[PATCH 1/2] cpufreq: Move get_cpu_idle_time() to cpufreq.c

[PATCH 1/2] cpufreq: Move get_cpu_idle_time() to cpufreq.c

[Viresh Kumar]

Governors other than ondemand and conservative can also use get_cpu_idle_time()
and they aren't required to compile cpufreq_governor.c. So, move these
independent routines to cpufreq.c instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
Bot Targeted for 3.11

 drivers/cpufreq/cpufreq.c          | 38 ++++++++++++++++++++++++++++++++++++++
 drivers/cpufreq/cpufreq_governor.c | 36 ------------------------------------
 drivers/cpufreq/cpufreq_governor.h |  1 -
 include/linux/cpufreq.h            |  1 +
 4 files changed, 39 insertions(+), 37 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 2d5a829..e3d7112 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -17,7 +17,9 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <asm/cputime.h>
 #include <linux/kernel.h>
+#include <linux/kernel_stat.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/notifier.h>
@@ -25,6 +27,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/tick.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
@@ -143,6 +146,41 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
 }
 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
 
+static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
+{
+	u64 idle_time;
+	u64 cur_wall_time;
+	u64 busy_time;
+
+	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
+
+	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
+
+	idle_time = cur_wall_time - busy_time;
+	if (wall)
+		*wall = cputime_to_usecs(cur_wall_time);
+
+	return cputime_to_usecs(idle_time);
+}
+
+u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
+{
+	u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
+
+	if (idle_time == -1ULL)
+		return get_cpu_idle_time_jiffy(cpu, wall);
+	else if (!io_busy)
+		idle_time += get_cpu_iowait_time_us(cpu, wall);
+
+	return idle_time;
+}
+EXPORT_SYMBOL_GPL(get_cpu_idle_time);
+
 static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
 {
 	struct cpufreq_policy *data;
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index d1421b4..b6cfd55 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -23,7 +23,6 @@
 #include <linux/kernel_stat.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
-#include <linux/tick.h>
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
@@ -37,41 +36,6 @@ static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
 		return dbs_data->cdata->attr_group_gov_sys;
 }
 
-static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
-{
-	u64 idle_time;
-	u64 cur_wall_time;
-	u64 busy_time;
-
-	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
-
-	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
-	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
-	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
-	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
-	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
-	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
-
-	idle_time = cur_wall_time - busy_time;
-	if (wall)
-		*wall = cputime_to_usecs(cur_wall_time);
-
-	return cputime_to_usecs(idle_time);
-}
-
-u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
-{
-	u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
-
-	if (idle_time == -1ULL)
-		return get_cpu_idle_time_jiffy(cpu, wall);
-	else if (!io_busy)
-		idle_time += get_cpu_iowait_time_us(cpu, wall);
-
-	return idle_time;
-}
-EXPORT_SYMBOL_GPL(get_cpu_idle_time);
-
 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 {
 	struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
diff --git a/drivers/cpufreq/cpufreq_governor.h b/drivers/cpufreq/cpufreq_governor.h
index e16a961..e7bbf76 100644
--- a/drivers/cpufreq/cpufreq_governor.h
+++ b/drivers/cpufreq/cpufreq_governor.h
@@ -256,7 +256,6 @@ static ssize_t show_sampling_rate_min_gov_pol				\
 	return sprintf(buf, "%u\n", dbs_data->min_sampling_rate);	\
 }
 
-u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
 void dbs_check_cpu(struct dbs_data *dbs_data, int cpu);
 bool need_load_eval(struct cpu_dbs_common_info *cdbs,
 		unsigned int sampling_rate);
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 7ffb4d5..cbdf5a4 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -337,6 +337,7 @@ const char *cpufreq_get_current_driver(void);
 /*********************************************************************
  *                        CPUFREQ 2.6. INTERFACE                     *
  *********************************************************************/
+u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy);
 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 int cpufreq_update_policy(unsigned int cpu);
 bool have_governor_per_policy(void);
-- 
1.7.12.rc2.18.g61b472e

[PATCH 2/2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directory

[Viresh Kumar]

When we don't have any file in cpu/cpufreq directory we shouldn't create it.
Specially with the introduction of per-policy governor instance patchset, even
governors are moved to cpu/cpu*/cpufreq/governor-name directory and so this
directory is just not required.

