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From: Leonard Crestez <leonard.crestez@nxp.com>
To: Chanwoo Choi <cw00.choi@samsung.com>,
	MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: "Kyungmin Park" <kyungmin.park@samsung.com>,
	"Artur Świgoń" <a.swigon@partner.samsung.com>,
	"Saravana Kannan" <saravanak@google.com>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Alexandre Bailon" <abailon@baylibre.com>,
	"Georgi Djakov" <georgi.djakov@linaro.org>,
	"Abel Vesa" <abel.vesa@nxp.com>, "Jacky Bai" <ping.bai@nxp.com>,
	"Viresh Kumar" <viresh.kumar@linaro.org>,
	linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 1/6] PM / devfreq: Don't take lock in devfreq_add_device
Date: Mon, 26 Aug 2019 16:44:28 +0300	[thread overview]
Message-ID: <26a030f735922b0b9ec821491981baa3f46fa3a8.1566826075.git.leonard.crestez@nxp.com> (raw)
In-Reply-To: <cover.1566826075.git.leonard.crestez@nxp.com>
In-Reply-To: <cover.1566826075.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 afbe2a8f7529..15270293bea9 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -636,11 +636,10 @@ 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;
 	devfreq->profile = profile;
 	strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
@@ -648,28 +647,24 @@ 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;
 
@@ -678,42 +673,37 @@ 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;
 	}
 
 	devfreq->trans_table = devm_kzalloc(&devfreq->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_devfreq;
 	}
 
 	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
 			devfreq->profile->max_state,
 			sizeof(unsigned long),
 			GFP_KERNEL);
 	if (!devfreq->time_in_state) {
-		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
 	devfreq->last_stat_updated = jiffies;
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
-	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


WARNING: multiple messages have this Message-ID (diff)
From: Leonard Crestez <leonard.crestez@nxp.com>
To: Chanwoo Choi <cw00.choi@samsung.com>,
	MyungJoo Ham <myungjoo.ham@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>,
	"Kyungmin Park" <kyungmin.park@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 v4 1/6] PM / devfreq: Don't take lock in devfreq_add_device
Date: Mon, 26 Aug 2019 16:44:28 +0300	[thread overview]
Message-ID: <26a030f735922b0b9ec821491981baa3f46fa3a8.1566826075.git.leonard.crestez@nxp.com> (raw)
In-Reply-To: <cover.1566826075.git.leonard.crestez@nxp.com>
In-Reply-To: <cover.1566826075.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 afbe2a8f7529..15270293bea9 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -636,11 +636,10 @@ 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;
 	devfreq->profile = profile;
 	strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
@@ -648,28 +647,24 @@ 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;
 
@@ -678,42 +673,37 @@ 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;
 	}
 
 	devfreq->trans_table = devm_kzalloc(&devfreq->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_devfreq;
 	}
 
 	devfreq->time_in_state = devm_kcalloc(&devfreq->dev,
 			devfreq->profile->max_state,
 			sizeof(unsigned long),
 			GFP_KERNEL);
 	if (!devfreq->time_in_state) {
-		mutex_unlock(&devfreq->lock);
 		err = -ENOMEM;
 		goto err_devfreq;
 	}
 
 	devfreq->last_stat_updated = jiffies;
 
 	srcu_init_notifier_head(&devfreq->transition_notifier_list);
 
-	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


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-08-26 13:44 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-26 13:44 [PATCH v4 0/6] PM / devfreq: Add dev_pm_qos support Leonard Crestez
2019-08-26 13:44 ` Leonard Crestez
2019-08-26 13:44 ` Leonard Crestez [this message]
2019-08-26 13:44   ` [PATCH v4 1/6] PM / devfreq: Don't take lock in devfreq_add_device Leonard Crestez
2019-08-26 13:44 ` [PATCH v4 2/6] PM / devfreq: Add to devfreq_list immediately after registration Leonard Crestez
2019-08-26 13:44   ` Leonard Crestez
2019-08-26 13:44 ` [PATCH v4 3/6] PM / devfreq: Introduce devfreq_get_freq_range Leonard Crestez
2019-08-26 13:44   ` Leonard Crestez
2019-08-26 13:44 ` [PATCH v4 4/6] PM / devfreq: Add dev_pm_qos support Leonard Crestez
2019-08-26 13:44   ` Leonard Crestez
2019-08-26 13:44 ` [PATCH v4 5/6] PM / devfreq: Use dev_pm_qos for sysfs min/max_freq Leonard Crestez
2019-08-26 13:44   ` Leonard Crestez
2019-08-26 13:44 ` [PATCH v4 6/6] PM / devfreq: Move opp notifier registration to core Leonard Crestez
2019-08-26 13:44   ` Leonard Crestez
     [not found] <CGME20190917050135epcms1p15ba77f52d2a34db0236fd81107dba07f@epcms1p1>
2019-09-17  5:01 ` [PATCH v4 1/6] PM / devfreq: Don't take lock in devfreq_add_device MyungJoo Ham
2019-09-17  5:01   ` MyungJoo Ham
2019-09-17 20:07   ` Leonard Crestez
2019-09-17 20:07     ` Leonard Crestez

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