| Subject | Re: [PATCH AUTOSEL 5.2 190/249] cpufreq: Avoid calling cpufreq_verify_current_freq() from handle_update() | From | "Rafael J. Wysocki" <> | Date | Tue, 16 Jul 2019 11:25:00 +0200 |
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On 7/15/2019 3:45 PM, Sasha Levin wrote: > From: Viresh Kumar <viresh.kumar@linaro.org> > > [ Upstream commit 70a59fde6e69d1d8579f84bf4555bfffb3ce452d ] > > On some occasions cpufreq_verify_current_freq() schedules a work whose > callback is handle_update(), which further calls cpufreq_update_policy() > which may end up calling cpufreq_verify_current_freq() again. > > On the other hand, when cpufreq_update_policy() is called from > handle_update(), the pointer to the cpufreq policy is already > available, but cpufreq_cpu_acquire() is still called to get it in > cpufreq_update_policy(), which should be avoided as well. > > To fix these issues, create a new helper, refresh_frequency_limits(), > and make both handle_update() call it cpufreq_update_policy(). > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > [ rjw: Rename reeval_frequency_limits() as refresh_frequency_limits() ] > [ rjw: Changelog ] > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > drivers/cpufreq/cpufreq.c | 26 ++++++++++++++++---------- > 1 file changed, 16 insertions(+), 10 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c > index e84bf0eb7239..876a4cb09de3 100644 > --- a/drivers/cpufreq/cpufreq.c > +++ b/drivers/cpufreq/cpufreq.c > @@ -1114,13 +1114,25 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy, unsigned int cp > return ret; > } > > +static void refresh_frequency_limits(struct cpufreq_policy *policy) > +{ > + struct cpufreq_policy new_policy = *policy; > + > + pr_debug("updating policy for CPU %u\n", policy->cpu); > + > + new_policy.min = policy->user_policy.min; > + new_policy.max = policy->user_policy.max; > + > + cpufreq_set_policy(policy, &new_policy); > +} > + > static void handle_update(struct work_struct *work) > { > struct cpufreq_policy *policy = > container_of(work, struct cpufreq_policy, update); > - unsigned int cpu = policy->cpu; > - pr_debug("handle_update for cpu %u called\n", cpu); > - cpufreq_update_policy(cpu); > + > + pr_debug("handle_update for cpu %u called\n", policy->cpu); > + refresh_frequency_limits(policy); > } > > static struct cpufreq_policy *cpufreq_policy_alloc(unsigned int cpu) > @@ -2392,7 +2404,6 @@ int cpufreq_set_policy(struct cpufreq_policy *policy, > void cpufreq_update_policy(unsigned int cpu) > { > struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu); > - struct cpufreq_policy new_policy; > > if (!policy) > return; > @@ -2405,12 +2416,7 @@ void cpufreq_update_policy(unsigned int cpu) > (cpufreq_suspended || WARN_ON(!cpufreq_update_current_freq(policy)))) > goto unlock; > > - pr_debug("updating policy for CPU %u\n", cpu); > - memcpy(&new_policy, policy, sizeof(*policy)); > - new_policy.min = policy->user_policy.min; > - new_policy.max = policy->user_policy.max; > - > - cpufreq_set_policy(policy, &new_policy); > + refresh_frequency_limits(policy); > > unlock: > cpufreq_cpu_release(policy);
I don't think this is suitable for -stable.
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