Lets have it only when required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/cpufreq/acpi-cpufreq.c     |  4 ++--
 drivers/cpufreq/cpufreq.c          | 48 ++++++++++++++++++++++++++++++++++----
 drivers/cpufreq/cpufreq_governor.c |  6 +++++
 include/linux/cpufreq.h            |  4 ++++
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index ce28c34..ae0918d 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -947,7 +947,7 @@ static void __init acpi_cpufreq_boost_init(void)
 	/* We create the boost file in any case, though for systems without
 	 * hardware support it will be read-only and hardwired to return 0.
 	 */
-	if (sysfs_create_file(cpufreq_global_kobject, &(global_boost.attr)))
+	if (cpufreq_sysfs_create_file(&(global_boost.attr)))
 		pr_warn(PFX "could not register global boost sysfs file\n");
 	else
 		pr_debug("registered global boost sysfs file\n");
@@ -955,7 +955,7 @@ static void __init acpi_cpufreq_boost_init(void)
 
 static void __exit acpi_cpufreq_boost_exit(void)
 {
-	sysfs_remove_file(cpufreq_global_kobject, &(global_boost.attr));
+	cpufreq_sysfs_remove_file(&(global_boost.attr));
 
 	if (msrs) {
 		unregister_cpu_notifier(&boost_nb);
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e3d7112..2e18b3d 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -678,9 +678,6 @@ static struct attribute *default_attrs[] = {
 	NULL
 };
 
-struct kobject *cpufreq_global_kobject;
-EXPORT_SYMBOL(cpufreq_global_kobject);
-
 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 #define to_attr(a) container_of(a, struct freq_attr, attr)
 
@@ -751,6 +748,49 @@ static struct kobj_type ktype_cpufreq = {
 	.release	= cpufreq_sysfs_release,
 };
 
+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
+static int cpufreq_global_kobject_usage;
+
+int get_cpufreq_global_kobject(void)
+{
+	if (!cpufreq_global_kobject_usage++)
+		return kobject_add(cpufreq_global_kobject,
+				&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
+
+	return 0;
+}
+EXPORT_SYMBOL(get_cpufreq_global_kobject);
+
+void put_cpufreq_global_kobject(void)
+{
+	if (!--cpufreq_global_kobject_usage)
+		kobject_del(cpufreq_global_kobject);
+}
+EXPORT_SYMBOL(put_cpufreq_global_kobject);
+
+int cpufreq_sysfs_create_file(const struct attribute *attr)
+{
+	int ret = get_cpufreq_global_kobject();
+
+	if (!ret) {
+		ret = sysfs_create_file(cpufreq_global_kobject, attr);
+		if (ret)
+			put_cpufreq_global_kobject();
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
+
+void cpufreq_sysfs_remove_file(const struct attribute *attr)
+{
+	sysfs_remove_file(cpufreq_global_kobject, attr);
+	put_cpufreq_global_kobject();
+}
+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
+
 /* symlink affected CPUs */
 static int cpufreq_add_dev_symlink(unsigned int cpu,
 				   struct cpufreq_policy *policy)
@@ -2022,7 +2062,7 @@ static int __init cpufreq_core_init(void)
 		init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
 	}
 
-	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
+	cpufreq_global_kobject = kobject_create();
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);
 
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index b6cfd55..09a86f3 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -231,6 +231,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			return rc;
 		}
 
+		if (!have_governor_per_policy())
+			WARN_ON(get_cpufreq_global_kobject());
+
 		rc = sysfs_create_group(get_governor_parent_kobj(policy),
 				get_sysfs_attr(dbs_data));
 		if (rc) {
@@ -269,6 +272,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			sysfs_remove_group(get_governor_parent_kobj(policy),
 					get_sysfs_attr(dbs_data));
 
+			if (!have_governor_per_policy())
+				put_cpufreq_global_kobject();
+
 			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
 				(policy->governor->initialized == 1)) {
 				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index cbdf5a4..77a73c9 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -71,6 +71,10 @@ struct cpufreq_governor;
 
 /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 extern struct kobject *cpufreq_global_kobject;
+int get_cpufreq_global_kobject(void);
+void put_cpufreq_global_kobject(void);
+int cpufreq_sysfs_create_file(const struct attribute *attr);
+void cpufreq_sysfs_remove_file(const struct attribute *attr);
 
 #define CPUFREQ_ETERNAL			(-1)
 struct cpufreq_cpuinfo {
-- 
1.7.12.rc2.18.g61b472e

Re: [PATCH 2/2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directory

[Francesco Lavra]

