net: tc_skbedit: Make the skbedit priority offloadable

The skbedit action "priority" is used for adjusting SKB priority. Allow
drivers to offload the action by introducing two new skbedit getters and a
new flow action, and initializing appropriately in tc_setup_flow_action().
Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/flow_offload.h

@@ -137,6 +137,7 @@ enum flow_action_id {
 	FLOW_ACTION_CSUM,
 	FLOW_ACTION_MARK,
 	FLOW_ACTION_PTYPE,
+	FLOW_ACTION_PRIORITY,
 	FLOW_ACTION_WAKE,
 	FLOW_ACTION_QUEUE,
 	FLOW_ACTION_SAMPLE,
@@ -211,6 +212,7 @@ struct flow_action_entry {
 		u32			csum_flags;	/* FLOW_ACTION_CSUM */
 		u32			mark;		/* FLOW_ACTION_MARK */
 		u16                     ptype;          /* FLOW_ACTION_PTYPE */
+		u32			priority;	/* FLOW_ACTION_PRIORITY */
 		struct {				/* FLOW_ACTION_QUEUE */
 			u32		ctx;
 			u32		index;

include/net/tc_act/tc_skbedit.h

@@ -77,4 +77,21 @@ static inline u32 tcf_skbedit_ptype(const struct tc_action *a)
 	return ptype;
 }
 
+/* Return true iff action is priority */
+static inline bool is_tcf_skbedit_priority(const struct tc_action *a)
+{
+	return is_tcf_skbedit_with_flag(a, SKBEDIT_F_PRIORITY);
+}
+
+static inline u32 tcf_skbedit_priority(const struct tc_action *a)
+{
+	u32 priority;
+
+	rcu_read_lock();
+	priority = rcu_dereference(to_skbedit(a)->params)->priority;
+	rcu_read_unlock();
+
+	return priority;
+}
+
 #endif /* __NET_TC_SKBEDIT_H */

net/sched/cls_api.c

@@ -3665,6 +3665,9 @@ int tc_setup_flow_action(struct flow_action *flow_action,
 		} else if (is_tcf_skbedit_ptype(act)) {
 			entry->id = FLOW_ACTION_PTYPE;
 			entry->ptype = tcf_skbedit_ptype(act);
+		} else if (is_tcf_skbedit_priority(act)) {
+			entry->id = FLOW_ACTION_PRIORITY;
+			entry->priority = tcf_skbedit_priority(act);
 		} else {
 			err = -EOPNOTSUPP;
 			goto err_out_locked;