Re: [PATCH 1/4] PM / OPP: add some lockdep annotations

From: Viresh Kumar
Date: Tue Dec 16 2014 - 23:10:49 EST


On 17 December 2014 at 04:39, Dmitry Torokhov <dtor@xxxxxxxxxxxx> wrote:
> Certain OPP APIs need to be called under RCU lock; let's add a few
> rcu_lockdep_assert() calls to warn about potential misuse.
>
> Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxxxx>
> ---
> drivers/base/power/opp.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
>
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index d24dd614a..b78c14d 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -108,6 +108,14 @@ static LIST_HEAD(dev_opp_list);
> /* Lock to allow exclusive modification to the device and opp lists */
> static DEFINE_MUTEX(dev_opp_list_lock);
>
> +#define opp_rcu_lockdep_assert() \
> +do { \
> + rcu_lockdep_assert(rcu_read_lock_held() || \
> + lockdep_is_held(&dev_opp_list_lock), \
> + "Missing rcu_read_lock() or " \
> + "dev_opp_list_lock protection"); \
> +} while (0)
> +
> /**
> * find_device_opp() - find device_opp struct using device pointer
> * @dev: device pointer used to lookup device OPPs
> @@ -218,6 +226,8 @@ int dev_pm_opp_get_opp_count(struct device *dev)
> struct dev_pm_opp *temp_opp;
> int count = 0;
>
> + opp_rcu_lockdep_assert();
> +
> dev_opp = find_device_opp(dev);
> if (IS_ERR(dev_opp)) {
> int r = PTR_ERR(dev_opp);
> @@ -267,6 +277,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
> struct device_opp *dev_opp;
> struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
>
> + opp_rcu_lockdep_assert();
> +
> dev_opp = find_device_opp(dev);
> if (IS_ERR(dev_opp)) {
> int r = PTR_ERR(dev_opp);
> @@ -313,6 +325,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
> struct device_opp *dev_opp;
> struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
>
> + opp_rcu_lockdep_assert();
> +
> if (!dev || !freq) {
> dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
> return ERR_PTR(-EINVAL);
> @@ -361,6 +375,8 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
> struct device_opp *dev_opp;
> struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
>
> + opp_rcu_lockdep_assert();
> +
> if (!dev || !freq) {
> dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
> return ERR_PTR(-EINVAL);

Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
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