Hi,

On 05/17/2013 01:26 PM, Viresh Kumar wrote:
> When we don't have any file in cpu/cpufreq directory we shouldn't create it.
> Specially with the introduction of per-policy governor instance patchset, even
> governors are moved to cpu/cpu*/cpufreq/governor-name directory and so this
> directory is just not required.
> 
> Lets have it only when required.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
[...]
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index e3d7112..2e18b3d 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -678,9 +678,6 @@ static struct attribute *default_attrs[] = {
>  	NULL
>  };
>  
> -struct kobject *cpufreq_global_kobject;
> -EXPORT_SYMBOL(cpufreq_global_kobject);
> -
>  #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
>  #define to_attr(a) container_of(a, struct freq_attr, attr)
>  
> @@ -751,6 +748,49 @@ static struct kobj_type ktype_cpufreq = {
>  	.release	= cpufreq_sysfs_release,
>  };
>  
> +struct kobject *cpufreq_global_kobject;
> +EXPORT_SYMBOL(cpufreq_global_kobject);
> +
> +static int cpufreq_global_kobject_usage;
> +
> +int get_cpufreq_global_kobject(void)
> +{
> +	if (!cpufreq_global_kobject_usage++)
> +		return kobject_add(cpufreq_global_kobject,
> +				&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(get_cpufreq_global_kobject);
> +
> +void put_cpufreq_global_kobject(void)
> +{
> +	if (!--cpufreq_global_kobject_usage)
> +		kobject_del(cpufreq_global_kobject);
> +}
> +EXPORT_SYMBOL(put_cpufreq_global_kobject);

Global symbol names should begin with a sensible prefix; in this case,
it looks like cpufreq_get_global_kobject and cpufreq_put_global_kobject
would be more appropriate names.

Regards,
Francesco

Re: [PATCH 2/2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directory

[Viresh Kumar]

On 20 May 2013 00:13, Francesco Lavra <francescolavra.fl@gmail.com> wrote:
> On 05/17/2013 01:26 PM, Viresh Kumar wrote:
>> +EXPORT_SYMBOL(get_cpufreq_global_kobject);
>> +EXPORT_SYMBOL(put_cpufreq_global_kobject);
>
> Global symbol names should begin with a sensible prefix; in this case,
> it looks like cpufreq_get_global_kobject and cpufreq_put_global_kobject
> would be more appropriate names.

Sure. Thanks.

Re: [PATCH 2/2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq directory

[Viresh Kumar]

[-- Attachment #1: Type: text/plain, Size: 5844 bytes --]

On 20 May 2013 00:13, Francesco Lavra <francescolavra.fl@gmail.com> wrote:
> On 05/17/2013 01:26 PM, Viresh Kumar wrote:
>> +EXPORT_SYMBOL(get_cpufreq_global_kobject);
>> +EXPORT_SYMBOL(put_cpufreq_global_kobject);
>
> Global symbol names should begin with a sensible prefix; in this case,
> it looks like cpufreq_get_global_kobject and cpufreq_put_global_kobject
> would be more appropriate names.

Please see if V2 looks fine. Attached too for applying.

------------x--------------------x------------------

From: Viresh Kumar <viresh.kumar@linaro.org>
Date: Fri, 17 May 2013 16:09:09 +0530
Subject: [PATCH V2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq
 directory

When we don't have any file in cpu/cpufreq directory we shouldn't create it.
Specially with the introduction of per-policy governor instance patchset, even
governors are moved to cpu/cpu*/cpufreq/governor-name directory and so this
directory is just not required.

Lets have it only when required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V1->V2: Replace: {get|put}_cpufreq_global_kobject with
cpufreq_{get|put}_global_kobject.

 drivers/cpufreq/acpi-cpufreq.c     |  4 ++--
 drivers/cpufreq/cpufreq.c          | 48 ++++++++++++++++++++++++++++++++++----
 drivers/cpufreq/cpufreq_governor.c |  6 +++++
 include/linux/cpufreq.h            |  4 ++++
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index ce28c34..ae0918d 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -947,7 +947,7 @@ static void __init acpi_cpufreq_boost_init(void)
 	/* We create the boost file in any case, though for systems without
 	 * hardware support it will be read-only and hardwired to return 0.
 	 */
-	if (sysfs_create_file(cpufreq_global_kobject, &(global_boost.attr)))
+	if (cpufreq_sysfs_create_file(&(global_boost.attr)))
 		pr_warn(PFX "could not register global boost sysfs file\n");
 	else
 		pr_debug("registered global boost sysfs file\n");
@@ -955,7 +955,7 @@ static void __init acpi_cpufreq_boost_init(void)

 static void __exit acpi_cpufreq_boost_exit(void)
 {
-	sysfs_remove_file(cpufreq_global_kobject, &(global_boost.attr));
+	cpufreq_sysfs_remove_file(&(global_boost.attr));

 	if (msrs) {
 		unregister_cpu_notifier(&boost_nb);
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e3d7112..74a1a60 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -678,9 +678,6 @@ static struct attribute *default_attrs[] = {
 	NULL
 };

