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From: Bjorn Andersson <bjorn.andersson@linaro.org>
To: MyungJoo Ham <myungjoo.ham@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Chanwoo Choi <cw00.choi@samsung.com>
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 4/6] PM / devfreq: Remove unnecessary locking
Date: Tue, 24 Apr 2018 15:35:19 -0700	[thread overview]
Message-ID: <20180424223521.28193-5-bjorn.andersson@linaro.org> (raw)
In-Reply-To: <20180424223521.28193-1-bjorn.andersson@linaro.org>

The devfreq lock is used to prevent concurrent access to the devfreq
object, but as all operations leading up to the registration of the
devfreq device are local to devfreq_add_device() there's no reason to
hold the lock.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 drivers/devfreq/devfreq.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 2e50f5d9d92a..70588dc2032c 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -584,7 +584,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 
 	mutex_init(&devfreq->lock);
-	mutex_lock(&devfreq->lock);
 	devfreq->dev.parent = dev;
 	devfreq->dev.class = devfreq_class;
 	devfreq->dev.release = devfreq_dev_release;
@@ -596,16 +595,13 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	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->min_freq = find_available_min_freq(devfreq);
 	if (!devfreq->min_freq) {
-		mutex_unlock(&devfreq->lock);
 		err = -EINVAL;
 		goto err_dev;
 	}
@@ -613,7 +609,6 @@ struct devfreq *devfreq_add_device(struct device *dev,
 
 	devfreq->max_freq = find_available_max_freq(devfreq);
 	if (!devfreq->max_freq) {
-		mutex_unlock(&devfreq->lock);
 		err = -EINVAL;
 		goto err_dev;
 	}
@@ -635,12 +630,9 @@ struct devfreq *devfreq_add_device(struct device *dev,
 				atomic_inc_return(&devfreq_no));
 	err = device_register(&devfreq->dev);
 	if (err) {
-		mutex_unlock(&devfreq->lock);
 		goto err_dev;
 	}
 
-	mutex_unlock(&devfreq->lock);
-
 	mutex_lock(&devfreq_list_lock);
 	list_add(&devfreq->node, &devfreq_list);
 
-- 
2.16.2

  parent reply	other threads:[~2018-04-24 22:36 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-24 22:35 [PATCH 0/6] Misc devfreq_add_device() fixes Bjorn Andersson
2018-04-24 22:35 ` [PATCH 1/6] PM / devfreq: Free devfreq upon set_freq_table error Bjorn Andersson
2018-04-24 22:35 ` [PATCH 2/6] PM / devfreq: Use the device release function for cleanup Bjorn Andersson
2018-04-24 22:35 ` [PATCH 3/6] PM / devfreq: Reorder devfreq_add_device() Bjorn Andersson
2018-04-24 22:35 ` Bjorn Andersson [this message]
2018-04-24 22:35 ` [PATCH 5/6] PM / devfreq: Use put_device() on device_register error Bjorn Andersson
2018-04-24 22:35 ` [PATCH 6/6] PM / devfreq: Reject client provided freq_table Bjorn Andersson

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