Commit 5b650b38 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

PM / OPP: Take kref from _find_opp_table() 



Take reference of the OPP table from within _find_opp_table(). Also
update the callers of _find_opp_table() to call
dev_pm_opp_put_opp_table() after they have used the OPP table.

Note that _find_opp_table() increments the reference under the
opp_table_lock.

Now that the OPP table wouldn't get freed until the callers of
_find_opp_table() call dev_pm_opp_put_opp_table(), there is no need to
take the opp_table_lock or rcu_read_lock() around it. Drop them.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 8a31d9d9

drivers/base/power/opp/core.c

+86 −105
Original line number Diff line number Diff line
@@ -54,6 +54,21 @@ static struct opp_device *_find_opp_dev(const struct device *dev, 
	return NULL;

}



struct opp_table *_find_opp_table_unlocked(struct device *dev)

{

	struct opp_table *opp_table;



	list_for_each_entry(opp_table, &opp_tables, node) {

		if (_find_opp_dev(dev, opp_table)) {

			_get_opp_table_kref(opp_table);



			return opp_table;

		}

	}



	return ERR_PTR(-ENODEV);

}



/**

 * _find_opp_table() - find opp_table struct using device pointer

 * @dev:	device pointer used to lookup OPP table
@@ -64,28 +79,22 @@ static struct opp_device *_find_opp_dev(const struct device *dev, 
 * Return: pointer to 'struct opp_table' if found, otherwise -ENODEV or

 * -EINVAL based on type of error.

 *

 * Locking: For readers, this function must be called under rcu_read_lock().

 * opp_table is a RCU protected pointer, which means that opp_table is valid

 * as long as we are under RCU lock.

 *

 * For Writers, this function must be called with opp_table_lock held.

 * The callers must call dev_pm_opp_put_opp_table() after the table is used.

 */

struct opp_table *_find_opp_table(struct device *dev)

{

	struct opp_table *opp_table;



	opp_rcu_lockdep_assert();



	if (IS_ERR_OR_NULL(dev)) {

		pr_err("%s: Invalid parameters\n", __func__);

		return ERR_PTR(-EINVAL);

	}



	list_for_each_entry_rcu(opp_table, &opp_tables, node)

		if (_find_opp_dev(dev, opp_table))

			return opp_table;

	mutex_lock(&opp_table_lock);

	opp_table = _find_opp_table_unlocked(dev);

	mutex_unlock(&opp_table_lock);



	return ERR_PTR(-ENODEV);

	return opp_table;

}



/**
@@ -175,23 +184,20 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo); 
 * @dev:	device for which we do this operation

 *

 * Return: This function returns the max clock latency in nanoseconds.

 *

 * Locking: This function takes rcu_read_lock().

 */

unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)

{

	struct opp_table *opp_table;

	unsigned long clock_latency_ns;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table))

		clock_latency_ns = 0;

	else

		return 0;



	clock_latency_ns = opp_table->clock_latency_ns_max;



	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return clock_latency_ns;

}

EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
@@ -201,15 +207,13 @@ static int _get_regulator_count(struct device *dev) 
	struct opp_table *opp_table;

	int count;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (!IS_ERR(opp_table))

	if (IS_ERR(opp_table))

		return 0;



	count = opp_table->regulator_count;

	else

		count = 0;



	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return count;

}
@@ -248,13 +252,11 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev) 
	if (!uV)

		goto free_regulators;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		rcu_read_unlock();

	if (IS_ERR(opp_table))

		goto free_uV;

	}



	rcu_read_lock();



	memcpy(regulators, opp_table->regulators, count * sizeof(*regulators));
@@ -274,6 +276,7 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev) 
	}



	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	/*

	 * The caller needs to ensure that opp_table (and hence the regulator)
@@ -323,17 +326,15 @@ unsigned long dev_pm_opp_get_suspend_opp_freq(struct device *dev) 
	struct opp_table *opp_table;

	unsigned long freq = 0;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table) || !opp_table->suspend_opp ||

	    !opp_table->suspend_opp->available)

		goto unlock;

	if (IS_ERR(opp_table))

		return 0;



	if (opp_table->suspend_opp && opp_table->suspend_opp->available)

		freq = dev_pm_opp_get_freq(opp_table->suspend_opp);



unlock:

	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return freq;

}

EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp_freq);
@@ -353,23 +354,24 @@ int dev_pm_opp_get_opp_count(struct device *dev) 
	struct dev_pm_opp *temp_opp;

	int count = 0;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		count = PTR_ERR(opp_table);

		dev_err(dev, "%s: OPP table not found (%d)\n",

			__func__, count);

		goto out_unlock;

		return count;

