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

Serge Semin
2020-05-18T10:31:12Z

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?

-Sergey
>
> --
> viresh