[PATCH v2 08/10] PM: EM: Implement em_notify_pd_deleted().

[Changwoo Min <changwoo@igalia.com>]

Add the event notification infrastructure and implement the event
notification for when a performance domain is deleted (EM_CMD_PD_DELETED).

The event contains the ID of the performance domain (EM_A_PD_TABLE_PD_ID)
so the userspace can identify the changed performance domain for further
processing.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
---
 kernel/power/em_netlink.c | 56 +++++++++++++++++++++++++++++++++++++++
 kernel/power/em_netlink.h | 18 +++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/kernel/power/em_netlink.c b/kernel/power/em_netlink.c
index 981bbf1f9a2f..4e34799fd1f8 100644
--- a/kernel/power/em_netlink.c
+++ b/kernel/power/em_netlink.c
@@ -213,6 +213,62 @@ int em_nl_get_pd_table_doit(struct sk_buff *skb, struct genl_info *info)
 	return -EMSGSIZE;
 }
 
+
+/**************************** Event encoding *********************************/
+int em_notify_pd_created(const struct em_perf_domain *pd)
+{
+	return -EOPNOTSUPP;
+}
+
+int em_notify_pd_updated(const struct em_perf_domain *pd)
+{
+	return -EOPNOTSUPP;
+}
+
+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 */
+
+	return nlmsg_total_size(genlmsg_msg_size(id_sz));
+}
+
+int em_notify_pd_deleted(const struct em_perf_domain *pd)
+{
+	struct sk_buff *msg;
+	int ret = -EMSGSIZE;
+	void *hdr;
+	int msg_sz;
+
+	if (!genl_has_listeners(&em_nl_family, &init_net, EM_NLGRP_EVENT))
+		return 0;
+
+	msg_sz = __em_notify_pd_deleted_size(pd);
+
+	msg = genlmsg_new(msg_sz, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	hdr = genlmsg_put(msg, 0, 0, &em_nl_family, 0, EM_CMD_PD_DELETED);
+	if (!hdr)
+		goto out_free_msg;
+
+	if (nla_put_u32(msg, EM_A_PD_TABLE_PD_ID, pd->id)) {
+		ret = -EMSGSIZE;
+		goto out_free_msg;
+	}
+
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast(&em_nl_family, msg, 0, EM_NLGRP_EVENT, GFP_KERNEL);
+
+	return 0;
+
+out_free_msg:
+	nlmsg_free(msg);
+	return ret;
+}
+
+/**************************** Initialization *********************************/
 static int __init em_netlink_init(void)
 {
 	return genl_register_family(&em_nl_family);
diff --git a/kernel/power/em_netlink.h b/kernel/power/em_netlink.h
index acd186c92d6b..938c84ca1f40 100644
--- a/kernel/power/em_netlink.h
+++ b/kernel/power/em_netlink.h
@@ -10,7 +10,25 @@
 #define _EM_NETLINK_H
 
 #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_NET)
+int em_notify_pd_created(const struct em_perf_domain *pd);
+int em_notify_pd_deleted(const struct em_perf_domain *pd);
+int em_notify_pd_updated(const struct em_perf_domain *pd);
+
 #else
+static inline int em_notify_pd_created(const struct em_perf_domain *pd)
+{
+	return 0;
+}
+
+static inline int em_notify_pd_deleted(const struct em_perf_domain *pd)
+{
+	return 0;
+}
+
+static inline int em_notify_pd_updated(const struct em_perf_domain *pd)
+{
+	return 0;
+}
 #endif
 
 #endif /* _EM_NETLINK_H */
-- 
2.49.0