[PATCH AUTOSEL 6.11 116/244] pmdomain: core: Don't hold the genpd-lock when calling dev_pm_domain_set()

Sasha Levin
2024-09-25T11:42:19Z

From: Ulf Hansson <ulf.hansson@linaro.org>

[ Upstream commit b87eee38605c396f0e1fa435939960e5c6cd41d6 ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pmdomain/core.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pmdomain/core.c b/drivers/pmdomain/core.c
index 7a61aa88c0614..7b2f8b1417de8 100644
--- a/drivers/pmdomain/core.c
+++ b/drivers/pmdomain/core.c
@@ -1758,7 +1758,6 @@ 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)
@@ -1767,6 +1766,7 @@ 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);
@@ -1823,12 +1823,13 @@ 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);

--
2.43.0