Re: [PATCH v3 4/4] drivers/thermal/exymos: Use guard notation when acquiring mutex

Hi Lukasz,

On Fri, 28 Feb 2025 at 22:58, Lukasz Luba [off-list ref] wrote:

On 2/16/25 19:58, Anand Moon wrote:

quoted

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 <redacted>
---
v3: new patch
---
  drivers/thermal/samsung/exynos_tmu.c | 21 +++++++--------------
  1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c
index fe090c1a93ab..a34ba3858d64 100644
--- a/drivers/thermal/samsung/exynos_tmu.c
+++ b/drivers/thermal/samsung/exynos_tmu.c

@@ -256,7 +256,7 @@ 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 +270,6 @@ 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 +291,12 @@ 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 +323,11 @@ 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 +642,7 @@ 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 +652,6 @@ 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 +716,10 @@ 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 +755,13 @@ 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 +981,7 @@ 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 +994,6 @@ 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;
  }

Thanks for your review comments.

IMO you should be able to even use something like we have
core framework:

guard(thermal_zone)(tz);

Your mutex name is simply 'lock' in the struct exynos_tmu_data
so you should be able to leverage this by:

guard(exynos_tmu_data)(data);

Please try that.

Ok, I will check this

Thanks
-Anand