Re: [PATCH] PM/CORE: Fix using sizeof without parenthesis in the sysfs.c

[Lan Tianyu <lantianyu1986@gmail.com>]

于 2013/1/28 21:13, Rafael J. Wysocki 写道:
> On Monday, January 28, 2013 09:04:29 PM Lan Tianyu wrote:
>> 于 2013/1/28 20:18, Rafael J. Wysocki 写道:
>>> On Monday, January 28, 2013 09:03:28 AM James Courtier-Dutton wrote:
>>>> On 28 January 2013 08:31, Lan Tianyu <tianyu.lan@intel.com> wrote:
>>>>> -       if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
>>>>> +       if (len == sizeof(ctrl_auto - 1) && strncmp(buf, ctrl_auto, len) == 0)
>>>>
>>>> This looks wrong to me.
>>>> sizeof ctrl_auto - 1
>>>> is not the same value as
>>>> sizeof(ctrl_auto - 1)
>>>> because sizeof(x) is normally the same as sizeof(x - 1), unless sizeof
>>>> x and sizeof 1 are different.
>>>> Consider that is maybe should be:
>>>> if (len == (sizeof(ctrl_auto) - 1)) && strncmp(buf, ctrl_auto, len) == 0)
>> Hi James:
>> 	Yes. You are correct. Thanks for your review.
>>>
>>> The outer parentheses in the comparison with len are not necessary.
>>>
>>>> I a not sure what the correct answer is for this particular bit of
>>>> code, because I have not looked at it in detail,I just wanted to point
>>>> out that the brackets might be in the wrong place here.
>>>
>>> You are right and the patch doesn't make sense.
>> Hi Rafael:
>> 	So this patch is not necessary?
> 
> It is incorrect in the first place.
> 
Yeah. Sorry for this and will be careful.
> Yes, you could change spaces to parentheses in those places, but first, please
> do that correctly and second, it's just going to be a cosmetic change.  The
> code works as is.
Ok. I get it.
> 
> Thanks,
> Rafael
> 
> 

-- 
Best regards
Tianyu Lan