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Commit 1690d8bb authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
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cpufreq: scpi/scmi: Fix freeing of dynamic OPPs 



Since the commit 2a4eb735 "OPP: Don't remove dynamic OPPs from
_dev_pm_opp_remove_table()", dynamically created OPP aren't
automatically removed anymore by dev_pm_opp_cpumask_remove_table(). This
affects the scpi and scmi cpufreq drivers which no longer free OPPs on
failures or on invocations of the policy->exit() callback.

Create a generic OPP helper dev_pm_opp_remove_all_dynamic() which can be
called from these drivers instead of dev_pm_opp_cpumask_remove_table().

In dev_pm_opp_remove_all_dynamic(), we need to make sure that the
opp_list isn't getting accessed simultaneously from other parts of the
OPP core while the helper is freeing dynamic OPPs, i.e. we can't drop
the opp_table->lock while traversing through the OPP list. And to
accomplish that, this patch also creates _opp_kref_release_unlocked()
which can be called from this new helper with the opp_table lock already
held.

Cc: 4.20 <stable@vger.kernel.org> # v4.20
Reported-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Fixes: 2a4eb735 "OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()"
Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Tested-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Reviewed-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 088d923a

drivers/cpufreq/scmi-cpufreq.c

+2 −2
Original line number Diff line number Diff line
@@ -176,7 +176,7 @@ static int scmi_cpufreq_init(struct cpufreq_policy *policy) 
out_free_priv:

	kfree(priv);

out_free_opp:

	dev_pm_opp_cpumask_remove_table(policy->cpus);

	dev_pm_opp_remove_all_dynamic(cpu_dev);



	return ret;

}
@@ -188,7 +188,7 @@ static int scmi_cpufreq_exit(struct cpufreq_policy *policy) 
	cpufreq_cooling_unregister(priv->cdev);

	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);

	kfree(priv);

	dev_pm_opp_cpumask_remove_table(policy->related_cpus);

	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);



	return 0;

}

drivers/cpufreq/scpi-cpufreq.c

+2 −2
Original line number Diff line number Diff line
@@ -177,7 +177,7 @@ static int scpi_cpufreq_init(struct cpufreq_policy *policy) 
out_free_priv:

	kfree(priv);

out_free_opp:

	dev_pm_opp_cpumask_remove_table(policy->cpus);

	dev_pm_opp_remove_all_dynamic(cpu_dev);



	return ret;

}
@@ -190,7 +190,7 @@ static int scpi_cpufreq_exit(struct cpufreq_policy *policy) 
	clk_put(priv->clk);

	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);

	kfree(priv);

	dev_pm_opp_cpumask_remove_table(policy->related_cpus);

	dev_pm_opp_remove_all_dynamic(priv->cpu_dev);



	return 0;

}

drivers/opp/core.c

+58 −5
Original line number Diff line number Diff line
@@ -988,11 +988,9 @@ void _opp_free(struct dev_pm_opp *opp) 
	kfree(opp);

}



static void _opp_kref_release(struct kref *kref)

static void _opp_kref_release(struct dev_pm_opp *opp,

			      struct opp_table *opp_table)

{

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

	struct opp_table *opp_table = opp->opp_table;



	/*

	 * Notify the changes in the availability of the operable

	 * frequency/voltage list.
@@ -1002,7 +1000,22 @@ static void _opp_kref_release(struct kref *kref) 
	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);

}
@@ -1013,10 +1026,16 @@ 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, &opp->opp_table->lock);

	kref_put_mutex(&opp->kref, _opp_kref_release_locked,

		       &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
@@ -1060,6 +1079,40 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) 
}

EXPORT_SYMBOL_GPL(dev_pm_opp_remove);



/**

 * dev_pm_opp_remove_all_dynamic() - Remove all dynamically created OPPs

 * @dev:	device for which we do this operation

 *

 * This function removes all dynamically created OPPs from the opp table.

 */

void dev_pm_opp_remove_all_dynamic(struct device *dev)

{

	struct opp_table *opp_table;

	struct dev_pm_opp *opp, *temp;

	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);

			count++;

		}

	}

	mutex_unlock(&opp_table->lock);



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

	while (count--)

		dev_pm_opp_put_opp_table(opp_table);



	/* Drop the reference taken by _find_opp_table() */

	dev_pm_opp_put_opp_table(opp_table);

}

EXPORT_SYMBOL_GPL(dev_pm_opp_remove_all_dynamic);



struct dev_pm_opp *_opp_allocate(struct opp_table *table)

{

	struct dev_pm_opp *opp;

include/linux/pm_opp.h

+5 −0
Original line number Diff line number Diff line
@@ -108,6 +108,7 @@ void dev_pm_opp_put(struct dev_pm_opp *opp); 
int dev_pm_opp_add(struct device *dev, unsigned long freq,

		   unsigned long u_volt);

void dev_pm_opp_remove(struct device *dev, unsigned long freq);

void dev_pm_opp_remove_all_dynamic(struct device *dev);



int dev_pm_opp_enable(struct device *dev, unsigned long freq);
@@ -217,6 +218,10 @@ static inline void dev_pm_opp_remove(struct device *dev, unsigned long freq) 
{

}



static inline void dev_pm_opp_remove_all_dynamic(struct device *dev)

{

}



static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)

{

	return 0;