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

From: Asbjørn Sloth Tønnesen
Date: Thu Feb 15 2024 - 18:39:34 EST


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