net: ethernet: stmicro: stmmac: fix possible memory leak in __stmmac_open

Fix a possible memory leak in __stmmac_open when stmmac_init_phy fails.
It's also needed to free everything allocated by stmmac_setup_dma_desc
and not just the dma_conf struct.

Drop free_dma_desc_resources from __stmmac_open and correctly call
free_dma_desc_resources on each user of __stmmac_open on error.

Reported-by: Jose Abreu <Jose.Abreu@synopsys.com>
Fixes: ba39b34 ("net: ethernet: stmicro: stmmac: generate stmmac dma conf before open")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Cc: stable@vger.kernel.org
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jose Abreu <Jose.Abreu@synopsys.com>
Link: https://lore.kernel.org/r/20230614091714.15912-1-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Ansuel

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -3873,7 +3873,6 @@ static int __stmmac_open(struct net_device *dev,
 
 	stmmac_hw_teardown(dev);
 init_error:
-	free_dma_desc_resources(priv, &priv->dma_conf);
 	phylink_disconnect_phy(priv->phylink);
 init_phy_error:
 	pm_runtime_put(priv->device);
@@ -3891,6 +3890,9 @@ static int stmmac_open(struct net_device *dev)
 		return PTR_ERR(dma_conf);
 
 	ret = __stmmac_open(dev, dma_conf);
+	if (ret)
+		free_dma_desc_resources(priv, dma_conf);
+
 	kfree(dma_conf);
 	return ret;
 }
@@ -5633,12 +5635,15 @@ static int stmmac_change_mtu(struct net_device *dev, int new_mtu)
 		stmmac_release(dev);
 
 		ret = __stmmac_open(dev, dma_conf);
-		kfree(dma_conf);
 		if (ret) {
+			free_dma_desc_resources(priv, dma_conf);
+			kfree(dma_conf);
 			netdev_err(priv->dev, "failed reopening the interface after MTU change\n");
 			return ret;
 		}
 
+		kfree(dma_conf);
+
 		stmmac_set_rx_mode(dev);
 	}