Messages in this thread | | | Date | Wed, 30 Mar 2022 08:23:35 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 1/5] hwmon: introduce hwmon_sanitize_name() |
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On 3/30/22 07:51, Xu Yilun wrote: > On Wed, Mar 30, 2022 at 10:11:39AM +0000, David Laight wrote: >> From: Xu Yilun >>> Sent: 30 March 2022 07:51 >>> >>> On Tue, Mar 29, 2022 at 06:07:26PM +0200, 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 | 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 >>> >>> I suggest to duplicate the name and replace ... >> >> You are now going to get code that passed in NULL when the kmalloc() fails. >> If 'sanitizing' the name is the correct thing to do then sanitize it >> when the copy is made into the allocated structure. > > Then the driver is unaware of the name change, which makes more > confusing. > >> (I'm assuming that the 'const char *name' parameter doesn't have to >> be persistent - that would be another bug just waiting to happen.) > > The hwmon core does require a persistent "name" parameter now. No name > copy is made when hwmon dev register. > >> >> Seems really pointless to be do a kmalloc() just to pass a string >> into a function. > > Maybe we should not force a kmalloc() when the sanitizing is needed, let > the driver decide whether to duplicate the string or not. >
Drivers can do that today, and in all existing cases they do so (which is why I had suggested to handle the duplication in the convenience function in the first place). Drivers don't _have_ to use the provided convenience functions. At the same time, convenience functions should cover the most common use cases.
Michael, let's just drop the changes outside drivers/hwmon from the series, and let's keep hwmon_is_bad_char() in the include file. Let's just document it, explaining its use case.
Code outside drivers/hwmon can then be independently modified or not at a later time, based on driver author and/or maintainer preference.
Thanks, Guenter
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