PM / devfreq: passive: Use non-devm notifiers

cdleonard · myungjoo · commit 0ef7c7cce43f · 2019-08-25T12:47:31.000+09:00
The devfreq passive governor registers and unregisters devfreq transition notifiers on DEVFREQ_GOV_START/GOV_STOP using devm wrappers. If devfreq itself is registered with devm then a warning is triggered on rmmod from devm_devfreq_unregister_notifier. Call stack looks like this: devm_devfreq_unregister_notifier+0x30/0x40 devfreq_passive_event_handler+0x4c/0x88 devfreq_remove_device.part.8+0x6c/0x9c devm_devfreq_dev_release+0x18/0x20 release_nodes+0x1b0/0x220 devres_release_all+0x78/0x84 device_release_driver_internal+0x100/0x1c0 driver_detach+0x4c/0x90 bus_remove_driver+0x7c/0xd0 driver_unregister+0x2c/0x58 platform_driver_unregister+0x10/0x18 imx_devfreq_platdrv_exit+0x14/0xd40 [imx_devfreq] This happens because devres_release_all will first remove all the nodes into a separate todo list so the nested devres_release from devm_devfreq_unregister_notifier won't find anything. Fix the warning by calling the non-devm APIS for frequency notification. Using devm wrappers is not actually useful for a governor anyway: it relies on the devfreq core to correctly match the GOV_START/GOV_STOP notifications. Fixes: 9961331 ("PM / devfreq: Add new passive governor") Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> Acked-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
@@ -165,12 +165,12 @@ static int devfreq_passive_event_handler(struct devfreq *devfreq,
 			p_data->this = devfreq;
 
 		nb->notifier_call = devfreq_passive_notifier_call;
-		ret = devm_devfreq_register_notifier(dev, parent, nb,
+		ret = devfreq_register_notifier(parent, nb,
 					DEVFREQ_TRANSITION_NOTIFIER);
 		break;
 	case DEVFREQ_GOV_STOP:
-		devm_devfreq_unregister_notifier(dev, parent, nb,
-					DEVFREQ_TRANSITION_NOTIFIER);
+		WARN_ON(devfreq_unregister_notifier(parent, nb,
+					DEVFREQ_TRANSITION_NOTIFIER));
 		break;
 	default:
 		break;
