drm/i915/hwmon: Fix locking inversion in sysfs getter

From Janusz Krzysztofik
510c5f5e4837cab803c4f594c5f79783ff7b463d in linux-6.6.y/6.6.24
b212b79768ccde74429f872c37618c543fa11333 in mainline linux

diff --git a/sys/dev/pci/drm/i915/i915_hwmon.c b/sys/dev/pci/drm/i915/i915_hwmon.c
index 77f7eca..4ad8ab0 100644 (file)
--- a/sys/dev/pci/drm/i915/i915_hwmon.c
+++ b/sys/dev/pci/drm/i915/i915_hwmon.c
@@ -72,12 +72,13 @@ hwm_locked_with_pm_intel_uncore_rmw(struct hwm_drvdata *ddat,
        struct intel_uncore *uncore = ddat->uncore;
        intel_wakeref_t wakeref;
 
-       mutex_lock(&hwmon->hwmon_lock);
+       with_intel_runtime_pm(uncore->rpm, wakeref) {
+               mutex_lock(&hwmon->hwmon_lock);
 
-       with_intel_runtime_pm(uncore->rpm, wakeref)
                intel_uncore_rmw(uncore, reg, clear, set);
 
-       mutex_unlock(&hwmon->hwmon_lock);
+               mutex_unlock(&hwmon->hwmon_lock);
+       }
 }
 
 /*
@@ -136,20 +137,21 @@ hwm_energy(struct hwm_drvdata *ddat, long *energy)
        else
                rgaddr = hwmon->rg.energy_status_all;
 
-       mutex_lock(&hwmon->hwmon_lock);
+       with_intel_runtime_pm(uncore->rpm, wakeref) {
+               mutex_lock(&hwmon->hwmon_lock);
 
-       with_intel_runtime_pm(uncore->rpm, wakeref)
                reg_val = intel_uncore_read(uncore, rgaddr);
 
-       if (reg_val >= ei->reg_val_prev)
-               ei->accum_energy += reg_val - ei->reg_val_prev;
-       else
-               ei->accum_energy += UINT_MAX - ei->reg_val_prev + reg_val;
-       ei->reg_val_prev = reg_val;
+               if (reg_val >= ei->reg_val_prev)
+                       ei->accum_energy += reg_val - ei->reg_val_prev;
+               else
+                       ei->accum_energy += UINT_MAX - ei->reg_val_prev + reg_val;
+               ei->reg_val_prev = reg_val;
 
-       *energy = mul_u64_u32_shr(ei->accum_energy, SF_ENERGY,
-                                 hwmon->scl_shift_energy);
-       mutex_unlock(&hwmon->hwmon_lock);
+               *energy = mul_u64_u32_shr(ei->accum_energy, SF_ENERGY,
+                                         hwmon->scl_shift_energy);
+               mutex_unlock(&hwmon->hwmon_lock);
+       }
 }
 
 static ssize_t
@@ -404,6 +406,7 @@ hwm_power_max_write(struct hwm_drvdata *ddat, long val)
 
        /* Block waiting for GuC reset to complete when needed */
        for (;;) {
+               wakeref = intel_runtime_pm_get(ddat->uncore->rpm);
                mutex_lock(&hwmon->hwmon_lock);
 
                prepare_to_wait(&ddat->waitq, &wait, TASK_INTERRUPTIBLE);
@@ -417,14 +420,13 @@ hwm_power_max_write(struct hwm_drvdata *ddat, long val)
                }
 
                mutex_unlock(&hwmon->hwmon_lock);
+               intel_runtime_pm_put(ddat->uncore->rpm, wakeref);
 
                schedule();
        }
        finish_wait(&ddat->waitq, &wait);
        if (ret)
-               goto unlock;
-
-       wakeref = intel_runtime_pm_get(ddat->uncore->rpm);
+               goto exit;
 
        /* Disable PL1 limit and verify, because the limit cannot be disabled on all platforms */
        if (val == PL1_DISABLE) {
@@ -444,9 +446,8 @@ hwm_power_max_write(struct hwm_drvdata *ddat, long val)
        intel_uncore_rmw(ddat->uncore, hwmon->rg.pkg_rapl_limit,
                         PKG_PWR_LIM_1_EN | PKG_PWR_LIM_1, nval);
 exit:
-       intel_runtime_pm_put(ddat->uncore->rpm, wakeref);
-unlock:
        mutex_unlock(&hwmon->hwmon_lock);
+       intel_runtime_pm_put(ddat->uncore->rpm, wakeref);
        return ret;
 }