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Date: Thu, 15 Feb 2024 18:25:42 +0100
From: Jiri Pirko <jiri@resnulli.us>
To: =?iso-8859-1?Q?Asbj=F8rn_Sloth_T=F8nnesen?= <ast@fiberby.net>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, llu@fiberby.dk
Subject: Re: [PATCH net-next 2/3] net: sched: cls_api: add filter counter
Message-ID: <Zc5JFhLI_KZtdy5P@nanopsycho>
References: <20240215160458.1727237-1-ast@fiberby.net>
 <20240215160458.1727237-3-ast@fiberby.net>
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In-Reply-To: <20240215160458.1727237-3-ast@fiberby.net>

Thu, Feb 15, 2024 at 05:04:43PM CET, ast@fiberby.net wrote:
>Maintain a count of filters per block.
>
>Counter updates are protected by cb_lock, which is
>also used to protect the offload counters.
>
>Signed-off-by: Asbj?rn Sloth T?nnesen <ast@fiberby.net>
>---
> include/net/sch_generic.h |  2 ++
> net/sched/cls_api.c       | 20 ++++++++++++++++++++
> 2 files changed, 22 insertions(+)
>
>diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
>index 46a63d1818a0..7af0621db226 100644
>--- a/include/net/sch_generic.h
>+++ b/include/net/sch_generic.h
>@@ -427,6 +427,7 @@ struct tcf_proto {
> 	 */
> 	spinlock_t		lock;
> 	bool			deleting;
>+	bool			counted;
> 	refcount_t		refcnt;
> 	struct rcu_head		rcu;
> 	struct hlist_node	destroy_ht_node;
>@@ -476,6 +477,7 @@ struct tcf_block {
> 	struct flow_block flow_block;
> 	struct list_head owner_list;
> 	bool keep_dst;
>+	atomic_t filtercnt; /* Number of filters */
> 	atomic_t skipswcnt; /* Number of skip_sw filters */
> 	atomic_t offloadcnt; /* Number of oddloaded filters */
> 	unsigned int nooffloaddevcnt; /* Number of devs unable to do offload */
>diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
>index 397c3d29659c..c750cb662142 100644
>--- a/net/sched/cls_api.c
>+++ b/net/sched/cls_api.c
>@@ -411,11 +411,13 @@ static void tcf_proto_get(struct tcf_proto *tp)
> }
> 
> static void tcf_chain_put(struct tcf_chain *chain);
>+static void tcf_block_filter_cnt_update(struct tcf_block *block, bool *counted, bool add);
> 
> static void tcf_proto_destroy(struct tcf_proto *tp, bool rtnl_held,
> 			      bool sig_destroy, struct netlink_ext_ack *extack)
> {
> 	tp->ops->destroy(tp, rtnl_held, extack);
>+	tcf_block_filter_cnt_update(tp->chain->block, &tp->counted, false);
> 	if (sig_destroy)
> 		tcf_proto_signal_destroyed(tp->chain, tp);
> 	tcf_chain_put(tp->chain);
>@@ -2364,6 +2366,7 @@ static int tc_new_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
> 	err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
> 			      flags, extack);
> 	if (err == 0) {
>+		tcf_block_filter_cnt_update(block, &tp->counted, true);
> 		tfilter_notify(net, skb, n, tp, block, q, parent, fh,
> 			       RTM_NEWTFILTER, false, rtnl_held, extack);
> 		tfilter_put(tp, fh);
>@@ -3478,6 +3481,23 @@ int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
> }
> EXPORT_SYMBOL(tcf_exts_dump_stats);
> 
>+static void tcf_block_filter_cnt_update(struct tcf_block *block, bool *counted, bool add)

Can't you move this up to avoid forward declaration?


>+{
>+	lockdep_assert_not_held(&block->cb_lock);
>+
>+	down_write(&block->cb_lock);
>+	if (*counted != add) {
>+		if (add) {
>+			atomic_inc(&block->filtercnt);
>+			*counted = true;
>+		} else {
>+			atomic_dec(&block->filtercnt);
>+			*counted = false;
>+		}
>+	}
>+	up_write(&block->cb_lock);
>+}
>+
> static void tcf_block_offload_inc(struct tcf_block *block, u32 *flags)
> {
> 	if (*flags & TCA_CLS_FLAGS_IN_HW)
>-- 
>2.43.0
>