1 files changed, 95 insertions, 76 deletions

diff --git a/drivers/cpufreq/cpufreq_userspace.c b/drivers/cpufreq/cpufreq_userspace.c
index 03078090b5f7..77d62152cd38 100644
--- a/drivers/cpufreq/cpufreq_userspace.c
+++ b/drivers/cpufreq/cpufreq_userspace.c
@@ -1,14 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 
 /*
  *  linux/drivers/cpufreq/cpufreq_userspace.c
  *
  *  Copyright (C)  2001 Russell King
  *            (C)  2002 - 2004 Dominik Brodowski <linux@brodo.de>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -17,9 +13,13 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/slab.h>
 
-static DEFINE_PER_CPU(unsigned int, cpu_is_managed);
-static DEFINE_MUTEX(userspace_mutex);
+struct userspace_policy {
+	unsigned int is_managed;
+	unsigned int setspeed;
+	struct mutex mutex;
+};
 
 /**
  * cpufreq_set - set the CPU frequency
@@ -31,27 +31,19 @@ static DEFINE_MUTEX(userspace_mutex);
 static int cpufreq_set(struct cpufreq_policy *policy, unsigned int freq)
 {
 	int ret = -EINVAL;
+	struct userspace_policy *userspace = policy->governor_data;
 
 	pr_debug("cpufreq_set for cpu %u, freq %u kHz\n", policy->cpu, freq);
 
-	mutex_lock(&userspace_mutex);
-	if (!per_cpu(cpu_is_managed, policy->cpu))
+	mutex_lock(&userspace->mutex);
+	if (!userspace->is_managed)
 		goto err;
 
-	/*
-	 * We're safe from concurrent calls to ->target() here
-	 * as we hold the userspace_mutex lock. If we were calling
-	 * cpufreq_driver_target, a deadlock situation might occur:
-	 * A: cpufreq_set (lock userspace_mutex) ->
-	 *      cpufreq_driver_target(lock policy->lock)
-	 * B: cpufreq_set_policy(lock policy->lock) ->
-	 *      __cpufreq_governor ->
-	 *         cpufreq_governor_userspace (lock userspace_mutex)
-	 */
-	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
+	userspace->setspeed = freq;
 
+	ret = __cpufreq_driver_target(policy, freq, CPUFREQ_RELATION_L);
  err:
-	mutex_unlock(&userspace_mutex);
+	mutex_unlock(&userspace->mutex);
 	return ret;
 }
 
@@ -60,75 +52,102 @@ static ssize_t show_speed(struct cpufreq_policy *policy, char *buf)
 	return sprintf(buf, "%u\n", policy->cur);
 }
 
-static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
-				   unsigned int event)
+static int cpufreq_userspace_policy_init(struct cpufreq_policy *policy)
 {
-	unsigned int cpu = policy->cpu;
-	int rc = 0;
-
-	switch (event) {
-	case CPUFREQ_GOV_START:
-		BUG_ON(!policy->cur);
-		pr_debug("started managing cpu %u\n", cpu);
-
-		mutex_lock(&userspace_mutex);
-		per_cpu(cpu_is_managed, cpu) = 1;
-		mutex_unlock(&userspace_mutex);
-		break;
-	case CPUFREQ_GOV_STOP:
-		pr_debug("managing cpu %u stopped\n", cpu);
-
-		mutex_lock(&userspace_mutex);
-		per_cpu(cpu_is_managed, cpu) = 0;
-		mutex_unlock(&userspace_mutex);
-		break;
-	case CPUFREQ_GOV_LIMITS:
-		mutex_lock(&userspace_mutex);
-		pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz\n",
-			cpu, policy->min, policy->max,
-			policy->cur);
-
-		if (policy->max < policy->cur)
-			__cpufreq_driver_target(policy, policy->max,
-						CPUFREQ_RELATION_H);
-		else if (policy->min > policy->cur)
-			__cpufreq_driver_target(policy, policy->min,
-						CPUFREQ_RELATION_L);
-		mutex_unlock(&userspace_mutex);
-		break;
-	}
-	return rc;
+	struct userspace_policy *userspace;
+
+	userspace = kzalloc(sizeof(*userspace), GFP_KERNEL);
+	if (!userspace)
+		return -ENOMEM;
+
+	mutex_init(&userspace->mutex);
+
+	policy->governor_data = userspace;
+	return 0;
 }
 
-#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
-static
-#endif
-struct cpufreq_governor cpufreq_gov_userspace = {
-	.name		= "userspace",
-	.governor	= cpufreq_governor_userspace,
-	.store_setspeed	= cpufreq_set,
-	.show_setspeed	= show_speed,
-	.owner		= THIS_MODULE,
-};
+/*
+ * Any routine that writes to the policy struct will hold the "rwsem" of
+ * policy struct that means it is free to free "governor_data" here.
+ */
+static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
+{
+	kfree(policy->governor_data);
+	policy->governor_data = NULL;
+}
+
+static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
+{
+	struct userspace_policy *userspace = policy->governor_data;
+
+	BUG_ON(!policy->cur);
+	pr_debug("started managing cpu %u\n", policy->cpu);
 
-static int __init cpufreq_gov_userspace_init(void)
+	mutex_lock(&userspace->mutex);
+	userspace->is_managed = 1;
+	userspace->setspeed = policy->cur;
+	mutex_unlock(&userspace->mutex);
+	return 0;
+}
+
+static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
 {
-	return cpufreq_register_governor(&cpufreq_gov_userspace);
+	struct userspace_policy *userspace = policy->governor_data;
+
+	pr_debug("managing cpu %u stopped\n", policy->cpu);
+
+	mutex_lock(&userspace->mutex);
+	userspace->is_managed = 0;
+	userspace->setspeed = 0;
+	mutex_unlock(&userspace->mutex);
 }
 
-static void __exit cpufreq_gov_userspace_exit(void)
+static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
 {
-	cpufreq_unregister_governor(&cpufreq_gov_userspace);
+	struct userspace_policy *userspace = policy->governor_data;
+
+	mutex_lock(&userspace->mutex);
+
+	pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
+		 policy->cpu, policy->min, policy->max, policy->cur, userspace->setspeed);
+
+	if (policy->max < userspace->setspeed)
+		__cpufreq_driver_target(policy, policy->max,
+					CPUFREQ_RELATION_H);
+	else if (policy->min > userspace->setspeed)
+		__cpufreq_driver_target(policy, policy->min,
+					CPUFREQ_RELATION_L);
+	else
+		__cpufreq_driver_target(policy, userspace->setspeed,
+					CPUFREQ_RELATION_L);
+
+	mutex_unlock(&userspace->mutex);
 }
 
+static struct cpufreq_governor cpufreq_gov_userspace = {
+	.name		= "userspace",
+	.init		= cpufreq_userspace_policy_init,
+	.exit		= cpufreq_userspace_policy_exit,
+	.start		= cpufreq_userspace_policy_start,
+	.stop		= cpufreq_userspace_policy_stop,
+	.limits		= cpufreq_userspace_policy_limits,
+	.store_setspeed	= cpufreq_set,
+	.show_setspeed	= show_speed,
+	.owner		= THIS_MODULE,
+	.flags		= CPUFREQ_GOV_STRICT_TARGET,
+};
+
 MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>, "
 		"Russell King <rmk@arm.linux.org.uk>");
 MODULE_DESCRIPTION("CPUfreq policy governor 'userspace'");
 MODULE_LICENSE("GPL");
 
 #ifdef CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE
-fs_initcall(cpufreq_gov_userspace_init);
-#else
-module_init(cpufreq_gov_userspace_init);
+struct cpufreq_governor *cpufreq_default_governor(void)
+{
+	return &cpufreq_gov_userspace;
+}
 #endif
-module_exit(cpufreq_gov_userspace_exit);
+
+cpufreq_governor_init(cpufreq_gov_userspace);
+cpufreq_governor_exit(cpufreq_gov_userspace);