pmdomain: core: Don't hold the genpd-lock when calling dev_pm_domain_set()

There is no need to hold the genpd-lock, while assigning the
dev->pm_domain. In fact, it becomes a problem on a PREEMPT_RT based
configuration as the genpd-lock may be a raw spinlock, while the lock
acquired through the call to dev_pm_domain_set() is a regular spinlock.

To fix the problem, let's simply move the calls to dev_pm_domain_set()
outside the genpd-lock.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Raghavendra Kakarla <quic_rkakarla@quicinc.com>  # qcm6490 with PREEMPT_RT set
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20240527142557.321610-3-ulf.hansson@linaro.org

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 8c798a46ffec046051f22c01c8f5b0197949a9c9..ef61486d41ee9921069beda28e3482def1506e76 100644 (file)
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -1800,7 +1800,6 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
        genpd_lock(genpd);
 
        genpd_set_cpumask(genpd, gpd_data->cpu);
-       dev_pm_domain_set(dev, &genpd->domain);
 
        genpd->device_count++;
        if (gd)
@@ -1809,6 +1808,7 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
        list_add_tail(&gpd_data->base.list_node, &genpd->dev_list);
 
        genpd_unlock(genpd);
+       dev_pm_domain_set(dev, &genpd->domain);
  out:
        if (ret)
                genpd_free_dev_data(dev, gpd_data);
@@ -1865,12 +1865,13 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
                genpd->gd->max_off_time_changed = true;
 
        genpd_clear_cpumask(genpd, gpd_data->cpu);
-       dev_pm_domain_set(dev, NULL);
 
        list_del_init(&pdd->list_node);
 
        genpd_unlock(genpd);
 
+       dev_pm_domain_set(dev, NULL);
+
        if (genpd->detach_dev)
                genpd->detach_dev(genpd, dev);