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Commit 37a73ec0 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
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PM / OPP: Add per OPP table mutex 



Add per OPP table lock to protect opp_table->opp_list.

Note that at few places opp_list is used under the rcu_read_lock() and
so a mutex can't be added there for now. This will be fixed by a later
patch.

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 b6160e26

drivers/base/power/opp/core.c

+27 −4
Original line number Diff line number Diff line
@@ -854,6 +854,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev) 


	srcu_init_notifier_head(&opp_table->srcu_head);

	INIT_LIST_HEAD(&opp_table->opp_list);

	mutex_init(&opp_table->lock);



	/* Secure the device table modification */

	list_add_rcu(&opp_table->node, &opp_tables);
@@ -909,6 +910,7 @@ static void _free_opp_table(struct opp_table *opp_table) 
	/* dev_list must be empty now */

	WARN_ON(!list_empty(&opp_table->dev_list));



	mutex_destroy(&opp_table->lock);

	list_del_rcu(&opp_table->node);

	call_srcu(&opp_table->srcu_head.srcu, &opp_table->rcu_head,

		  _kfree_device_rcu);
@@ -969,6 +971,8 @@ static void _kfree_opp_rcu(struct rcu_head *head) 
 */

static void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp)

{

	mutex_lock(&opp_table->lock);



	/*

	 * Notify the changes in the availability of the operable

	 * frequency/voltage list.
@@ -978,6 +982,8 @@ static void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp) 
	list_del_rcu(&opp->node);

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



	mutex_unlock(&opp_table->lock);



	_remove_opp_table(opp_table);

}
@@ -1007,6 +1013,8 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) 
	if (IS_ERR(opp_table))

		goto unlock;



	mutex_lock(&opp_table->lock);



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

		if (opp->rate == freq) {

			found = true;
@@ -1014,6 +1022,8 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) 
		}

	}



	mutex_unlock(&opp_table->lock);



	if (!found) {

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

			 __func__, freq);
@@ -1083,7 +1093,7 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, 
	     struct opp_table *opp_table)

{

	struct dev_pm_opp *opp;

	struct list_head *head = &opp_table->opp_list;

	struct list_head *head;

	int ret;



	/*
@@ -1094,6 +1104,9 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, 
	 * loop, don't replace it with head otherwise it will become an infinite

	 * loop.

	 */

	mutex_lock(&opp_table->lock);

	head = &opp_table->opp_list;



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

		if (new_opp->rate > opp->rate) {

			head = &opp->node;
@@ -1110,12 +1123,17 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, 
			 new_opp->supplies[0].u_volt, new_opp->available);



		/* Should we compare voltages for all regulators here ? */

		return opp->available &&

		ret = opp->available &&

		      new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? -EBUSY : -EEXIST;



		mutex_unlock(&opp_table->lock);

		return ret;

	}



	new_opp->opp_table = opp_table;

	list_add_rcu(&new_opp->node, head);

	mutex_unlock(&opp_table->lock);



	new_opp->opp_table = opp_table;



	ret = opp_debug_create_one(new_opp, opp_table);

	if (ret)
@@ -1779,6 +1797,8 @@ static int _opp_set_availability(struct device *dev, unsigned long freq, 
		goto unlock;

	}



	mutex_lock(&opp_table->lock);



	/* Do we have the frequency? */

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

		if (tmp_opp->rate == freq) {
@@ -1786,6 +1806,9 @@ static int _opp_set_availability(struct device *dev, unsigned long freq, 
			break;

		}

	}



	mutex_unlock(&opp_table->lock);



	if (IS_ERR(opp)) {

		r = PTR_ERR(opp);

		goto unlock;

drivers/base/power/opp/opp.h

+2 −0
Original line number Diff line number Diff line
@@ -131,6 +131,7 @@ enum opp_table_access { 
 * @rcu_head:	RCU callback head used for deferred freeing

 * @dev_list:	list of devices that share these OPPs

 * @opp_list:	table of opps

 * @lock:	mutex protecting the opp_list.

 * @np:		struct device_node pointer for opp's DT node.

 * @clock_latency_ns_max: Max clock latency in nanoseconds.

 * @shared_opp: OPP is shared between multiple devices.
@@ -163,6 +164,7 @@ struct opp_table { 
	struct rcu_head rcu_head;

	struct list_head dev_list;

	struct list_head opp_list;

	struct mutex lock;



	struct device_node *np;

	unsigned long clock_latency_ns_max;