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PM / OPP: Fix memory leak while adding duplicate OPPs 

There are two types of duplicate OPPs that get different behavior from
the core:
A) An earlier OPP is marked 'available' and has same freq/voltages as
   the new one.
B) An earlier OPP with same frequency, but is marked 'unavailable' OR
   doesn't have same voltages as the new one.

The OPP core returns 0 for the first one, but -EEXIST for the second.

While the OPP core returns 0 for the first case, its callers don't free
the newly allocated OPP structure which isn't used anymore. Fix that by
returning -EBUSY instead of 0, but make the callers return 0 eventually.

As this isn't a critical fix, its not getting marked for stable kernel.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar 2017-01-02 14:40:55 +05:30 committed by Rafael J. Wysocki
parent 7a308bb301
commit 7f8538ebae
2 changed files with 21 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/base/power/opp/core.c
View File

@ -1067,6 +1067,16 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
return true;
}
/*
* Returns:
* 0: On success. And appropriate error message for duplicate OPPs.
* -EBUSY: For OPP with same freq/volt and is available. The callers of
* _opp_add() must return 0 if they receive -EBUSY from it. This is to make
* sure we don't print error messages unnecessarily if different parts of
* kernel try to initialize the OPP table.
* -EEXIST: For OPP with same freq but different volt or is unavailable. This
* should be considered an error by the callers of _opp_add().
*/
int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
struct opp_table *opp_table)
{
@ -1099,7 +1109,7 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
/* Should we compare voltages for all regulators here ? */
return opp->available &&
new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? 0 : -EEXIST;
new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? -EBUSY : -EEXIST;
}
new_opp->opp_table = opp_table;
@ -1173,8 +1183,12 @@ int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
new_opp->dynamic = dynamic;
ret = _opp_add(dev, new_opp, opp_table);
if (ret)
if (ret) {
/* Don't return error for duplicate OPPs */
if (ret == -EBUSY)
ret = 0;
goto free_opp;
}
mutex_unlock(&opp_table_lock);

6
drivers/base/power/opp/of.c
View File

@ -327,8 +327,12 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
goto free_opp;
ret = _opp_add(dev, new_opp, opp_table);
if (ret)
if (ret) {
/* Don't return error for duplicate OPPs */
if (ret == -EBUSY)
ret = 0;
goto free_opp;
}
/* OPP to select on device suspend */
if (of_property_read_bool(np, "opp-suspend")) {