From 84a8cbf64731568c0750137ec38091a46b81d502 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Fri, 4 Jan 2019 15:14:33 +0530 Subject: [PATCH] cpufreq: scpi/scmi: Fix freeing of dynamic OPPs Commit 1690d8bb91e370ab772062b79bd434ce815c4729 upstream Since the commit 2a4eb7358aba "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 # v4.20 Reported-by: Valentin Schneider Fixes: 2a4eb7358aba "OPP: Don't remove dynamic OPPs from _dev_pm_opp_remove_table()" Signed-off-by: Viresh Kumar Tested-by: Valentin Schneider Reviewed-by: Sudeep Holla Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/scmi-cpufreq.c | 4 +-- drivers/cpufreq/scpi-cpufreq.c | 4 +-- drivers/opp/core.c | 63 +++++++++++++++++++++++++++++++--- include/linux/pm_opp.h | 5 +++ 4 files changed, 67 insertions(+), 9 deletions(-) --- a/drivers/cpufreq/scmi-cpufreq.c +++ b/drivers/cpufreq/scmi-cpufreq.c @@ -176,7 +176,7 @@ static int scmi_cpufreq_init(struct cpuf 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 cpuf 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; } --- a/drivers/cpufreq/scpi-cpufreq.c +++ b/drivers/cpufreq/scpi-cpufreq.c @@ -177,7 +177,7 @@ out_free_cpufreq_table: 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 cpuf 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; } --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -884,11 +884,9 @@ 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. @@ -897,7 +895,22 @@ static void _opp_kref_release(struct kre 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); dev_pm_opp_put_opp_table(opp_table); } @@ -909,10 +922,16 @@ void dev_pm_opp_get(struct dev_pm_opp *o 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 @@ -952,6 +971,40 @@ void dev_pm_opp_remove(struct device *de } 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; --- a/include/linux/pm_opp.h +++ b/include/linux/pm_opp.h @@ -107,6 +107,7 @@ void dev_pm_opp_put(struct dev_pm_opp *o 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); @@ -208,6 +209,10 @@ static inline void dev_pm_opp_remove(str { } +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;