-struct kobject *cpufreq_global_kobject;
-EXPORT_SYMBOL(cpufreq_global_kobject);
-
 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 #define to_attr(a) container_of(a, struct freq_attr, attr)

@@ -751,6 +748,49 @@ static struct kobj_type ktype_cpufreq = {
 	.release	= cpufreq_sysfs_release,
 };

+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
+static int cpufreq_global_kobject_usage;
+
+int cpufreq_get_global_kobject(void)
+{
+	if (!cpufreq_global_kobject_usage++)
+		return kobject_add(cpufreq_global_kobject,
+				&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
+
+	return 0;
+}
+EXPORT_SYMBOL(cpufreq_get_global_kobject);
+
+void cpufreq_put_global_kobject(void)
+{
+	if (!--cpufreq_global_kobject_usage)
+		kobject_del(cpufreq_global_kobject);
+}
+EXPORT_SYMBOL(cpufreq_put_global_kobject);
+
+int cpufreq_sysfs_create_file(const struct attribute *attr)
+{
+	int ret = cpufreq_get_global_kobject();
+
+	if (!ret) {
+		ret = sysfs_create_file(cpufreq_global_kobject, attr);
+		if (ret)
+			cpufreq_put_global_kobject();
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
+
+void cpufreq_sysfs_remove_file(const struct attribute *attr)
+{
+	sysfs_remove_file(cpufreq_global_kobject, attr);
+	cpufreq_put_global_kobject();
+}
+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
+
 /* symlink affected CPUs */
 static int cpufreq_add_dev_symlink(unsigned int cpu,
 				   struct cpufreq_policy *policy)
@@ -2022,7 +2062,7 @@ static int __init cpufreq_core_init(void)
 		init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
 	}

-	cpufreq_global_kobject = kobject_create_and_add("cpufreq",
&cpu_subsys.dev_root->kobj);
+	cpufreq_global_kobject = kobject_create();
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);

diff --git a/drivers/cpufreq/cpufreq_governor.c
b/drivers/cpufreq/cpufreq_governor.c
index b6cfd55..7532570 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -231,6 +231,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			return rc;
 		}

+		if (!have_governor_per_policy())
+			WARN_ON(cpufreq_get_global_kobject());
+
 		rc = sysfs_create_group(get_governor_parent_kobj(policy),
 				get_sysfs_attr(dbs_data));
 		if (rc) {
@@ -269,6 +272,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			sysfs_remove_group(get_governor_parent_kobj(policy),
 					get_sysfs_attr(dbs_data));

+			if (!have_governor_per_policy())
+				cpufreq_put_global_kobject();
+
 			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
 				(policy->governor->initialized == 1)) {
 				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index cbdf5a4..b97d99b 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -71,6 +71,10 @@ struct cpufreq_governor;

 /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 extern struct kobject *cpufreq_global_kobject;
+int cpufreq_get_global_kobject(void);
+void cpufreq_put_global_kobject(void);
+int cpufreq_sysfs_create_file(const struct attribute *attr);
+void cpufreq_sysfs_remove_file(const struct attribute *attr);

 #define CPUFREQ_ETERNAL			(-1)
 struct cpufreq_cpuinfo {

[-- Attachment #2: 0001-cpufreq-Don-t-create-empty-sys-devices-system-cpu-cp.patch --]
[-- Type: application/octet-stream, Size: 5537 bytes --]

From 3e4c74ca4441abe2b93707991071e239e413fa7d Mon Sep 17 00:00:00 2001
Message-Id: <3e4c74ca4441abe2b93707991071e239e413fa7d.1369024637.git.viresh.kumar@linaro.org>
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: Fri, 17 May 2013 16:09:09 +0530
Subject: [PATCH V2] cpufreq: Don't create empty /sys/devices/system/cpu/cpufreq
 directory

When we don't have any file in cpu/cpufreq directory we shouldn't create it.
Specially with the introduction of per-policy governor instance patchset, even
governors are moved to cpu/cpu*/cpufreq/governor-name directory and so this
directory is just not required.

