diff mbox series

[v4,4/4] drivers/thermal/exymos: Use guard notation when acquiring mutex

Message ID 20250310143450.8276-5-linux.amoon@gmail.com (mailing list archive)
State New
Headers show
Series Exynos Thermal code improvement | expand

Commit Message

Anand Moon March 10, 2025, 2:34 p.m. UTC 
Using guard notation makes the code more compact and error handling
more robust by ensuring that mutexes are released in all code paths
when control leaves critical section.

Signed-off-by: Anand Moon <linux.amoon@gmail.com>
---
v4: used DEFINE_GUARD macro to guard exynos_tmu_data structure.
    However, incorporating guard(exynos_tmu_data)(data); results
    in a recursive deadlock with the mutex during initialization, as this
    data structure is common to all the code configurations of Exynos TMU
v3: New patch
---
 drivers/thermal/samsung/exynos_tmu.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

Comments

Krzysztof Kozlowski March 11, 2025, 5:30 p.m. UTC | #1 
On 10/03/2025 15:34, Anand Moon wrote:
> Using guard notation makes the code more compact and error handling
> more robust by ensuring that mutexes are released in all code paths
> when control leaves critical section.
> 

Subject: typo, exynos

> Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> ---
> v4: used DEFINE_GUARD macro to guard exynos_tmu_data structure.
>     However, incorporating guard(exynos_tmu_data)(data); results
>     in a recursive deadlock with the mutex during initialization, as this
>     data structure is common to all the code configurations of Exynos TMU
> v3: New patch

If you ever use cleanup or guards, you must build your code with recent
clang and W=1. Failure to do so means you ask reviewers manually to spot
issues not visible in the context, instead of using tools. It's a NAK
for me.

> ---
>  drivers/thermal/samsung/exynos_tmu.c | 25 +++++++++++--------------
>  1 file changed, 11 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
> index a71cde0a4b17e..85f88c5e0f11c 100644
> --- a/drivers/thermal/samsung/exynos_tmu.c
> +++ b/drivers/thermal/samsung/exynos_tmu.c
> @@ -12,6 +12,7 @@
>   */
>  
>  #include <linux/clk.h>
> +#include <linux/cleanup.h>
>  #include <linux/io.h>
>  #include <linux/interrupt.h>
>  #include <linux/module.h>
> @@ -199,6 +200,9 @@ struct exynos_tmu_data {
>  	void (*tmu_clear_irqs)(struct exynos_tmu_data *data);
>  };
>  
> +DEFINE_GUARD(exynos_tmu_data, struct exynos_tmu_data *,

I do not understand why do you need custom guard.

> +	     mutex_lock(&_T->lock), mutex_unlock(&_T->lock))
> +
>  /*
>   * TMU treats temperature as a mapped temperature code.
>   * The temperature is converted differently depending on the calibration type.
> @@ -256,7 +260,7 @@ static int exynos_tmu_initialize(struct platform_device *pdev)
>  	unsigned int status;
>  	int ret = 0;
>  
> -	mutex_lock(&data->lock);
> +	guard(mutex)(&data->lock);

Which you do not use... Please don't use cleanup.h if you do not know
it. It leads to bugs.


Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
index a71cde0a4b17e..85f88c5e0f11c 100644
--- a/drivers/thermal/samsung/exynos_tmu.c
+++ b/drivers/thermal/samsung/exynos_tmu.c
@@ -12,6 +12,7 @@ 
  */
 
 #include <linux/clk.h>
+#include <linux/cleanup.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
@@ -199,6 +200,9 @@  struct exynos_tmu_data {
 	void (*tmu_clear_irqs)(struct exynos_tmu_data *data);
 };
 
+DEFINE_GUARD(exynos_tmu_data, struct exynos_tmu_data *,
+	     mutex_lock(&_T->lock), mutex_unlock(&_T->lock))
+
 /*
  * TMU treats temperature as a mapped temperature code.
  * The temperature is converted differently depending on the calibration type.
@@ -256,7 +260,7 @@  static int exynos_tmu_initialize(struct platform_device *pdev)
 	unsigned int status;
 	int ret = 0;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 	clk_enable(data->clk_sec);
 
@@ -270,7 +274,6 @@  static int exynos_tmu_initialize(struct platform_device *pdev)
 
 	clk_disable(data->clk_sec);
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 
 	return ret;
 }
@@ -292,13 +295,12 @@  static int exynos_thermal_zone_configure(struct platform_device *pdev)
 		return ret;
 	}
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 
 	data->tmu_set_crit_temp(data, temp / MCELSIUS);
 
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 
 	return 0;
 }
@@ -325,12 +327,11 @@  static void exynos_tmu_control(struct platform_device *pdev, bool on)
 {
 	struct exynos_tmu_data *data = platform_get_drvdata(pdev);
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 	data->tmu_control(pdev, on);
 	data->enabled = on;
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 }
 
 static void exynos_tmu_update_bit(struct exynos_tmu_data *data, int reg_off,
@@ -645,7 +646,7 @@  static int exynos_get_temp(struct thermal_zone_device *tz, int *temp)
 		 */
 		return -EAGAIN;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 
 	value = data->tmu_read(data);
@@ -655,7 +656,6 @@  static int exynos_get_temp(struct thermal_zone_device *tz, int *temp)
 		*temp = code_to_temp(data, value) * MCELSIUS;
 
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 
 	return ret;
 }
@@ -720,11 +720,10 @@  static int exynos_tmu_set_emulation(struct thermal_zone_device *tz, int temp)
 	if (temp && temp < MCELSIUS)
 		goto out;
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 	data->tmu_set_emulation(data, temp);
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 	return 0;
 out:
 	return ret;
@@ -760,14 +759,13 @@  static irqreturn_t exynos_tmu_threaded_irq(int irq, void *id)
 
 	thermal_zone_device_update(data->tzd, THERMAL_EVENT_UNSPECIFIED);
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 
 	/* TODO: take action based on particular interrupt */
 	data->tmu_clear_irqs(data);
 
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 
 	return IRQ_HANDLED;
 }
@@ -987,7 +985,7 @@  static int exynos_set_trips(struct thermal_zone_device *tz, int low, int high)
 {
 	struct exynos_tmu_data *data = thermal_zone_device_priv(tz);
 
-	mutex_lock(&data->lock);
+	guard(mutex)(&data->lock);
 	clk_enable(data->clk);
 
 	if (low > INT_MIN)
@@ -1000,7 +998,6 @@  static int exynos_set_trips(struct thermal_zone_device *tz, int low, int high)
 		data->tmu_disable_high(data);
 
 	clk_disable(data->clk);
-	mutex_unlock(&data->lock);
 
 	return 0;
 }