[PATCH v2 13/14] drm/xe/hwmon: Fix mutex destroy

[Lucas De Marchi]

On Thu, Feb 06, 2025 at 03:23:31PM -0800, Lucas De Marchi wrote:
>Since the mutex is used if userspace kept the fd open, it can't be
>released together with the dev cleanup and needs to be delayed. Also,
>there's no need to add an action just to release the mutex: use the
>specific drmm_mutex_init() that should be smarter if mutex_destroy() is
>actually a nop.
>
>Cc: Badal Nilawar <badal.nilawar at intel.com>
>Cc: Karthik Poosa <karthik.poosa at intel.com>
>Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>

oops... 3a13c2de442d6bfaef9c102cd1092e6cae22b753

the reasoning is true, but the entire thing is in struct devm allocated.
Then CI complains:

<4> [321.873848] WARNING: CPU: 13 PID: 12544 at kernel/locking/mutex-debug.c:114 mutex_destroy+0x5b/0x60


Lucas De Marchi

>---
> drivers/gpu/drm/xe/xe_hwmon.c | 10 +---------
> 1 file changed, 1 insertion(+), 9 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
>index 7f327e3342123..0fc91c184570d 100644
>--- a/drivers/gpu/drm/xe/xe_hwmon.c
>+++ b/drivers/gpu/drm/xe/xe_hwmon.c
>@@ -869,13 +869,6 @@ xe_hwmon_get_preregistration_info(struct xe_device *xe)
> 			xe_hwmon_energy_get(hwmon, channel, &energy);
> }
>
>-static void xe_hwmon_mutex_destroy(void *arg)
>-{
>-	struct xe_hwmon *hwmon = arg;
>-
>-	mutex_destroy(&hwmon->hwmon_lock);
>-}
>-
> void xe_hwmon_register(struct xe_device *xe)
> {
> 	struct device *dev = xe->drm.dev;
>@@ -895,8 +888,7 @@ void xe_hwmon_register(struct xe_device *xe)
>
> 	xe->hwmon = hwmon;
>
>-	mutex_init(&hwmon->hwmon_lock);
>-	if (devm_add_action_or_reset(dev, xe_hwmon_mutex_destroy, hwmon))
>+	if (drmm_mutex_init(&xe->drm, &hwmon->hwmon_lock))
> 		return;
>
> 	/* There's only one instance of hwmon per device */
>-- 
>2.48.1
>