| Message ID | 1441303892-32004-2-git-send-email-b.zolnierkie@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 03-09-15, 20:11, Bartlomiej Zolnierkiewicz wrote: > Add dev_pm_opp_get_suspend_opp() helper to obtain suspend opp. > > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: Thomas Abraham <thomas.ab@samsung.com> > Cc: Javier Martinez Canillas <javier@osg.samsung.com> > Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Cc: Marek Szyprowski <m.szyprowski@samsung.com> > Cc: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > --- > drivers/base/power/opp.c | 28 ++++++++++++++++++++++++++++ > include/linux/pm_opp.h | 6 ++++++ > 2 files changed, 34 insertions(+) > > diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c > index eb25449..eaafca7 100644 > --- a/drivers/base/power/opp.c > +++ b/drivers/base/power/opp.c > @@ -341,6 +341,34 @@ unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev) > EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency); > > /** > + * dev_pm_opp_get_suspend_opp() - Get suspend opp > + * @dev: device for which we do this operation > + * > + * Return: This function returns pointer to the suspend opp if it is > + * defined, otherwise it returns NULL. > + * > + * Locking: This function takes rcu_read_lock(). > + */ > +struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev) > +{ > + struct device_opp *dev_opp; > + struct dev_pm_opp *suspend_opp; > + > + rcu_read_lock(); This is wrong. Please have a look at other exported APIs that return an OPP. RCU protected structures must be accessed from within RCU locks _ONLY_. But your function returns the pointer after dropping the locks. Which essentially means that the OPP can be freed by core, by the time you start using it. :) So, in such cases, its upto the caller to ensure that locks are taken properly. You can look at dev_pm_opp_find_freq_exact() as an example.
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index eb25449..eaafca7 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -341,6 +341,34 @@ unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev) EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency); /** + * dev_pm_opp_get_suspend_opp() - Get suspend opp + * @dev: device for which we do this operation + * + * Return: This function returns pointer to the suspend opp if it is + * defined, otherwise it returns NULL. + * + * Locking: This function takes rcu_read_lock(). + */ +struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev) +{ + struct device_opp *dev_opp; + struct dev_pm_opp *suspend_opp; + + rcu_read_lock(); + + dev_opp = _find_device_opp(dev); + if (IS_ERR(dev_opp)) + suspend_opp = NULL; + else + suspend_opp = dev_opp->suspend_opp; + + rcu_read_unlock(); + + return suspend_opp; +} +EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp); + +/** * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list * @dev: device for which we do this operation * diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h index cab7ba5..e817722 100644 --- a/include/linux/pm_opp.h +++ b/include/linux/pm_opp.h @@ -34,6 +34,7 @@ bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp); int dev_pm_opp_get_opp_count(struct device *dev); unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev); +struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev); struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, unsigned long freq, @@ -80,6 +81,11 @@ static inline unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev) return 0; } +static inline struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev) +{ + return NULL; +} + static inline struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev, unsigned long freq, bool available) {
Add dev_pm_opp_get_suspend_opp() helper to obtain suspend opp. Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Thomas Abraham <thomas.ab@samsung.com> Cc: Javier Martinez Canillas <javier@osg.samsung.com> Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Tobias Jakobi <tjakobi@math.uni-bielefeld.de> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> --- drivers/base/power/opp.c | 28 ++++++++++++++++++++++++++++ include/linux/pm_opp.h | 6 ++++++ 2 files changed, 34 insertions(+)