	}



	rcu_read_lock();



	list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {

		if (temp_opp->available)

			count++;

	}



out_unlock:

	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return count;

}

EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
@@ -404,17 +406,16 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, 
	struct opp_table *opp_table;

	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		int r = PTR_ERR(opp_table);



		dev_err(dev, "%s: OPP table not found (%d)\n", __func__, r);

		rcu_read_unlock();

		return ERR_PTR(r);

	}



	rcu_read_lock();



	list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {

		if (temp_opp->available == available &&

				temp_opp->rate == freq) {
@@ -427,6 +428,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, 
	}



	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return opp;

}
@@ -480,17 +482,16 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev, 
		return ERR_PTR(-EINVAL);

	}



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		rcu_read_unlock();

	if (IS_ERR(opp_table))

		return ERR_CAST(opp_table);

	}



	rcu_read_lock();



	opp = _find_freq_ceil(opp_table, freq);



	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return opp;

}
@@ -525,13 +526,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, 
		return ERR_PTR(-EINVAL);

	}



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		rcu_read_unlock();

	if (IS_ERR(opp_table))

		return ERR_CAST(opp_table);

	}



	rcu_read_lock();



	list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {

		if (temp_opp->available) {
@@ -547,6 +546,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev, 
	if (!IS_ERR(opp))

		dev_pm_opp_get(opp);

	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	if (!IS_ERR(opp))

		*freq = opp->rate;
@@ -564,22 +564,18 @@ static struct clk *_get_opp_clk(struct device *dev) 
	struct opp_table *opp_table;

	struct clk *clk;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		dev_err(dev, "%s: device opp doesn't exist\n", __func__);

		clk = ERR_CAST(opp_table);

		goto unlock;

		return ERR_CAST(opp_table);

	}



	clk = opp_table->clk;

	if (IS_ERR(clk))

		dev_err(dev, "%s: No clock available for the device\n",

			__func__);

	dev_pm_opp_put_opp_table(opp_table);



unlock:

	rcu_read_unlock();

	return clk;

}
@@ -715,15 +711,14 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) 
		return 0;

	}



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		dev_err(dev, "%s: device opp doesn't exist\n", __func__);

		rcu_read_unlock();

		return PTR_ERR(opp_table);

	}



	rcu_read_lock();



	old_opp = _find_freq_ceil(opp_table, &old_freq);

	if (IS_ERR(old_opp)) {

		dev_err(dev, "%s: failed to find current OPP for freq %lu (%ld)\n",
@@ -738,6 +733,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) 
		if (!IS_ERR(old_opp))

			dev_pm_opp_put(old_opp);

		rcu_read_unlock();

		dev_pm_opp_put_opp_table(opp_table);

		return ret;

	}
@@ -752,6 +748,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) 
		if (!IS_ERR(old_opp))

			dev_pm_opp_put(old_opp);

		rcu_read_unlock();

		dev_pm_opp_put_opp_table(opp_table);

		return _generic_set_opp_clk_only(dev, clk, old_freq, freq);

	}
@@ -780,6 +777,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq) 
	if (!IS_ERR(old_opp))

		dev_pm_opp_put(old_opp);

	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return set_opp(data);

}
@@ -893,11 +891,9 @@ struct opp_table *dev_pm_opp_get_opp_table(struct device *dev) 
	/* Hold our table modification lock here */

	mutex_lock(&opp_table_lock);



	opp_table = _find_opp_table(dev);

	if (!IS_ERR(opp_table)) {

		_get_opp_table_kref(opp_table);

	opp_table = _find_opp_table_unlocked(dev);

	if (!IS_ERR(opp_table))

		goto unlock;

	}



	opp_table = _allocate_opp_table(dev);
@@ -1004,12 +1000,9 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) 
	struct opp_table *opp_table;

	bool found = false;



	/* Hold our table modification lock here */

	mutex_lock(&opp_table_lock);



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table))

		goto unlock;

		return;



	mutex_lock(&opp_table->lock);
@@ -1022,15 +1015,14 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) 


	mutex_unlock(&opp_table->lock);



	if (!found) {

	if (found) {

		dev_pm_opp_put(opp);

	} else {

		dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",

			 __func__, freq);

		goto unlock;

	}



	dev_pm_opp_put(opp);

unlock:

	mutex_unlock(&opp_table_lock);

	dev_pm_opp_put_opp_table(opp_table);

}

EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
@@ -1648,14 +1640,12 @@ static int _opp_set_availability(struct device *dev, unsigned long freq, 
	if (!new_opp)

		return -ENOMEM;



	mutex_lock(&opp_table_lock);



	/* Find the opp_table */

	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		r = PTR_ERR(opp_table);

