l3cfg: let l3cfg emit signal on idle handler for platform changes

Currently all NMDevice instance register to the platform change signals,
then if a signal for their IP ifindex appears, they schedule a task on
an idle handler. That is wasteful.

NML3Cfg already gets a notification on an idle handler and can just re-emit
it to the respective listeners.

With this, there is only one subscriber to the platform signals (NMNetns)
which then multiplexes the signals to the right NML3Cfg instances, and
further.

4 files changed, 40 insertions, 2 deletions

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 254ef965ef..4d9f1c0ef4 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -3014,6 +3014,7 @@ _dev_l3_cfg_notify_cb (NML3Cfg *l3cfg,
 	case NM_L3_CONFIG_NOTIFY_TYPE_ACD_COMPLETED:
 		_dev_l3_cfg_acd_maybe_comlete (self);
 		return;
+	case NM_L3_CONFIG_NOTIFY_TYPE_NOTIFY_PLATFORM_CHANGE_ON_IDLE:
 	case NM_L3_CONFIG_NOTIFY_TYPE_ROUTES_TEMPORARY_NOT_AVAILABLE_EXPIRED:
 		/* FIXME(l3cfg) */
 		return;
diff --git a/src/nm-l3cfg.c b/src/nm-l3cfg.c
index 9b71713d82..272b79e3d6 100644
--- a/src/nm-l3cfg.c
+++ b/src/nm-l3cfg.c
@@ -620,8 +620,20 @@ _load_link (NML3Cfg *self, gboolean initial)
 void
 _nm_l3cfg_notify_platform_change_on_idle (NML3Cfg *self, guint32 obj_type_flags)
 {
+	NML3ConfigNotifyPayload payload;
+
 	if (NM_FLAGS_ANY (obj_type_flags, nmp_object_type_to_flags (NMP_OBJECT_TYPE_LINK)))
 		_load_link (self, FALSE);
+
+	payload = (NML3ConfigNotifyPayload) {
+		.platform_change_on_idle = {
+			.obj_type_flags = obj_type_flags,
+		},
+	};
+	_l3cfg_emit_signal_notify (self,
+	                           NM_L3_CONFIG_NOTIFY_TYPE_NOTIFY_PLATFORM_CHANGE_ON_IDLE,
+	                           &payload);
+
 	if (NM_FLAGS_ANY (obj_type_flags, nmp_object_type_to_flags (NMP_OBJECT_TYPE_IP4_ROUTE)))
 		_property_emit_notify (self, NM_L3CFG_PROPERTY_EMIT_TYPE_IP4_ROUTE);
 	if (NM_FLAGS_ANY (obj_type_flags, nmp_object_type_to_flags (NMP_OBJECT_TYPE_IP6_ROUTE)))
diff --git a/src/nm-l3cfg.h b/src/nm-l3cfg.h
index 4da85babde..1a598d1af4 100644
--- a/src/nm-l3cfg.h
+++ b/src/nm-l3cfg.h
@@ -22,6 +22,13 @@ typedef enum {
 	NM_L3_CONFIG_NOTIFY_TYPE_ROUTES_TEMPORARY_NOT_AVAILABLE_EXPIRED,
 	NM_L3_CONFIG_NOTIFY_TYPE_ACD_FAILED,
 	NM_L3_CONFIG_NOTIFY_TYPE_ACD_COMPLETED,
+
+	/* NML3Cfg hooks to the NMPlatform signals for link, addresses and routes.
+	 * It re-emits the signal on an idle handler. The purpose is for something
+	 * like NMDevice which is already subscribed to these signals, it can get the
+	 * notifications without also subscribing directly to the platform. */
+	NM_L3_CONFIG_NOTIFY_TYPE_NOTIFY_PLATFORM_CHANGE_ON_IDLE,
+
 	_NM_L3_CONFIG_NOTIFY_TYPE_NUM,
 } NML3ConfigNotifyType;
 
@@ -38,6 +45,10 @@ typedef struct {
 			guint sources_len;
 			const NML3ConfigNotifyPayloadAcdFailedSource *sources;
 		} acd_failed;
+
+		struct {
+			guint32 obj_type_flags;
+		} platform_change_on_idle;
 	};
 } NML3ConfigNotifyPayload;
 
diff --git a/src/nm-netns.c b/src/nm-netns.c
index a9596eaf00..53414af6a8 100644
--- a/src/nm-netns.c
+++ b/src/nm-netns.c
@@ -8,6 +8,7 @@
 #include "nm-netns.h"
 
 #include "nm-glib-aux/nm-dedup-multi.h"
+#include "nm-glib-aux/nm-c-list.h"
 
 #include "NetworkManagerUtils.h"
 #include "nm-core-internal.h"
@@ -175,14 +176,27 @@ _platform_signal_on_idle_cb (gpointer user_data)
 	gs_unref_object NMNetns *self = g_object_ref (NM_NETNS (user_data));
 	NMNetnsPrivate *priv = NM_NETNS_GET_PRIVATE (self);
 	L3CfgData *l3cfg_data;
+	CList work_list;
 
-	while ((l3cfg_data = c_list_first_entry (&priv->l3cfg_signal_pending_lst_head, L3CfgData, signal_pending_lst))) {
+	priv->signal_pending_idle_id = 0;
+
+	/* we emit all queued signals together. However, we don't want to hook the
+	 * main loop for longer than the currently queued elements.
+	 *
+	 * If we catch more change events, they will be queued and processed by a future
+	 * idle handler.
+	 *
+	 * Hence, move the list to a temporary list. Isn't CList great? */
+
+	c_list_init (&work_list);
+	c_list_splice (&work_list, &priv->l3cfg_signal_pending_lst_head);
+
+	while ((l3cfg_data = c_list_first_entry (&work_list, L3CfgData, signal_pending_lst))) {
 		c_list_unlink (&l3cfg_data->signal_pending_lst);
 		_nm_l3cfg_notify_platform_change_on_idle (l3cfg_data->l3cfg,
 		                                          nm_steal_int (&l3cfg_data->signal_pending_flag));
 	}
 
-	priv->signal_pending_idle_id = 0;
 	return G_SOURCE_REMOVE;
 }