[CPUFREQ] Remove unneeded locks

There cannot be any concurrent access to these through
different cpu sysfs files anymore, because these tunables
are now all global (not per cpu).

I still have some doubts whether some of these locks
were needed at all. Anyway, let's get rid of them.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
CC: cpufreq@vger.kernel.org

drivers/cpufreq/cpufreq_conservative.c

@@ -76,8 +76,7 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, cs_cpu_dbs_info);
 static unsigned int dbs_enable;	/* number of CPUs using this policy */
 
 /*
- * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
- * different CPUs. It protects dbs_enable in governor start/stop.
+ * dbs_mutex protects dbs_enable in governor start/stop.
  */
 static DEFINE_MUTEX(dbs_mutex);
 
@@ -195,10 +194,7 @@ static ssize_t store_sampling_down_factor(struct kobject *a,
 	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
 		return -EINVAL;
 
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.sampling_down_factor = input;
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -212,10 +208,7 @@ static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
 	if (ret != 1)
 		return -EINVAL;
 
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -226,16 +219,11 @@ static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
 	int ret;
 	ret = sscanf(buf, "%u", &input);
 
-	mutex_lock(&dbs_mutex);
 	if (ret != 1 || input > 100 ||
-			input <= dbs_tuners_ins.down_threshold) {
-		mutex_unlock(&dbs_mutex);
+			input <= dbs_tuners_ins.down_threshold)
 		return -EINVAL;
-	}
 
 	dbs_tuners_ins.up_threshold = input;
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -246,17 +234,12 @@ static ssize_t store_down_threshold(struct kobject *a, struct attribute *b,
 	int ret;
 	ret = sscanf(buf, "%u", &input);
 
-	mutex_lock(&dbs_mutex);
 	/* cannot be lower than 11 otherwise freq will not fall */
 	if (ret != 1 || input < 11 || input > 100 ||
-			input >= dbs_tuners_ins.up_threshold) {
-		mutex_unlock(&dbs_mutex);
+			input >= dbs_tuners_ins.up_threshold)
 		return -EINVAL;
-	}
 
 	dbs_tuners_ins.down_threshold = input;
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -275,11 +258,9 @@ static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
 	if (input > 1)
 		input = 1;
 
-	mutex_lock(&dbs_mutex);
-	if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
-		mutex_unlock(&dbs_mutex);
+	if (input == dbs_tuners_ins.ignore_nice) /* nothing to do */
 		return count;
-	}
+
 	dbs_tuners_ins.ignore_nice = input;
 
 	/* we need to re-evaluate prev_cpu_idle */
@@ -291,8 +272,6 @@ static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
 		if (dbs_tuners_ins.ignore_nice)
 			dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
 	}
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -311,10 +290,7 @@ static ssize_t store_freq_step(struct kobject *a, struct attribute *b,
 
 	/* no need to test here if freq_step is zero as the user might actually
 	 * want this, they would be crazy though :) */
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.freq_step = input;
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 

drivers/cpufreq/cpufreq_ondemand.c

@@ -99,8 +99,7 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, od_cpu_dbs_info);
 static unsigned int dbs_enable;	/* number of CPUs using this policy */
 
 /*
- * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
- * different CPUs. It protects dbs_enable in governor start/stop.
+ * dbs_mutex protects dbs_enable in governor start/stop.
  */
 static DEFINE_MUTEX(dbs_mutex);
 
@@ -265,11 +264,7 @@ static ssize_t store_sampling_rate(struct kobject *a, struct attribute *b,
 	ret = sscanf(buf, "%u", &input);
 	if (ret != 1)
 		return -EINVAL;
-
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.sampling_rate = max(input, min_sampling_rate);
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -282,11 +277,7 @@ static ssize_t store_io_is_busy(struct kobject *a, struct attribute *b,
 	ret = sscanf(buf, "%u", &input);
 	if (ret != 1)
 		return -EINVAL;
-
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.io_is_busy = !!input;
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -301,11 +292,7 @@ static ssize_t store_up_threshold(struct kobject *a, struct attribute *b,
 			input < MIN_FREQUENCY_UP_THRESHOLD) {
 		return -EINVAL;
 	}
-
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.up_threshold = input;
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -318,7 +305,6 @@ static ssize_t store_sampling_down_factor(struct kobject *a,
 
 	if (ret != 1 || input > MAX_SAMPLING_DOWN_FACTOR || input < 1)
 		return -EINVAL;
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.sampling_down_factor = input;
 
 	/* Reset down sampling multiplier in case it was active */
@@ -327,8 +313,6 @@ static ssize_t store_sampling_down_factor(struct kobject *a,
 		dbs_info = &per_cpu(od_cpu_dbs_info, j);
 		dbs_info->rate_mult = 1;
 	}
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -347,9 +331,7 @@ static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
 	if (input > 1)
 		input = 1;
 
-	mutex_lock(&dbs_mutex);
 	if (input == dbs_tuners_ins.ignore_nice) { /* nothing to do */
-		mutex_unlock(&dbs_mutex);
 		return count;
 	}
 	dbs_tuners_ins.ignore_nice = input;
@@ -364,8 +346,6 @@ static ssize_t store_ignore_nice_load(struct kobject *a, struct attribute *b,
 			dbs_info->prev_cpu_nice = kstat_cpu(j).cpustat.nice;
 
 	}
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }
 
@@ -382,11 +362,8 @@ static ssize_t store_powersave_bias(struct kobject *a, struct attribute *b,
 	if (input > 1000)
 		input = 1000;
 
-	mutex_lock(&dbs_mutex);
 	dbs_tuners_ins.powersave_bias = input;
 	ondemand_powersave_bias_init();
-	mutex_unlock(&dbs_mutex);
-
 	return count;
 }