[PATCH v2 3/3] devfreq: move statistics to separate struct

[Kamil Konieczny]

Count time and transitions between devfreq frequencies in separate struct
for improved code readability and maintenance.

Signed-off-by: Kamil Konieczny <k.konieczny@xxxxxxxxxxx>
---
Changes in v2:
 squash three patches into one, do not modify devfreq_profile and separate stats
 into devfreq_stats

 drivers/devfreq/devfreq.c | 68 +++++++++++++++++++++++----------------
 include/linux/devfreq.h   | 31 ++++++++++++------
 2 files changed, 62 insertions(+), 37 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 901af3b66a76..4d50c8f10bd2 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -198,6 +198,7 @@ static int set_freq_table(struct devfreq *devfreq)
  */
 int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 {
+	struct devfreq_stats *stats = devfreq->stats;
 	int lev, prev_lev, ret = 0;
 	unsigned long long cur_time;
 
@@ -214,8 +215,8 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 		goto out;
 	}
 
-	devfreq->time_in_state[prev_lev] +=
-			 cur_time - devfreq->last_stat_updated;
+	stats->time_in_state[prev_lev] +=
+			 cur_time - stats->last_stat_updated;
 
 	lev = devfreq_get_freq_level(devfreq, freq);
 	if (lev < 0) {
@@ -224,13 +225,12 @@ int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 	}
 
 	if (lev != prev_lev) {
-		devfreq->trans_table[(prev_lev *
-				devfreq->profile->max_state) + lev]++;
-		devfreq->total_trans++;
+		stats->trans_table[(prev_lev * stats->max_state) + lev]++;
+		stats->total_trans++;
 	}
 
 out:
-	devfreq->last_stat_updated = cur_time;
+	stats->last_stat_updated = cur_time;
 	return ret;
 }
 EXPORT_SYMBOL(devfreq_update_status);
@@ -525,7 +525,7 @@ void devfreq_monitor_resume(struct devfreq *devfreq)
 			msecs_to_jiffies(devfreq->profile->polling_ms));
 
 out_update:
-	devfreq->last_stat_updated = get_jiffies_64();
+	devfreq->stats->last_stat_updated = get_jiffies_64();
 	devfreq->stop_polling = false;
 
 	if (devfreq->profile->get_cur_freq &&
@@ -735,28 +735,38 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_out;
 	}
 
-	devfreq->trans_table = devm_kzalloc(&devfreq->dev,
+	devfreq->stats = devm_kzalloc(&devfreq->dev, sizeof(*devfreq->stats),
+				      GFP_KERNEL);
+	if (!devfreq->stats) {
+		mutex_unlock(&devfreq->lock);
+		err = -ENOMEM;
+		goto err_devfreq;
+	}
+
+	devfreq->stats->freq_table = devfreq->profile->freq_table;
+	devfreq->stats->max_state = devfreq->profile->max_state;
+	devfreq->stats->trans_table = devm_kzalloc(&devfreq->dev,
 			array3_size(sizeof(unsigned int),
-				    devfreq->profile->max_state,
-				    devfreq->profile->max_state),
+				    devfreq->stats->max_state,
+				    devfreq->stats->max_state),
 			GFP_KERNEL);
-	if (!devfreq->trans_table) {
+	if (!devfreq->stats->trans_table) {
 		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
-	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
-			devfreq->profile->max_state,
-			sizeof(*devfreq->time_in_state),
+	devfreq->stats->time_in_state = devm_kcalloc(&devfreq->dev,
+			devfreq->stats->max_state,
+			sizeof(*devfreq->stats->time_in_state),
 			GFP_KERNEL);
-	if (!devfreq->time_in_state) {
+	if (!devfreq->stats->time_in_state) {
 		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
-	devfreq->last_stat_updated = get_jiffies_64();
+	devfreq->stats->last_stat_updated = get_jiffies_64();
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
@@ -1435,9 +1445,10 @@ static ssize_t trans_stat_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
 	struct devfreq *devfreq = to_devfreq(dev);
+	struct devfreq_stats *stats = devfreq->stats;
+	unsigned int max_state = stats->max_state;
 	ssize_t len;
 	int i, j;
-	unsigned int max_state = devfreq->profile->max_state;
 
