Message-ID: <DM5PR1301MB2172A5961718F4D57EDDAD82E78A9@DM5PR1301MB2172.namprd13.prod.outlook.com>
Date:   Mon, 1 Nov 2021 09:44:34 +0000
From:   Baowen Zheng <baowen.zheng@...igine.com>
To:     Vlad Buslov <vladbu@...dia.com>,
        Simon Horman <simon.horman@...igine.com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Roi Dayan <roid@...dia.com>, Ido Schimmel <idosch@...dia.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        Baowen Zheng <notifications@...hub.com>,
        Louis Peens <louis.peens@...igine.com>,
        oss-drivers <oss-drivers@...igine.com>
Subject: RE: [RFC/PATCH net-next v3 3/8] flow_offload: allow user to offload
 tc action to net device

Thanks for your review and sorry for delay in responding.

On October 30, 2021 12:59 AM, Vlad Buslov <vladbu@...dia.com> wrote:
>On Thu 28 Oct 2021 at 14:06, Simon Horman <simon.horman@...igine.com>
>wrote:
>> From: Baowen Zheng <baowen.zheng@...igine.com>
>>
>> Use flow_indr_dev_register/flow_indr_dev_setup_offload to offload tc
>> action.
>>
>> We need to call tc_cleanup_flow_action to clean up tc action entry
>> since in tc_setup_action, some actions may hold dev refcnt, especially
>> the mirror action.
>>
>> Signed-off-by: Baowen Zheng <baowen.zheng@...igine.com>
>> Signed-off-by: Louis Peens <louis.peens@...igine.com>
>> Signed-off-by: Simon Horman <simon.horman@...igine.com>
>> ---
>>  include/linux/netdevice.h  |   1 +
>>  include/net/act_api.h      |   2 +-
>>  include/net/flow_offload.h |  17 ++++
>>  include/net/pkt_cls.h      |  15 ++++
>>  net/core/flow_offload.c    |  43 ++++++++--
>>  net/sched/act_api.c        | 166
>+++++++++++++++++++++++++++++++++++++
>>  net/sched/cls_api.c        |  29 ++++++-
>>  7 files changed, 260 insertions(+), 13 deletions(-)
>>
>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>> index 3ec42495a43a..9815c3a058e9 100644
>> --- a/include/linux/netdevice.h
>> +++ b/include/linux/netdevice.h
>> @@ -916,6 +916,7 @@ enum tc_setup_type {
>>  	TC_SETUP_QDISC_TBF,
>>  	TC_SETUP_QDISC_FIFO,
>>  	TC_SETUP_QDISC_HTB,
>> +	TC_SETUP_ACT,
>>  };
>>
>>  /* These structures hold the attributes of bpf state that are being
>> passed diff --git a/include/net/act_api.h b/include/net/act_api.h
>> index b5b624c7e488..9eb19188603c 100644
>> --- a/include/net/act_api.h
>> +++ b/include/net/act_api.h
>> @@ -239,7 +239,7 @@ static inline void
>> tcf_action_inc_overlimit_qstats(struct tc_action *a)  void
>tcf_action_update_stats(struct tc_action *a, u64 bytes, u64 packets,
>>  			     u64 drops, bool hw);
>>  int tcf_action_copy_stats(struct sk_buff *, struct tc_action *, int);
>> -
>> +int tcf_action_offload_del(struct tc_action *action);
>
>This doesn't seem to be used anywhere outside of act_api in this series, so
>why is it exported?
Thanks for bring this to us, we will fix this by moving the block of implement in act_api.c.
>>  int tcf_action_check_ctrlact(int action, struct tcf_proto *tp,
>>  			     struct tcf_chain **handle,
>>  			     struct netlink_ext_ack *newchain); diff --git
>> a/include/net/flow_offload.h b/include/net/flow_offload.h index
>> 3961461d9c8b..aa28592fccc0 100644
>> --- a/include/net/flow_offload.h
>> +++ b/include/net/flow_offload.h
>> @@ -552,6 +552,23 @@ struct flow_cls_offload {
>>  	u32 classid;
>>  };
>>
>> +enum flow_act_command {
>> +	FLOW_ACT_REPLACE,
>> +	FLOW_ACT_DESTROY,
>> +	FLOW_ACT_STATS,
>> +};
>> +
>> +struct flow_offload_action {
>> +	struct netlink_ext_ack *extack; /* NULL in FLOW_ACT_STATS
>process*/
>> +	enum flow_act_command command;
>> +	enum flow_action_id id;
>> +	u32 index;
>> +	struct flow_stats stats;
>> +	struct flow_action action;
>> +};
>> +
>> +struct flow_offload_action *flow_action_alloc(unsigned int
>> +num_actions);
>> +
>>  static inline struct flow_rule *
>>  flow_cls_offload_flow_rule(struct flow_cls_offload *flow_cmd)  { diff
>> --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index
>> 193f88ebf629..922775407257 100644
>> --- a/include/net/pkt_cls.h
>> +++ b/include/net/pkt_cls.h
>> @@ -258,6 +258,9 @@ static inline void tcf_exts_put_net(struct tcf_exts
>*exts)
>>  	for (; 0; (void)(i), (void)(a), (void)(exts))  #endif
>>
>> +#define tcf_act_for_each_action(i, a, actions) \
>> +	for (i = 0; i < TCA_ACT_MAX_PRIO && ((a) = actions[i]); i++)
>> +
>>  static inline void
>>  tcf_exts_stats_update(const struct tcf_exts *exts,
>>  		      u64 bytes, u64 packets, u64 drops, u64 lastuse, @@ -532,8
>> +535,19 @@ tcf_match_indev(struct sk_buff *skb, int ifindex)
>>  	return ifindex == skb->skb_iif;
>>  }
>>
>> +#ifdef CONFIG_NET_CLS_ACT
>>  int tc_setup_flow_action(struct flow_action *flow_action,
>>  			 const struct tcf_exts *exts);
>
>Why does existing cls_api function tc_setup_flow_action() now depend on
>CONFIG_NET_CLS_ACT?
