linux-kernel - Re: [PATCH 2/2 v2] gpio: sim: simplify code with cleanup helpers

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Message-ID: <CAMRc=Mehcxgy-5FnpawZo+M2dpweP8kG2oXTcZ=nuqpRB3taDA@mail.gmail.com>
Date:   Fri, 11 Aug 2023 16:41:06 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Kent Gibson <warthog618@...il.com>, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 2/2 v2] gpio: sim: simplify code with cleanup helpers

On Fri, Aug 11, 2023 at 4:24 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Fri, Aug 11, 2023 at 03:14:27PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> >
> > Use macros defined in linux/cleanup.h to automate resource lifetime
> > control in gpio-sim.
>
> ...
>
> >       struct gpio_sim_chip *chip = gpiochip_get_data(gc);
> >       int ret;
> >
> > -     mutex_lock(&chip->lock);
> > -     ret = !!test_bit(offset, chip->value_map);
> > -     mutex_unlock(&chip->lock);
> > +     scoped_guard(mutex, &chip->lock)
> > +             ret = !!test_bit(offset, chip->value_map);
> >
> >       return ret;
>
> Isn't the same approach applicable here?
>
> ...
>
> >  {
> >       struct gpio_sim_chip *chip = gpiochip_get_data(gc);
>
> With
>
>         unsigned long *map = ...->value_map;
>
> > -     mutex_lock(&chip->lock);
> > -     bitmap_replace(chip->value_map, chip->value_map, bits, mask, gc->ngpio);
> > -     mutex_unlock(&chip->lock);
> > +     scoped_guard(mutex, &chip->lock)
> > +             bitmap_replace(chip->value_map, chip->value_map, bits, mask,
> > +                            gc->ngpio);
>
> ...you can satisfy me as well :-)
>
>                 bitmap_replace(map, map, bits, mask, gc->ngpio);
>
> >  }
>
> ...
>
> >  {
> >       struct gpio_sim_chip *chip = gpiochip_get_data(gc);
> >
> > -     mutex_lock(&chip->lock);
> > -     __assign_bit(offset, chip->value_map, !!test_bit(offset, chip->pull_map));
> > -     mutex_unlock(&chip->lock);
> > +     scoped_guard(mutex, &chip->lock)
> > +             __assign_bit(offset, chip->value_map,
> > +                          !!test_bit(offset, chip->pull_map));
>
> Ditto (I checked the line size).
>

Sorry but no. This is bikeshedding. I'm not going to add temp
variables to only use them once.

Bart

> >  }
>
> ...
>
> >       struct gpio_sim_device *dev = gpio_sim_bank_get_device(bank);
> >       struct gpio_sim_chip_name_ctx ctx = { bank->swnode, page };
> > -     int ret;
> >
> > -     mutex_lock(&dev->lock);
> > +     guard(mutex)(&dev->lock);
> > +
> >       if (gpio_sim_device_is_live_unlocked(dev))
> > -             ret = device_for_each_child(&dev->pdev->dev, &ctx,
> > -                                         gpio_sim_emit_chip_name);
> > -     else
> > -             ret = sprintf(page, "none\n");
> > -     mutex_unlock(&dev->lock);
> > +             return device_for_each_child(&dev->pdev->dev, &ctx,
> > +                                          gpio_sim_emit_chip_name);
> >
> > -     return ret;
> > +     return sprintf(page, "none\n");
>
> I looked at the original and at the change and maybe it could be done as
>
>         struct device *parent = &dev->pdev->dev; // Naming?
>         bool live;
>
>         live = gpio_sim_device_is_live_unlocked(dev);
>         if (!live)
>                 return sprintf(page, "none\n");
>
>         return device_for_each_child(parent, &ctx, gpio_sim_emit_chip_name);
>
> ...
>
> >       int ret;
> >
> > -     mutex_lock(&dev->lock);
> > -     ret = sprintf(page, "%s\n", hog->name ?: "");
> > -     mutex_unlock(&dev->lock);
> > +     scoped_guard(mutex, &dev->lock)
> > +             ret = sprintf(page, "%s\n", hog->name ?: "");
> >
> >       return ret;
>
> guard() ?
>
> --
> With Best Regards,
> Andy Shevchenko
>
>