On Thu, Oct 26, 2017 at 11:38 AM, Rafael J. Wysocki <raf...@kernel.org> wrote:
> On Wed, Oct 25, 2017 at 10:06 PM, Andy Shevchenko
> <andy.shevche...@gmail.com> wrote:
>> On Tue, Oct 24, 2017 at 11:49 AM, Rafael J. Wysocki <r...@rjwysocki.net>
>> wrote:
>>> On Tuesday, October 24, 2017 7:54:09 AM CEST Ramesh Thomas wrote:
>>>> On 2017-10-20 at 13:27:34 +0200, Rafael J. Wysocki wrote:
>>
>>>> > static ssize_t pm_qos_resume_latency_store(struct device *dev,
>>>> > @@ -228,11 +235,19 @@ static ssize_t pm_qos_resume_latency_sto
>>>> > s32 value;
>>>> > int ret;
>>
>>>> > + if (!kstrtos32(buf, 0, &value)) {
>>>> > + /*
>>>> > + * Prevent users from writing negative or "no constraint"
>>>> > values
>>>> > + * directly.
>>>> > + */
>>>> > + if (value < 0 || value ==
>>>> > PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
>>>> > + return -EINVAL;
>>
>>>> > + if (value == 0)
>>>> > + value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
>>>> > + } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) {
>>>>
>>>> Can the 2 checks for "n/a" be combined by checking first 3 characters?
>>>
>>> No, because "n/asomething" would then match too.
>>
>> If I don't missed anything, kernfs is aware of \n which means the
>> first check is enough.
>> Am I correct?
>
> I'm not sure, honestly. :-)
Okay, just a summary:
1. kernfs guarantees that buffer is NULL terminated
2. sysfs guarantees that the buffer is not empty
3. kstrto* are aware of '\n'
4. sysfs_streq() and __sysfs_match_string() are aware of '\n'
Thus, we just may use sysfs_streq() for that.
I will prepare a clean up patch on top of this fix if you are okay with it.
> Anyway, that can be fixed up later and the bug in question is rather urgent.
Sure.
--
With Best Regards,
Andy Shevchenko
