Message-ID: <DM5PR1301MB217268DA282CFCF4DB201BEBE79F9@DM5PR1301MB2172.namprd13.prod.outlook.com>
Date:   Mon, 22 Nov 2021 02:18:30 +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>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Ido Schimmel <idosch@...dia.com>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>, Oz Shlomo <ozsh@...dia.com>,
        Roi Dayan <roid@...dia.com>,
        Louis Peens <louis.peens@...igine.com>,
        oss-drivers <oss-drivers@...igine.com>
Subject: RE: [PATCH v4 04/10] flow_offload: allow user to offload tc action to
 net device

On November 20, 2021 3:06 AM, Vlad Buslov wrote:
>On Thu 18 Nov 2021 at 15:07, 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/flow_offload.h |  17 ++++
>>  include/net/pkt_cls.h      |  12 +++
>>  net/core/flow_offload.c    |  43 ++++++++--
>>  net/sched/act_api.c        | 164 +++++++++++++++++++++++++++++++++++++
>>  net/sched/cls_api.c        |  31 ++++++-
>>  6 files changed, 256 insertions(+), 12 deletions(-)
>>
>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>> index 4f4a299e92de..ae189fcff3c6 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/flow_offload.h
>> b/include/net/flow_offload.h index f6970213497a..15662cad5bca 100644
>> --- a/include/net/flow_offload.h
>> +++ b/include/net/flow_offload.h
>> @@ -551,6 +551,23 @@ 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..14d098a887d0 100644
>> --- a/include/net/pkt_cls.h
>> +++ b/include/net/pkt_cls.h
>> @@ -258,6 +258,14 @@ 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 bool tc_act_bind(u32 flags) {
>> +	return !!(flags & TCA_ACT_FLAGS_BIND); }
>> +
>>  static inline void
>>  tcf_exts_stats_update(const struct tcf_exts *exts,
>>  		      u64 bytes, u64 packets, u64 drops, u64 lastuse, @@ -534,6
>> +542,9 @@ tcf_match_indev(struct sk_buff *skb, int ifindex)
>>
>>  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[]);
>>  void tc_cleanup_flow_action(struct flow_action *flow_action);
>>
>>  int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type
>> type, @@ -554,6 +565,7 @@ int tc_setup_cb_reoffload(struct tcf_block
>*block, struct tcf_proto *tp,
>>  			  enum tc_setup_type type, void *type_data,
>>  			  void *cb_priv, u32 *flags, unsigned int
>*in_hw_count);  unsigned
>> int tcf_exts_num_actions(struct tcf_exts *exts);
>> +unsigned int tcf_act_num_actions_single(struct tc_action *act);
>>
>>  #ifdef CONFIG_NET_CLS_ACT
>>  int tcf_qevent_init(struct tcf_qevent *qe, struct Qdisc *sch, diff
>> --git a/net/core/flow_offload.c b/net/core/flow_offload.c index
>> 6beaea13564a..6676431733ef 100644
>> --- a/net/core/flow_offload.c
>> +++ b/net/core/flow_offload.c
>> @@ -27,6 +27,27 @@ struct flow_rule *flow_rule_alloc(unsigned int
>> num_actions)  }  EXPORT_SYMBOL(flow_rule_alloc);
>>
>> +struct flow_offload_action *flow_action_alloc(unsigned int
>> +num_actions) {
>> +	struct flow_offload_action *fl_action;
>> +	int i;
>> +
>> +	fl_action = kzalloc(struct_size(fl_action, action.entries, num_actions),
>> +			    GFP_KERNEL);
>> +	if (!fl_action)
>> +		return NULL;
>> +
>> +	fl_action->action.num_entries = num_actions;
>> +	/* Pre-fill each action hw_stats with DONT_CARE.
>> +	 * Caller can override this if it wants stats for a given action.
