[CPUFREQ] ondemand - Use global sysfs dir for tuning settings

Ondemand has only global variables for userspace tunings via sysfs.
But they were exposed per CPU which wrongly implies to the user that
his settings are applied per cpu. Also locking sysfs against concurrent
access won't be necessary anymore after deprecation time.

This means the ondemand config dir is moved:
/sys/devices/system/cpu/cpu*/cpufreq/ondemand ->
/sys/devices/system/cpu/cpufreq/ondemand

The old files will still exist, but reading or writing to them will
result in one (printk_once) deprecation msg to syslog per file.

Signed-off-by: Thomas Renninger <[e-mail]>
Signed-off-by: Dave Jones <[e-mail]>

drivers/cpufreq/cpufreq_ondemand.c

···
 #define TRANSITION_LATENCY_LIMIT		(10 * 1000 * 1000)
 
 static void do_dbs_timer(struct work_struct *work);
+static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
+				unsigned int event);
+
+#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
+static
+#endif
+struct cpufreq_governor cpufreq_gov_ondemand = {
+       .name                   = "ondemand",
+       .governor               = cpufreq_governor_dbs,
+       .max_transition_latency = TRANSITION_LATENCY_LIMIT,
+       .owner                  = THIS_MODULE,
+};
 
 /* Sampling types */
 enum {DBS_NORMAL_SAMPLE, DBS_SUB_SAMPLE};
···
 }
 
 /************************** sysfs interface ************************/
-static ssize_t show_sampling_rate_max(struct cpufreq_policy *policy, char *buf)
+
+static ssize_t show_sampling_rate_max(struct kobject *kobj,
+				      struct attribute *attr, char *buf)
 {
 	printk_once(KERN_INFO "CPUFREQ: ondemand sampling_rate_max "
 	       "sysfs file is deprecated - used by: %s\n", current->comm);
 	return sprintf(buf, "%u\n", -1U);
 }
 
-static ssize_t show_sampling_rate_min(struct cpufreq_policy *policy, char *buf)
+static ssize_t show_sampling_rate_min(struct kobject *kobj,
+				      struct attribute *attr, char *buf)
 {
 	return sprintf(buf, "%u\n", min_sampling_rate);
 }
 
 #define define_one_ro(_name)		\
-static struct freq_attr _name =		\
+static struct global_attr _name =	\
 __ATTR(_name, 0444, show_##_name, NULL)
 
 define_one_ro(sampling_rate_max);
···
 /* cpufreq_ondemand Governor Tunables */
 #define show_one(file_name, object)					\
 static ssize_t show_##file_name						\
-(struct cpufreq_policy *unused, char *buf)				\
+(struct kobject *kobj, struct attribute *attr, char *buf)              \
 {									\
 	return sprintf(buf, "%u\n", dbs_tuners_ins.object);		\
 }
···
 show_one(ignore_nice_load, ignore_nice);
 show_one(powersave_bias, powersave_bias);
 
-static ssize_t store_sampling_rate(struct cpufreq_policy *unused,
-		const char *buf, size_t count)
+/*** delete after deprecation time ***/
+
+#define DEPRECATION_MSG(file_name)					\
+	printk_once(KERN_INFO "CPUFREQ: Per core ondemand sysfs "	\
+		    "interface is deprecated - " #file_name "\n");
+
+#define show_one_old(file_name)						\
+static ssize_t show_##file_name##_old					\
+(struct cpufreq_policy *unused, char *buf)				\
+{									\
+	printk_once(KERN_INFO "CPUFREQ: Per core ondemand sysfs "	\
+		    "interface is deprecated - " #file_name "\n");	\
+	return show_##file_name(NULL, NULL, buf);			\
+}
+show_one_old(sampling_rate);
+show_one_old(up_threshold);
+show_one_old(ignore_nice_load);
+show_one_old(powersave_bias);
+show_one_old(sampling_rate_min);
+show_one_old(sampling_rate_max);
+
+#define define_one_ro_old(object, _name)       \
+static struct freq_attr object =               \
+__ATTR(_name, 0444, show_##_name##_old, NULL)
+
+define_one_ro_old(sampling_rate_min_old, sampling_rate_min);
+define_one_ro_old(sampling_rate_max_old, sampling_rate_max);
+
+/*** delete after deprecation time ***/
+
+static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
+				   const char *buf, size_t count)
 {
 	unsigned int input;
 	int ret;
···
 	return count;
 }
 
-static ssize_t store_up_threshold(struct cpufreq_policy *unused,
-		const char *buf, size_t count)
+static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
+				  const char *buf, size_t count)
 {
 	unsigned int input;
 	int ret;
···
 	return count;
 }
 
