Re: [PATCH net-next v2 1/3] net/sched: act_ct: Create nf flow table per zone

[Paul Blakey <paulb@mellanox.com>]

On 3/1/2020 5:47 PM, Jiri Pirko wrote:
> Sun, Mar 01, 2020 at 01:58:41PM CET, paulb@mellanox.com wrote:
>> Use the NF flow tables infrastructure for CT offload.
>>
>> Create a nf flow table per zone.
>>
>> Next patches will add FT entries to this table, and do
>> the software offload.
>>
>> Signed-off-by: Paul Blakey <paulb@mellanox.com>
>> ---
>> Changelog:
>>  v1->v2:
>>    Use spin_lock_bh instead of spin_lock, and unlock for alloc (as it can sleep)
>>    Free ft on last tc act instance instead of last instance + last offloaded tuple,
>>    this removes cleanup cb and netfilter patches, and is simpler
>>    Removed accidental mlx5/core/en_tc.c change
>>    Removed reviewed by Jiri - patch changed
>>
>> include/net/tc_act/tc_ct.h |   2 +
>> net/sched/Kconfig          |   2 +-
>> net/sched/act_ct.c         | 143 ++++++++++++++++++++++++++++++++++++++++++++-
>> 3 files changed, 145 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/net/tc_act/tc_ct.h b/include/net/tc_act/tc_ct.h
>> index a8b1564..cf3492e 100644
>> --- a/include/net/tc_act/tc_ct.h
>> +++ b/include/net/tc_act/tc_ct.h
>> @@ -25,6 +25,8 @@ struct tcf_ct_params {
>> 	u16 ct_action;
>>
>> 	struct rcu_head rcu;
>> +
>> +	struct tcf_ct_flow_table *ct_ft;
>> };
>>
>> struct tcf_ct {
>> diff --git a/net/sched/Kconfig b/net/sched/Kconfig
>> index edde0e5..bfbefb7 100644
>> --- a/net/sched/Kconfig
>> +++ b/net/sched/Kconfig
>> @@ -972,7 +972,7 @@ config NET_ACT_TUNNEL_KEY
>>
>> config NET_ACT_CT
>> 	tristate "connection tracking tc action"
>> -	depends on NET_CLS_ACT && NF_CONNTRACK && NF_NAT
>> +	depends on NET_CLS_ACT && NF_CONNTRACK && NF_NAT && NF_FLOW_TABLE
>> 	help
>> 	  Say Y here to allow sending the packets to conntrack module.
>>
>> diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c
>> index f685c0d..43dfdd1 100644
>> --- a/net/sched/act_ct.c
>> +++ b/net/sched/act_ct.c
>> @@ -15,6 +15,7 @@
>> #include <linux/pkt_cls.h>
>> #include <linux/ip.h>
>> #include <linux/ipv6.h>
>> +#include <linux/rhashtable.h>
>> #include <net/netlink.h>
>> #include <net/pkt_sched.h>
>> #include <net/pkt_cls.h>
>> @@ -24,6 +25,7 @@
>> #include <uapi/linux/tc_act/tc_ct.h>
>> #include <net/tc_act/tc_ct.h>
>>
>> +#include <net/netfilter/nf_flow_table.h>
>> #include <net/netfilter/nf_conntrack.h>
>> #include <net/netfilter/nf_conntrack_core.h>
>> #include <net/netfilter/nf_conntrack_zones.h>
>> @@ -31,6 +33,117 @@
>> #include <net/netfilter/ipv6/nf_defrag_ipv6.h>
>> #include <uapi/linux/netfilter/nf_nat.h>
>>
>> +static struct workqueue_struct *act_ct_wq;
>> +static struct rhashtable zones_ht;
>> +static DEFINE_SPINLOCK(zones_lock);
>> +
>> +struct tcf_ct_flow_table {
>> +	struct rhash_head node; /* In zones tables */
>> +
>> +	struct rcu_work rwork;
>> +	struct nf_flowtable nf_ft;
>> +	u16 zone;
>> +	u32 ref;
>> +
>> +	bool dying;
>> +};
>> +
>> +static const struct rhashtable_params zones_params = {
>> +	.head_offset = offsetof(struct tcf_ct_flow_table, node),
>> +	.key_offset = offsetof(struct tcf_ct_flow_table, zone),
>> +	.key_len = sizeof_field(struct tcf_ct_flow_table, zone),
>> +	.automatic_shrinking = true,
>> +};
>> +
>> +static struct nf_flowtable_type flowtable_ct = {
>> +	.owner		= THIS_MODULE,
>> +};
>> +
>> +static int tcf_ct_flow_table_get(struct tcf_ct_params *params)
>> +{
>> +	struct tcf_ct_flow_table *ct_ft, *new_ct_ft;
>> +	int err;
>> +
>> +	spin_lock_bh(&zones_lock);
>> +	ct_ft = rhashtable_lookup_fast(&zones_ht, &params->zone, zones_params);
>> +	if (ct_ft)
>> +		goto take_ref;
>> +
>> +	spin_unlock_bh(&zones_lock);
>> +	new_ct_ft = kzalloc(sizeof(*new_ct_ft), GFP_KERNEL);
> Don't unlock-lock and just use GFP_ATOMIC.
