[PATCH v4 5/9] PM / QoS: Teach lockdep about dev_pm_qos_mtx locking order

Rob Clark
2023-08-07T17:12:43Z

Annotate dev_pm_qos_mtx to teach lockdep to scream about allocations
that could trigger reclaim under dev_pm_qos_mtx.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
drivers/base/power/qos.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index 5ec06585b6d1..63cb1086f195 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -1017,3 +1017,14 @@ void dev_pm_qos_hide_latency_tolerance(struct device *dev)
pm_runtime_put(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_tolerance);
+
+static int __init dev_pm_qos_init(void)
+{
+ /* Teach lockdep about lock ordering wrt. shrinker: */
+ fs_reclaim_acquire(GFP_KERNEL);
+ might_lock(&dev_pm_qos_mtx);
+ fs_reclaim_release(GFP_KERNEL);
+
+ return 0;
+}
+early_initcall(dev_pm_qos_init);
--
2.41.0