Originally the function tc_setup_flow_action deal with the dependence of CONFIG_NET_CLS_ACT
By calling the macro tcf_exts_for_each_action, now we change to call the function tc_setup_action
Then tc_setup_flow_action will refer to exts->actions, so it will depend on CONFIG_NET_CLS_ACT explicitly.
To fix this, we have to have the ifdef in tc_setup_flow_action declaration or in the implement in cls_api.c.
Do you think if it makes sense?
>> +#else
>> +static inline int tc_setup_flow_action(struct flow_action *flow_action,
>> +				       const struct tcf_exts *exts) {
>> +	return 0;
>> +}
>> +#endif
>> +
>> +int tc_setup_action(struct flow_action *flow_action,
>> +		    struct tc_action *actions[]);
>>  void tc_cleanup_flow_action(struct flow_action *flow_action);
>>
...
>>  #ifdef CONFIG_INET
>>  DEFINE_STATIC_KEY_FALSE(tcf_frag_xmit_count);
>> @@ -148,6 +161,7 @@ static int __tcf_action_put(struct tc_action *p, bool
>bind)
>>  		idr_remove(&idrinfo->action_idr, p->tcfa_index);
>>  		mutex_unlock(&idrinfo->lock);
>>
>> +		tcf_action_offload_del(p);
>>  		tcf_action_cleanup(p);
>>  		return 1;
>>  	}
>> @@ -341,6 +355,7 @@ static int tcf_idr_release_unsafe(struct tc_action *p)
>>  		return -EPERM;
>>
>>  	if (refcount_dec_and_test(&p->tcfa_refcnt)) {
>> +		tcf_action_offload_del(p);
>>  		idr_remove(&p->idrinfo->action_idr, p->tcfa_index);
>>  		tcf_action_cleanup(p);
>>  		return ACT_P_DELETED;
>> @@ -452,6 +467,7 @@ static int tcf_idr_delete_index(struct tcf_idrinfo
>*idrinfo, u32 index)
>>  						p->tcfa_index));
>>  			mutex_unlock(&idrinfo->lock);
>>
>> +			tcf_action_offload_del(p);
>
>tcf_action_offload_del() and tcf_action_cleanup() seem to be always called
>together. Consider moving the call to tcf_action_offload_del() into
>tcf_action_cleanup().
>
Thanks, we will consider to move tcf_action_offload_del() inside of tcf_action_cleanup.
>>  			tcf_action_cleanup(p);
>>  			module_put(owner);
>>  			return 0;
>> @@ -1061,6 +1077,154 @@ struct tc_action *tcf_action_init_1(struct net
>*net, struct tcf_proto *tp,
>>  	return ERR_PTR(err);
>>  }
>>
...
>> +/* offload the tc command after inserted */ static int
>> +tcf_action_offload_add(struct tc_action *action,
>> +				  struct netlink_ext_ack *extack) {
>> +	struct tc_action *actions[TCA_ACT_MAX_PRIO] = {
>> +		[0] = action,
>> +	};
>> +	struct flow_offload_action *fl_action;
>> +	int err = 0;
>> +
>> +	fl_action = flow_action_alloc(tcf_act_num_actions_single(action));
>> +	if (!fl_action)
>> +		return -EINVAL;
>
>Failed alloc-like functions usually result -ENOMEM.
>
Thanks, we will fix this in V4 patch.
