net/mlx5e: Lag, Only handle events from highest priority multipath entry

[ Upstream commit ad11c4f ]

There could be multiple multipath entries but changing the port affinity
for each one doesn't make much sense and there should be a default one.
So only track the entry with lowest priority value.
The commit doesn't affect existing users with a single entry.

Fixes: 544fe7c ("net/mlx5e: Activate HW multipath and handle port affinity based on FIB events")
Signed-off-by: Roi Dayan <roid@nvidia.com>
Reviewed-by: Maor Dickman <maord@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: roidayan

drivers/net/ethernet/mellanox/mlx5/core/lag_mp.c

@@ -123,6 +123,10 @@ static void mlx5_lag_fib_route_event(struct mlx5_lag *ldev,
 		return;
 	}
 
+	/* Handle multipath entry with lower priority value */
+	if (mp->mfi && mp->mfi != fi && fi->fib_priority >= mp->mfi->fib_priority)
+		return;
+
 	/* Handle add/replace event */
 	nhs = fib_info_num_path(fi);
 	if (nhs == 1) {
@@ -132,12 +136,13 @@ static void mlx5_lag_fib_route_event(struct mlx5_lag *ldev,
 			int i = mlx5_lag_dev_get_netdev_idx(ldev, nh_dev);
 
 			if (i < 0)
-				i = MLX5_LAG_NORMAL_AFFINITY;
-			else
-				++i;
+				return;
 
+			i++;
 			mlx5_lag_set_port_affinity(ldev, i);
 		}
+
+		mp->mfi = fi;
 		return;
 	}