The body is a bit hard to read, hard to extend, and has duplicated
conditions.

Clean up the "if (many conditions) else if (many conditions, some
of them repeated)" pattern by:

- Moving the repeated conditions out
- Replacing the repeated tests for the same variable with a switch/case
- Moving the protocol check inside the dsa_user_add_cls_matchall_mirred()
  function call.

This is pure refactoring, no logic has been changed, though some tests
were reordered. The order does not matter - they are independent things
to be tested for.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
v2->v3: none
v1->v2: add some more info in commit message

 net/dsa/user.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/net/dsa/user.c b/net/dsa/user.c
index 64f660d2334b..5d78a881ddc2 100644
--- a/net/dsa/user.c
+++ b/net/dsa/user.c
@@ -1377,6 +1377,9 @@ dsa_user_add_cls_matchall_mirred(struct net_device *dev,
 	struct dsa_port *to_dp;
 	int err;
 
+	if (cls->common.protocol != htons(ETH_P_ALL))
+		return -EOPNOTSUPP;
+
 	if (!ds->ops->port_mirror_add)
 		return -EOPNOTSUPP;
 
@@ -1486,17 +1489,21 @@ static int dsa_user_add_cls_matchall(struct net_device *dev,
 				     struct tc_cls_matchall_offload *cls,
 				     bool ingress)
 {
-	int err = -EOPNOTSUPP;
+	const struct flow_action *action = &cls->rule->action;
 
-	if (cls->common.protocol == htons(ETH_P_ALL) &&
-	    flow_offload_has_one_action(&cls->rule->action) &&
-	    cls->rule->action.entries[0].id == FLOW_ACTION_MIRRED)
-		err = dsa_user_add_cls_matchall_mirred(dev, cls, ingress);
-	else if (flow_offload_has_one_action(&cls->rule->action) &&
-		 cls->rule->action.entries[0].id == FLOW_ACTION_POLICE)
-		err = dsa_user_add_cls_matchall_police(dev, cls, ingress);
+	if (!flow_offload_has_one_action(action))
+		return -EOPNOTSUPP;
 
-	return err;
+	switch (action->entries[0].id) {
+	case FLOW_ACTION_MIRRED:
+		return dsa_user_add_cls_matchall_mirred(dev, cls, ingress);
+	case FLOW_ACTION_POLICE:
+		return dsa_user_add_cls_matchall_police(dev, cls, ingress);
+	default:
+		break;
+	}
+
+	return -EOPNOTSUPP;
 }
 
 static void dsa_user_del_cls_matchall(struct net_device *dev,
-- 
2.43.0