Lets have it only when required.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
V1->V2: Replace: {get|put}_cpufreq_global_kobject with cpufreq_{get|put}_global_kobject.

 drivers/cpufreq/acpi-cpufreq.c     |  4 ++--
 drivers/cpufreq/cpufreq.c          | 48 ++++++++++++++++++++++++++++++++++----
 drivers/cpufreq/cpufreq_governor.c |  6 +++++
 include/linux/cpufreq.h            |  4 ++++
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index ce28c34..ae0918d 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -947,7 +947,7 @@ static void __init acpi_cpufreq_boost_init(void)
 	/* We create the boost file in any case, though for systems without
 	 * hardware support it will be read-only and hardwired to return 0.
 	 */
-	if (sysfs_create_file(cpufreq_global_kobject, &(global_boost.attr)))
+	if (cpufreq_sysfs_create_file(&(global_boost.attr)))
 		pr_warn(PFX "could not register global boost sysfs file\n");
 	else
 		pr_debug("registered global boost sysfs file\n");
@@ -955,7 +955,7 @@ static void __init acpi_cpufreq_boost_init(void)
 
 static void __exit acpi_cpufreq_boost_exit(void)
 {
-	sysfs_remove_file(cpufreq_global_kobject, &(global_boost.attr));
+	cpufreq_sysfs_remove_file(&(global_boost.attr));
 
 	if (msrs) {
 		unregister_cpu_notifier(&boost_nb);
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index e3d7112..74a1a60 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -678,9 +678,6 @@ static struct attribute *default_attrs[] = {
 	NULL
 };
 
-struct kobject *cpufreq_global_kobject;
-EXPORT_SYMBOL(cpufreq_global_kobject);
-
 #define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
 #define to_attr(a) container_of(a, struct freq_attr, attr)
 
@@ -751,6 +748,49 @@ static struct kobj_type ktype_cpufreq = {
 	.release	= cpufreq_sysfs_release,
 };
 
+struct kobject *cpufreq_global_kobject;
+EXPORT_SYMBOL(cpufreq_global_kobject);
+
+static int cpufreq_global_kobject_usage;
+
+int cpufreq_get_global_kobject(void)
+{
+	if (!cpufreq_global_kobject_usage++)
+		return kobject_add(cpufreq_global_kobject,
+				&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
+
+	return 0;
+}
+EXPORT_SYMBOL(cpufreq_get_global_kobject);
+
+void cpufreq_put_global_kobject(void)
+{
+	if (!--cpufreq_global_kobject_usage)
+		kobject_del(cpufreq_global_kobject);
+}
+EXPORT_SYMBOL(cpufreq_put_global_kobject);
+
+int cpufreq_sysfs_create_file(const struct attribute *attr)
+{
+	int ret = cpufreq_get_global_kobject();
+
+	if (!ret) {
+		ret = sysfs_create_file(cpufreq_global_kobject, attr);
+		if (ret)
+			cpufreq_put_global_kobject();
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
+
+void cpufreq_sysfs_remove_file(const struct attribute *attr)
+{
+	sysfs_remove_file(cpufreq_global_kobject, attr);
+	cpufreq_put_global_kobject();
+}
+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
+
 /* symlink affected CPUs */
 static int cpufreq_add_dev_symlink(unsigned int cpu,
 				   struct cpufreq_policy *policy)
@@ -2022,7 +2062,7 @@ static int __init cpufreq_core_init(void)
 		init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
 	}
 
-	cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
+	cpufreq_global_kobject = kobject_create();
 	BUG_ON(!cpufreq_global_kobject);
 	register_syscore_ops(&cpufreq_syscore_ops);
 
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index b6cfd55..7532570 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -231,6 +231,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			return rc;
 		}
 
+		if (!have_governor_per_policy())
+			WARN_ON(cpufreq_get_global_kobject());
+
 		rc = sysfs_create_group(get_governor_parent_kobj(policy),
 				get_sysfs_attr(dbs_data));
 		if (rc) {
@@ -269,6 +272,9 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			sysfs_remove_group(get_governor_parent_kobj(policy),
 					get_sysfs_attr(dbs_data));
 
+			if (!have_governor_per_policy())
+				cpufreq_put_global_kobject();
+
 			if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
 				(policy->governor->initialized == 1)) {
 				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index cbdf5a4..b97d99b 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -71,6 +71,10 @@ struct cpufreq_governor;
 
 /* /sys/devices/system/cpu/cpufreq: entry point for global variables */
 extern struct kobject *cpufreq_global_kobject;
+int cpufreq_get_global_kobject(void);
+void cpufreq_put_global_kobject(void);
+int cpufreq_sysfs_create_file(const struct attribute *attr);
+void cpufreq_sysfs_remove_file(const struct attribute *attr);
 
 #define CPUFREQ_ETERNAL			(-1)
 struct cpufreq_cpuinfo {
-- 
1.7.12.rc2.18.g61b472e