-static ssize_t store_ignore_nice_load(struct cpufreq_policy *policy,
-		const char *buf, size_t count)
+static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
+				      const char *buf, size_t count)
 {
 	unsigned int input;
 	int ret;
···
 	return count;
 }
 
-static ssize_t store_powersave_bias(struct cpufreq_policy *unused,
-		const char *buf, size_t count)
+static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b,
+				    const char *buf, size_t count)
 {
 	unsigned int input;
 	int ret;
···
 }
 
 #define define_one_rw(_name) \
-static struct freq_attr _name = \
+static struct global_attr _name = \
 __ATTR(_name, 0644, show_##_name, store_##_name)
 
 define_one_rw(sampling_rate);
···
 	.attrs = dbs_attributes,
 	.name = "ondemand",
 };
+
+/*** delete after deprecation time ***/
+
+#define write_one_old(file_name)					\
+static ssize_t store_##file_name##_old					\
+(struct cpufreq_policy *unused, const char *buf, size_t count)		\
+{									\
+       printk_once(KERN_INFO "CPUFREQ: Per core ondemand sysfs "	\
+		   "interface is deprecated - " #file_name "\n");	\
+       return store_##file_name(NULL, NULL, buf, count);		\
+}
+write_one_old(sampling_rate);
+write_one_old(up_threshold);
+write_one_old(ignore_nice_load);
+write_one_old(powersave_bias);
+
+#define define_one_rw_old(object, _name)       \
+static struct freq_attr object =               \
+__ATTR(_name, 0644, show_##_name##_old, store_##_name##_old)
+
+define_one_rw_old(sampling_rate_old, sampling_rate);
+define_one_rw_old(up_threshold_old, up_threshold);
+define_one_rw_old(ignore_nice_load_old, ignore_nice_load);
+define_one_rw_old(powersave_bias_old, powersave_bias);
+
+static struct attribute *dbs_attributes_old[] = {
+       &sampling_rate_max_old.attr,
+       &sampling_rate_min_old.attr,
+       &sampling_rate_old.attr,
+       &up_threshold_old.attr,
+       &ignore_nice_load_old.attr,
+       &powersave_bias_old.attr,
+       NULL
+};
+
+static struct attribute_group dbs_attr_group_old = {
+       .attrs = dbs_attributes_old,
+       .name = "ondemand",
+};
+
+/*** delete after deprecation time ***/
 
 /************************** sysfs end ************************/
 
···
 
 		mutex_lock(&dbs_mutex);
 
-		rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
+		rc = sysfs_create_group(&policy->kobj, &dbs_attr_group_old);
 		if (rc) {
 			mutex_unlock(&dbs_mutex);
 			return rc;
···
 		}
 		this_dbs_info->cpu = cpu;
 		ondemand_powersave_bias_init_cpu(cpu);
-		mutex_init(&this_dbs_info->timer_mutex);
 		/*
 		 * Start the timerschedule work, when this governor
 		 * is used for first time
 		 */
 		if (dbs_enable == 1) {
 			unsigned int latency;
+
+			rc = sysfs_create_group(cpufreq_global_kobject,
+						&dbs_attr_group);
+			if (rc) {
+				mutex_unlock(&dbs_mutex);
+				return rc;
+			}
+
 			/* policy latency is in nS. Convert it to uS first */
 			latency = policy->cpuinfo.transition_latency / 1000;
 			if (latency == 0)
···
 		}
 		mutex_unlock(&dbs_mutex);
 
+		mutex_init(&this_dbs_info->timer_mutex);
 		dbs_timer_init(this_dbs_info);
 		break;
 
···
 		dbs_timer_exit(this_dbs_info);
 
 		mutex_lock(&dbs_mutex);
-		sysfs_remove_group(&policy->kobj, &dbs_attr_group);
+		sysfs_remove_group(&policy->kobj, &dbs_attr_group_old);
 		mutex_destroy(&this_dbs_info->timer_mutex);
 		dbs_enable--;
 		mutex_unlock(&dbs_mutex);
+		if (!dbs_enable)
+			sysfs_remove_group(cpufreq_global_kobject,
+					   &dbs_attr_group);
 
 		break;
 
···
 	}
 	return 0;
 }
-
-#ifndef CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND
-static
-#endif
-struct cpufreq_governor cpufreq_gov_ondemand = {
-	.name			= "ondemand",
-	.governor		= cpufreq_governor_dbs,
-	.max_transition_latency = TRANSITION_LATENCY_LIMIT,
-	.owner			= THIS_MODULE,
-};
 
 static int __init cpufreq_gov_dbs_init(void)
 {