[PATCH v1] thermal: core: Drop excessive lockdep_assert_held() calls

From: Rafael J. Wysocki
Date: Tue Mar 28 2023 - 14:43:57 EST


From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

The lockdep_assert_held() calls added to cooling_device_stats_setup()
and cooling_device_stats_destroy() by commit 790930f44289 ("thermal:
core: Introduce thermal_cooling_device_update()") trigger false-positive
lockdep reports in code paths that are not subject to race conditions
(before cooling device registration and after cooling device removal).

For this reason, remove the lockdep_assert_held() calls from both
cooling_device_stats_setup() and cooling_device_stats_destroy() and
add one to thermal_cooling_device_stats_reinit() that has to be called
under the cdev lock.

Fixes: 790930f44289 ("thermal: core: Introduce thermal_cooling_device_update()")
Link: https://lore.kernel.org/linux-acpi/ZCIDTLFt27Ei7+V6@xxxxxxxxxxxxxxxxxxxxxxx
Reported-by: Imre Deak <imre.deak@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/thermal/thermal_sysfs.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

Index: linux-pm/drivers/thermal/thermal_sysfs.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_sysfs.c
+++ linux-pm/drivers/thermal/thermal_sysfs.c
@@ -876,8 +876,6 @@ static void cooling_device_stats_setup(s
unsigned long states = cdev->max_state + 1;
int var;

- lockdep_assert_held(&cdev->lock);
-
var = sizeof(*stats);
var += sizeof(*stats->time_in_state) * states;
var += sizeof(*stats->trans_table) * states * states;
@@ -903,8 +901,6 @@ out:

static void cooling_device_stats_destroy(struct thermal_cooling_device *cdev)
{
- lockdep_assert_held(&cdev->lock);
-
kfree(cdev->stats);
cdev->stats = NULL;
}
@@ -931,6 +927,8 @@ void thermal_cooling_device_destroy_sysf

void thermal_cooling_device_stats_reinit(struct thermal_cooling_device *cdev)
{
+ lockdep_assert_held(&cdev->lock);
+
cooling_device_stats_destroy(cdev);
cooling_device_stats_setup(cdev);
}