[PATCH nf] netfilter: ipset: let destroy callbacks adjust ext mem size

[Florian Westphal <fw@strlen.de>]

For bitmap this change makes no difference, because destructors are
called synchronously.

sashiko pointed out list type destruction is partially done via call_rcu:
mem accounting could be subtracting after list_set_flush() did reset the
value to 0.  set->elements assignment can be removed for the same reason,
this already walks the entire set and does 'set->elements--' for each
entry synchronously.

Fixes: 9e41f26a505c ("netfilter: ipset: Count non-static extension memory for userspace")
Signed-off-by: Florian Westphal <fw@strlen.de>
---
 Won't apply, this assumes the pending nf PR is applied.
 In case that PR is rejected, this patch could be
 reworked to logically come before the atomic64 conversion,
 but it doesn't buy mutch.

 net/netfilter/ipset/ip_set_bitmap_gen.h | 2 +-
 net/netfilter/ipset/ip_set_list_set.c   | 3 +--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_bitmap_gen.h b/net/netfilter/ipset/ip_set_bitmap_gen.h
index 226fdf17b683..d6a7e6604542 100644
--- a/net/netfilter/ipset/ip_set_bitmap_gen.h
+++ b/net/netfilter/ipset/ip_set_bitmap_gen.h
@@ -77,7 +77,7 @@ mtype_flush(struct ip_set *set)
 		mtype_ext_cleanup(set);
 	bitmap_zero(map->members, map->elements);
 	set->elements = 0;
-	atomic64_set(&set->ext_size, 0);
+	DEBUG_NET_WARN_ON_ONCE(atomic64_read(&set->ext_size) > 0);
 }
 
 /* Calculate the actual memory size of the set data */
diff --git a/net/netfilter/ipset/ip_set_list_set.c b/net/netfilter/ipset/ip_set_list_set.c
index ca3ef9479e83..024de3bc9fc3 100644
--- a/net/netfilter/ipset/ip_set_list_set.c
+++ b/net/netfilter/ipset/ip_set_list_set.c
@@ -420,8 +420,7 @@ list_set_flush(struct ip_set *set)
 
 	list_for_each_entry_safe(e, n, &map->members, list)
 		list_set_del(set, e);
-	set->elements = 0;
-	atomic64_set(&set->ext_size, 0);
+	DEBUG_NET_WARN_ON_ONCE(set->elements > 0);
 }
 
 static void
-- 
2.54.0