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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 <[email protected]> # v4.20
Reported-by: Valentin Schneider <[email protected]>
Fixes: 2a4eb7358a "OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()"
Signed-off-by: Viresh Kumar <[email protected]>
Tested-by: Valentin Schneider <[email protected]>
Reviewed-by: Sudeep Holla <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
This commit is contained in:
Viresh Kumar 2019-01-04 15:14:33 +05:30 • committed by Rafael J. Wysocki
commit 1690d8bb91
4 changed files with 67 additions and 9 deletions
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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;