net/mlx5: fs, delete the FTE when there are no rules attached to it

[ Upstream commit 7b0c633 ]

When an FTE has no children is means all the rules where removed
and the FTE can be deleted regardless of the dests_size value.
While dests_size should be 0 when there are no children
be extra careful not to leak memory or get firmware syndrome
if the proper bookkeeping of dests_size wasn't done.

Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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

@@ -2031,16 +2031,16 @@ void mlx5_del_flow_rules(struct mlx5_flow_handle *handle)
 	down_write_ref_node(&fte->node, false);
 	for (i = handle->num_rules - 1; i >= 0; i--)
 		tree_remove_node(&handle->rule[i]->node, true);
-	if (fte->dests_size) {
-		if (fte->modify_mask)
-			modify_fte(fte);
-		up_write_ref_node(&fte->node, false);
-	} else if (list_empty(&fte->node.children)) {
+	if (list_empty(&fte->node.children)) {
 		del_hw_fte(&fte->node);
 		/* Avoid double call to del_hw_fte */
 		fte->node.del_hw_func = NULL;
 		up_write_ref_node(&fte->node, false);
 		tree_put_node(&fte->node, false);
+	} else if (fte->dests_size) {
+		if (fte->modify_mask)
+			modify_fte(fte);
+		up_write_ref_node(&fte->node, false);
 	} else {
 		up_write_ref_node(&fte->node, false);
 	}