linux-kernel - Re: [PATCH v2 1/5] hwmon: introduce hwmon_sanitize

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Date:   Wed, 30 Mar 2022 07:23:22 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Michael Walle <michael@...le.cc>, Xu Yilun <yilun.xu@...el.com>,
        Tom Rix <trix@...hat.com>, Jean Delvare <jdelvare@...e.com>,
        Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH v2 1/5] hwmon: introduce hwmon_sanitize_name()

On 3/29/22 09:07, Michael Walle wrote:
> More and more drivers will check for bad characters in the hwmon name
> and all are using the same code snippet. Consolidate that code by adding
> a new hwmon_sanitize_name() function.
> 
> Signed-off-by: Michael Walle <michael@...le.cc>
> ---
>   Documentation/hwmon/hwmon-kernel-api.rst |  9 ++++-
>   drivers/hwmon/hwmon.c                    | 49 ++++++++++++++++++++++++
>   include/linux/hwmon.h                    |  3 ++
>   3 files changed, 60 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
> index c41eb6108103..12f4a9bcef04 100644
> --- a/Documentation/hwmon/hwmon-kernel-api.rst
> +++ b/Documentation/hwmon/hwmon-kernel-api.rst
> @@ -50,6 +50,10 @@ register/unregister functions::
>   
>     void devm_hwmon_device_unregister(struct device *dev);
>   
> +  char *hwmon_sanitize_name(const char *name);
> +
> +  char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
> +
>   hwmon_device_register_with_groups registers a hardware monitoring device.
>   The first parameter of this function is a pointer to the parent device.
>   The name parameter is a pointer to the hwmon device name. The registration
> @@ -93,7 +97,10 @@ removal would be too late.
>   
>   All supported hwmon device registration functions only accept valid device
>   names. Device names including invalid characters (whitespace, '*', or '-')
> -will be rejected. The 'name' parameter is mandatory.
> +will be rejected. The 'name' parameter is mandatory. Before calling a
> +register function you should either use hwmon_sanitize_name or
> +devm_hwmon_sanitize_name to replace any invalid characters with an
> +underscore.

That needs more details and deserves its own paragraph. Calling one of
the functions is only necessary if the original name does or can include
unsupported characters; an unconditional "should" is therefore a bit
strong. Also, it is important to mention that the function duplicates
the name, and that it is the responsibility of the caller to release
the name if hwmon_sanitize_name() was called and the device is removed.

Thanks,
Guenter