cpufreq: intel_pstate: Rearrange max frequency updates handling code

Rename __intel_pstate_update_max_freq() to intel_pstate_update_max_freq()
and move the cpufreq policy reference counting and locking into it (and
implement the locking with the recently introduced cpufreq policy "write"
locking guard).

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/2315023.iZASKD2KPV@rjwysocki.net

Author: rafaeljw

drivers/cpufreq/intel_pstate.c

@@ -1353,54 +1353,41 @@ static void intel_pstate_update_policies(void)
 		cpufreq_update_policy(cpu);
 }
 
-static void __intel_pstate_update_max_freq(struct cpudata *cpudata,
-					   struct cpufreq_policy *policy)
+static bool intel_pstate_update_max_freq(struct cpudata *cpudata)
 {
+	struct cpufreq_policy *policy __free(put_cpufreq_policy);
+
+	policy = cpufreq_cpu_get(cpudata->cpu);
+	if (!policy)
+		return false;
+
+	guard(cpufreq_policy_write)(policy);
+
 	if (hwp_active)
 		intel_pstate_get_hwp_cap(cpudata);
 
 	policy->cpuinfo.max_freq = READ_ONCE(global.no_turbo) ?
 			cpudata->pstate.max_freq : cpudata->pstate.turbo_freq;
 
 	refresh_frequency_limits(policy);
+
+	return true;
 }
 
 static void intel_pstate_update_limits(unsigned int cpu)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
-	struct cpudata *cpudata;
-
-	if (!policy)
-		return;
-
-	cpudata = all_cpu_data[cpu];
-
-	__intel_pstate_update_max_freq(cpudata, policy);
-
-	/* Prevent the driver from being unregistered now. */
-	mutex_lock(&intel_pstate_driver_lock);
+	struct cpudata *cpudata = all_cpu_data[cpu];
 
-	cpufreq_cpu_release(policy);
-
-	hybrid_update_capacity(cpudata);
-
-	mutex_unlock(&intel_pstate_driver_lock);
+	if (intel_pstate_update_max_freq(cpudata))
+		hybrid_update_capacity(cpudata);
 }
 
 static void intel_pstate_update_limits_for_all(void)
 {
 	int cpu;
 
-	for_each_possible_cpu(cpu) {
-		struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpu);
-
-		if (!policy)
-			continue;
-
-		__intel_pstate_update_max_freq(all_cpu_data[cpu], policy);
-
-		cpufreq_cpu_release(policy);
-	}
+	for_each_possible_cpu(cpu)
+		intel_pstate_update_max_freq(all_cpu_data[cpu]);
 
 	mutex_lock(&hybrid_capacity_lock);
 
@@ -1840,13 +1827,8 @@ static void intel_pstate_notify_work(struct work_struct *work)
 {
 	struct cpudata *cpudata =
 		container_of(to_delayed_work(work), struct cpudata, hwp_notify_work);
-	struct cpufreq_policy *policy = cpufreq_cpu_acquire(cpudata->cpu);
-
-	if (policy) {
-		__intel_pstate_update_max_freq(cpudata, policy);
-
-		cpufreq_cpu_release(policy);
 
+	if (intel_pstate_update_max_freq(cpudata)) {
 		/*
 		 * The driver will not be unregistered while this function is
 		 * running, so update the capacity without acquiring the driver