[PATCH] platform/x86: dell-wmi-ddv: switch sensor mutex to devm_mutex_init()

[PATCH] platform/x86: dell-wmi-ddv: switch sensor mutex to devm_mutex_init()

[chitranshmandhaniya]

From: Chitransh Mandhaniya <Chitransh_Mandhaniya@dell.com>

Replace mutex_init() with devm_mutex_init() for the sensor caching
mutex so the mutex lifecycle is managed by devres. This allows
removing the manual mutex_destroy() call from the
dell_wmi_ddv_hwmon_cache_destroy() cleanup callback.

The translation_cache_lock in the same driver already uses
devm_mutex_init(); this brings the sensor lock in line.

Signed-off-by: Chitransh Mandhaniya <Chitransh_Mandhaniya@dell.com>
---
 drivers/platform/x86/dell/dell-wmi-ddv.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
index f8903ced461b..c7f3d07abbc7 100644
--- a/drivers/platform/x86/dell/dell-wmi-ddv.c
+++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
@@ -548,7 +548,6 @@ static void dell_wmi_ddv_hwmon_cache_destroy(void *data)
 	struct dell_wmi_ddv_sensors *sensors = data;
 
 	sensors->active = false;
-	mutex_destroy(&sensors->lock);
 	kfree(sensors->buffer);
 }
 
@@ -566,7 +565,9 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_init(struct wmi_device *w
 	if (ret < 0)
 		return ERR_PTR(ret);
 
-	mutex_init(&sensors->lock);
+	ret = devm_mutex_init(&wdev->dev, &sensors->lock);
+	if (ret < 0)
+		return ERR_PTR(ret);
 	sensors->active = true;
 
 	ret = devm_add_action_or_reset(&wdev->dev, dell_wmi_ddv_hwmon_cache_destroy, sensors);
-- 
2.43.0

Re: [PATCH] platform/x86: dell-wmi-ddv: switch sensor mutex to devm_mutex_init()

[Armin Wolf]

Am 27.10.26 um 05:48 schrieb chitranshmandhaniya@gmail.com:

> From: Chitransh Mandhaniya <Chitransh_Mandhaniya@dell.com>
>
> Replace mutex_init() with devm_mutex_init() for the sensor caching
> mutex so the mutex lifecycle is managed by devres. This allows
> removing the manual mutex_destroy() call from the
> dell_wmi_ddv_hwmon_cache_destroy() cleanup callback.
>
> The translation_cache_lock in the same driver already uses
> devm_mutex_init(); this brings the sensor lock in line.

Hi,

thanks for the patch, but now sensors->lock will remain initialized
even when dell_wmi_ddv_channel_create() fails. To be honest i do not
think that using devm_mutex_init() makes much sense here, because the
lifetime of the sensor cache can end before the device lifetime (if
dell_wmi_ddv_channel_create() returns an error).

Thanks,
Armin Wolf

> Signed-off-by: Chitransh Mandhaniya <Chitransh_Mandhaniya@dell.com>
> ---
>   drivers/platform/x86/dell/dell-wmi-ddv.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/platform/x86/dell/dell-wmi-ddv.c b/drivers/platform/x86/dell/dell-wmi-ddv.c
> index f8903ced461b..c7f3d07abbc7 100644
> --- a/drivers/platform/x86/dell/dell-wmi-ddv.c
> +++ b/drivers/platform/x86/dell/dell-wmi-ddv.c
> @@ -548,7 +548,6 @@ static void dell_wmi_ddv_hwmon_cache_destroy(void *data)
>   	struct dell_wmi_ddv_sensors *sensors = data;
>   
>   	sensors->active = false;
> -	mutex_destroy(&sensors->lock);
>   	kfree(sensors->buffer);
>   }
>   
> @@ -566,7 +565,9 @@ static struct hwmon_channel_info *dell_wmi_ddv_channel_init(struct wmi_device *w
>   	if (ret < 0)
>   		return ERR_PTR(ret);
>   
> -	mutex_init(&sensors->lock);
> +	ret = devm_mutex_init(&wdev->dev, &sensors->lock);
> +	if (ret < 0)
> +		return ERR_PTR(ret);
>   	sensors->active = true;
>   
>   	ret = devm_add_action_or_reset(&wdev->dev, dell_wmi_ddv_hwmon_cache_destroy, sensors);