>> +
>> +	err = flow_action_init(fl_action, action, FLOW_ACT_REPLACE, extack);
>> +	if (err)
>> +		goto fl_err;
>> +
>> +	err = tc_setup_action(&fl_action->action, actions);
>> +	if (err) {
>> +		NL_SET_ERR_MSG_MOD(extack,
>> +				   "Failed to setup tc actions for offload\n");
>> +		goto fl_err;
>> +	}
>> +
>> +	err = tcf_action_offload_cmd(fl_action, extack);
>> +	tc_cleanup_flow_action(&fl_action->action);
>> +
>> +fl_err:
>> +	kfree(fl_action);
>> +
>> +	return err;
>> +}
>> +
>> +int tcf_action_offload_del(struct tc_action *action) {
>> +	struct flow_offload_action fl_act;
>> +	int err = 0;
>> +
>> +	if (!action)
>> +		return -EINVAL;
>> +
>> +	err = flow_action_init(&fl_act, action, FLOW_ACT_DESTROY, NULL);
>> +	if (err)
>> +		return err;
>> +
>> +	return tcf_action_offload_cmd(&fl_act, NULL); }
>> +
>>  /* Returns numbers of initialized actions or negative error. */
>>
>>  int tcf_action_init(struct net *net, struct tcf_proto *tp, struct
>> nlattr *nla, @@ -1103,6 +1267,8 @@ int tcf_action_init(struct net *net,
>struct tcf_proto *tp, struct nlattr *nla,
>>  		sz += tcf_action_fill_size(act);
>>  		/* Start from index 0 */
>>  		actions[i - 1] = act;
>> +		if (!(flags & TCA_ACT_FLAGS_BIND))
>> +			tcf_action_offload_add(act, extack);
>>  	}
>>
>>  	/* We have to commit them all together, because if any error
>> happened in diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
>> index 2ef8f5a6205a..351d93988b8b 100644
>> --- a/net/sched/cls_api.c
>> +++ b/net/sched/cls_api.c
>> @@ -3544,8 +3544,8 @@ static enum flow_action_hw_stats
>tc_act_hw_stats(u8 hw_stats)
>>  	return hw_stats;
>>  }
>>
>> -int tc_setup_flow_action(struct flow_action *flow_action,
>> -			 const struct tcf_exts *exts)
>> +int tc_setup_action(struct flow_action *flow_action,
>> +		    struct tc_action *actions[])
>>  {
>>  	struct tc_action *act;
>>  	int i, j, k, err = 0;
>> @@ -3554,11 +3554,11 @@ int tc_setup_flow_action(struct flow_action
>*flow_action,
>>  	BUILD_BUG_ON(TCA_ACT_HW_STATS_IMMEDIATE !=
>FLOW_ACTION_HW_STATS_IMMEDIATE);
>>  	BUILD_BUG_ON(TCA_ACT_HW_STATS_DELAYED !=
>> FLOW_ACTION_HW_STATS_DELAYED);
>>
>> -	if (!exts)
>> +	if (!actions)
>>  		return 0;
>>
>>  	j = 0;
>> -	tcf_exts_for_each_action(i, act, exts) {
>> +	tcf_act_for_each_action(i, act, actions) {
>>  		struct flow_action_entry *entry;
>>
>>  		entry = &flow_action->entries[j];
>> @@ -3725,7 +3725,19 @@ int tc_setup_flow_action(struct flow_action
>*flow_action,
>>  	spin_unlock_bh(&act->tcfa_lock);
>>  	goto err_out;
>>  }
>> +EXPORT_SYMBOL(tc_setup_action);
>> +
>> +#ifdef CONFIG_NET_CLS_ACT
>
>Maybe just move tc_setup_action() to act_api and ifdef its definition in
>pkt_cls.h instead of existing tc_setup_flow_action()?
As explanation above, after the change, tc_setup_flow_action will call function of 
tc_setup_action and refer to exts->actions, so just move tc_setup_action can not
fix this problem.
>> +int tc_setup_flow_action(struct flow_action *flow_action,
>> +			 const struct tcf_exts *exts)
>> +{
>> +	if (!exts)
>> +		return 0;
>> +
>> +	return tc_setup_action(flow_action, exts->actions); }
>>  EXPORT_SYMBOL(tc_setup_flow_action);
>> +#endif
>>
>>  unsigned int tcf_exts_num_actions(struct tcf_exts *exts)  { @@
>> -3743,6 +3755,15 @@ unsigned int tcf_exts_num_actions(struct tcf_exts
>> *exts)  }  EXPORT_SYMBOL(tcf_exts_num_actions);
>>
>> +unsigned int tcf_act_num_actions_single(struct tc_action *act) {
>> +	if (is_tcf_pedit(act))
>> +		return tcf_pedit_nkeys(act);
>> +	else
>> +		return 1;
>> +}
>> +EXPORT_SYMBOL(tcf_act_num_actions_single);
>> +
>>  #ifdef CONFIG_NET_CLS_ACT
>>  static int tcf_qevent_parse_block_index(struct nlattr *block_index_attr,
>>  					u32 *p_block_index,

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