus_probe(struct platform_device *pdev)
> >  		return -EINVAL;
> >  	}
> >  
> > -	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
> > +	bus = devm_kzalloc(dev, sizeof(*bus), GFP_KERNEL);
> 
> ditto.
> It depends on personal style. Don't change it because we cannot
> modify them at the all device driver. If is not wrong,
> just keep the original code.

Please note that there exists this variable in exynos_bus_probe():

struct device *dev = &pdev->dev;

but the expression '&pdev->dev' is reused twice more ('dev' itself
is also used). Is there any reason for such inconsistency?

> 
> >  	if (!bus)
> >  		return -ENOMEM;
> >  	mutex_init(&bus->lock);
> > -	bus->dev = &pdev->dev;
> > +	bus->dev = dev;
> 
> ditto.
> It depends on personal style. Don't change it because we cannot
> modify them at the all device driver. If is not wrong,
> just keep the original code.

(See above)

> 
> >  	platform_set_drvdata(pdev, bus);
> >  
> >  	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
> >  	if (!profile)
> >  		return -ENOMEM;
> >  
> > -	node = of_parse_phandle(dev->of_node, "devfreq", 0);
> > +	node = of_parse_phandle(np, "devfreq", 0);
> >  	if (node) {
> >  		of_node_put(node);
> >  		passive = true;
> > 
> 

Best regards,
-- 
Artur Świgoń
Samsung R&D Institute Poland
Samsung Electronics