[PATCH net-next 6/8] netfilter: introduce total count of hw offload 'del' workqueue tasks

[Vlad Buslov <vladbu@xxxxxxxxxx>]

To improve hardware offload debuggability extend struct netns_nftables with
'count_wq_del' counter and expose it to userspace as
'nf_flowtable_count_wq_del' sysctl entry. Increment the counter when
allocating new workqueue task and decrement it after
flow_offload_work_del() is finished.

Signed-off-by: Vlad Buslov <vladbu@xxxxxxxxxx>
Signed-off-by: Oz Shlomo <ozsh@xxxxxxxxxx>
Reviewed-by: Paul Blakey <paulb@xxxxxxxxxx>
---
 include/net/netns/nftables.h            | 1 +
 net/netfilter/nf_conntrack_standalone.c | 8 ++++++++
 net/netfilter/nf_flow_table_offload.c   | 3 +++
 3 files changed, 12 insertions(+)

diff --git a/include/net/netns/nftables.h b/include/net/netns/nftables.h
index ce270803ef27..ad6058d2b5f9 100644
--- a/include/net/netns/nftables.h
+++ b/include/net/netns/nftables.h
@@ -10,6 +10,7 @@ struct netns_nftables {
 	int			max_hw;
 	atomic_t		count_wq_add;
 	int			max_wq_add;
+	atomic_t		count_wq_del;
 };
 
 #endif
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 26e2b86eb060..cebdf389f7eb 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -623,6 +623,7 @@ enum nf_ct_sysctl_index {
 	NF_SYSCTL_CT_MAX_HW,
 	NF_SYSCTL_CT_COUNT_WQ_ADD,
 	NF_SYSCTL_CT_MAX_WQ_ADD,
+	NF_SYSCTL_CT_COUNT_WQ_DEL,
 #endif
 
 	__NF_SYSCTL_CT_LAST_SYSCTL,
@@ -1005,6 +1006,12 @@ static struct ctl_table nf_ct_sysctl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	[NF_SYSCTL_CT_COUNT_WQ_DEL] = {
+		.procname	= "nf_flowtable_count_wq_del",
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
 #endif
 	{}
 };
@@ -1147,6 +1154,7 @@ static int nf_conntrack_standalone_init_sysctl(struct net *net)
 	table[NF_SYSCTL_CT_MAX_HW].data = &net->nft.max_hw;
 	table[NF_SYSCTL_CT_COUNT_WQ_ADD].data = &net->nft.count_wq_add;
 	table[NF_SYSCTL_CT_MAX_WQ_ADD].data = &net->nft.max_wq_add;
+	table[NF_SYSCTL_CT_COUNT_WQ_DEL].data = &net->nft.count_wq_del;
 #endif
 
 	nf_conntrack_standalone_init_tcp_sysctl(net, table);
diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c
index e29aa51696f5..82cd78c8eb25 100644
--- a/net/netfilter/nf_flow_table_offload.c
+++ b/net/netfilter/nf_flow_table_offload.c
@@ -965,6 +965,7 @@ static void flow_offload_work_handler(struct work_struct *work)
 			break;
 		case FLOW_CLS_DESTROY:
 			flow_offload_work_del(offload);
+			atomic_dec(&net->nft.count_wq_del);
 			break;
 		case FLOW_CLS_STATS:
 			flow_offload_work_stats(offload);
@@ -1038,12 +1039,14 @@ void nf_flow_offload_add(struct nf_flowtable *flowtable,
 void nf_flow_offload_del(struct nf_flowtable *flowtable,
 			 struct flow_offload *flow)
 {
+	struct net *net = read_pnet(&flowtable->net);
 	struct flow_offload_work *offload;
 
 	offload = nf_flow_offload_work_alloc(flowtable, flow, FLOW_CLS_DESTROY);
 	if (!offload)
 		return;
 
+	atomic_inc(&net->nft.count_wq_del);
 	set_bit(NF_FLOW_HW_DYING, &flow->flags);
 	flow_offload_queue_work(offload);
 }
-- 
2.31.1