>> +	 */
>> +	for (i = 0; i < num_actions; i++)
>> +		fl_action->action.entries[i].hw_stats =
>> +FLOW_ACTION_HW_STATS_DONT_CARE;
>> +
>> +	return fl_action;
>> +}
>> +EXPORT_SYMBOL(flow_action_alloc);
>> +
>>  #define FLOW_DISSECTOR_MATCH(__rule, __type, __out)
>		\
>>  	const struct flow_match *__m = &(__rule)->match;
>	\
>>  	struct flow_dissector *__d = (__m)->dissector;
>	\
>> @@ -549,19 +570,25 @@ int flow_indr_dev_setup_offload(struct
>net_device *dev,	struct Qdisc *sch,
>>  				void (*cleanup)(struct flow_block_cb
>*block_cb))  {
>>  	struct flow_indr_dev *this;
>> +	u32 count = 0;
>> +	int err;
>>
>>  	mutex_lock(&flow_indr_block_lock);
>> +	if (bo) {
>> +		if (bo->command == FLOW_BLOCK_BIND)
>> +			indir_dev_add(data, dev, sch, type, cleanup, bo);
>> +		else if (bo->command == FLOW_BLOCK_UNBIND)
>> +			indir_dev_remove(data);
>> +	}
>>
>> -	if (bo->command == FLOW_BLOCK_BIND)
>> -		indir_dev_add(data, dev, sch, type, cleanup, bo);
>> -	else if (bo->command == FLOW_BLOCK_UNBIND)
>> -		indir_dev_remove(data);
>> -
>> -	list_for_each_entry(this, &flow_block_indr_dev_list, list)
>> -		this->cb(dev, sch, this->cb_priv, type, bo, data, cleanup);
>> +	list_for_each_entry(this, &flow_block_indr_dev_list, list) {
>> +		err = this->cb(dev, sch, this->cb_priv, type, bo, data, cleanup);
>> +		if (!err)
>> +			count++;
>> +	}
>>
>>  	mutex_unlock(&flow_indr_block_lock);
>>
>> -	return list_empty(&bo->cb_list) ? -EOPNOTSUPP : 0;
>> +	return (bo && list_empty(&bo->cb_list)) ? -EOPNOTSUPP : count;
>>  }
>>  EXPORT_SYMBOL(flow_indr_dev_setup_offload);
>> diff --git a/net/sched/act_api.c b/net/sched/act_api.c index
>> 3258da3d5bed..c3d08b710661 100644
>> --- a/net/sched/act_api.c
>> +++ b/net/sched/act_api.c
>> @@ -21,6 +21,19 @@
>>  #include <net/pkt_cls.h>
>>  #include <net/act_api.h>
>>  #include <net/netlink.h>
>> +#include <net/tc_act/tc_pedit.h>
>> +#include <net/tc_act/tc_mirred.h>
>> +#include <net/tc_act/tc_vlan.h>
>> +#include <net/tc_act/tc_tunnel_key.h> #include <net/tc_act/tc_csum.h>
>> +#include <net/tc_act/tc_gact.h> #include <net/tc_act/tc_police.h>
>> +#include <net/tc_act/tc_sample.h> #include <net/tc_act/tc_skbedit.h>
>> +#include <net/tc_act/tc_ct.h> #include <net/tc_act/tc_mpls.h>
>> +#include <net/tc_act/tc_gate.h> #include <net/flow_offload.h>
>>
>>  #ifdef CONFIG_INET
>>  DEFINE_STATIC_KEY_FALSE(tcf_frag_xmit_count);
>> @@ -129,8 +142,157 @@ static void free_tcf(struct tc_action *p)
>>  	kfree(p);
>>  }
>>
>> +static int flow_action_init(struct flow_offload_action *fl_action,
>> +			    struct tc_action *act,
>> +			    enum flow_act_command cmd,
>> +			    struct netlink_ext_ack *extack) {
>> +	if (!fl_action)
>> +		return -EINVAL;
>
>Multiple functions in this patch verify action argument that seemingly can't be
>NULL neither in this change nor in the following ones in series. Any particular
>motivation for this?
>
We will make a check and delete this check if it is redundant.
>> +
>> +	fl_action->extack = extack;
>> +	fl_action->command = cmd;
>> +	fl_action->index = act->tcfa_index;
>> +
>> +	if (is_tcf_gact_ok(act)) {
>> +		fl_action->id = FLOW_ACTION_ACCEPT;
>> +	} else if (is_tcf_gact_shot(act)) {
>> +		fl_action->id = FLOW_ACTION_DROP;
>> +	} else if (is_tcf_gact_trap(act)) {
>> +		fl_action->id = FLOW_ACTION_TRAP;
>> +	} else if (is_tcf_gact_goto_chain(act)) {
>> +		fl_action->id = FLOW_ACTION_GOTO;
>> +	} else if (is_tcf_mirred_egress_redirect(act)) {
>> +		fl_action->id = FLOW_ACTION_REDIRECT;
>> +	} else if (is_tcf_mirred_egress_mirror(act)) {
>> +		fl_action->id = FLOW_ACTION_MIRRED;
>> +	} else if (is_tcf_mirred_ingress_redirect(act)) {
>> +		fl_action->id = FLOW_ACTION_REDIRECT_INGRESS;
>> +	} else if (is_tcf_mirred_ingress_mirror(act)) {
>> +		fl_action->id = FLOW_ACTION_MIRRED_INGRESS;
>> +	} else if (is_tcf_vlan(act)) {
>> +		switch (tcf_vlan_action(act)) {
>> +		case TCA_VLAN_ACT_PUSH:
>> +			fl_action->id = FLOW_ACTION_VLAN_PUSH;
