linux-kernel - Re: [PATCH v4 7/7] x86/tlb: add tlb_flushall_factor into sysfs for user testing/tuning

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Message-ID: <4FAD0BB9.3070206@intel.com>
Date:	Fri, 11 May 2012 20:53:13 +0800
From:	Alex Shi <alex.shi@...el.com>
To:	Borislav Petkov <bp@...64.org>
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Subject: Re: [PATCH v4 7/7] x86/tlb: add tlb_flushall_factor into sysfs for
 user testing/tuning

On 05/11/2012 05:51 PM, Borislav Petkov wrote:

> On Fri, May 11, 2012 at 08:52:09AM +0800, Alex Shi wrote:
>>>> +#ifdef CONFIG_DEBUG_TLBFLUSH
>>
>>>> +static ssize_t __tlb_flushall_factor_store(const char *buf,
>>>> +					size_t count, int smt)
>>>> +{
>>>> +	short factor = 0;
>>>> +
>>>> +	if (sscanf(buf, "%hd", &factor) != 1)
>>>> +		return -EINVAL;
>>>
>>> This means only single-digit factors, right?
>>
>> No, you can try '32' '16' etc. not a 'single-digit'.
> 
> Ah, misread sscanf, nevermind.
> 
>>> Why not use kstrtoul?
>>
>> any advantage of this?
> 
> Well, sscanf uses simple_strto* and those miss overflow checks etc, see
> 33ee3b2e2eb9b4b6c64dcf9ed66e2ac3124e748c for details.


Thanks for reminder!

> 
> Btw, there are other kstrto* functions which you could use to fit better
> the argument type and size passed to tlb_flushall_factor.
> 
> 


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