On Tue, Jul 16, 2019 at 11:25:00AM +0200, Rafael J. Wysocki wrote:
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.
I've dropped it, thanks!
-- Thanks, Sasha