Sure will do.
>
>
>> +	if (!new_ct_ft)
>> +		return -ENOMEM;
>> +
>> +	new_ct_ft->zone = params->zone;
>> +	spin_lock_bh(&zones_lock);
>> +	ct_ft = rhashtable_lookup_get_insert_fast(&zones_ht, &new_ct_ft->node,
>> +						  zones_params);
>> +	if (IS_ERR(ct_ft)) {
>> +		err = PTR_ERR(ct_ft);
>> +		goto err_insert;
>> +	} else if (ct_ft) {
>> +		/* Already exists */
>> +		kfree(new_ct_ft);
>> +		goto take_ref;
>> +	}
>> +
>> +	ct_ft = new_ct_ft;
>> +	ct_ft->nf_ft.type = &flowtable_ct;
>> +	err = nf_flow_table_init(&ct_ft->nf_ft);
>> +	if (err)
>> +		goto err_init;
>> +
>> +	__module_get(THIS_MODULE);
>> +take_ref:
>> +	params->ct_ft = ct_ft;
>> +	ct_ft->ref++;
>> +	spin_unlock_bh(&zones_lock);
>> +
>> +	return 0;
>> +
>> +err_init:
>> +	rhashtable_remove_fast(&zones_ht, &new_ct_ft->node, zones_params);
>> +err_insert:
>> +	spin_unlock_bh(&zones_lock);
>> +	kfree(new_ct_ft);
>> +	return err;
>> +}
>> +
>> +static void tcf_ct_flow_table_cleanup_work(struct work_struct *work)
>> +{
>> +	struct tcf_ct_flow_table *ct_ft;
>> +
>> +	ct_ft = container_of(to_rcu_work(work), struct tcf_ct_flow_table,
>> +			     rwork);
>> +	nf_flow_table_free(&ct_ft->nf_ft);
>> +	kfree(ct_ft);
>> +
>> +	module_put(THIS_MODULE);
>> +}
>> +
>> +static void tcf_ct_flow_table_put(struct tcf_ct_params *params)
>> +{
>> +	struct tcf_ct_flow_table *ct_ft = params->ct_ft;
>> +
>> +	spin_lock_bh(&zones_lock);
>> +	if (--params->ct_ft->ref == 0) {
>> +		rhashtable_remove_fast(&zones_ht, &ct_ft->node, zones_params);
>> +		INIT_RCU_WORK(&ct_ft->rwork, tcf_ct_flow_table_cleanup_work);
>> +		queue_rcu_work(act_ct_wq, &ct_ft->rwork);
>> +	}
>> +	spin_unlock_bh(&zones_lock);
>> +}
>> +
>> +static int tcf_ct_flow_tables_init(void)
>> +{
>> +	return rhashtable_init(&zones_ht, &zones_params);
>> +}
>> +
>> +static void tcf_ct_flow_tables_uninit(void)
>> +{
>> +	rhashtable_destroy(&zones_ht);
>> +}
>> +
>> static struct tc_action_ops act_ct_ops;
>> static unsigned int ct_net_id;
>>
>> @@ -207,6 +320,8 @@ static void tcf_ct_params_free(struct rcu_head *head)
>> 	struct tcf_ct_params *params = container_of(head,
>> 						    struct tcf_ct_params, rcu);
>>
>> +	tcf_ct_flow_table_put(params);
>> +
>> 	if (params->tmpl)
>> 		nf_conntrack_put(&params->tmpl->ct_general);
>> 	kfree(params);
>> @@ -730,6 +845,10 @@ static int tcf_ct_init(struct net *net, struct nlattr *nla,
>> 	if (err)
>> 		goto cleanup;
>>
>> +	err = tcf_ct_flow_table_get(params);
>> +	if (err)
>> +		goto cleanup;
>> +
>> 	spin_lock_bh(&c->tcf_lock);
>> 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
>> 	params = rcu_replace_pointer(c->params, params,
>> @@ -974,12 +1093,34 @@ static void __net_exit ct_exit_net(struct list_head *net_list)
>>
>> static int __init ct_init_module(void)
>> {
>> -	return tcf_register_action(&act_ct_ops, &ct_net_ops);
>> +	int err;
>> +
>> +	act_ct_wq = alloc_ordered_workqueue("act_ct_workqueue", 0);
>> +	if (!act_ct_wq)
>> +		return -ENOMEM;
>> +
>> +	err = tcf_ct_flow_tables_init();
>> +	if (err)
>> +		goto err_tbl_init;
>> +
>> +	err = tcf_register_action(&act_ct_ops, &ct_net_ops);
>> +	if (err)
>> +		goto err_register;
>> +
>> +	return 0;
>> +
>> +err_tbl_init:
>> +	destroy_workqueue(act_ct_wq);
>> +err_register:
>> +	tcf_ct_flow_tables_uninit();
>> +	return err;
>> }
>>
>> static void __exit ct_cleanup_module(void)
>> {
>> 	tcf_unregister_action(&act_ct_ops, &ct_net_ops);
>> +	tcf_ct_flow_tables_uninit();
>> +	destroy_workqueue(act_ct_wq);
>> }
>>
>> module_init(ct_init_module);
>> -- 
>> 1.8.3.1
>>