Re: [PATCH net-next 2/3] net: sched: cls_api: add filter counter

[Asbjørn Sloth Tønnesen]

Hi Jiri,

Thanks for the review.

On 2/15/24 17:25, Jiri Pirko wrote:
> Thu, Feb 15, 2024 at 05:04:43PM CET, ast@xxxxxxxxxxx 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: Asbjørn Sloth Tønnesen <ast@xxxxxxxxxxx>
> > ---
> > 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?

Sure, will do that in v2.

I had considered it, but in the end decided to keep it next to the related offloadcnt logic.


> > +{
> > +	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

--
Best regards
Asbjørn Sloth Tønnesen
Network Engineer
Fiberby - AS42541