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> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Viresh Kumar · Rafael J. Wysocki
1 parent 72a4ce340a
Showing 4 changed files with 56 additions and 6 deletions Side-by-side Diff
drivers/cpufreq/acpi-cpufreq.c
drivers/cpufreq/cpufreq.c
drivers/cpufreq/cpufreq_governor.c
include/linux/cpufreq.h
@@ -947,7 +947,7 @@
 	/* 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 __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);
@@ -678,9 +678,6 @@
 	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 @@
 	.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)
@@ -2020,7 +2060,7 @@
 		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);
  
@@ -231,6 +231,9 @@
 			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) {
@@ -268,6 +271,9 @@
 		if (!--dbs_data->usage_count) {
 			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)) {
@@ -71,6 +71,10 @@
  
 /* /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 {
...	...	@@ -947,7 +947,7 @@
947	947	/* We create the boost file in any case, though for systems without
948	948	* hardware support it will be read-only and hardwired to return 0.
949	949	*/
950		- if (sysfs_create_file(cpufreq_global_kobject, &(global_boost.attr)))
	950	+ if (cpufreq_sysfs_create_file(&(global_boost.attr)))
951	951	pr_warn(PFX "could not register global boost sysfs file\n");
952	952	else
953	953	pr_debug("registered global boost sysfs file\n");
...	...	@@ -955,7 +955,7 @@
955	955
956	956	static void __exit acpi_cpufreq_boost_exit(void)
957	957	{
958		- sysfs_remove_file(cpufreq_global_kobject, &(global_boost.attr));
	958	+ cpufreq_sysfs_remove_file(&(global_boost.attr));
959	959
960	960	if (msrs) {
961	961	unregister_cpu_notifier(&boost_nb);
...	...	@@ -678,9 +678,6 @@
678	678	NULL
679	679	};
680	680
681		-struct kobject *cpufreq_global_kobject;
682		-EXPORT_SYMBOL(cpufreq_global_kobject);
683		-
684	681	#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
685	682	#define to_attr(a) container_of(a, struct freq_attr, attr)
686	683
...	...	@@ -751,6 +748,49 @@
751	748	.release = cpufreq_sysfs_release,
752	749	};
753	750
	751	+struct kobject *cpufreq_global_kobject;
	752	+EXPORT_SYMBOL(cpufreq_global_kobject);
	753	+
	754	+static int cpufreq_global_kobject_usage;
	755	+
	756	+int cpufreq_get_global_kobject(void)
	757	+{
	758	+ if (!cpufreq_global_kobject_usage++)
	759	+ return kobject_add(cpufreq_global_kobject,
	760	+ &cpu_subsys.dev_root->kobj, "%s", "cpufreq");
	761	+
	762	+ return 0;
	763	+}
	764	+EXPORT_SYMBOL(cpufreq_get_global_kobject);
	765	+
	766	+void cpufreq_put_global_kobject(void)
	767	+{
	768	+ if (!--cpufreq_global_kobject_usage)
	769	+ kobject_del(cpufreq_global_kobject);
	770	+}
	771	+EXPORT_SYMBOL(cpufreq_put_global_kobject);
	772	+
	773	+int cpufreq_sysfs_create_file(const struct attribute *attr)
	774	+{
	775	+ int ret = cpufreq_get_global_kobject();
	776	+
	777	+ if (!ret) {
	778	+ ret = sysfs_create_file(cpufreq_global_kobject, attr);
	779	+ if (ret)
	780	+ cpufreq_put_global_kobject();
	781	+ }
	782	+
	783	+ return ret;
	784	+}
	785	+EXPORT_SYMBOL(cpufreq_sysfs_create_file);
	786	+
	787	+void cpufreq_sysfs_remove_file(const struct attribute *attr)
	788	+{
	789	+ sysfs_remove_file(cpufreq_global_kobject, attr);
	790	+ cpufreq_put_global_kobject();
	791	+}
	792	+EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
	793	+
754	794	/* symlink affected CPUs */
755	795	static int cpufreq_add_dev_symlink(unsigned int cpu,
756	796	struct cpufreq_policy *policy)
...	...	@@ -2020,7 +2060,7 @@
2020	2060	init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
2021	2061	}
2022	2062
2023		- cpufreq_global_kobject = kobject_create_and_add("cpufreq", &cpu_subsys.dev_root->kobj);
	2063	+ cpufreq_global_kobject = kobject_create();
2024	2064	BUG_ON(!cpufreq_global_kobject);
2025	2065	register_syscore_ops(&cpufreq_syscore_ops);
2026	2066
...	...	@@ -231,6 +231,9 @@
231	231	return rc;
232	232	}
233	233
	234	+ if (!have_governor_per_policy())
	235	+ WARN_ON(cpufreq_get_global_kobject());
	236	+
234	237	rc = sysfs_create_group(get_governor_parent_kobj(policy),
235	238	get_sysfs_attr(dbs_data));
236	239	if (rc) {
...	...	@@ -268,6 +271,9 @@
268	271	if (!--dbs_data->usage_count) {
269	272	sysfs_remove_group(get_governor_parent_kobj(policy),
270	273	get_sysfs_attr(dbs_data));
	274	+
	275	+ if (!have_governor_per_policy())
	276	+ cpufreq_put_global_kobject();
271	277
272	278	if ((dbs_data->cdata->governor == GOV_CONSERVATIVE) &&
273	279	(policy->governor->initialized == 1)) {
...	...	@@ -71,6 +71,10 @@
71	71
72	72	/* /sys/devices/system/cpu/cpufreq: entry point for global variables */
73	73	extern struct kobject *cpufreq_global_kobject;
	74	+int cpufreq_get_global_kobject(void);
	75	+void cpufreq_put_global_kobject(void);
	76	+int cpufreq_sysfs_create_file(const struct attribute *attr);
	77	+void cpufreq_sysfs_remove_file(const struct attribute *attr);
74	78
75	79	#define CPUFREQ_ETERNAL (-1)
76	80	struct cpufreq_cpuinfo {