 	if (max_state == 0)
 		return sprintf(buf, "Not Supported.\n");
@@ -1454,28 +1465,28 @@ static ssize_t trans_stat_show(struct device *dev,
 	len += sprintf(buf + len, "           :");
 	for (i = 0; i < max_state; i++)
 		len += sprintf(buf + len, "%10lu",
-				devfreq->profile->freq_table[i]);
+				stats->freq_table[i]);
 
 	len += sprintf(buf + len, "   time(ms)\n");
 
 	for (i = 0; i < max_state; i++) {
-		if (devfreq->profile->freq_table[i]
+		if (stats->freq_table[i]
 					== devfreq->previous_freq) {
 			len += sprintf(buf + len, "*");
 		} else {
 			len += sprintf(buf + len, " ");
 		}
 		len += sprintf(buf + len, "%10lu:",
-				devfreq->profile->freq_table[i]);
+				stats->freq_table[i]);
 		for (j = 0; j < max_state; j++)
 			len += sprintf(buf + len, "%10u",
-				devfreq->trans_table[(i * max_state) + j]);
+				stats->trans_table[(i * max_state) + j]);
 		len += sprintf(buf + len, "%10llu\n", (u64)
-			jiffies64_to_msecs(devfreq->time_in_state[i]));
+			jiffies64_to_msecs(stats->time_in_state[i]));
 	}
 
 	len += sprintf(buf + len, "Total transition : %u\n",
-					devfreq->total_trans);
+					stats->total_trans);
 	return len;
 }
 
@@ -1484,16 +1495,17 @@ static ssize_t trans_stat_store(struct device *dev,
 				const char *buf, size_t count)
 {
 	struct devfreq *df = to_devfreq(dev);
-	unsigned int cnt = df->profile->max_state;
+	struct devfreq_stats *stats = df->stats;
+	unsigned int cnt = stats->max_state;
 
 	if (cnt == 0)
 		return count;
 
 	mutex_lock(&df->lock);
-	memset(df->time_in_state, 0, cnt * sizeof(u64));
-	memset(df->trans_table, 0, cnt * cnt * sizeof(int));
-	df->last_stat_updated = get_jiffies_64();
-	df->total_trans = 0;
+	memset(stats->time_in_state, 0, cnt * sizeof(u64));
+	memset(stats->trans_table, 0, cnt * cnt * sizeof(int));
+	stats->last_stat_updated = get_jiffies_64();
+	stats->total_trans = 0;
 	mutex_unlock(&df->lock);
 
 	return count;
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index b81a86e47fb9..2715719924e7 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -106,6 +106,25 @@ struct devfreq_dev_profile {
 	unsigned int max_state;
 };
 
+/**
+ * struct devfreq_stats - Devfreq's transitions stats counters
+ * @freq_table:		List of frequencies in ascending order.
+ * @max_state:		The size of freq_table.
+ * @total_trans:	Number of devfreq transitions.
+ * @trans_table:	Statistics of devfreq transitions.
+ * @time_in_state:	Statistics of devfreq states.
+ * @last_stat_updated:	The last time stats were updated.
+ */
+struct devfreq_stats {
+	unsigned long *freq_table;
+	unsigned int max_state;
+
+	unsigned int total_trans;
+	unsigned int *trans_table;
+	u64 *time_in_state;
+	unsigned long long last_stat_updated;
+};
+
 /**
  * struct devfreq - Device devfreq structure
  * @node:	list node - contains the devices with devfreq that have been
@@ -131,10 +150,7 @@ struct devfreq_dev_profile {
  * @suspend_freq:	 frequency of a device set during suspend phase.
  * @resume_freq:	 frequency of a device set in resume phase.
  * @suspend_count:	 suspend requests counter for a device.
- * @total_trans:	Number of devfreq transitions
- * @trans_table:	Statistics of devfreq transitions
- * @time_in_state:	Statistics of devfreq states
- * @last_stat_updated:	The last time stat updated
+ * @stats:	Statistics of devfreq transitions and states times
  * @transition_notifier_list: list head of DEVFREQ_TRANSITION_NOTIFIER notifier
  *
  * This structure stores the devfreq information for a give device.
@@ -171,11 +187,8 @@ struct devfreq {
 	unsigned long resume_freq;
 	atomic_t suspend_count;
 
-	/* information for device frequency transition */
-	unsigned int total_trans;
-	unsigned int *trans_table;
-	u64 *time_in_state;
-	unsigned long long last_stat_updated;
+	/* information for device frequency transitions */
+	struct devfreq_stats *stats;
 
 	struct srcu_notifier_head transition_notifier_list;
 };
-- 
2.24.0