From: Viresh Kumar <viresh.kumar@linaro.org>
To: Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
Stephen Boyd <sboyd@kernel.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
linux-pm@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
Rafael Wysocki <rjw@rjwysocki.net>,
Ulf Hansson <ulf.hansson@linaro.org>,
Douglas Anderson <dianders@chromium.org>,
Naresh Kamboju <naresh.kamboju@linaro.org>,
Anders Roxell <anders.roxell@linaro.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH] opp: Don't drop reference for an OPP table that was never parsed
Date: Mon, 31 Aug 2020 14:56:56 +0530 [thread overview]
Message-ID: <922ff0759a16299e24cacfc981ac07914d8f1826.1598865786.git.viresh.kumar@linaro.org> (raw)
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 <naresh.kamboju@linaro.org>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
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
reply other threads:[~2020-08-31 9:27 UTC|newest]
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