From cf1fac943c6341dfed1db1293864c9fcad47bac3 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 19 Nov 2020 11:24:32 +0530 Subject: 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: Rob Clark Signed-off-by: Viresh Kumar --- drivers/opp/core.c | 94 +++++++++++++++++++++++++++--------------------------- 1 file changed, 47 insertions(+), 47 deletions(-) (limited to 'drivers/opp/core.c') diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 9915e8487f0b..27a0e49b24ab 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -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 @@ unlock: 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); - count++; - } + /* + * 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--) -- cgit v1.2.3-59-g8ed1b