From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34F56EE49A0 for ; Wed, 23 Aug 2023 09:39:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234966AbjHWJjD (ORCPT ); Wed, 23 Aug 2023 05:39:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235854AbjHWJhi (ORCPT ); Wed, 23 Aug 2023 05:37:38 -0400 Received: from ganesha.gnumonks.org (ganesha.gnumonks.org [IPv6:2001:780:45:1d:225:90ff:fe52:c662]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FDE44EF3 for ; Wed, 23 Aug 2023 02:29:21 -0700 (PDT) Received: from [78.30.34.192] (port=38414 helo=gnumonks.org) by ganesha.gnumonks.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1qYkAv-0047wR-Cn; Wed, 23 Aug 2023 11:29:19 +0200 Date: Wed, 23 Aug 2023 11:29:16 +0200 From: Pablo Neira Ayuso To: Florian Westphal Cc: netfilter-devel@vger.kernel.org Subject: Re: [PATCH nf] netfilter: nf_tables: defer gc run if previous batch is still pending Message-ID: References: <20230823073401.16625-1-fw@strlen.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230823073401.16625-1-fw@strlen.de> Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Wed, Aug 23, 2023 at 09:33:58AM +0200, Florian Westphal wrote: > Don't queue more gc work, else we may queue the same elements multiple > times. > > If an element is flagged as dead, this can mean that either the previous > gc request was invalidated/discarded by a transaction or that the previous > request is still pending in the system work queue. > > The latter will happen if the gc interval is set to a very low value, > e.g. 1ms, and system work queue is backlogged. > > The sets refcount is 1 if no previous gc requeusts are queued, so add > a helper for this and skip gc run if old requests are pending. > > Add a helper for this and skip the gc run in this case. > > Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API") > Signed-off-by: Florian Westphal Reviewed-by: Pablo Neira Ayuso > --- > include/net/netfilter/nf_tables.h | 5 +++++ > net/netfilter/nft_set_hash.c | 3 +++ > net/netfilter/nft_set_rbtree.c | 3 +++ > 3 files changed, 11 insertions(+) > > diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h > index ffcbdf08380f..dd40c75011d2 100644 > --- a/include/net/netfilter/nf_tables.h > +++ b/include/net/netfilter/nf_tables.h > @@ -587,6 +587,11 @@ static inline void *nft_set_priv(const struct nft_set *set) > return (void *)set->data; > } > > +static inline bool nft_set_gc_is_pending(const struct nft_set *s) > +{ > + return refcount_read(&s->refs) != 1; > +} > + > static inline struct nft_set *nft_set_container_of(const void *priv) > { > return (void *)priv - offsetof(struct nft_set, data); > diff --git a/net/netfilter/nft_set_hash.c b/net/netfilter/nft_set_hash.c > index cef5df846000..524763659f25 100644 > --- a/net/netfilter/nft_set_hash.c > +++ b/net/netfilter/nft_set_hash.c > @@ -326,6 +326,9 @@ static void nft_rhash_gc(struct work_struct *work) > nft_net = nft_pernet(net); > gc_seq = READ_ONCE(nft_net->gc_seq); > > + if (nft_set_gc_is_pending(set)) > + goto done; > + > gc = nft_trans_gc_alloc(set, gc_seq, GFP_KERNEL); > if (!gc) > goto done; > diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c > index f9d4c8fcbbf8..c6435e709231 100644 > --- a/net/netfilter/nft_set_rbtree.c > +++ b/net/netfilter/nft_set_rbtree.c > @@ -611,6 +611,9 @@ static void nft_rbtree_gc(struct work_struct *work) > nft_net = nft_pernet(net); > gc_seq = READ_ONCE(nft_net->gc_seq); > > + if (nft_set_gc_is_pending(set)) > + goto done; > + > gc = nft_trans_gc_alloc(set, gc_seq, GFP_KERNEL); > if (!gc) > goto done; > -- > 2.41.0 >