Re: [RFC PATCH 04/11] devfreq: exynos-bus: Clean up code

From: Krzysztof Kozlowski <krzk@kernel.org>
To: cwchoi00@gmail.com
Cc: "Artur Świgoń" <a.swigon@partner.samsung.com>,
	devicetree <devicetree@vger.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"Linux PM list" <linux-pm@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	"Chanwoo Choi" <cw00.choi@samsung.com>,
	"MyungJoo Ham" <myungjoo.ham@samsung.com>,
	"Inki Dae" <inki.dae@samsung.com>,
	"Seung-Woo Kim" <sw0312.kim@samsung.com>,
	georgi.djakov@linaro.org,
	"Marek Szyprowski" <m.szyprowski@samsung.com>
Subject: Re: [RFC PATCH 04/11] devfreq: exynos-bus: Clean up code
Date: Fri, 26 Jul 2019 12:45:44 +0200	[thread overview]
Message-ID: <CAJKOXPfsD0XFs2hM64Kf0eG2G+xhWef3QZKjk9NU2ECzgQeqsA@mail.gmail.com> (raw)
In-Reply-To: <CAGTfZH3Z334D3OKpBOGSfS9RoHkOX-s_2M858z1Ye2NoMtVh4g@mail.gmail.com>

On Thu, 25 Jul 2019 at 14:51, Chanwoo Choi <cwchoi00@gmail.com> wrote:
>
> 2019년 7월 24일 (수) 오전 8:07, Artur Świgoń <a.swigon@partner.samsung.com>님이 작성:
> >
> > This patch adds minor improvements to the exynos-bus driver.
> >
> > Signed-off-by: Artur Świgoń <a.swigon@partner.samsung.com>
> > ---
> >  drivers/devfreq/exynos-bus.c | 49 ++++++++++++++++--------------------
> >  1 file changed, 22 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> > index 4bb83b945bf7..412511ca7703 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
> >  #define DEFAULT_VOLTAGE_TOLERANCE      2
> > @@ -256,7 +255,7 @@ static int exynos_bus_parent_parse_of(struct device_node *np,
> >                                         struct exynos_bus *bus)
> >  {
> >         struct device *dev = bus->dev;
> > -       int i, ret, count, size;
> > +       int i, ret, count;
> >
> >         /* Get the regulator to provide each bus with the power */
> >         bus->regulator = devm_regulator_get(dev, "vdd");
> > @@ -283,8 +282,7 @@ 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);
> >         if (!bus->edev) {
> >                 ret = -ENOMEM;
> >                 goto err_regulator;
> > @@ -388,7 +386,7 @@ static int exynos_bus_profile_init(struct exynos_bus *bus,
> >         ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
> >         if (!ondemand_data) {
> >                 ret = -ENOMEM;
> > -               goto err;
> > +               goto out;
> >         }
> >         ondemand_data->upthreshold = 40;
> >         ondemand_data->downdifferential = 5;
> > @@ -400,14 +398,14 @@ static int exynos_bus_profile_init(struct exynos_bus *bus,
> >         if (IS_ERR(bus->devfreq)) {
> >                 dev_err(dev, "failed to add devfreq device\n");
> >                 ret = PTR_ERR(bus->devfreq);
> > -               goto err;
> > +               goto out;
> >         }
> >
> >         /* 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;
> > +               goto out;
> >         }
> >
> >         /*
> > @@ -417,16 +415,16 @@ 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;
> > +               goto out;
> >         }
> >
> >         ret = exynos_bus_set_event(bus);
> >         if (ret < 0) {
> >                 dev_err(dev, "failed to set event to devfreq-event devices\n");
> > -               goto err;
> > +               goto out;
> >         }
> >
> > -err:
> > +out:
> >         return ret;
> >  }
> >
> > @@ -446,27 +444,28 @@ static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
> >         parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
> >         if (IS_ERR(parent_devfreq)) {
> >                 ret = -EPROBE_DEFER;
> > -               goto err;
> > +               goto out;
> >         }
> >
> >         passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
> >         if (!passive_data) {
> >                 ret = -ENOMEM;
> > -               goto err;
> > +               goto out;
> >         }
> >         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,
> >                                                 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;
> > +               goto out;
> >         }
> >
> > -err:
> > +out:
> >         return ret;
> >  }
> >
> > @@ -484,11 +483,11 @@ 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);
> >         if (!bus)
> >                 return -ENOMEM;
> >         mutex_init(&bus->lock);
> > -       bus->dev = &pdev->dev;
> > +       bus->dev = dev;
> >         platform_set_drvdata(pdev, bus);
> >
> >         /* Parse the device-tree to get the resource information */
> > @@ -502,7 +501,7 @@ static int exynos_bus_probe(struct platform_device *pdev)
> >                 goto err;
> >         }
> >
> > -       node = of_parse_phandle(dev->of_node, "devfreq", 0);
> > +       node = of_parse_phandle(np, "devfreq", 0);
> >         if (node) {
> >                 of_node_put(node);
> >                 ret = exynos_bus_profile_init_passive(bus, profile);
> > @@ -547,12 +546,10 @@ static int exynos_bus_resume(struct device *dev)
> >         int ret;
> >
> >         ret = exynos_bus_enable_edev(bus);
> > -       if (ret < 0) {
> > +       if (ret < 0)
> >                 dev_err(dev, "failed to enable the devfreq-event devices\n");
> > -               return ret;
> > -       }
> >
> > -       return 0;
> > +       return ret;
> >  }
> >
> >  static int exynos_bus_suspend(struct device *dev)
> > @@ -561,12 +558,10 @@ static int exynos_bus_suspend(struct device *dev)
> >         int ret;
> >
>
> NACK.

Instead of simple nack you should explain what is wrong with proposed
approach. The existing code could be improved and this patch clearly
improves the readability. "err" label is confusing if it is used for
correct exit path. The last "if() return" block is subjective - but
then explain exactly why you prefer one over another. No just "nack"
for peoples contributions.

> >         ret = exynos_bus_disable_edev(bus);
> > -       if (ret < 0) {
> > +       if (ret < 0)
> >                 dev_err(dev, "failed to disable the devfreq-event devices\n");
> > -               return ret;
> > -       }
> >
> > -       return 0;
> > +       return ret;
> >  }
> >  #endif
> >
> > --
> > 2.17.1
> >
>
> NACK.
>
> As I already commented, It has never any benefit.
> I think that it is not usful. Please drop it.

The benefit for me is clear - makes the code easier to understand.

Best regards,
Krzysztof