Commit cf1fac94 authored by Viresh Kumar's avatar Viresh Kumar
Browse files

opp: Reduce the size of critical section in _opp_kref_release() 



There is a lot of stuff here which can be done outside of the
opp_table->lock, do that. This helps avoiding a circular dependency
lockdeps around debugfs.

Reported-by: default avatarRob Clark <robdclark@gmail.com>
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
parent 9e62edac

drivers/opp/core.c

+47 −47
Original line number Diff line number Diff line
@@ -1252,9 +1252,14 @@ void _opp_free(struct dev_pm_opp *opp) 
	kfree(opp);

}



static void _opp_kref_release(struct dev_pm_opp *opp,

			      struct opp_table *opp_table)

static void _opp_kref_release(struct kref *kref)

{

	struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);

	struct opp_table *opp_table = opp->opp_table;



	list_del(&opp->node);

	mutex_unlock(&opp_table->lock);



	/*

	 * Notify the changes in the availability of the operable

	 * frequency/voltage list.
@@ -1262,27 +1267,9 @@ static void _opp_kref_release(struct dev_pm_opp *opp, 
	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_REMOVE, opp);

	_of_opp_free_required_opps(opp_table, opp);

	opp_debug_remove_one(opp);

	list_del(&opp->node);

	kfree(opp);

}



static void _opp_kref_release_unlocked(struct kref *kref)

{

	struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);

	struct opp_table *opp_table = opp->opp_table;



	_opp_kref_release(opp, opp_table);

}



static void _opp_kref_release_locked(struct kref *kref)

{

	struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);

	struct opp_table *opp_table = opp->opp_table;



	_opp_kref_release(opp, opp_table);

	mutex_unlock(&opp_table->lock);

}



void dev_pm_opp_get(struct dev_pm_opp *opp)

{

	kref_get(&opp->kref);
@@ -1290,16 +1277,10 @@ void dev_pm_opp_get(struct dev_pm_opp *opp) 


void dev_pm_opp_put(struct dev_pm_opp *opp)

{

	kref_put_mutex(&opp->kref, _opp_kref_release_locked,

		       &opp->opp_table->lock);

	kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock);

}

EXPORT_SYMBOL_GPL(dev_pm_opp_put);



static void dev_pm_opp_put_unlocked(struct dev_pm_opp *opp)

{

	kref_put(&opp->kref, _opp_kref_release_unlocked);

}



/**

 * dev_pm_opp_remove()  - Remove an OPP from OPP table

 * @dev:	device for which we do this operation
@@ -1343,30 +1324,49 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) 
}

EXPORT_SYMBOL_GPL(dev_pm_opp_remove);



static struct dev_pm_opp *_opp_get_next(struct opp_table *opp_table,

					bool dynamic)

{

	struct dev_pm_opp *opp = NULL, *temp;



	mutex_lock(&opp_table->lock);

	list_for_each_entry(temp, &opp_table->opp_list, node) {

		if (dynamic == temp->dynamic) {

			opp = temp;

			break;

		}

	}



	mutex_unlock(&opp_table->lock);

	return opp;

}



bool _opp_remove_all_static(struct opp_table *opp_table)

{

	struct dev_pm_opp *opp, *tmp;

	bool ret = true;

	struct dev_pm_opp *opp;



	mutex_lock(&opp_table->lock);



	if (!opp_table->parsed_static_opps) {

		ret = false;

		goto unlock;

		mutex_unlock(&opp_table->lock);

		return false;

	}



	if (--opp_table->parsed_static_opps)

		goto unlock;



	list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) {

		if (!opp->dynamic)

			dev_pm_opp_put_unlocked(opp);

	if (--opp_table->parsed_static_opps) {

		mutex_unlock(&opp_table->lock);

		return true;

	}



unlock:

	mutex_unlock(&opp_table->lock);



	return ret;

	/*

	 * Can't remove the OPP from under the lock, debugfs removal needs to

	 * happen lock less to avoid circular dependency issues.

	 */

	while ((opp = _opp_get_next(opp_table, false)))

		dev_pm_opp_put(opp);



	return true;

}



/**
@@ -1378,21 +1378,21 @@ bool _opp_remove_all_static(struct opp_table *opp_table) 
void dev_pm_opp_remove_all_dynamic(struct device *dev)

{

	struct opp_table *opp_table;

	struct dev_pm_opp *opp, *temp;

	struct dev_pm_opp *opp;

	int count = 0;



	opp_table = _find_opp_table(dev);

	if (IS_ERR(opp_table))

		return;



	mutex_lock(&opp_table->lock);

	list_for_each_entry_safe(opp, temp, &opp_table->opp_list, node) {

		if (opp->dynamic) {

			dev_pm_opp_put_unlocked(opp);

	/*

	 * Can't remove the OPP from under the lock, debugfs removal needs to

	 * happen lock less to avoid circular dependency issues.

	 */

	while ((opp = _opp_get_next(opp_table, true))) {

		dev_pm_opp_put(opp);

		count++;

	}

	}

	mutex_unlock(&opp_table->lock);



	/* Drop the references taken by dev_pm_opp_add() */

	while (count--)