defer the freeing of art tables and nodes to a task.

this will allow us to sleep in srp_finalize before freeing the
memory.

the defer is done by putting the tables and nodes on a list which
is serviced by a task. the task removes all the entries from the
list and pool_puts them.

the art_tables gc code uses at_parent as its list entry, and the
art_node gc code uses a union with the an_dst pointer. both at_parent
and an_dst are only used when theyre active as part of an art data
structure, and are not used in lookups. once the art is done with
them we can reuse these pointers safely.

ok mpi@

1 files changed, 7 insertions, 2 deletions

diff --git a/sys/net/art.h b/sys/net/art.h
index 48e172bce95..856a80bc182 100644
--- a/sys/net/art.h
+++ b/sys/net/art.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: art.h,v 1.12 2016/04/13 08:04:14 mpi Exp $ */
+/* $OpenBSD: art.h,v 1.13 2016/06/03 03:59:43 dlg Exp $ */
 
 /*
  * Copyright (c) 2015 Martin Pieuchot
@@ -44,9 +44,14 @@ struct rtentry;
  */
 struct art_node {
 	SRPL_HEAD(, rtentry)	 an_rtlist;	/* Route related to this node */
-	struct sockaddr		*an_dst;	/* Destination address (key) */
+	union {
+		struct sockaddr	*an__dst;	/* Destination address (key) */
+		struct art_node	*an__gc;	/* Entry on GC list */
+	}			 an_pointer;
 	uint8_t			 an_plen;	/* Prefix length */
 };
+#define an_dst	an_pointer.an__dst
+#define an_gc	an_pointer.an__gc
 
 void		 art_init(void);
 struct art_root	*art_alloc(unsigned int, unsigned int, unsigned int);