Re: [PATCH 01/10] PM / OPP: Fix memory leak while adding duplicate OPPs

[Stephen Boyd <sboyd@codeaurora.org>]

On 12/06, Viresh Kumar wrote:
> 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>

Makes sense.

> ---
>  drivers/base/power/opp/core.c | 14 ++++++++++++--
>  drivers/base/power/opp/of.c   |  6 +++++-
>  2 files changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
> index a0e6294baf1d..cc69f903fd34 100644
> --- a/drivers/base/power/opp/core.c
> +++ b/drivers/base/power/opp/core.c
> @@ -1080,6 +1080,12 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
>  	return true;
>  }
>  
> +/*
> + * Returns:
> + * 0: On success. And appropriate error message for Duplicate OPPs.

lowercase duplicate please

> + * -EBUSY: For OPP with same freq/volt and is available.
> + * -EEXIST: For OPP with same freq but different volt or is unavailable.
> + */
>  int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
>  	     struct opp_table *opp_table)
>  {
> @@ -1112,7 +1118,7 @@ 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;
> @@ -1186,8 +1192,12 @@ 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 */

Yes, but why?

> +		if (ret == -EBUSY)
> +			ret = 0;
>  		goto free_opp;
> +	}
>  
>  	mutex_unlock(&opp_table_lock);
>  

-- 
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