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Subject: Re: [PATCH v3 1/2] hwmon: introduce hwmon_sanitize_name()
To:     Michael Walle <michael@walle.cc>, Xu Yilun <yilun.xu@intel.com>,
        Jean Delvare <jdelvare@suse.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, David Laight <David.Laight@ACULAB.COM>
References: <20220404184340.3973329-1-michael@walle.cc>
 <20220404184340.3973329-2-michael@walle.cc>
From:   Tom Rix <trix@redhat.com>
Message-ID: <428c28e4-87cc-50a4-ef13-41ae36702a84@redhat.com>
Date:   Mon, 4 Apr 2022 16:14:55 -0700
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On 4/4/22 11:43 AM, 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@walle.cc>
> ---
>   Documentation/hwmon/hwmon-kernel-api.rst | 16 ++++++++
>   drivers/hwmon/hwmon.c                    | 50 ++++++++++++++++++++++++
>   include/linux/hwmon.h                    |  3 ++
>   3 files changed, 69 insertions(+)
>
> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
> index c41eb6108103..e2975d5caf34 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
> @@ -95,6 +99,18 @@ 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.
>   
> +If the driver doesn't use a static device name (for example it uses
> +dev_name()), and therefore cannot make sure the name only contains valid
> +characters, hwmon_sanitize_name can be used. This convenience function
> +will duplicate the string and replace any invalid characters with an
> +underscore. It will allocate memory for the new string and it is the
> +responsibility of the caller to release the memory when the device is
> +removed.
> +
> +devm_hwmon_sanitize_name is the resource managed version of
> +hwmon_sanitize_name; the memory will be freed automatically on device
> +removal.
> +
>   Using devm_hwmon_device_register_with_info()
>   --------------------------------------------
>   
> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> index 989e2c8496dd..cc4a16a466a0 100644
> --- a/drivers/hwmon/hwmon.c
> +++ b/drivers/hwmon/hwmon.c
> @@ -1057,6 +1057,56 @@ void devm_hwmon_device_unregister(struct device *dev)
>   }
>   EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
>   
> +static char *__hwmon_sanitize_name(struct device *dev, const char *old_name)
> +{
> +	char *name, *p;
> +
> +	if (dev)
> +		name = devm_kstrdup(dev, old_name, GFP_KERNEL);
> +	else
> +		name = kstrdup(old_name, GFP_KERNEL);
> +	if (!name)
> +		return NULL;
should return ERR_PTR(-ENOMEM)
> +
> +	for (p = name; *p; p++)
> +		if (hwmon_is_bad_char(*p))
> +			*p = '_';
> +
> +	return name;
> +}
> +
> +/**
> + * hwmon_sanitize_name - Replaces invalid characters in a hwmon name
> + * @name: NUL-terminated name
> + *
> + * Allocates a new string where any invalid characters will be replaced
> + * by an underscore. It is the responsibility of the caller to release
> + * the memory.
> + *
> + * Returns newly allocated name or %NULL in case of error.
> + */
> +char *hwmon_sanitize_name(const char *name)
> +{
> +	return __hwmon_sanitize_name(NULL, name);
> +}
> +EXPORT_SYMBOL_GPL(hwmon_sanitize_name);
> +
> +/**
> + * devm_hwmon_sanitize_name - resource managed hwmon_sanitize_name()
> + * @dev: device to allocate memory for
> + * @name: NUL-terminated name
> + *
> + * Allocates a new string where any invalid characters will be replaced
> + * by an underscore.
> + *
> + * Returns newly allocated name or %NULL in case of error.
> + */
> +char *devm_hwmon_sanitize_name(struct device *dev, const char *name)
> +{
> +	return __hwmon_sanitize_name(dev, name);
Should have a (!dev) check.
> +}
> +EXPORT_SYMBOL_GPL(devm_hwmon_sanitize_name);
> +
>   static void __init hwmon_pci_quirks(void)
>   {
>   #if defined CONFIG_X86 && defined CONFIG_PCI
> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
> index eba380b76d15..4efaf06fd2b8 100644
> --- a/include/linux/hwmon.h
> +++ b/include/linux/hwmon.h
> @@ -461,6 +461,9 @@ void devm_hwmon_device_unregister(struct device *dev);
>   int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
>   		       u32 attr, int channel);
>   
> +char *hwmon_sanitize_name(const char *name);
> +char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
> +
>   /**
>    * hwmon_is_bad_char - Is the char invalid in a hwmon name

This still needed in *.h ?

Tom

>    * @ch: the char to be considered