>> +			break;
>> +		case TCA_VLAN_ACT_POP:
>> +			fl_action->id = FLOW_ACTION_VLAN_POP;
>> +			break;
>> +		case TCA_VLAN_ACT_MODIFY:
>> +			fl_action->id = FLOW_ACTION_VLAN_MANGLE;
>> +			break;
>> +		default:
>> +			return -EOPNOTSUPP;
>> +		}
>> +	} else if (is_tcf_tunnel_set(act)) {
>> +		fl_action->id = FLOW_ACTION_TUNNEL_ENCAP;
>> +	} else if (is_tcf_tunnel_release(act)) {
>> +		fl_action->id = FLOW_ACTION_TUNNEL_DECAP;
>> +	} else if (is_tcf_csum(act)) {
>> +		fl_action->id = FLOW_ACTION_CSUM;
>> +	} else if (is_tcf_skbedit_mark(act)) {
>> +		fl_action->id = FLOW_ACTION_MARK;
>> +	} else if (is_tcf_sample(act)) {
>> +		fl_action->id = FLOW_ACTION_SAMPLE;
>> +	} else if (is_tcf_police(act)) {
>> +		fl_action->id = FLOW_ACTION_POLICE;
>> +	} else if (is_tcf_ct(act)) {
>> +		fl_action->id = FLOW_ACTION_CT;
>> +	} else if (is_tcf_mpls(act)) {
>> +		switch (tcf_mpls_action(act)) {
>> +		case TCA_MPLS_ACT_PUSH:
>> +			fl_action->id = FLOW_ACTION_MPLS_PUSH;
>> +			break;
>> +		case TCA_MPLS_ACT_POP:
>> +			fl_action->id = FLOW_ACTION_MPLS_POP;
>> +			break;
>> +		case TCA_MPLS_ACT_MODIFY:
>> +			fl_action->id = FLOW_ACTION_MPLS_MANGLE;
>> +			break;
>> +		default:
>> +			return -EOPNOTSUPP;
>> +		}
>> +	} else if (is_tcf_skbedit_ptype(act)) {
>> +		fl_action->id = FLOW_ACTION_PTYPE;
>> +	} else if (is_tcf_skbedit_priority(act)) {
>> +		fl_action->id = FLOW_ACTION_PRIORITY;
>> +	} else if (is_tcf_gate(act)) {
>> +		fl_action->id = FLOW_ACTION_GATE;
>> +	} else {
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int tcf_action_offload_cmd(struct flow_offload_action *fl_act,
>> +				  struct netlink_ext_ack *extack) {
>> +	int err;
>> +
>> +	if (IS_ERR(fl_act))
>> +		return PTR_ERR(fl_act);
>
>Ditto.
>
We will make a check and delete this check if it is redundant.
>> +
>> +	err = flow_indr_dev_setup_offload(NULL, NULL, TC_SETUP_ACT,
>> +					  fl_act, NULL, NULL);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	return 0;
>> +}
>> +
>> +/* 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 -ENOMEM;
>> +
>> +	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;
>> +}
>> +
>> +static int tcf_action_offload_del(struct tc_action *action) {
>> +	struct flow_offload_action fl_act;
>
>This is the only usage of uninitialized flow_offload_action instance.
>Since there is no reference driver implementation, it is not clear to me
>whether this is intentional because flow_action_init() is guaranteed to
>initialize all data that is necessary for delete, or just an omission.
>
We will add the initialization.
>> +	int err = 0;
>> +
>> +	if (!action)
>> +		return -EINVAL;
>
>Seemingly redundant check again.
>
Will delete the redundant check.
>> +
>> +	err = flow_action_init(&fl_act, action, FLOW_ACT_DESTROY, NULL);
>> +	if (err)
>> +		return err;
>> +
>> +	return tcf_action_offload_cmd(&fl_act, NULL); }
>> +
>>  static void tcf_action_cleanup(struct tc_action *p)  {
>> +	tcf_action_offload_del(p);
>>  	if (p->ops->cleanup)
>>  		p->ops->cleanup(p);
>>
>> @@ -1103,6 +1265,8 @@ 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 (!tc_act_bind(flags))
>> +			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 d9d6ff0bf361..55fa48999d43 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];
>> @@ -3724,6 +3724,20 @@ int tc_setup_flow_action(struct flow_action
>*flow_action,
>>  	spin_unlock_bh(&act->tcfa_lock);
>>  	goto err_out;
>>  }
>> +EXPORT_SYMBOL(tc_setup_action);
>> +
>> +int tc_setup_flow_action(struct flow_action *flow_action,
>> +			 const struct tcf_exts *exts)
>> +{
>> +#ifdef CONFIG_NET_CLS_ACT
>> +	if (!exts)
>> +		return 0;
>> +
>> +	return tc_setup_action(flow_action, exts->actions); #else
>> +	return 0;
>> +#endif
>> +}
>>  EXPORT_SYMBOL(tc_setup_flow_action);
>>
>>  unsigned int tcf_exts_num_actions(struct tcf_exts *exts) @@ -3742,6
>> +3756,15 @@ 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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