linux-kernel - [PATCH 3/6] PM / devfreq: Reorder devfreq_add

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Date:   Tue, 24 Apr 2018 15:35:18 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/6] PM / devfreq: Reorder devfreq_add_device()

The devfreq lock is used to ensure that the devfreq object is fully
initialized before e.g. the sysfs interface is accessing it. Moving all
these operations before the device_register() call ensures the same
thing without a lock; as it's yet to be shared outside the current
context.

This allows us to simplify the locking done in devfreq_add_device().

Instead of using devres for trans_table and time_in_state we use the
release function to free them as the devfreq device is released.

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---
 drivers/devfreq/devfreq.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index d5b278b8f20e..2e50f5d9d92a 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -539,6 +539,8 @@ static void devfreq_dev_release(struct device *dev)
 		devfreq->profile->exit(devfreq->dev.parent);
 
 	mutex_destroy(&devfreq->lock);
+	kfree(devfreq->time_in_state);
+	kfree(devfreq->trans_table);
 	kfree(devfreq);
 }
 
@@ -617,6 +619,18 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 	devfreq->scaling_max_freq = devfreq->max_freq;
 
+	devfreq->trans_table =	kcalloc(devfreq->profile->max_state *
+					devfreq->profile->max_state,
+					sizeof(unsigned int),
+					GFP_KERNEL);
+	devfreq->time_in_state = kcalloc(devfreq->profile->max_state,
+					 sizeof(unsigned long),
+					 GFP_KERNEL);
+
+	devfreq->last_stat_updated = jiffies;
+
+	srcu_init_notifier_head(&devfreq->transition_notifier_list);
+
 	dev_set_name(&devfreq->dev, "devfreq%d",
 				atomic_inc_return(&devfreq_no));
 	err = device_register(&devfreq->dev);
@@ -625,19 +639,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		goto err_dev;
 	}
 
-	devfreq->trans_table =	devm_kzalloc(&devfreq->dev,
-						sizeof(unsigned int) *
-						devfreq->profile->max_state *
-						devfreq->profile->max_state,
-						GFP_KERNEL);
-	devfreq->time_in_state = devm_kzalloc(&devfreq->dev,
-						sizeof(unsigned long) *
-						devfreq->profile->max_state,
-						GFP_KERNEL);
-	devfreq->last_stat_updated = jiffies;
-
-	srcu_init_notifier_head(&devfreq->transition_notifier_list);
-
 	mutex_unlock(&devfreq->lock);
 
 	mutex_lock(&devfreq_list_lock);
@@ -669,6 +670,8 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 err_dev:
 	mutex_destroy(&devfreq->lock);
+	kfree(devfreq->time_in_state);
+	kfree(devfreq->trans_table);
 	kfree(devfreq);
 err_out:
 	return ERR_PTR(err);
-- 
2.16.2