[PATCH 6.1.y] leds: mlxreg: Use devm_mutex_init() for mutex initialization

[PATCH 6.1.y] leds: mlxreg: Use devm_mutex_init() for mutex initialization

[bin.lan.cn]

From: George Stark <gnstark@salutedevices.com>

[ Upstream commit efc347b9efee1c2b081f5281d33be4559fa50a16 ]

In this driver LEDs are registered using devm_led_classdev_register()
so they are automatically unregistered after module's remove() is done.
led_classdev_unregister() calls module's led_set_brightness() to turn off
the LEDs and that callback uses mutex which was destroyed already
in module's remove() so use devm API instead.

Signed-off-by: George Stark <gnstark@salutedevices.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240411161032.609544-8-gnstark@salutedevices.com
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
Signed-off-by: He Zhe <zhe.he@windriver.com>
---
Verified the build test.
---
 drivers/leds/leds-mlxreg.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/leds/leds-mlxreg.c b/drivers/leds/leds-mlxreg.c
index b7855c93bd72..31eca8394a26 100644
--- a/drivers/leds/leds-mlxreg.c
+++ b/drivers/leds/leds-mlxreg.c
@@ -258,6 +258,7 @@ static int mlxreg_led_probe(struct platform_device *pdev)
 {
 	struct mlxreg_core_platform_data *led_pdata;
 	struct mlxreg_led_priv_data *priv;
+	int err;
 
 	led_pdata = dev_get_platdata(&pdev->dev);
 	if (!led_pdata) {
@@ -269,28 +270,21 @@ static int mlxreg_led_probe(struct platform_device *pdev)
 	if (!priv)
 		return -ENOMEM;
 
-	mutex_init(&priv->access_lock);
+	err = devm_mutex_init(&pdev->dev, &priv->access_lock);
+	if (err)
+		return err;
+
 	priv->pdev = pdev;
 	priv->pdata = led_pdata;
 
 	return mlxreg_led_config(priv);
 }
 
-static int mlxreg_led_remove(struct platform_device *pdev)
-{
-	struct mlxreg_led_priv_data *priv = dev_get_drvdata(&pdev->dev);
-
-	mutex_destroy(&priv->access_lock);
-
-	return 0;
-}
-
 static struct platform_driver mlxreg_led_driver = {
 	.driver = {
 	    .name = "leds-mlxreg",
 	},
 	.probe = mlxreg_led_probe,
-	.remove = mlxreg_led_remove,
 };
 
 module_platform_driver(mlxreg_led_driver);
-- 
2.34.1

Re: [PATCH 6.1.y] leds: mlxreg: Use devm_mutex_init() for mutex initialization

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: efc347b9efee1c2b081f5281d33be4559fa50a16

WARNING: Author mismatch between patch and upstream commit:
Backport author: bin.lan.cn@windriver.com
Commit author: George Stark<gnstark@salutedevices.com>

Status in newer kernel trees:
6.13.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (different SHA1: 172ffd26a5af)

Note: The patch differs from the upstream commit:
---
1:  efc347b9efee1 ! 1:  86f4e68bf53db leds: mlxreg: Use devm_mutex_init() for mutex initialization
    @@ Metadata
      ## Commit message ##
         leds: mlxreg: Use devm_mutex_init() for mutex initialization
     
    +    [ Upstream commit efc347b9efee1c2b081f5281d33be4559fa50a16 ]
    +
         In this driver LEDs are registered using devm_led_classdev_register()
         so they are automatically unregistered after module's remove() is done.
         led_classdev_unregister() calls module's led_set_brightness() to turn off
    @@ Commit message
         Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
         Link: https://lore.kernel.org/r/20240411161032.609544-8-gnstark@salutedevices.com
         Signed-off-by: Lee Jones <lee@kernel.org>
    +    Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
    +    Signed-off-by: He Zhe <zhe.he@windriver.com>
     
      ## drivers/leds/leds-mlxreg.c ##
     @@ drivers/leds/leds-mlxreg.c: static int mlxreg_led_probe(struct platform_device *pdev)
    @@ drivers/leds/leds-mlxreg.c: static int mlxreg_led_probe(struct platform_device *
      	return mlxreg_led_config(priv);
      }
      
    --static void mlxreg_led_remove(struct platform_device *pdev)
    +-static int mlxreg_led_remove(struct platform_device *pdev)
     -{
     -	struct mlxreg_led_priv_data *priv = dev_get_drvdata(&pdev->dev);
     -
     -	mutex_destroy(&priv->access_lock);
    +-
    +-	return 0;
     -}
     -
      static struct platform_driver mlxreg_led_driver = {
    @@ drivers/leds/leds-mlxreg.c: static int mlxreg_led_probe(struct platform_device *
      	    .name = "leds-mlxreg",
      	},
      	.probe = mlxreg_led_probe,
    --	.remove_new = mlxreg_led_remove,
    +-	.remove = mlxreg_led_remove,
      };
      
      module_platform_driver(mlxreg_led_driver);
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |