Re: [PATCH V4 3/9] PM / QOS: Keep common notifier list for genpd constraints

From: Ulf Hansson
Date: Wed Apr 19 2017 - 10:07:01 EST

On 20 March 2017 at 10:32, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> Only the resume_latency constraint uses the notifiers right now. In
> order to prepare for adding new constraint types with notifiers, move to
> a common notifier list.
>
> Update pm_qos_update_target() to pass a pointer to the constraint
> structure to the notifier callbacks. Also update the notifier callbacks
> as well to error out for unexpected constraints.
>
> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> ---
> drivers/base/power/domain.c | 26 +++++++++++++++++++-------
> drivers/base/power/qos.c | 15 ++++-----------
> include/linux/pm_qos.h | 7 +++++++
> kernel/power/qos.c | 2 +-
> 4 files changed, 31 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 1a0549f1944a..6e4e22aa14a2 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -416,14 +416,10 @@ static int genpd_power_on(struct generic_pm_domain *genpd, unsigned int depth)
> return ret;
> }
>
> -static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
> - unsigned long val, void *ptr)
> +static int __resume_latency_notifier(struct generic_pm_domain_data *gpd_data,
> + unsigned long val)

Could you perhaps rename this to genpd_latency_notifier(), as I think
it better follows the naming conventions in genpd.

> {
> - struct generic_pm_domain_data *gpd_data;
> - struct device *dev;
> -
> - gpd_data = container_of(nb, struct generic_pm_domain_data, nb);
> - dev = gpd_data->base.dev;
> + struct device *dev = gpd_data->base.dev;
>
> for (;;) {
> struct generic_pm_domain *genpd;
> @@ -456,6 +452,22 @@ static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
> return NOTIFY_DONE;
> }
>
> +static int genpd_dev_pm_qos_notifier(struct notifier_block *nb,
> + unsigned long val, void *ptr)
> +{
> + struct generic_pm_domain_data *gpd_data;
> + struct device *dev;
> +
> + gpd_data = container_of(nb, struct generic_pm_domain_data, nb);
> + dev = gpd_data->base.dev;
> +
> + if (dev_pm_qos_notifier_is_resume_latency(dev, ptr))
> + return __resume_latency_notifier(gpd_data, val);
> +
> + dev_err(dev, "%s: Unexpected notifier call\n", __func__);
> + return NOTIFY_BAD;
> +}
> +
> /**
> * genpd_power_off_work_fn - Power off PM domain whose subdomain count is 0.
> * @work: Work structure used for scheduling the execution of this function.
> diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
> index f850daeffba4..654d8a12c2e7 100644
> --- a/drivers/base/power/qos.c
> +++ b/drivers/base/power/qos.c
> @@ -172,18 +172,12 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
> {
> struct dev_pm_qos *qos;
> struct pm_qos_constraints *c;
> - struct blocking_notifier_head *n;
>
> qos = kzalloc(sizeof(*qos), GFP_KERNEL);
> if (!qos)
> return -ENOMEM;
>
> - n = kzalloc(sizeof(*n), GFP_KERNEL);
> - if (!n) {
> - kfree(qos);
> - return -ENOMEM;
> - }
> - BLOCKING_INIT_NOTIFIER_HEAD(n);
> + BLOCKING_INIT_NOTIFIER_HEAD(&qos->notifiers);
>
> c = &qos->resume_latency;
> plist_head_init(&c->list);
> @@ -191,7 +185,7 @@ static int dev_pm_qos_constraints_allocate(struct device *dev)
> c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
> c->no_constraint_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
> c->type = PM_QOS_MIN;
> - c->notifiers = n;
> + c->notifiers = &qos->notifiers;
>
> c = &qos->latency_tolerance;
> plist_head_init(&c->list);
> @@ -268,7 +262,6 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
> dev->power.qos = ERR_PTR(-ENODEV);
> spin_unlock_irq(&dev->power.lock);
>
> - kfree(qos->resume_latency.notifiers);
> kfree(qos);
>
> out:
> @@ -487,7 +480,7 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier)
> ret = dev_pm_qos_constraints_allocate(dev);
>
> if (!ret)
> - ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
> + ret = blocking_notifier_chain_register(&dev->power.qos->notifiers,
> notifier);
>
> mutex_unlock(&dev_pm_qos_mtx);
> @@ -514,7 +507,7 @@ int dev_pm_qos_remove_notifier(struct device *dev,
>
> /* Silently return if the constraints object is not present. */
> if (!IS_ERR_OR_NULL(dev->power.qos))
> - retval = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
> + retval = blocking_notifier_chain_unregister(&dev->power.qos->notifiers,
> notifier);
>
> mutex_unlock(&dev_pm_qos_mtx);
> diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
> index 032b55909145..bcae6abb3f21 100644
> --- a/include/linux/pm_qos.h
> +++ b/include/linux/pm_qos.h
> @@ -100,6 +100,7 @@ struct dev_pm_qos {
> struct dev_pm_qos_request *resume_latency_req;
> struct dev_pm_qos_request *latency_tolerance_req;
> struct dev_pm_qos_request *flags_req;
> + struct blocking_notifier_head notifiers; /* common for all constraints */
> };
>
> /* Action requested to pm_qos_update_target */
> @@ -114,6 +115,12 @@ static inline int dev_pm_qos_request_active(struct dev_pm_qos_request *req)
> return req->dev != NULL;
> }
>
> +static inline bool dev_pm_qos_notifier_is_resume_latency(struct device *dev,

A quite long name... Maybe we can remove "notifier", such as
:dev_pm_qos_is_resume_latency()?

> + struct pm_qos_constraints *c)
> +{
> + return &dev->power.qos->resume_latency == c;
> +}
> +
> int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
> enum pm_qos_req_action action, int value);
> bool pm_qos_update_flags(struct pm_qos_flags *pqf,
> diff --git a/kernel/power/qos.c b/kernel/power/qos.c
> index 97b0df71303e..073324e0c3c8 100644
> --- a/kernel/power/qos.c
> +++ b/kernel/power/qos.c
> @@ -315,7 +315,7 @@ int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
> if (c->notifiers)
> blocking_notifier_call_chain(c->notifiers,
> (unsigned long)curr_value,
> - NULL);
> + c);
> } else {
> ret = 0;
> }
> --
> 2.12.0.432.g71c3a4f4ba37
>

Besides the nitpicks above, feel free to add:

Acked-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>

Kind regards
Uffe