[PATCH] opp: Don't drop reference for an OPP table that was never parsed
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REVIEWED: 1 (0M)
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2020-08-31 09:27:20
Also in:
lkml
Subsystem:
operating performance points (opp), the rest · Maintainers:
Viresh Kumar, Nishanth Menon, Stephen Boyd, Linus Torvalds
1 review trailer.
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 <redacted>
Reported-by: Anders Roxell <redacted>
Tested-by: Naresh Kamboju <redacted>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
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);
--
2.25.0.rc1.19.g042ed3e048af