firmware: arm_scmi: Simplify scmi_devm_notifier_unregister

Unregistering SCMI notifications using the managed devres interface can be
done providing as a reference simply the previously successfully registered
notification block since it could have been registered only on one kernel
notification_chain: drop any reference to SCMI protocol, events and
sources.

Devres internal helpers can search for the provided notification block
reference and, once found, the associated devres object will already
provide the above SCMI references for the event.

Signed-off-by: Cristian Marussi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sudeep Holla <[email protected]>

Author: cris-ma

drivers/firmware/arm_scmi/notify.c

@@ -1513,28 +1513,19 @@ static int scmi_devm_notifier_register(struct scmi_device *sdev,
 static int scmi_devm_notifier_match(struct device *dev, void *res, void *data)
 {
 	struct scmi_notifier_devres *dres = res;
-	struct scmi_notifier_devres *xres = data;
+	struct notifier_block *nb = data;
 
-	if (WARN_ON(!dres || !xres))
+	if (WARN_ON(!dres || !nb))
 		return 0;
 
-	return dres->proto_id == xres->proto_id &&
-		dres->evt_id == xres->evt_id &&
-		dres->nb == xres->nb &&
-		((!dres->src_id && !xres->src_id) ||
-		  (dres->src_id && xres->src_id &&
-		   dres->__src_id == xres->__src_id));
+	return dres->nb == nb;
 }
 
 /**
  * scmi_devm_notifier_unregister()  - Managed un-registration of a
  * notifier_block for an event
  * @sdev: A reference to an scmi_device whose embedded struct device is to
  *	  be used for devres accounting.
- * @proto_id: Protocol ID
- * @evt_id: Event ID
- * @src_id: Source ID, when NULL register for events coming form ALL possible
- *	    sources
  * @nb: A standard notifier block to register for the specified event
  *
  * Generic devres managed helper to explicitly un-register a notifier_block
@@ -1544,25 +1535,12 @@ static int scmi_devm_notifier_match(struct device *dev, void *res, void *data)
  * Return: 0 on Success
  */
 static int scmi_devm_notifier_unregister(struct scmi_device *sdev,
-					 u8 proto_id, u8 evt_id,
-					 const u32 *src_id,
 					 struct notifier_block *nb)
 {
 	int ret;
-	struct scmi_notifier_devres dres;
-
-	dres.handle = sdev->handle;
-	dres.proto_id = proto_id;
-	dres.evt_id = evt_id;
-	if (src_id) {
-		dres.__src_id = *src_id;
-		dres.src_id = &dres.__src_id;
-	} else {
-		dres.src_id = NULL;
-	}
 
 	ret = devres_release(&sdev->dev, scmi_devm_release_notifier,
-			     scmi_devm_notifier_match, &dres);
+			     scmi_devm_notifier_match, nb);
 
 	WARN_ON(ret);
 

include/linux/scmi_protocol.h

@@ -783,8 +783,6 @@ struct scmi_notify_ops {
 					    const u32 *src_id,
 					    struct notifier_block *nb);
 	int (*devm_event_notifier_unregister)(struct scmi_device *sdev,
-					      u8 proto_id, u8 evt_id,
-					      const u32 *src_id,
 					      struct notifier_block *nb);
 	int (*event_notifier_register)(const struct scmi_handle *handle,
 				       u8 proto_id, u8 evt_id,