linux-kernel - Re: [PATCH] staging: fieldbus: remove unnecessary double negation

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Date:   Mon, 25 Apr 2022 17:47:35 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Ian Cowan <ian@...ux.cowan.aero>
Cc:     Sven Van Asbroeck <TheSven73@...il.com>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] staging: fieldbus: remove unnecessary double negation

On Mon, Apr 25, 2022 at 10:54:40AM -0400, Ian Cowan wrote:
> Remove the double negation (!!) from the code since this does nothing
> and may create confusion on whether or not those values are negated.
> 
> Signed-off-by: Ian Cowan <ian@...ux.cowan.aero>
> ---
>  drivers/staging/fieldbus/dev_core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/fieldbus/dev_core.c b/drivers/staging/fieldbus/dev_core.c
> index 5aab734606ea..6766b2b13482 100644
> --- a/drivers/staging/fieldbus/dev_core.c
> +++ b/drivers/staging/fieldbus/dev_core.c
> @@ -28,7 +28,7 @@ static ssize_t online_show(struct device *dev, struct device_attribute *attr,
>  {
>  	struct fieldbus_dev *fb = dev_get_drvdata(dev);
>  
> -	return sprintf(buf, "%d\n", !!fb->online);
> +	return sprintf(buf, "%d\n", fb->online);
>  }
>  static DEVICE_ATTR_RO(online);
>  
> @@ -39,7 +39,7 @@ static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
>  
>  	if (!fb->enable_get)
>  		return -EINVAL;
> -	return sprintf(buf, "%d\n", !!fb->enable_get(fb));
> +	return sprintf(buf, "%d\n", fb->enable_get(fb));

This is a common pattern to turn any value into a boolean (0/1).  The
fact that this is a boolean to start with makes this change not affect
anything.  So you should say that in the changelog, the values are
obviously not negated.

thanks,

greg k-h