		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);

		goto unlock;

		goto free_opp;

	}



	mutex_lock(&opp_table->lock);
@@ -1668,8 +1658,6 @@ static int _opp_set_availability(struct device *dev, unsigned long freq, 
		}

	}



	mutex_unlock(&opp_table->lock);



	if (IS_ERR(opp)) {

		r = PTR_ERR(opp);

		goto unlock;
@@ -1685,7 +1673,6 @@ static int _opp_set_availability(struct device *dev, unsigned long freq, 
	new_opp->available = availability_req;



	list_replace_rcu(&opp->node, &new_opp->node);

	mutex_unlock(&opp_table_lock);

	call_srcu(&opp_table->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);



	/* Notify the change of the OPP availability */
@@ -1696,10 +1683,14 @@ static int _opp_set_availability(struct device *dev, unsigned long freq, 
		srcu_notifier_call_chain(&opp_table->srcu_head,

					 OPP_EVENT_DISABLE, new_opp);



	mutex_unlock(&opp_table->lock);

	dev_pm_opp_put_opp_table(opp_table);

	return 0;



unlock:

	mutex_unlock(&opp_table_lock);

	mutex_unlock(&opp_table->lock);

	dev_pm_opp_put_opp_table(opp_table);

free_opp:

	kfree(new_opp);

	return r;

}
@@ -1767,18 +1758,16 @@ int dev_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb) 
	struct opp_table *opp_table;

	int ret;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		ret = PTR_ERR(opp_table);

		goto unlock;

	}

	if (IS_ERR(opp_table))

		return PTR_ERR(opp_table);



	rcu_read_lock();



	ret = srcu_notifier_chain_register(&opp_table->srcu_head, nb);



unlock:

	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return ret;

}
@@ -1797,18 +1786,14 @@ int dev_pm_opp_unregister_notifier(struct device *dev, 
	struct opp_table *opp_table;

	int ret;



	rcu_read_lock();



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {

		ret = PTR_ERR(opp_table);

		goto unlock;

	}

	if (IS_ERR(opp_table))

		return PTR_ERR(opp_table);



	ret = srcu_notifier_chain_unregister(&opp_table->srcu_head, nb);



unlock:

	rcu_read_unlock();

	dev_pm_opp_put_opp_table(opp_table);



	return ret;

}
@@ -1839,9 +1824,6 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all) 
{

	struct opp_table *opp_table;



	/* Hold our table modification lock here */

	mutex_lock(&opp_table_lock);



	/* Check for existing table for 'dev' */

	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table)) {
@@ -1852,13 +1834,12 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all) 
			     IS_ERR_OR_NULL(dev) ?

					"Invalid device" : dev_name(dev),

			     error);

		goto unlock;

		return;

	}



	_dev_pm_opp_remove_table(opp_table, dev, remove_all);



unlock:

	mutex_unlock(&opp_table_lock);

	dev_pm_opp_put_opp_table(opp_table);

}



/**

drivers/base/power/opp/cpu.c

+9 −17
Original line number Diff line number Diff line
@@ -174,13 +174,9 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, 
	struct device *dev;

	int cpu, ret = 0;



	mutex_lock(&opp_table_lock);



	opp_table = _find_opp_table(cpu_dev);

	if (IS_ERR(opp_table)) {

		ret = PTR_ERR(opp_table);

		goto unlock;

	}

	if (IS_ERR(opp_table))

		return PTR_ERR(opp_table);



	for_each_cpu(cpu, cpumask) {

		if (cpu == cpu_dev->id)
@@ -203,8 +199,8 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, 
		/* Mark opp-table as multiple CPUs are sharing it now */

		opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;

	}

unlock:

	mutex_unlock(&opp_table_lock);



	dev_pm_opp_put_opp_table(opp_table);



	return ret;

}
@@ -232,17 +228,13 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) 
	struct opp_table *opp_table;

	int ret = 0;



	mutex_lock(&opp_table_lock);



	opp_table = _find_opp_table(cpu_dev);

	if (IS_ERR(opp_table)) {

		ret = PTR_ERR(opp_table);

		goto unlock;

	}

	if (IS_ERR(opp_table))

		return PTR_ERR(opp_table);



	if (opp_table->shared_opp == OPP_TABLE_ACCESS_UNKNOWN) {

		ret = -EINVAL;

		goto unlock;

		goto put_opp_table;

	}



	cpumask_clear(cpumask);
@@ -254,8 +246,8 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask) 
		cpumask_set_cpu(cpu_dev->id, cpumask);

	}



unlock:

	mutex_unlock(&opp_table_lock);

put_opp_table:

	dev_pm_opp_put_opp_table(opp_table);



	return ret;

}

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