flow_offload: allow user to offload tc action to net device

Use flow_indr_dev_register/flow_indr_dev_setup_offload to
offload tc action.

We offload the tc action mainly for ovs meter configuration.
Make some basic changes for different vendors to return EOPNOTSUPP.

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.

As per review from the RFC, the kernel test robot will fail to run, so
we add CONFIG_NET_CLS_ACT control for the action offload.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>

drivers/net/ethernet/broadcom/bnxt/bnxt_tc.c

@@ -1951,7 +1951,7 @@ static int bnxt_tc_setup_indr_cb(struct net_device *netdev, struct Qdisc *sch, v
 				 void *data,
 				 void (*cleanup)(struct flow_block_cb *block_cb))
 {
-	if (!bnxt_is_netdev_indr_offload(netdev))
+	if (!netdev || !bnxt_is_netdev_indr_offload(netdev))
 		return -EOPNOTSUPP;
 
 	switch (type) {

drivers/net/ethernet/mellanox/mlx5/core/en/rep/tc.c

@@ -486,6 +486,9 @@ int mlx5e_rep_indr_setup_cb(struct net_device *netdev, struct Qdisc *sch, void *
 			    void *data,
 			    void (*cleanup)(struct flow_block_cb *block_cb))
 {
+	if (!netdev)
+		return -EOPNOTSUPP;
+
 	switch (type) {
 	case TC_SETUP_BLOCK:
 		return mlx5e_rep_indr_setup_block(netdev, sch, cb_priv, type_data,

drivers/net/ethernet/netronome/nfp/flower/offload.c

@@ -1869,6 +1869,9 @@ nfp_flower_indr_setup_tc_cb(struct net_device *netdev, struct Qdisc *sch, void *
 			    void *data,
 			    void (*cleanup)(struct flow_block_cb *block_cb))
 {
+	if (!netdev)
+		return -EOPNOTSUPP;
+
 	if (!nfp_fl_is_netdev_to_offload(netdev))
 		return -EOPNOTSUPP;
 

include/linux/netdevice.h

@@ -923,6 +923,7 @@ 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

include/net/flow_offload.h

@@ -553,6 +553,21 @@ 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;
+	enum flow_act_command command;
+	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)
 {

include/net/pkt_cls.h

@@ -266,6 +266,9 @@ 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,
@@ -536,8 +539,19 @@ 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);
+#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);
 
 int tc_setup_cb_call(struct tcf_block *block, enum tc_setup_type type,
@@ -558,6 +572,7 @@ 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(struct tc_action *actions[]);
 
 #ifdef CONFIG_NET_CLS_ACT
 int tcf_qevent_init(struct tcf_qevent *qe, struct Qdisc *sch,

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;				\
@@ -476,6 +497,9 @@ int flow_indr_dev_setup_offload(struct net_device *dev, struct Qdisc *sch,
 
 	mutex_unlock(&flow_indr_block_lock);
 
-	return list_empty(&bo->cb_list) ? -EOPNOTSUPP : 0;
+	if (bo)
+		return list_empty(&bo->cb_list) ? -EOPNOTSUPP : 0;
+	else
+		return 0;
 }
 EXPORT_SYMBOL(flow_indr_dev_setup_offload);

net/sched/act_api.c

@@ -1060,6 +1060,36 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp,
 	return ERR_PTR(err);
 }
 
+/* offload the tc command after inserted */
+int tcf_action_offload_cmd(struct tc_action *actions[],
+			   struct netlink_ext_ack *extack)
+{
+	struct flow_offload_action *fl_act;
+	int err = 0;
+
+	fl_act = flow_action_alloc(tcf_act_num_actions(actions));
+	if (!fl_act)
+		return -ENOMEM;
+
+	fl_act->extack = extack;
+	err = tc_setup_action(&fl_act->action, actions);
+	if (err) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Failed to setup tc actions for offload\n");
+		goto err_out;
+	}
+	fl_act->command = FLOW_ACT_REPLACE;
+
+	flow_indr_dev_setup_offload(NULL, NULL, TC_SETUP_ACT, fl_act, NULL, NULL);
+
+	tc_cleanup_flow_action(&fl_act->action);
+
+err_out:
+	kfree(fl_act);
+	return err;
+}
+EXPORT_SYMBOL(tcf_action_offload_cmd);
+
 /* Returns numbers of initialized actions or negative error. */
 
 int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
@@ -1514,6 +1544,9 @@ static int tcf_action_add(struct net *net, struct nlattr *nla,
 		return ret;
 	ret = tcf_add_notify(net, n, actions, portid, attr_size, extack);
 
+	/* offload actions to hardware if possible */
+	tcf_action_offload_cmd(actions, extack);
+
 	/* only put existing actions */
 	for (i = 0; i < TCA_ACT_MAX_PRIO; i++)
 		if (init_res[i] == ACT_P_CREATED)

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
+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 +3755,22 @@ unsigned int tcf_exts_num_actions(struct tcf_exts *exts)
 }
 EXPORT_SYMBOL(tcf_exts_num_actions);
 
+unsigned int tcf_act_num_actions(struct tc_action *actions[])
+{
+	unsigned int num_acts = 0;
+	struct tc_action *act;
+	int i;
+
+	tcf_act_for_each_action(i, act, actions) {
+		if (is_tcf_pedit(act))
+			num_acts += tcf_pedit_nkeys(act);
+		else
+			num_acts++;
+	}
+	return num_acts;
+}
+EXPORT_SYMBOL(tcf_act_num_actions);
+
 #ifdef CONFIG_NET_CLS_ACT
 static int tcf_qevent_parse_block_index(struct nlattr *block_index_attr,
 					u32 *p_block_index,