On Mon, 15 Apr 2024, "Dixit, Ashutosh" <ashutosh.dixit@xxxxxxxxx> wrote: > On Mon, 15 Apr 2024 16:35:02 -0700, Armin Wolf wrote: >> > > Hi Armin, > >> Am 16.04.24 um 00:36 schrieb Ashutosh Dixit: >> > @@ -818,10 +818,10 @@ void i915_hwmon_register(struct drm_i915_private *i915) >> > hwm_get_preregistration_info(i915); >> > >> > /* hwmon_dev points to device hwmon<i> */ >> > - hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat->name, >> > - ddat, >> > - &hwm_chip_info, >> > - hwm_groups); >> > + hwmon_dev = hwmon_device_register_with_info(dev, ddat->name, >> > + ddat, >> > + &hwm_chip_info, >> > + hwm_groups); >> > if (IS_ERR(hwmon_dev)) { >> > i915->hwmon = NULL; >> >> you need to free hwmon here, since it is not managed by devres anymore. > > Thanks a lot for catching this, I had missed it in v2, it's fixed in v3. I > am actually reusing i915_hwmon_unregister() for error unwinding in v3. > >> >> > return; >> > @@ -838,10 +838,10 @@ void i915_hwmon_register(struct drm_i915_private *i915) >> > if (!hwm_gt_is_visible(ddat_gt, hwmon_energy, hwmon_energy_input, 0)) >> > continue; >> > >> > - hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat_gt->name, >> > - ddat_gt, >> > - &hwm_gt_chip_info, >> > - NULL); >> > + hwmon_dev = hwmon_device_register_with_info(dev, ddat_gt->name, >> > + ddat_gt, >> > + &hwm_gt_chip_info, >> > + NULL); >> > if (!IS_ERR(hwmon_dev)) >> > ddat_gt->hwmon_dev = hwmon_dev; >> > } >> > @@ -849,5 +849,26 @@ void i915_hwmon_register(struct drm_i915_private *i915) >> > >> > void i915_hwmon_unregister(struct drm_i915_private *i915) >> > { >> > - fetch_and_zero(&i915->hwmon); >> > + struct i915_hwmon *hwmon = fetch_and_zero(&i915->hwmon); >> >> Why is fetch_and_zero() necessary here? > > As mentioned, in v3 i915_hwmon_unregister() itself is used for error > unwinding so we need to prevent multiple device_unregister's etc. That is > the purpose of setting i915->hwmon to NULL. But even earlier, though it is > not obvious, i915_hwmon_unregister() is called multiple times. So e.g. it > will be called at device unbind as well as module unload. So once again we > prevent multiple device_unregister's by setting and checking for NULL > i915->hwmon. IMO it's more obvious to set i915->hwmon to NULL separately. BR, Jani. > >> >> > + struct hwm_drvdata *ddat = &hwmon->ddat; >> > + struct intel_gt *gt; >> > + int i; >> > + >> > + if (!hwmon) >> > + return; >> > + >> > + for_each_gt(gt, i915, i) { >> > + struct hwm_drvdata *ddat_gt = hwmon->ddat_gt + i; >> > + >> > + if (ddat_gt->hwmon_dev) { >> > + hwmon_device_unregister(ddat_gt->hwmon_dev); >> > + ddat_gt->hwmon_dev = NULL; >> > + } >> > + } >> > + >> > + if (ddat->hwmon_dev) >> > + hwmon_device_unregister(ddat->hwmon_dev); >> > + >> > + mutex_destroy(&hwmon->hwmon_lock); >> > + kfree(hwmon); >> > } > > Thanks. > -- > Ashutosh -- Jani Nikula, Intel