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cpufreq: scpi/scmi: Fix freeing of dynamic OPPs

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Since the commit 2a4eb7358a "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: Valentin Schneider <valentin.schneider@arm.com>
Fixes: 2a4eb7358a "OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()"
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2019-01-04 15:14:33 +05:30 committed by Rafael J. Wysocki
parent 088d923a11
commit 1690d8bb91
4 changed files with 67 additions and 9 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
drivers/cpufreq/scmi-cpufreq.c
View file

@ -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;
}

4
drivers/cpufreq/scpi-cpufreq.c
View file

@ -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;
}

63
drivers/opp/core.c
View file

@ -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;

5
include/linux/pm_opp.h
View file

@ -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;