linux-kernel - Re: [PATCH] ACPI: fan: Replace sprintf/scnprintf with sysfs

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Message-ID: <CAJZ5v0hKLpD87YtPQfNJwNKyEDrQBKSdZLEKnUxTqj=tZ7DOeA@mail.gmail.com>
Date: Wed, 2 Jul 2025 19:58:58 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Abdelrahman Fekry <abdelrahmanfekry375@...il.com>
Cc: rafael@...nel.org, lenb@...nel.org, skhan@...uxfoundation.com, 
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-kernel-mentees@...ts.linux.dev
Subject: Re: [PATCH] ACPI: fan: Replace sprintf/scnprintf with sysfs_emit in
 show functions

On Sat, Jun 21, 2025 at 7:52 AM Abdelrahman Fekry
<abdelrahmanfekry375@...il.com> wrote:
>
> Update two sysfs show() functions in the ACPI fan driver to use sysfs_emit()
> and sysfs_emit_at() instead of sprintf() and scnprintf().
>
> - show_fan_speed(): replaced sprintf() with sysfs_emit().
> - show_state(): replaced scnprintf() with sysfs_emit() for the first write,
>   and retained sysfs_emit_at() for incremental writes.
>
> This change is in accordance with Documentation/filesystems/sysfs.rst,
> which recommends using sysfs_emit/sysfs_emit_at in all sysfs show()
> callbacks for buffer safety, clarity, and consistency.
>
> Signed-off-by: Abdelrahman Fekry <abdelrahmanfekry375@...il.com>
> ---
>  drivers/acpi/fan_attr.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/fan_attr.c b/drivers/acpi/fan_attr.c
> index 22d29ac2447c..6a53da3d6d82 100644
> --- a/drivers/acpi/fan_attr.c
> +++ b/drivers/acpi/fan_attr.c
> @@ -22,9 +22,9 @@ static ssize_t show_state(struct device *dev, struct device_attribute *attr, cha
>         int count;
>
>         if (fps->control == 0xFFFFFFFF || fps->control > 100)
> -               count = scnprintf(buf, PAGE_SIZE, "not-defined:");
> +               count = sysfs_emit(buf, "not-defined:");
>         else
> -               count = scnprintf(buf, PAGE_SIZE, "%lld:", fps->control);
> +               count = sysfs_emit(buf, "%lld:", fps->control);
>
>         if (fps->trip_point == 0xFFFFFFFF || fps->trip_point > 9)
>                 count += sysfs_emit_at(buf, count, "not-defined:");
> @@ -59,7 +59,7 @@ static ssize_t show_fan_speed(struct device *dev, struct device_attribute *attr,
>         if (status)
>                 return status;
>
> -       return sprintf(buf, "%lld\n", fst.speed);
> +       return sysfs_emit(buf, "%lld\n", fst.speed);
>  }
>
>  static ssize_t show_fine_grain_control(struct device *dev, struct device_attribute *attr, char *buf)
> --

Applied as 6.17 material, thanks!