PM: EM: Implement em_notify_pd_created/updated()

Implement two event notifications when a performance domain is created
(EM_CMD_PD_CREATED) and updated (EM_CMD_PD_UPDATED). The message format
of these two event notifications is the same as EM_CMD_GET_PD_TABLE --
containing the performance domain's ID and its energy model table.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/20251020220914.320832-10-changwoo@igalia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: multics69

kernel/power/em_netlink.c

@@ -215,6 +215,50 @@ int em_nl_get_pd_table_doit(struct sk_buff *skb, struct genl_info *info)
 
 
 /**************************** Event encoding *********************************/
+static void __em_notify_pd_table(const struct em_perf_domain *pd, int ntf_type)
+{
+	struct sk_buff *msg;
+	int msg_sz, ret = -EMSGSIZE;
+	void *hdr;
+
+	if (!genl_has_listeners(&em_nl_family, &init_net, EM_NLGRP_EVENT))
+		return;
+
+	msg_sz = __em_nl_get_pd_table_size(pd);
+
+	msg = genlmsg_new(msg_sz, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	hdr = genlmsg_put(msg, 0, 0, &em_nl_family, 0, ntf_type);
+	if (!hdr)
+		goto out_free_msg;
+
+	ret = __em_nl_get_pd_table(msg, pd);
+	if (ret)
+		goto out_free_msg;
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast(&em_nl_family, msg, 0, EM_NLGRP_EVENT, GFP_KERNEL);
+
+	return;
+
+out_free_msg:
+	nlmsg_free(msg);
+	return;
+}
+
+void em_notify_pd_created(const struct em_perf_domain *pd)
+{
+	__em_notify_pd_table(pd, EM_CMD_PD_CREATED);
+}
+
+void em_notify_pd_updated(const struct em_perf_domain *pd)
+{
+	__em_notify_pd_table(pd, EM_CMD_PD_UPDATED);
+}
+
 static int __em_notify_pd_deleted_size(const struct em_perf_domain *pd)
 {
 	int id_sz = nla_total_size(sizeof(u32)); /* EM_A_PD_TABLE_PD_ID */

kernel/power/em_netlink.h

@@ -13,7 +13,9 @@
 int for_each_em_perf_domain(int (*cb)(struct em_perf_domain*, void *),
 			    void *data);
 struct em_perf_domain *em_perf_domain_get_by_id(int id);
+void em_notify_pd_created(const struct em_perf_domain *pd);
 void em_notify_pd_deleted(const struct em_perf_domain *pd);
+void em_notify_pd_updated(const struct em_perf_domain *pd);
 #else
 static inline
 int for_each_em_perf_domain(int (*cb)(struct em_perf_domain*, void *),
@@ -27,7 +29,11 @@ struct em_perf_domain *em_perf_domain_get_by_id(int id)
 	return NULL;
 }
 
+static inline void em_notify_pd_created(const struct em_perf_domain *pd) {}
+
 static inline void em_notify_pd_deleted(const struct em_perf_domain *pd) {}
+
+static inline void em_notify_pd_updated(const struct em_perf_domain *pd) {}
 #endif
 
 #endif /* _EM_NETLINK_H */