From 922ff0759a16299e24cacfc981ac07914d8f1826 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 31 Aug 2020 13:03:06 +0530 Subject: [PATCH 1/2] opp: Don't drop reference for an OPP table that was never parsed dev_pm_opp_remove_table() should drop a reference to the OPP table only if the DT OPP table was parsed earlier with a call to dev_pm_opp_of_add_table() earlier. Else it may end up dropping the reference to the OPP table, which was added as a result of other calls like dev_pm_opp_set_clkname(). And would hence result in undesirable behavior later on when caller would try to free the resource again. Fixes: 03758d60265c ("opp: Replace list_kref with a local counter") Reported-by: Naresh Kamboju Reported-by: Anders Roxell Tested-by: Naresh Kamboju Signed-off-by: Viresh Kumar --- drivers/opp/core.c | 22 ++++++++++++++++------ drivers/opp/opp.h | 2 +- 2 files changed, 17 insertions(+), 7 deletions(-) diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 9d7fb45b1786..31ce5d19ee9e 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -1291,13 +1291,19 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq) } EXPORT_SYMBOL_GPL(dev_pm_opp_remove); -void _opp_remove_all_static(struct opp_table *opp_table) +bool _opp_remove_all_static(struct opp_table *opp_table) { struct dev_pm_opp *opp, *tmp; + bool ret = true; mutex_lock(&opp_table->lock); - if (!opp_table->parsed_static_opps || --opp_table->parsed_static_opps) + if (!opp_table->parsed_static_opps) { + ret = false; + goto unlock; + } + + if (--opp_table->parsed_static_opps) goto unlock; list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) { @@ -1307,6 +1313,8 @@ void _opp_remove_all_static(struct opp_table *opp_table) unlock: mutex_unlock(&opp_table->lock); + + return ret; } /** @@ -2409,13 +2417,15 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev) return; } - _opp_remove_all_static(opp_table); + /* + * Drop the extra reference only if the OPP table was successfully added + * with dev_pm_opp_of_add_table() earlier. + **/ + if (_opp_remove_all_static(opp_table)) + dev_pm_opp_put_opp_table(opp_table); /* Drop reference taken by _find_opp_table() */ dev_pm_opp_put_opp_table(opp_table); - - /* Drop reference taken while the OPP table was added */ - dev_pm_opp_put_opp_table(opp_table); } /** diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h index e51646ff279e..c3fcd571e446 100644 --- a/drivers/opp/opp.h +++ b/drivers/opp/opp.h @@ -212,7 +212,7 @@ struct opp_table { /* Routines internal to opp core */ void dev_pm_opp_get(struct dev_pm_opp *opp); -void _opp_remove_all_static(struct opp_table *opp_table); +bool _opp_remove_all_static(struct opp_table *opp_table); void _get_opp_table_kref(struct opp_table *opp_table); int _get_opp_count(struct opp_table *opp_table); struct opp_table *_find_opp_table(struct device *dev); From ded10c47f39e0f850d53f5a2b418fbafdef53347 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Thu, 20 Aug 2020 15:46:20 +0530 Subject: [PATCH 2/2] cpufreq: imx6q: Unconditionally call dev_pm_opp_of_remove_table() dev_pm_opp_of_remove_table() doesn't report any errors when it fails to find the OPP table with error -ENODEV (i.e. OPP table not present for the device). And we can call dev_pm_opp_of_remove_table() unconditionally here. Signed-off-by: Viresh Kumar --- drivers/cpufreq/imx6q-cpufreq.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c index ef7b34c1fd2b..5bf5fc759881 100644 --- a/drivers/cpufreq/imx6q-cpufreq.c +++ b/drivers/cpufreq/imx6q-cpufreq.c @@ -48,7 +48,6 @@ static struct clk_bulk_data clks[] = { }; static struct device *cpu_dev; -static bool free_opp; static struct cpufreq_frequency_table *freq_table; static unsigned int max_freq; static unsigned int transition_latency; @@ -390,9 +389,6 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev) goto put_reg; } - /* Because we have added the OPPs here, we must free them */ - free_opp = true; - if (of_machine_is_compatible("fsl,imx6ul") || of_machine_is_compatible("fsl,imx6ull")) { ret = imx6ul_opp_check_speed_grading(cpu_dev); @@ -507,8 +503,7 @@ soc_opp_out: free_freq_table: dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); out_free_opp: - if (free_opp) - dev_pm_opp_of_remove_table(cpu_dev); + dev_pm_opp_of_remove_table(cpu_dev); put_reg: if (!IS_ERR(arm_reg)) regulator_put(arm_reg); @@ -528,8 +523,7 @@ static int imx6q_cpufreq_remove(struct platform_device *pdev) { cpufreq_unregister_driver(&imx6q_cpufreq_driver); dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table); - if (free_opp) - dev_pm_opp_of_remove_table(cpu_dev); + dev_pm_opp_of_remove_table(cpu_dev); regulator_put(arm_reg); if (!IS_ERR(pu_reg)) regulator_put(pu_reg);