4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
commit 96b33300fba880ec0eafcf3d82486f3463b4b6da upstream.
rbtree GC does not modify the datastructure, instead it collects expired
elements and it enqueues a GC transaction. Use a read spinlock instead
to avoid data contention while GC worker is running.
Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API")
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netfilter/nft_set_rbtree.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -629,8 +629,7 @@ static void nft_rbtree_gc(struct work_st
if (!gc)
goto done;
- write_lock_bh(&priv->lock);
- write_seqcount_begin(&priv->count);
+ read_lock_bh(&priv->lock);
for (node = rb_first(&priv->root); node != NULL; node = rb_next(node)) {
/* Ruleset has been updated, try later. */
@@ -679,8 +678,7 @@ dead_elem:
}
try_later:
- write_seqcount_end(&priv->count);
- write_unlock_bh(&priv->lock);
+ read_unlock_bh(&priv->lock);
if (gc)
nft_trans_gc_queue_async_done(gc);
