[PATCH 4/8] PM / devfreq: Don't take lock in devfreq_add_device

From: Leonard Crestez <leonard.crestez@nxp.com>
To: MyungJoo Ham <myungjoo.ham@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>
Cc: "Artur Świgoń" <a.swigon@partner.samsung.com>,
	"Abel Vesa" <abel.vesa@nxp.com>,
	"Saravana Kannan" <saravanak@google.com>,
	linux-pm@vger.kernel.org,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Chanwoo Choi" <cw00.choi@samsung.com>,
	"Alexandre Bailon" <abailon@baylibre.com>,
	"Georgi Djakov" <georgi.djakov@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	"Jacky Bai" <ping.bai@nxp.com>
Subject: [PATCH 4/8] PM / devfreq: Don't take lock in devfreq_add_device
Date: Wed, 18 Sep 2019 03:18:23 +0300	[thread overview]
Message-ID: <2fe8d1000bed5de70b08ed77fc8360d159ae4434.1568764439.git.leonard.crestez@nxp.com> (raw)
In-Reply-To: <cover.1568764439.git.leonard.crestez@nxp.com>
In-Reply-To: <cover.1568764439.git.leonard.crestez@nxp.com>

A device usually doesn't need to lock itself during initialization
because it is not yet reachable from other threads.

This simplifies the code and helps avoid recursive lock warnings.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
---
 drivers/devfreq/devfreq.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 57a217fc92de..860cbbab476c 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -634,11 +634,10 @@ struct devfreq *devfreq_add_device(struct device *dev,
 		err = -ENOMEM;
 		goto err_out;
 	}
 
 	mutex_init(&devfreq->lock);
-	mutex_lock(&devfreq->lock);
 	devfreq->dev.parent = dev;
 	devfreq->dev.class = devfreq_class;
 	devfreq->dev.release = devfreq_dev_release;
 	INIT_LIST_HEAD(&devfreq->node);
 	devfreq->profile = profile;
@@ -647,28 +646,24 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->last_status.current_frequency = profile->initial_freq;
 	devfreq->data = data;
 	devfreq->nb.notifier_call = devfreq_notifier_call;
 
 	if (!devfreq->profile->max_state && !devfreq->profile->freq_table) {
-		mutex_unlock(&devfreq->lock);
 		err = set_freq_table(devfreq);
 		if (err < 0)
 			goto err_dev;
-		mutex_lock(&devfreq->lock);
 	}
 
 	devfreq->scaling_min_freq = find_available_min_freq(devfreq);
 	if (!devfreq->scaling_min_freq) {
-		mutex_unlock(&devfreq->lock);
 		err = -EINVAL;
 		goto err_dev;
 	}
 	devfreq->min_freq = devfreq->scaling_min_freq;
 
 	devfreq->scaling_max_freq = find_available_max_freq(devfreq);
 	if (!devfreq->scaling_max_freq) {
-		mutex_unlock(&devfreq->lock);
 		err = -EINVAL;
 		goto err_dev;
 	}
 	devfreq->max_freq = devfreq->scaling_max_freq;
 
@@ -679,20 +674,18 @@ struct devfreq *devfreq_add_device(struct device *dev,
 			array3_size(sizeof(unsigned int),
 				    devfreq->profile->max_state,
 				    devfreq->profile->max_state),
 			GFP_KERNEL);
 	if (!devfreq->trans_table) {
-		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_dev;
 	}
 
 	devfreq->time_in_state = kcalloc(devfreq->profile->max_state,
 					 sizeof(unsigned long),
 					 GFP_KERNEL);
 	if (!devfreq->time_in_state) {
-		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_dev;
 	}
 
 	devfreq->last_stat_updated = jiffies;
@@ -701,17 +694,14 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	dev_set_name(&devfreq->dev, "devfreq%d",
 				atomic_inc_return(&devfreq_no));
 	err = device_register(&devfreq->dev);
 	if (err) {
-		mutex_unlock(&devfreq->lock);
 		put_device(&devfreq->dev);
 		goto err_out;
 	}
 
-	mutex_unlock(&devfreq->lock);
-
 	mutex_lock(&devfreq_list_lock);
 
 	governor = try_then_request_governor(devfreq->governor_name);
 	if (IS_ERR(governor)) {
 		dev_err(dev, "%s: Unable to find governor for the device\n",
-- 
2.17.1


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