Re: [PATCH v2 20/20] cpufreq: Return zero on success in boost sw setting

Xiongfeng Wang
2020-05-19T01:50:12Z

Hi Rafael,

On 2020/5/18 19:05, Rafael J. Wysocki wrote:
> On Mon, May 18, 2020 at 12:56 PM Serge Semin
> <Sergey.Semin@baikalelectronics.ru> wrote:
>>
>> On Mon, May 18, 2020 at 12:51:15PM +0200, Rafael J. Wysocki wrote:
>>> On Mon, May 18, 2020 at 12:46 PM Serge Semin
>>> <Sergey.Semin@baikalelectronics.ru> wrote:
>>>>
>>>> On Mon, May 18, 2020 at 12:41:19PM +0200, Rafael J. Wysocki wrote:
>>>>> On Monday, May 18, 2020 12:31:02 PM CEST Serge Semin wrote:
>>>>>> On Mon, May 18, 2020 at 03:54:15PM +0530, Viresh Kumar wrote:
>>>>>>> On 18-05-20, 12:22, Rafael J. Wysocki wrote:
>>>>>>>> On Monday, May 18, 2020 12:11:09 PM CEST Viresh Kumar wrote:
>>>>>>>>> On 18-05-20, 11:53, Rafael J. Wysocki wrote:
>>>>>>>>>> That said if you really only want it to return 0 on success, you may as well
>>>>>>>>>> add a ret = 0; statement (with a comment explaining why it is needed) after
>>>>>>>>>> the last break in the loop.
>>>>>>>>>
>>>>>>>>> That can be done as well, but will be a bit less efficient as the loop
>>>>>>>>> will execute once for each policy, and so the statement will run
>>>>>>>>> multiple times. Though it isn't going to add any significant latency
>>>>>>>>> in the code.
>>>>>>>>
>>>>>>>> Right.
>>>>>>>>
>>>>>>>> However, the logic in this entire function looks somewhat less than
>>>>>>>> straightforward to me, because it looks like it should return an
>>>>>>>> error on the first policy without a frequency table (having a frequency
>>>>>>>> table depends on the driver and that is the same for all policies, so it
>>>>>>>> is pointless to iterate any further in that case).
>>>>>>>>
>>>>>>>> Also, the error should not be -EINVAL, because that means "invalid
>>>>>>>> argument" which would be the state value.
>>>>>>>>
>>>>>>>> So I would do something like this:
>>>>>>>>
>>>>>>>> ---
>>>>>>>> drivers/cpufreq/cpufreq.c | 11 ++++++-----
>>>>>>>> 1 file changed, 6 insertions(+), 5 deletions(-)
>>>>>>>>
>>>>>>>> Index: linux-pm/drivers/cpufreq/cpufreq.c
>>>>>>>> ===================================================================
>>>>>>>> --- linux-pm.orig/drivers/cpufreq/cpufreq.c
>>>>>>>> +++ linux-pm/drivers/cpufreq/cpufreq.c
>>>>>>>> @@ -2535,26 +2535,27 @@ EXPORT_SYMBOL_GPL(cpufreq_update_limits)
>>>>>>>> static int cpufreq_boost_set_sw(int state)
>>>>>>>> {
>>>>>>>> struct cpufreq_policy *policy;
>>>>>>>> - int ret = -EINVAL;
>>>>>>>>
>>>>>>>> for_each_active_policy(policy) {
>>>>>>>> + int ret;
>>>>>>>> +
>>>>>>>> if (!policy->freq_table)
>>>>>>>> - continue;
>>>>>>>> + return -ENXIO;
>>>>>>>>
>>>>>>>> ret = cpufreq_frequency_table_cpuinfo(policy,
>>>>>>>> policy->freq_table);
>>>>>>>> if (ret) {
>>>>>>>> pr_err("%s: Policy frequency update failed\n",
>>>>>>>> __func__);
>>>>>>>> - break;
>>>>>>>> + return ret;
>>>>>>>> }
>>>>>>>>
>>>>>>>> ret = freq_qos_update_request(policy->max_freq_req, policy->max);
>>>>>>>> if (ret < 0)
>>>>>>>> - break;
>>>>>>>> + return ret;
>>>>>>>> }
>>>>>>>>
>>>>>>>> - return ret;
>>>>>>>> + return 0;
>>>>>>>> }
>>>>>>>>
>>>>>>>> int cpufreq_boost_trigger_state(int state)
>>>>>>>
>>>>>>> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>>>>>>
>>>>>> Ok. Thanks for the comments. Shall I resend the patch with update Rafael
>>>>>> suggests or you'll merge the Rafael's fix in yourself?
>>>>>
>>>>> I'll apply the fix directly, thanks!
>>>>
>>>> Great. Is it going to be available in the repo:
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/
>>>> ?
>>>
>>> Yes, it is. Please see the bleeding-edge branch in there, thanks!

Thanks for CCing me. I will write my next version based on this branch.

Thanks,
Xiongfeng

>>
>> No credits with at least Reported-by tag? That's sad.(
>
> OK, done now, but you are not the only reported of it, so I've added
> the other reporter too.
>
> Thanks!
>
> .
>