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

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Date:   Fri, 11 Aug 2023 17:24:43 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>
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 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).

>  }

...

>  	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