Re: [PATCH 2/2] x86/resctrl: Use appropriate API for strings terminated by newline

[Reinette Chatre]

Hi Andy,

On 4/3/2020 12:27 AM, Andy Shevchenko wrote:
> On Fri, Apr 3, 2020 at 12:54 AM Reinette Chatre
> <reinette.chatre@xxxxxxxxx> wrote:
>> On 4/2/2020 6:06 AM, Andy Shevchenko wrote:
>>> On Wed, Apr 01, 2020 at 11:30:48AM -0700, Reinette Chatre wrote:

...

>>>>      /* Valid input requires a trailing newline */
>>>>      if (nbytes == 0 || buf[nbytes - 1] != '\n')
>>>>              return -EINVAL;
>>>> -    buf[nbytes - 1] = '\0';
>>>
>>> The above test is not needed and comment now is misleading.
>>> WRT nbytes I believe that kernel fs code checks for that.
> 
> This module provides it's own kernfs_ops...
> 
>> If nbytes is 0 it is still passed to this function. You are correct that
>> those tests are not needed though (if nbytes is 0 then
>> sysfs_match_string() will not find a match and return EINVAL via that path).
>>
>> Thank you for catching this. I'll remove those unnecessary checks.
> 
> ...which means that nbytes == 0 is a valid check. Please keep it
> there. It will protect from unnecessary locking and loading CPU for
> nothing.
> 

Will do. Thank you.

Reinette