From 684332b7d271a0209411d421c09f995424901d0a Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Thu, 22 Feb 2024 13:31:11 +0100
Subject: [PATCH] Replacing the NHU table loop flag with a proper event

---
 nest/route.h    |  3 ++-
 nest/rt-table.c | 18 +++++++++---------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/nest/route.h b/nest/route.h
index cc39cb92..e5811706 100644
--- a/nest/route.h
+++ b/nest/route.h
@@ -110,6 +110,7 @@ extern uint rtable_max_id;
     struct rtable_config *config;	/* Configuration of this table */			\
     struct birdloop *loop;		/* Service thread */					\
     netindex_hash *netindex;		/* Prefix index for this table */			\
+    event *nhu_event;			/* Nexthop updater */					\
 
 /* The complete rtable structure */
 struct rtable_private {
@@ -182,6 +183,7 @@ LOBJ_UNLOCK_CLEANUP(rtable, rtable);
 
 #define RT_IS_LOCKED(tab)	LOBJ_IS_LOCKED((tab), rtable)
 #define RT_LOCKED(tab, tp)	LOBJ_LOCKED((tab), tp, rtable, rtable)
+#define RT_LOCK(tab, tp)	LOBJ_LOCK((tab), tp, rtable, rtable)
 
 #define RT_LOCK_SIMPLE(tab)	LOBJ_LOCK_SIMPLE((tab), rtable)
 #define RT_UNLOCK_SIMPLE(tab)	LOBJ_UNLOCK_SIMPLE((tab), rtable)
@@ -192,7 +194,6 @@ LOBJ_UNLOCK_CLEANUP(rtable, rtable);
 
 /* Flags for birdloop_flag() */
 #define RTF_CLEANUP	1
-#define RTF_NHU		2
 #define RTF_EXPORT	4
 #define RTF_DELETE	8
 
diff --git a/nest/rt-table.c b/nest/rt-table.c
index b3809d24..8dcf8e1b 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -138,7 +138,7 @@ struct rt_export_block {
 
 static void rt_free_hostcache(struct rtable_private *tab);
 static void rt_update_hostcache(void *tab);
-static void rt_next_hop_update(struct rtable_private *tab);
+static void rt_next_hop_update(void *_tab);
 static void rt_nhu_uncork(void *_tab);
 static inline void rt_next_hop_resolve_rte(rte *r);
 static inline void rt_flowspec_resolve_rte(rte *r, struct channel *c);
@@ -2479,7 +2479,7 @@ rt_schedule_nhu(struct rtable_private *tab)
      *   NHU_RUNNING -> NHU_DIRTY
      */
     if ((tab->nhu_state |= NHU_SCHEDULED) == NHU_SCHEDULED)
-      birdloop_flag(tab->loop, RTF_NHU);
+      ev_send_loop(tab->loop, tab->nhu_event);
   }
 }
 
@@ -2516,9 +2516,6 @@ rt_flag_handler(struct birdloop_flag_handler *fh, u32 flags)
     ASSERT_DIE(birdloop_inside(tab->loop));
     rt_lock_table(tab);
 
-    if (flags & RTF_NHU)
-      rt_next_hop_update(tab);
-
     if (flags & RTF_EXPORT)
       rt_kick_export_settle(tab);
 
@@ -2845,6 +2842,7 @@ rt_setup(pool *pp, struct rtable_config *cf)
   hmap_set(&t->id_map, 0);
 
   t->fh = (struct birdloop_flag_handler) { .hook = rt_flag_handler, };
+  t->nhu_event = ev_new_init(p, rt_next_hop_update, t);
   t->nhu_uncork_event = ev_new_init(p, rt_nhu_uncork, t);
   t->prune_timer = tm_new_init(p, rt_prune_timer, t, 0, 0);
   t->last_rt_change = t->gc_time = current_time();
@@ -3854,13 +3852,15 @@ rt_nhu_uncork(void *_tab)
     tab->nhu_corked = 0;
     rt_trace(tab, D_STATES, "Next hop updater uncorked");
 
-    birdloop_flag(tab->loop, RTF_NHU);
+    ev_send_loop(tab->loop, tab->nhu_event);
   }
 }
 
 static void
-rt_next_hop_update(struct rtable_private *tab)
+rt_next_hop_update(void *_tab)
 {
+  RT_LOCK((rtable *) _tab, tab);
+
   ASSERT_DIE(birdloop_inside(tab->loop));
 
   if (tab->nhu_corked)
@@ -3903,7 +3903,7 @@ rt_next_hop_update(struct rtable_private *tab)
 
       if (max_feed <= 0)
 	{
-	  birdloop_flag(tab->loop, RTF_NHU);
+	  ev_send_loop(tab->loop, tab->nhu_event);
 	  return;
 	}
 
@@ -3920,7 +3920,7 @@ rt_next_hop_update(struct rtable_private *tab)
    *   NHU_RUNNING -> NHU_CLEAN
    */
   if ((tab->nhu_state &= NHU_SCHEDULED) == NHU_SCHEDULED)
-    birdloop_flag(tab->loop, RTF_NHU);
+    ev_send_loop(tab->loop, tab->nhu_event);
 }
 
 void